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[0] Suner S, Fellows MR, Vargas-Irwin C, Nakata GK, Donoghue JP, Reliability of signals from a chronically implanted, silicon-based electrode array in non-human primate primary motor cortex.IEEE Trans Neural Syst Rehabil Eng 13:4, 524-41 (2005 Dec)

[0] Westby GW, Wang H, A floating microwire technique for multichannel chronic neural recording and stimulation in the awake freely moving rat.J Neurosci Methods 76:2, 123-33 (1997 Oct 3)

[0] Rousche PJ, Normann RA, Chronic recording capability of the Utah Intracortical Electrode Array in cat sensory cortex.J Neurosci Methods 82:1, 1-15 (1998 Jul 1)

[0] Mohseni P, Najafi K, Eliades SJ, Wang X, Wireless multichannel biopotential recording using an integrated FM telemetry circuit.IEEE Trans Neural Syst Rehabil Eng 13:3, 263-71 (2005 Sep)

[0] Mojarradi M, Binkley D, Blalock B, Andersen R, Ulshoefer N, Johnson T, Del Castillo L, A miniaturized neuroprosthesis suitable for implantation into the brain.IEEE Trans Neural Syst Rehabil Eng 11:1, 38-42 (2003 Mar)

[0] Santhanam G, Linderman MD, Gilja V, Afshar A, Ryu SI, Meng TH, Shenoy KV, HermesB: a continuous neural recording system for freely behaving primates.IEEE Trans Biomed Eng 54:11, 2037-50 (2007 Nov)

[0] Kipke DR, Vetter RJ, Williams JC, Hetke JF, Silicon-substrate intracortical microelectrode arrays for long-term recording of neuronal spike activity in cerebral cortex.IEEE Trans Neural Syst Rehabil Eng 11:2, 151-5 (2003 Jun)

[0] Porada I, Bondar I, Spatz WB, Kruger J, Rabbit and monkey visual cortex: more than a year of recording with up to 64 microelectrodes.J Neurosci Methods 95:1, 13-28 (2000 Jan 31)

[0] Nicolelis MA, Dimitrov D, Carmena JM, Crist R, Lehew G, Kralik JD, Wise SP, Chronic, multisite, multielectrode recordings in macaque monkeys.Proc Natl Acad Sci U S A 100:19, 11041-6 (2003 Sep 16)

[0] Sodagar AM, Wise KD, Najafi K, A fully integrated mixed-signal neural processor for implantable multichannel cortical recording.IEEE Trans Biomed Eng 54:6 Pt 1, 1075-88 (2007 Jun)

[0] Csicsvari J, Henze DA, Jamieson B, Harris KD, Sirota A, Bartho P, Wise KD, Buzsaki G, Massively parallel recording of unit and local field potentials with silicon-based electrodes.J Neurophysiol 90:2, 1314-23 (2003 Aug)

[0] Williams JC, Rennaker RL, Kipke DR, Long-term neural recording characteristics of wire microelectrode arrays implanted in cerebral cortex.Brain Res Brain Res Protoc 4:3, 303-13 (1999 Dec)

[1] Obeid I, Nicolelis MA, Wolf PD, A low power multichannel analog front end for portable neural signal recordings.J Neurosci Methods 133:1-2, 27-32 (2004 Feb 15)

[0] Ativanichayaphong T, He JW, Hagains CE, Peng YB, Chiao JC, A combined wireless neural stimulating and recording system for study of pain processing.J Neurosci Methods 170:1, 25-34 (2008 May 15)

[0] Kennedy PR, Mirra SS, Bakay RA, The cone electrode: ultrastructural studies following long-term recording in rat and monkey cortex.Neurosci Lett 142:1, 89-94 (1992 Aug 3)

[0] Vyssotski AL, Serkov AN, Itskov PM, Dell'Omo G, Latanov AV, Wolfer DP, Lipp HP, Miniature neurologgers for flying pigeons: multichannel EEG and action and field potentials in combination with GPS recording.J Neurophysiol 95:2, 1263-73 (2006 Feb)[1] Otto KJ, Johnson MD, Kipke DR, Voltage pulses change neural interface properties and improve unit recordings with chronically implanted microelectrodes.IEEE Trans Biomed Eng 53:2, 333-40 (2006 Feb)

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ref: -0 tags: PEDOT PSS electroplate eletrodeposition neural recording michigan probe stimulation CSC date: 04-27-2017 01:36 gmt revision:1 [0] [head]

PMID-19543541 Poly(3,4-ethylenedioxythiophene) as a micro-neural interface material for electrostimulation

  • 23k on a 177um^2 site.
  • demonstrated in-vitro durable stimulation.
  • Electrodeposited with 6na for 900 seconds per electrode.
    • Which is high -- c.f. 100pA for 600 seconds {1356}
  • Greater CSC and lower impedance / phase than (comparable?) Ir or IrOx plating.

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ref: Gilgunn-2012 tags: kozai neural recording electrodes compliant parylene flexible dissolve date: 02-24-2017 19:14 gmt revision:5 [4] [3] [2] [1] [0] [head]

IEEE-6170092 (pdf) An ultra-compliant, scalable neural probe with molded biodissolvable delivery vehicle

    • Optical coherence tomography is cool.
  • Large footprint - 150 or 300um, 135um thick (13500 or 40500 um^2; c.f. tungsten needle 1963 (50um) or 490 (25um) um^2.)
  • Delivery vehicle is fabricated from biodissolvable carboxy-methylcellulose (CMC).
    • Device dissolves within three minutes of implantation.
    • Yet stiff enough to penetrate the dura of rats (with what degree of dimpling?)
    • Lithographic patterning process pretty clever, actually.
    • Parylene-X is ~ 1.1 um thick.
    • 500nm Pt is patterned via ion milling with a photoresist mask.
    • Use thin 20nm Cr etch mask for both DRIE (STS ICP) and parylene etch.
  • Probes are tiny -- 10um wide, 2.7um thick, coated in parylene-X.
  • CMC polymer tends to bend and warp due to stress -- must be clamped in a special jig.
  • No histology. Follow-up?

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ref: Seymour-2007.09 tags: neural probe design recording Kipke Seymour parelene MEA histology PEDOT date: 02-23-2017 23:52 gmt revision:13 [12] [11] [10] [9] [8] [7] [head]

PMID-17517431[0] Neural probe design for reduced tissue encapsulation in CNS.

  • See conference proceedings too: PMID-17947102[1] Fabrication of polymer neural probes with sub-cellular features for reduced tissue encapsulation.
    • -- useful information.
  • They use SU8 - photoresist! - as a structural material. See also this.
    • They use silicon as a substrate for the fabrication, but ultimately remove it. Electrodes could be made of titanium, modulo low conductivity.
  • Did not / could not record from these devices. Only immunochemistry.
  • Polymer fibers smaller than 7um are basically invisible to the immune system. See [2]
  • Their peripheral recording site is 4 x 5um - but still not invisible to microglia. Perhaps this is because of residual insertion trauma, or movement trauma? They implanted the device flush with the cortical surface, so there should have been little cranial tethering.
  • Checked the animals 4 weeks after implantation.
  • Peripheral electrode site was better than shank location, but still not perfect. Well, any improvement is a good one...
  • No statistical difference between 4x5um lattice probes, 10x4um probes, 30x4um, and solid (100um) knife edge.
    • Think that this may be because of electrode micromotion -- the lateral edge sites are still relatively well connected to the thick, rigid shank.
  • Observed two classes of immune reactivity --
    • GFAP reactive hypertrophied astrocytes.
    • devoid of GFAP, neurofilament, and NEuN, but always OX-42 and often firbronectin and laminin positive as well.
    • Think that the second may be from meningeal cells pulled in with the stab wound.
  • Sensitivity is expected to increase with decreased surface area (but similar low impedance -- platinum black or oxidized iridium or PEDOT {1112} ).
  • Thoughts: it may be possible to put 'barbs' to relieve mechanical stress slightly after the probe location, preferably spikes that expand after implantation.
  • His thesis {1110}

____References____

[0] Seymour JP, Kipke DR, Neural probe design for reduced tissue encapsulation in CNS.Biomaterials 28:25, 3594-607 (2007 Sep)
[1] Seymour JP, Kipke DR, Fabrication of polymer neural probes with sub-cellular features for reduced tissue encapsulation.Conf Proc IEEE Eng Med Biol Soc 1no Issue 4606-9 (2006)
[2] Sanders JE, Stiles CE, Hayes CL, Tissue response to single-polymer fibers of varying diameters: evaluation of fibrous encapsulation and macrophage density.J Biomed Mater Res 52:1, 231-7 (2000 Oct)

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ref: -0 tags: iridium oxide nanotube intracellular recording electroplate MEA date: 02-22-2017 22:41 gmt revision:0 [head]

PMID-24487777 Iridium oxide nanotube electrodes for sensitive and prolonged intracellular measurement of action potentials.

  • Electrodeposition of IrOx "magically" forms 500nm tubes.
  • Holes in Si3N4 / SiO2 were formed via e-beam lithography; underlying Pt wires via liftoff.
  • Showed long (minutes) intracellular access, though it tended to dip with time.

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ref: -0 tags: myoelectric EMG recording TMR prosthetics date: 02-13-2017 20:43 gmt revision:0 [head]

PMID: Man/machine interface based on the discharge timings of spinal motor neurons after targeted muscle reinnervation

  • General idea: deconvolve a grid-recorded EMG signal to infer the spinal motorneron spikes, and use this to more accurately decode user intention.
  • EMG envelope is still fairly good...

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ref: -0 tags: review neural recording penn state extensive biopolymers date: 02-06-2017 23:09 gmt revision:0 [head]

PMID-24677434 A Review of Organic and Inorganic Biomaterials for Neural Interfaces

  • Not necessarily insightful, but certainly exhaustive review of all the various problems and strategies for neural interfacing.
  • Some emphasis on graphene, conductive polymers, and biological surface treatments for reducing FBR.
  • Cites 467 articles!

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ref: -0 tags: intracellular juxtacellular recording tungsten nanowire whole cell patch date: 02-06-2017 22:39 gmt revision:2 [1] [0] [head]

PMID-22905231 Neuronal recordings with solid-conductor intracellular nanoelectrodes (SCINEs).

  • <300 nm diameter W fibers, several um long, fabricated via FIB.
  • Functionalized with a hydrophobic silane on the oxide.
    • Quite complete & custom methods here.
  • Not quite whole cell recording, but excellent SNR; 4mv APs.
    • Slice, rat hippocampus organotypic.
    • Expected much larger recorded APs; suspect partial membrane penetration.
    • Only lasted a few seconds to minutes.
  • Needed custom recording setup for interfacing with 100Gohm electrodes; stray capacitance < 4 pf.
  • Intracellular electrodes must be designed to not shunt the membrane open upon insertion.
    • In a study where whole-cell recordings were established prior sharp microelectrode penetration, all neurons showed significant depolarization following impalement.
    • Here there was no change in membrane voltage in 10% of insertions of the silane-functionalized SCINEs. only in the functionalized electrodes).
    • Minor distortion of the AP was observed.
  • In whole-cell patch clamping, diffusion from the pipette to the cytosol interrupts biochemical processes necessary for normal cellular function (e.g. respiration!).
  • The hardness of the tungsten ensures that SCINEs can be repeatedly inserted millimeter-deep into brain tissue without noticeable damage to the tip.
    • E.g. 300 nm tungsten will not easily navigate vasculature...

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ref: -0 tags: Leiber nanoFET review silicon neural recording intracellular date: 02-01-2017 03:32 gmt revision:5 [4] [3] [2] [1] [0] [head]

PMID-23451719 Synthetic Nanoelectronic Probes for Biological Cells and Tissue

  • Review of nanowireFETS for biological sensing
  • Silicon nanowires can be grown via vapor-liquid-solid or vapor-solid-solid, 1D catalyzed growth, usually with a Au nanoparticle.
  • Interestingly, kinks can be introduced via "iterative control over nucleation and growth", 'allowing the synthesis of complex 2D and 3D structures akin to organic chemistry"
    • Doping can similarly be introduced in highly localized areas.
    • This bottom-up synthesis is adaptable to flexible and organic substrates.
  • Initial tests used polylysine patterning to encourage axonal and dendritic growth across a nanoFET.
    • Positively charged amino group interacts with negative surface charge phospholipid
    • Lieber's group coats their SU-8 electrodes in poly-d-lysine as well {1352}
  • Have tested multiple configurations of the nanowire FET, including kinked, one with a SiO2 nanopipette channel for integration with the cell membrane, and one where the cell-attached fluid membrane functions as the semiconductor; see figure 4.
    • Were able to show recordings as one of the electrodes was endovascularized.
  • It's not entirely clear how stable and scalable these are; Si and SiO2 gradually dissolve in physiological fluid, and no mention was made of longevity.

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ref: -0 tags: juxtacellular recording gold mushroom cultured hippocampal neurons Spira date: 02-01-2017 02:44 gmt revision:7 [6] [5] [4] [3] [2] [1] [head]

Large-Scale Juxtacellular Recordings from Cultured Hippocampal Neurons by an Array of Gold-Mushroom Shaped Microelectrodes

  • Micrometer sized Au mushroom MEA electrodes.
  • Functionalized by poly-ethylene-imine (PEI, positively charged)/laminin (extracellular matrix protein) undergo a process to form juxtacellular junctions between the neurons and the gMµEs.
  • No figures, but:
    • Whereas substrate integrated planar MEA record FPs dominated by negative-peak or biphasic-signals with amplitudes typically ranging between 40-100 µV and a signal to noise ratio of ≤ 5,
    • The gMµE-MEA recordings were dominated by positive monophasic action potentials.
    • It is important to note that monophasic high peak amplitudes ≥ 100 µV are rarely obtained using planar electrodes arrays, whereas when using the gMµE-MEA, 34.48 % of the gMµEs recorded potentials ≥ 200 µV and 10.64 % recorded potentials in the range of 300-5,085 µV.
  • So, there is a distribution of coupling, approximately 10% "good".

PMID-27256971 Multisite electrophysiological recordings by self-assembled loose-patch-like junctions between cultured hippocampal neurons and mushroom-shaped microelectrodes.

  • Note 300uV - 1mV extracellular 'juxtacellular' action potentials from these mushroom recordings. This is 2 - 5x better than microwire extacellular in-vivo ephys; coupling is imperfect.
    • Sharp glass-insulated W electrodes, ~ 10Mohm, might achieve better SNR if driven carefully.
  • 2um mushroom cap Au electrodes, 1um diameter 1um long shaft
    • No coating, other than the rough one left by electroplating process.
    • Impedance 10 - 25 Mohm.
  • APs decline within a burst of up to 35% -- electrostatic reasons?
  • Most electrodes record more than one neuron, similar to in-vivo ephys, with less LFP coupling.

PMID-23380931 Multi-electrode array technologies for neuroscience and cardiology

  • The key to the multi-electrode-array ‘in-cell recording’ approach developed by us is the outcome of three converging cell biological principals:
    • (a) the activation of endocytotic-like mechanisms in which cultured Aplysia neurons are induced to actively engulf gold mushroom-shaped microelectrodes (gMμE) that protrude from a flat substrate,
    • (b) the generation of high Rseal between the cell’s membrane and the engulfed gMμE, and
    • (c) the increased junctional membrane conductance.
  • Functionalized the Au mushrooms with an RGD-based peptide
    • RGD is an extracellular matrix binding site on fibronectin, which mediates it's interaction with integrin, a cell surface receptor; it is thought that other elements of fibronectin regulate specificity with its receptor. PMID-2418980

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ref: -0 tags: vertical nanowire juxtacellular recording date: 02-01-2017 00:50 gmt revision:2 [1] [0] [head]

PMID-22231664 Vertical nanowire electrode arrays as a scalable platform for intracellular interfacing to neuronal circuits.

  • Note actual coupling is low, 0.002, compared to patch-clamp (400uV vs 200mV). Signal is rather noisy.
  • Dissociated cultures of rat cortical neurons
  • Stimulation current 200 pa enough to change membrane potential, but not initiate a spike.
    • This is 200e-12 / 20e-6 = 5 orders of magnitude lower current than typical ICMS.

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ref: Bartels-2008.09 tags: neurotrophic kennedy speech FM transmitter wireless Georga recording electrophysiology electrode date: 01-19-2017 02:18 gmt revision:6 [5] [4] [3] [2] [1] [0] [head]

PMID-18672003[0] Neurotrophic electrode: method of assembly and implantation into human motor speech cortex.

  • Glass electrode with 3-4 2mil Teflon insulated Au wires within it to record spiking.
  • Induce neurites (e.g. dendrites, axons, blood vessels, oligodendrocytes) to grow up into it using autologous sciatic nerve, and stay for the lifetime of the patient (Kennedy 1989) [1].
    • Histology has revealed axons, but not neurons, within the tissue inside the tip. (Kennedy 1989, 1992a.)
    • No glia in rat and monkey tests; PMID-1421115
    • Inserted 5-6mm into the cortex at an angle of 45 deg. far!?
  • Bipolar amplification on pairs of the Au wires.
  • patients damaged their electrodes due to spasms; same for monkeys, presumably. Seems the electronice and gold wires are also highly fragile. I'm quite familiar with this.
  • Includes a sine wave source for calibration. good idea!
  • Inductively powered @ 1Mhz.
  • FM modulation at 39.2Mz and 43.9Mhz. COTS?
    • The implantable electronics are bulky as can be seen in Figs. 14 and ​and 19. (what a mess?!)
  • 3 patients, 4 years in 2 patients that dies from unrelated causes, over 3 years in a third.
  • describe construction of electrode -- not complicated.

____References____

[0] Bartels J, Andreasen D, Ehirim P, Mao H, Seibert S, Wright EJ, Kennedy P, Neurotrophic electrode: method of assembly and implantation into human motor speech cortex.J Neurosci Methods 174:2, 168-76 (2008 Sep 30)
[1] Kennedy PR, The cone electrode: a long-term electrode that records from neurites grown onto its recording surface.J Neurosci Methods 29:3, 181-93 (1989 Sep)

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ref: -0 tags: gold micrograin recording electrodes electroplating impedance date: 10-17-2016 20:28 gmt revision:5 [4] [3] [2] [1] [0] [head]

PMID-23071004 Gold nanograin microelectrodes for neuroelectronic interfaces.

  • We report a single-cell sized microelectrode, which has unique gold nanograin structures, using a simple electrochemical deposition method.
  • Fabricated microelectrode had a sunflower shape with 1-5 (um of micropetals along the circumference of the microelectrode and 500 nm nanograins at the center.
  • The nanograin electrodes had 69-fold decrease of impedance and 10-fold increase in electrical stimulation capability compared to unmodified flat gold microelectrodes.
  • images/1270_1.pdf pdf
  • The deposition was conducted with an aqueous solution containing 25 mM HAuCl (HAuCl · 3H O, Sigma-Aldrich, MO, 4 4 2USA) and 20 g/L polyvinylpyrrolidone (surfactant, stabilizing agent)

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ref: -0 tags: physical principles of scalable neural recording marblestone date: 08-25-2014 20:21 gmt revision:0 [head]

PMID-24187539 Physical principles for scalable neural recording.

  • Marblestone AH1, Zamft BM, Maguire YG, Shapiro MG, Cybulski TR, Glaser JI, Amodei D, Stranges PB, Kalhor R, Dalrymple DA, Seo D, Alon E, Maharbiz MM, Carmena JM, Rabaey JM, Boyden ES, Church GM, Kording KP.

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ref: Seymour-2011.06 tags: PEDOT Seymour electrode recording parylene date: 08-06-2014 22:39 gmt revision:3 [2] [1] [0] [head]

PMID-21301965[0] Novel multi-sided, microelectrode arrays for implantable neural applications.

  • There are problems with parylene multielectrode arrays:
    • water and salts will rapidly diffuse into the various interfacial boundaries
    • Interfacial delamination due to poor wet adhesion of parylene on metal
      • This possibly due to mechanical stress
      • causes excessive cross-talk or noise.
    • Parylene-C devices are prone to poor adhesion at either the dielectric to dielectric interface or at the dielectric to metal interface *** (Sharma and Yasuda 1982; Yasuda et al 2001)
  • solution: PPXCH 2NH 2 and PPXCHO -- reactive parylene (amine bonds?!)
  • PEDOT is absolutely essential for attaining reasonable performance / impedance from the 85um^2 gold electrodes.
    • Thermal noise on 280um^2 and 170um^2 Au electrodes was too high to record neurons.
    • AU thickness 0.5um.
  • Performed soak tests on their electrodes; the reactive parylene is good, but not sure if it's a worthy improvement.

____References____

[0] Seymour JP, Langhals NB, Anderson DJ, Kipke DR, Novel multi-sided, microelectrode arrays for implantable neural applications.Biomed Microdevices 13:3, 441-51 (2011 Jun)

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ref: -0 tags: polyimide platinum nanowire recording electrode plating date: 06-28-2013 00:46 gmt revision:2 [1] [0] [head]

IEEE-5734597 (pdf) A novel platinum nanowire-coated neural electrode and its electrochemical and biological characterization

  • Young-Hyun Jin ; IMTEK, Univ. of Freiburg, Freiburg, Germany ; Daubinger, P. ; Fiebich, B.L. ; Stieglitz, T.
  • 10um thick RIE etched polyimide and platinum electrodes.
  • polyimide was spin coated onto wafers.
  • Used relatively simple wet chemistry to plate platinum onto electrodes:
    • 0.14 M-% chloroplatin acid hexahydrate (H2PtCl6·6H2O, Sigma-Aldrich) and 7.4 M-% formic acid (HCOOH, Sigma-Aldrich) were mixed in de-ionized (DI) water. The fabricated device was floated upside down on the solution.
  • Let this plate for 7 days & effective site was enlarged by 617 times!

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ref: -0 tags: parylene silicon neural recording probes date: 06-07-2013 00:15 gmt revision:4 [3] [2] [1] [0] [head]

http://thesis.library.caltech.edu/4671/1/PhDThesisFinalChanglinPang.pdf

  • Notes: Michigan probes suffer from thickness limited to <15um, hence are often not stiff enough to penetrate the pia & arachnoid.
  • Likewise, utach arrays are fabricated through a substrate, so cannot be made longer than 1.5-2mm. Plus, they are connected with 25um gold wires, which is both rigid and requires a fair bit of work. (Perhaps with a wirebond machine?)
  • SiO2 suffers from high internal stress (formed at high temperature) and tends to hydrate over time, both making it a less than ideal insulator for biological applications.
    • Silicon is slowly attacked in saline.
  • Use Cr/Au traces, and Ti/Pt electrode sites on his probes.
    • 2.5um minimum trace width.
  • Importantly, they solve the problem of parylene to silicon interconnect by simply fabricating the wires on parylene -- like ours -- and only use silicon as a structural support.
    • Silicon is roughened via XeF2 for good parylene adhesion.
      • Alas, does not survive a long-term soak -- but maybe this is useful? (page 102)
        • This too can be solved via bringing the parylene in vacuum up to melting temperature to better bond with Si.
  • Metal pads on parylene are destroyed by wedge bonding -- heat and pressure are too high!
  • Their solution is to use conductive epoxy & fan the wires out to omnetics pitch (635um) in what they call parylene-PCB-omnetics connector (PPO).
  • Plated a 5um x 5um electrode with platinum black to reduce the impedance from 1.1M to 9.2k (!!)
    • Problem is that Pt black is fragile, and may be scraped off during insertion -- see figure on page 95.
  • Probe shanks are ~ 170um x 150um, tip spade-type patterned via DRIE.
  • To be able to sustain soaking and lifetime testing, thick parylene layers are needed for the flexible parylene cable. The total parylene thickness of our neural probes is about 13 μm which results in a long etching time. We use photoresist as a mask when etching parylene using RIE O2 plasma etching; the etching rate of parylene and photoresist in RIE is roughly 1:1. Thick photoresist (> 20 μm) with high resolution is needed. AZ 9260 thick-film photoresist is designed for the more-demanding higher-resolution thick-resist requirements. It provides high resolution with superior aspect ratios, as well as wide focus and exposure latitude and good sidewall profiles. A process of two spinning coats using AZ 9260 has been developed to make a high-resolution thick photoresist mask of about 30 μm. Figure 4-11 shows the thick photoresist on the probe tip to guarantee a sharp tip after plasma etching. The photoresist is hard baked in oven at 120 oC for 30 min; the thick photoresist needs to be carefully handled during baking to avoid thermal cracking.
  • Otline electrolysis-based actuators ... interesting but hopefully not needed.

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ref: -0 tags: brain mapping recording Yuste date: 04-10-2013 19:31 gmt revision:1 [0] [head]

PMID-22726828 The Brain Activity Map Project and the Challenge of Functional Connectomics

  • They are more interested in every neuron within a local circuit, e.g. cortical column.
  • Referenced papers, optical:
    • Yuste et al 2011 -- referenced several times.
    • Helmchen 2011
    • Yuste and Katz 1991 (calcium)
    • Grienberger and Konnerth 2012 (1000 recorded neurons)
    • Peterka 2011 -- voltage imaging
    • Mochalin 2012 -- nanodiamonds.
  • The optical techniques only gets you .. 400um? 2mm?
    • Suggest GRIn objectives for invasive recording of the e.g. hippocampus.
  • Interesting: DNA polymerases could be used as spike sensors since their error rates are dependent on cation concentration.
    • use synthetic cells, then sequence the molecular recording.
  • The Drosophila connectome is currently 20% complete at the mesoscale (Chiang et al 2011)
    • Drosophila has 135,000 neurons
  • Bock et al 2011 have reconstructed 1,500 cell bodies with 1e13 pixels.
  • In the human genome project, every dollar invested generated $141 in the economy. (Battelle 2011).

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ref: -0 tags: brain mapping Deisseroth Donoghue widescale recording date: 04-10-2013 19:31 gmt revision:1 [0] [head]

PMID-23514423 Nanotools for Neuroscience and Brain Activity Mapping

  • human brain has roughly 85e9 neurons, 1e14 synapses, 100 neurotransmitters.
  • focus on novel nanoprobes.
  • Assuming a uniform connaction probability, the lielihood of finding synaptically coupled cells increases quadratically with N.
  • pretty high-level article.
  • Multiferroic antennas (?) -- must look this up!
  • Look up ref 146 -- microendoscope. Did they design the camera module?

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ref: Suner-2005.12 tags: Suner Utah probe electrophysiology reliability chronic electrode recording longevity histology MEA date: 01-31-2013 22:27 gmt revision:7 [6] [5] [4] [3] [2] [1] [head]

PMID-16425835Reliability of signals from a chronically implanted, silicon-based electrode array in non-human primate primary motor cortex

  • claim that they have done a logitudinal development series that included 39 array implants in 18 monkeys.
  • can get reliable recordings out to 3 months (only? probably the array was forced out of the brain?)
    • however, it seems that their recording quality did not decrease dramatically over those 3 months.
  • excellent methods section.
  • also {1027}

____References____

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ref: -0 tags: microelectrodes original metal pipette glass recording MEA date: 01-31-2013 19:46 gmt revision:6 [5] [4] [3] [2] [1] [0] [head]

IEEE-4065599 (pdf) Comments on Microelectrodes

  • The amplifiers themselves, even back in 1950's, posed no problems -- low bandwidth. All that is required is low noise and high input impedance.
  • KCl Glass electrodes are LPF (10M resistive + 10pf parasitic capacitance); metal HPF (capacitive).
    • The fluid tip will not see external triphasic spikes of vertebrate axons above the noise level.
  • Metal probe the most useful.
  • Pt electrode in CSF behaves like a capacitor at low voltage across a broad frequency range. CSF has compounds that retard oxidation; impedance is more resistive with physiological saline.
  • Noise voltage generated by a metal electrode best specified by equivalent noise resistance at room temperature, E rmsnoise=4kTR nδF R_n should equal the real part of the electrode impedance at the same frequency.
  • Much of electrochemistry: solid AgCl diffuses away from an electrode tip with great speed and can hardly be continuously formed with an imposed current. Silver forms extremely stable complexes with organic molecules having attached amino and sulfhydril groups which occur in plenty where the electrode damages the tissue. Finally, the reduction-oxidation potential of axoplasm is low enough to reduce methylene blue, which places it below hydrogen. AgCl and HgCl are reduced.
  • The external current of nerve fibers is the second derivative of the traveling spike, the familiar triphasic (??) transient.
  • Svaetichin [1] and Dowben and Rose [3] plated with Platinum black. This increases the surface area.
    • Very quickly it burns onto itself a shell of very adherent stuff. It is kept from intimate contact with the tissue around it by a shell.
    • We found that if we add gelatin to the chloroplatinic acid bath from which we plate the Pt, the ball is not only made adherent to the tip but is, in a sense, prepoisoned and does not burn a shell into itself.
  • glass insulation using woods metal (which melts at a very low temperature). Platinum ball was plated onto 2-3um pipette tip. 3um gelatinized platinum black ball, impedance 100kOhm at 1kHz.
    • Highly capacitive probe: can be biased to 1 volt by a polarizing current of 1e-10 amp. (0.1nA).
  • Getting KCl solution into 1um pipettes is quite hard! They advise vacuum boiling to remove the air bubbles.
  • Humble authors, informative paper.

____References____

' ''' ()

{781}
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ref: Polikov-2005.1 tags: neural response glia histology immune electrodes recording 2005 Tresco Michigan microglia date: 01-29-2013 00:34 gmt revision:10 [9] [8] [7] [6] [5] [4] [head]

PMID-16198003[0] Response of brain tissue to chronically implanted neural electrodes

  • Good review (the kind where figures are taken from other papers). Nothing terribly new (upon a very cursory inspection)
  • When CNS damage severs blood vessels, microglia are indistinguishable from the blood borne, monocyte-derived macrophages that are recruited by the degranulation of platelets and the cellular release of cytokines.
  • Furthermore, microglia are known to secrete, either constitutively, or in response to pathological stimuli, neurotrophic factors that aid in neuronal survival and growth.
    • Also release cytotoxic and neurotoxic factors that can lead to neuronal death in vitro.
    • It has been suggested that the presence of insoluble materials in the brain may lead to a state of 'frustrated phagocytosis' or inability of the macrophages to remove the foreign body, resulting in persistent release of neurotoxic substances.
  • When a 10x10 array of silicon probes was implanted in feline cortex, 60% of the needle tracks showed evidence of hemorrhage and 25% showed edema upon explantation of the probes after one day (Schmidt et al 1993) {1163}
    • Although a large number of the tracks were affected, only 3-5% of the area was actually covered by hemorrhages and edema, suggesting the actual damage to blood vessels may have been relatively minor. (!!)
  • Excess fluid and cellular debris diminishes 6-8 days due to the action of activated microglia and re-absorption.
  • As testament to the transitory nature of this mechanically induced wound healing response, electrode tracks could not be found in animals after several months when the electrode was inerted and quickly removed (Yuen and Agnew 1995, Rousche et al 2001; Csicsvari et al 2003, Biran et al 2005).
  • Biran et al 2005: observed persistent ED-1 immunoreactivity around silicon microelectrode arrays implanted in rat cortex at 2 and 4 weeks following implantation; not seen in microelectrode stab wound controls.
  • On the glial scar:
    • observed in the CNS of all vertebrates, presumably to isolate damaged parts of the nervous system and maintain the integrity of the blood-brain barrier.
    • mostly composed of reactive astrocytes.
    • presumably the glial scar insulates electrodes from nearby neurons, hindering diffusion and increasing impedance.
  • On the meninges:
    • Meningeal fibroblasts, which also stain for vimentin, but not for GFAP, may migrate down the electrode shaft from the brain surface and form the early basis for the glial scar.
  • On recording quality:
    • Histological examination upon explantation revealed that every electrode with stable unit recordings had at least one large neuron near the electrode tip, while every electrode that was not able to record resolvable action potentials was explanted from a site with no large neurons nearby.
  • Perhaps the clearest example of this variability was observed in the in vivo response to plastic “mock electrodes” implanted in rabbit brain by Stensaas and Stensaas (1976) {1210} and explanted over the course of 2 years. They separated the response into three types: Type 1 was characterized by little to no gliosis with neurons adjacent to the implant, Type 2 had a reactive astrocyte zone, and Type 3 exhibited a layer of connective tissue between the reactive astrocyte layer and the implant, with neurons pushed more than 100 um away. All three responses are well documented in the literature; however this study found that the model electrodes produced all three types of reactions simultaneously,depending on where along the electrode one looked.

____References____

[0] Polikov VS, Tresco PA, Reichert WM, Response of brain tissue to chronically implanted neural electrodes.J Neurosci Methods 148:1, 1-18 (2005 Oct 15)

{946}
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ref: Salcman-1976.01 tags: Salcman electrodes recording chronic microelectrode array MEA original parylene date: 01-28-2013 22:18 gmt revision:8 [7] [6] [5] [4] [3] [2] [head]

PMID-1256090[0] A new chronic recording intracortical microelectrode

  • maintain that tethering is the rational way to go: it "re-establishes the normal biomechanics of the intact cranial vault". (Salcman 1972, 1973) {1010}
    • have model of electrode tip motion in response to brain-skull displacements (Goldstein and Salcman 1973) {1011}
      • Electrode would have a tip displacement of about 5um in response to a 1mm displacement of the electrode's point of entry into the skull.
      • Exponential dependence on recording amplitude and distance (Rall, 1962). Gradient: 7.5uv/um; movements of more than 1-2um can radically alter the recordnig shape.
      • Probably our electrodes work because the dura & gliosis becomes firmly attached to the electrode shafts.
    • not really an array so much as a number (10-12) of single-unit electrodes.
  • Details the process of parylene-C deposition, electrode microwelding, etc. Pretty cool stuff -- what has happened to this technology?
  • Each bubble is glued with cyanocrylate to the pia. (they too question the safety of this).
  • arrays can be manually inserted via forceps.
  • 25um iridium wire electroplated in 1-2um of gold
    • then electo-etched until the desired tip geometry is achieved, 1-3um diameter
    • and vacuum coated in 3um of parylene-C.
    • Impedance 1-2M with a 1kHz sine wave at 10nA. Impedance is inversely related to the frequency of the test current, phase angle of 70-80deg.
      • Ref Robinson, 1968.
    • We must emphasize the extreme sensitivity of electrode measurements to the test conditions. Measured values of Z e are usually increased 1-3M when the electrode has been stored away for a few days. Removing the electrode from the test bath for a few minutes in air can lead to equally large increases when the electrode is tested upon remersion. [...] might be oxide.
    • Pinholes are the usual failure mechanism (KD Wise 2004), {149}; parylene is 'pinhole-free'.
  • The connecting 25um Au lead is very flexible and imposes little stress on the iridium electrode.
    • Connecting wire coated in 12um of parylene C
    • Would prefer even finer wire, 12um.
  • Perspex window over the craniotomy; had a vent in this window which they could open.
  • Opening the vent would cause the brain to pulse, moving the electrodes through the cortex and changing neural activity.
  • Size of an electrode is limited by ability to introduce it into the brain.
    • Electrode must be introduced through the pia; as the pial vessels supply the cortex (or drain the cortex).
    • For their electrodes, P crit=0.9g ; the force necessary to penetrate the pia is 0.05 - 0.2g.
  • pure iridium is stiffer than Pt-Ir by a factor of 3 or so. (521 G N/m^2 = 521 GPa, higher than tungsten, which is 400 Gpa)
    • Pure iridium is apparently the stiffest metallic element ref
  • Interesting: "Once again we are impressed by the fact that passive recording electrodes exhibit drops in impedance in the living system which they never show on in vitro testing in protein solutions at 37C.
    • Between 40 and 50 days, a slow downward trend becomes noticeable; this trend continues for the life of the animal and asymptotically approaches values below 500k. Electrodes still record.
    • See {999}
    • Surmise that pure iridium electrodes have a different metal-electrolyte interface than more conventional metals (Pl and W).
  • Mention that the ultimate purpose is for a neural prosthesis.
    • Their then use was for recordings from M1 in monkeys and V1 from cats. (Schmidt, Bak, McIntosh 1974)
  • Ref Wise et al {1012}.

____References____

[0] Salcman M, Bak MJ, A new chronic recording intracortical microelectrode.Med Biol Eng 14:1, 42-50 (1976 Jan)

{748}
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ref: Leung-2008.08 tags: biocompatibility alginate tissue response immunochemistry microglia insulation spin coating Tresco recording histology MEA date: 01-28-2013 21:19 gmt revision:4 [3] [2] [1] [0] [head]

PMID-18485471[0] Characterization of microglial attachment and cytokine release on biomaterials of differing surface chemistry

  • The important result is that materials with low protein-binding (e.g. alginate) have fewer bound microglia, hence better biocompatibility. It also seems to help if the material is highly hydrophilic.
    • Yes alginate is made from algae.
  • Used Michigan probes for implantation.
  • ED1 = pan-macrophage marker.
    • (quote:) Quantification of cells on the surface indicated that the number of adherent microglia appeared higher on the smooth side of the electrode compared to the grooved, recording site side (Fig. 2B), and declined with time. However, at no point were electrodes completely free of attached and activated microglial cells nor did these cells disappear from the interfacial zone along the electrode tract.
    • but these were not coated with anything new .. ???

____References____

[0] Leung BK, Biran R, Underwood CJ, Tresco PA, Characterization of microglial attachment and cytokine release on biomaterials of differing surface chemistry.Biomaterials 29:23, 3289-97 (2008 Aug)

{1221}
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ref: Chestek-2011.08 tags: shenoy Utah array reliability recording BMI date: 01-28-2013 20:54 gmt revision:2 [1] [0] [head]

PMID-21775782[0] Long-term stability of neural prosthetic control signals from silicon cortical arrays in rhesus macaque motor cortex (Shenoy)

  • Overall, this study suggests that action potential amplitude declines more slowly than previously supposed, and performance can be maintained over the course of multiple years when decoding from threshold-crossing events rather than isolated action potentials.
  • During most time periods, decoder performance was not well correlated with action potential amplitude (p > 0.05 for three of four arrays)
    • Perhaps we are chasing the wrong dragon?
    • Still, minimal invasiveness / more channels is useful.

____References____

[0] Chestek CA, Gilja V, Nuyujukian P, Foster JD, Fan JM, Kaufman MT, Churchland MM, Rivera-Alvidrez Z, Cunningham JP, Ryu SI, Shenoy KV, Long-term stability of neural prosthetic control signals from silicon cortical arrays in rhesus macaque motor cortex.J Neural Eng 8:4, 045005 (2011 Aug)

{1036}
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ref: -0 tags: decoding recording todo read biocompatibility histology electrodes future date: 01-28-2013 20:52 gmt revision:9 [8] [7] [6] [5] [4] [3] [head]

Things to read!

decoding:

  • PMID-20359500 Population decoding of motor cortical activity using a generalized linear model with hidden states
  • Robust satisficing linear regression: Performance/robustness trade-off and consistency criterion
  • PMID-15813408 Closed-loop cortical control of direction using support vector machines
  • Efficient Decoding With Steady-State Kalman Filter in Neural Interface Systems
    • Fixed gain: We analyze a low-complexity Kalman filter implementation in which the filter gain is approximated by its steady-state form, computed offline before real-time decoding commences.
    • We also find that the steady-state Kalman filter reduces the computational load (algorithm execution time) for decoding the firing rates of 25±3 single units by a factor of 7.0±0.9.

electrodes:

other random scribblings: Vascularization {1027} histology {736},{737} and size {1028},{747},{1026}, insulation {1033}. How very very important -- as important or moreso than the recording technology. What has happened to {149} ?

{1177}
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ref: -0 tags: magnetic flexible insertion japan neural recording electrodes date: 01-28-2013 03:54 gmt revision:2 [1] [0] [head]

IEEE-1196780 (pdf) 3D flexible multichannel neural probe array

  • Shoji Takeuchi1, Takafumi Suzuki2, Kunihiko Mabuchi2 and Hiroyuki Fujita
  • wild -- they use a magnetic field to make the electrodes stand up!
  • Electrodes released with DRIE, as with Michigan probes.
  • As with many other electrodes, pretty high electrical impedance - 1.5M @ 1kHz.
    • 20x20um recording sites on 10um parylene.
  • Could push these into a rat and record extracellular APs, but nothing quantitative, no histology either.
  • Used a PEG coating to make them stiff enough to insert into the ctx (phantom in IEEE conference proceedings.)

{895}
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ref: XindongLiu-2006.03 tags: neural recording electrodes stability cat parlene McCreery MEA date: 01-28-2013 02:50 gmt revision:7 [6] [5] [4] [3] [2] [1] [head]

IEEE-1605268 (pdf) Evaluation of the Stability of Intracortical Microelectrode Arrays

  • 35-50um IR electrodes, electrolytically sharpened at a 10 deg angle, with a 5um blunted tip.
  • Electrodes coated in parylene, and exposed at the tip with an eximer laser. Surface area of tip ~500um^2.
  • Sorted based on features (duration, pk-pk, ratio of + to -, ratio of + time to - time), followed by a demixing matrix (PCA?)
  • Did experiments in 25 cats with some task (for another paper?); got recordings for up to 800 days. Seems consistent with our results.
  • Neurons were stable (by their metrics) for up to 60 days.
  • sparse arrays showed stable recordings sooner than dense arrays, perhaps because they are larger and more qucikly become attached to the dura.
  • Electrodes were always unstable for the first 2-3 months. Stability index is as high as 30-40 days.
  • Average electrode yield was ~ 25%.
  • no histology.

____References____

Xindong Liu and McCreery, D.B. and Bullara, L.A. and Agnew, W.F. Evaluation of the stability of intracortical microelectrode arrays Neural Systems and Rehabilitation Engineering, IEEE Transactions on 14 1 91 -100 (2006)

{1010}
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ref: Salcman-1973.07 tags: Salcman MEA microelectrodes chronic recording glass cyanocrylate date: 01-28-2013 02:37 gmt revision:6 [5] [4] [3] [2] [1] [0] [head]

IEEE-4120641 (pdf) Design, Fabrication, and In Vivo Behavior of Chronic Recording Intracortical Microelectrodes

  • Teflon-coated 25um Pt-Ir (90/10)
  • Heat fuse this with a glass micropipette & backfill with cyanoacrylate. {1011}
    • Isobutyl acrylate is hydrolysed more slowly and hence is less toxic to the surronding tissue
    • cyanoacrylate is apparently biodegradable.
  • Durable, stable: one electrode displayed a single cortical spike (though not necessarily the same one) for more than 90 consecutive days.
  • unacceptably low impedance = 100K or less
  • Unit activity was present only 10-24H after surgery.
  • formal review of even older microelectrode studies.
  • 10nA should be 100x too small to have any effect on a platinum tip [17]
  • A seperable cell with a SNR of 3:1 would become lost if the electrode tip moved 15um away from a 20um soma.
    • "It becomes clear that the problem of holding single units for prolonged periods in the unrestrained animal is not achieved without considerable difficulty". Yet they think they have solved it.

____References____

Salcman, Michael and Bak, Martin J. Design, Fabrication, and In Vivo Behavior of Chronic Recording Intracortical Microelectrodes Biomedical Engineering, IEEE Transactions on BME-20 4 253 -260 (1973)

{1114}
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ref: Feingold-2012.04 tags: Feingold Graybeil electrode moveable recording date: 01-28-2013 02:13 gmt revision:1 [0] [head]

PMID-22170970[0] A system for recording neural activity chronically and simultaneously from multiple cortical and subcortical regions in non-human primates.

  • Up to 127 electrodes in 14 brain areas for up to a year at a time.

____References____

[0] Feingold J, Desrochers TM, Fujii N, Harlan R, Tierney PL, Shimazu H, Amemori K, Graybiel AM, A system for recording neural activity chronically and simultaneously from multiple cortical and subcortical regions in nonhuman primates.J Neurophysiol 107:7, 1979-95 (2012 Apr)

{898}
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ref: Ward-2009.07 tags: microelectrode arrays immune response recording MEA Purdue date: 01-28-2013 01:52 gmt revision:8 [7] [6] [5] [4] [3] [2] [head]

PMID-19486899[0] Toward a comparison of microelectrodes for acute and chronic recordings.

  • Good research, paper well written.
  • Results suggest significant variability within and between microelectrode types with no clearly superior array (from the abstract).
  • As Miguel mantains, "Much of the new technology, however, does not supersede traditional microwire technology in its ability to evade a host immune response".
  • Initial implantation wound initiates a cascade of immune responses which culminates in a sheath of microglia, astrocytes, various ectracellular matrix constituents, and macrophages.
    • Decent citation list -- many people have been working on MEAs.
  • Fibrous encapusulation of the electrode is much less conductive than healthy nervous tissue, hence impedance measurements can be used to track tissue response.
  • Used Osort to sort the recorded neurons.
  • "Despite differing implant locations, and thus potentially differing levels of background neural activity, and differing scarring responses, which relates to the level of thermal noise in the observed signal (Ludwig et al., 2006), no significant SNR differences were observed among the MEA types for the duration of the study."
  • SNR trends did not seem to relate to site impedance trends over the 31-day period, and by inference, the extent of tissue encapsulation and neuronal density loss.
    • SNR is likely controlled by background neural noise, not thermal noise (which would be linked to impedance).
  • Electrodes with lower impedance generally recorded units from more sites than arrays with higher impedance.

____References____

[0] Ward MP, Rajdev P, Ellison C, Irazoqui PP, Toward a comparison of microelectrodes for acute and chronic recordings.Brain Res 1282no Issue 183-200 (2009 Jul 28)

{311}
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ref: Westby-1997.1 tags: recording microwire electrode MEA sweet sucrose saliva dissolving FET floating date: 01-28-2013 00:28 gmt revision:5 [4] [3] [2] [1] [0] [head]

PMID-9350963 A floating microwire technique for multichannel neural recording and stimulation in the awake rat

  • sweet electrodes -- attached to glass micropipette with sucrose or saliva.
    • Chorover and DeLuca 1972 "A sweet new multiple electrode for chronic single unit recording". {1019}
  • 42 implanted rats, 252 implanted wires, 79% yield. 62% of electrodes still working at 5 weeks.
    • Targeting an area with really large somas (50um).
  • fully-floating 25um microwire ellectrodes.
  • platinum iridium, 25um, teflon coated, handled only with silastic-protected pliers & tweezers to prevent damage to the insulation.
  • electrode impdance range 200-900kOhms; check insulation by applying -3V to each electrode & looking for hydrogen bubbles.
  • soldering hardens platinum iridium alloy (huh).
  • (!!!) wires are stiffened for implantation by temporarily attaching them to a micropipette guide with sucrose which subsequently dissolves in the brain!
  • the smooth sucrose (40 grams in 50ml of water heated to 118C) coating requires about a week of desiccation to become hard enough for insertion into the brain without premature softening. Sucrose becomes clear like glass once fully desiccated.
  • the air above the craniotomy is sufficiently humid to dissolve the sucrose if left there for more than a few seconds.
  • used a miniature single-channel FET amplifier as a headstage - only one channel out of 6 could be recorded at once :( Thus their reults only apply to the best of the microwires implanted - not to all of them.
  • recorded onto a mac quadra (hahah) 20khz 12 bit
  • applying 160ua microstimulation pulses can restore low (200kohm) electrode impedance. Recording quality was generally improved for a few days following stimulation but then returned to an asymptotic level with the impedance at approximately 900kOhm.
  • electrodes only seemed to last 5 weeks, whence they declined to about 27% yeild - see figure 8.
  • good review of microelectrode recording up to that point (1997).

____References____

{736}
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ref: Liu-1999.09 tags: electrodes recording tissue response MEA histology date: 01-28-2013 00:24 gmt revision:7 [6] [5] [4] [3] [2] [1] [head]

PMID-10498377[0] Stability of the interface between neural tissue and chronically implanted intracortical microelectrodes.

  • implanted 7-shaft 35um iridium electrodes into the pericruciate gyrus of cats & measured the stability of recordings over several months.
  • electrodes were floating, under the dura; they note that connective tissue can force these floating arrays out of the brain, in further, or can encapsulate the electrodes.
    • electrodes activated by 'potentiodynamic cycling' to remove the insulation from the tip, I guess.
    • Insulation is epoxylite epoxy (5-10um thick) which is baked for curing and degassing at 100 and 170C each for 30 minutes.
    • more information on their fabrication in {1105}
  • Used the now-standard techniques for recording & analysis - amazing that this was all very new 10 years ago!
  • Measure stability not only on waveform shape (which will change as the position of the electrode relative to the neuron changes) but also neural tuning.
  • Lymphocytes were found to accumulate around the tips of the microstimulated sites.
  • Electrode sites that yielded recordings ('active') were all clean, with large neurons near the end, and with minimal connective tissue sheath (2-8 um; distance to nearby neurons was 30-50um).
    • Longest period for an active electrode was 242 days.
    • Electrode impedance was usually between 50 and 75 kOhm; there was no insulation failure.
  • Electrodes were stable even when the cat vigorously shook it's head in response to water placed on the head (!).
  • Electrodes were very unstable the first 2 weeks - 1 month ; rather stable thereafter.
    • Active electrodes tended to remain active ; inactive electrodes tended to remain inactive.

____References____

[0] Liu X, McCreery DB, Carter RR, Bullara LA, Yuen TG, Agnew WF, Stability of the interface between neural tissue and chronically implanted intracortical microelectrodes.IEEE Trans Rehabil Eng 7:3, 315-26 (1999 Sep)
[1] Bullara LA, McCreery DB, Yuen TG, Agnew WF, A microelectrode for delivery of defined charge densities.J Neurosci Methods 9:1, 15-21 (1983 Sep)

{1195}
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ref: Stevenson-2011.02 tags: Kording neural recording doubling northwestern chicago date: 01-28-2013 00:12 gmt revision:1 [0] [head]

PMID-21270781[0] How advances in neural recording affect data analysis.

  • Number of recorded channels doubles about every 7 years (slowish).
  • "Emerging data analysis techniques should consider both the computational costs and the potential for more accurate models associated with this exponential growth of the number of recorded neurons."

____References____

[0] Stevenson IH, Kording KP, How advances in neural recording affect data analysis.Nat Neurosci 14:2, 139-42 (2011 Feb)

{746}
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ref: Sanders-2000.1 tags: polymer fiber immune reaction biocompatibility rats polycaprolactone recording electrodes histology MEA date: 01-28-2013 00:01 gmt revision:11 [10] [9] [8] [7] [6] [5] [head]

PMID-10906696[0] Tissue response to single-polymer fibers of varying diameters: evaluation of fibrous encapsulation and macrophage density.

  • Fibers smaller than 6μm show reduced immune response.
    • Fibers implanted in the subcutaneous dorsum (below the skin in the back of rats).
    • Polypropylene. (like rope).
    • Wish the result extended to small beads & small electrodes. 7μm is tiny, but possible with insulated Au wires.
      • Beads: try PMID-1913150 -- shows that the 600um - 50um beads ('microspheres') are well tolerated.
      • Also {750}.
  • Macrophage density in tissue with fiber diameters 2.1-5.9um comparable to that of unoperated contralateral control.

"

fiber diametercapsule thickness
2.1-5.90.6
6.5-10.611.7
11.1-15.820.3
16.7-26.725.5

____References____

[0] Sanders JE, Stiles CE, Hayes CL, Tissue response to single-polymer fibers of varying diameters: evaluation of fibrous encapsulation and macrophage density.J Biomed Mater Res 52:1, 231-7 (2000 Oct)

{897}
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ref: Harris-2011.08 tags: microelectrodes nanocomposite immune response glia recording MEA date: 01-27-2013 22:19 gmt revision:5 [4] [3] [2] [1] [0] [head]

PMID-21654037[0] In vivo deployment of mechanically adaptive nanocomposites for intracortical microelectrodes

  • J P Harris, A E Hess, S J Rowan, C Weder, C A Zorman, D J Tyler and J R Capadona Case Western University.
  • Simple idea: electrodes should be rigid enough to penetrate the brain, yet soft enough to not damage it once implanted.
  • Many studies have shown that shear stress around a microelectrode shaft causes neural die-off and glial response.
  • You can only record from neurons if they are < 100um from the electrode tip.
  • Nanocomposite material is inspired by sea cucumber skin.
    • Our materials exhibit this behaviour by mimicking the architecture and proposed switching mechanism at play in the sea cucumber dermis by utilizing a polymer NC consisting of a controllable structural scaffold of rigid cellulose nanofibres embedded within a soft polymeric matrix. When the nanofibres percolate, they interact with each other through hydrogen bonding and form a nanofibre network that becomes the load-bearing element, leading to a high overall stiffness of the NC. When combined with a polymer system which additionally undergoes a phase transition at physiologically relevant temperatures, a contrast of over two orders of magnitude for the tensile elastic modulus is exhibited.
  • Probes were 200um wide, 100um thick, and had a point sharpened to 45deg.
  • Buckle force testing was done on 53um thick, 125um wide probes sharpened to a 30deg point.
  • Penetration stress through the rat pia is 1.2e7 dynes/cm^2 for a Si probe 40um thick and 80um wide.
  • See also {1198}

____References____

[0] Harris JP, Hess AE, Rowan SJ, Weder C, Zorman CA, Tyler DJ, Capadona JR, In vivo deployment of mechanically adaptive nanocomposites for intracortical microelectrodes.J Neural Eng 8:4, 046010 (2011 Aug)

{1205}
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ref: Rennaker-2005.03 tags: electrode recording longevity mechanical insertion Oklahoma MEA date: 01-25-2013 01:21 gmt revision:3 [2] [1] [0] [head]

PMID-15698656[0] A comparison of chronic multi-channel cortical implantation techniques: manual versus mechanical insertion.

  • Over 60% of the animals implanted with the mechanical insertion device had driven activity at week 6
    • whereas none of the animals with manually inserted arrays exhibited functional responses after 3 weeks.
      • Roughly identical responses immediately following surgery.
      • Could be that the manual inserter had horizontal movement / shear. (This is solveable with a stereotax).
      • Other research showed little difference in tissue response at 10um/s or 100um/s PMID-21896383[1]
  • Multi-wire electrodes.
  • Mechanical insertion device was capable of rapidly inserting the electrode without visible compression of the brain.
  • Response measured relative to auditory stimulus.
  • Their insertion device looks like a pen.

____References____

[0] Rennaker RL, Street S, Ruyle AM, Sloan AM, A comparison of chronic multi-channel cortical implantation techniques: manual versus mechanical insertion.J Neurosci Methods 142:2, 169-76 (2005 Mar 30)
[1] Welkenhuysen M, Andrei A, Ameye L, Eberle W, Nuttin B, Effect of insertion speed on tissue response and insertion mechanics of a chronically implanted silicon-based neural probe.IEEE Trans Biomed Eng 58:11, 3250-9 (2011 Nov)

{1206}
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ref: -0 tags: flexible polymer electrode recording polypyrrole Bizzi date: 01-25-2013 00:39 gmt revision:0 [head]

PMID-19164034 Cortical recording with polypyrrole microwire electrodes.

  • http://web.mit.edu/bcs/bizzilab/publications/bae2008.pdf
  • Electropolymerization of PPy on a glassy carbon electrode in solution.
  • Polypyrrole microwires were prepared by mounting a PPy film perpendicular to the stage of a cryo-microtome and slicing it in 20um sections.
  • Electrode mounted inside a glass capillary tube.
  • Impedance: 1e5 @ 1kHz.

{1111}
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ref: Stice-2007.06 tags: electrodes recording small rats S1 PGA histology GFAP date: 01-24-2013 21:07 gmt revision:9 [8] [7] [6] [5] [4] [3] [head]

PMID-17409479[0] Thin microelectrodes reduce GFAP expression in the implant site in rodent somatosensory cortex.

  • Implanted 12 um and 25 um polymide coated stainless steel
    • Wires coated with poly-glycolic acid (PGA) to facilitate implantation.
  • Only looked to 4 weeks.
  • 12 um implants significantly less GFAP (astrocyte) reactivity at 4 weeks, no difference at 2 weeks (figure 9 & 10).
    • B = bare, P = PGA coated.
  • Can use to bolster the idea that smaller implants are less irritating.

____References____

[0] Stice P, Gilletti A, Panitch A, Muthuswamy J, Thin microelectrodes reduce GFAP expression in the implant site in rodent somatosensory cortex.J Neural Eng 4:2, 42-53 (2007 Jun)

{749}
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ref: Biran-2007.07 tags: tresco biocompatibility tether skull electrodes Michigan probe recording Tresco date: 01-24-2013 20:11 gmt revision:6 [5] [4] [3] [2] [1] [0] [head]

PMID-17266019[0] The brain tissue response to implanted silicon microelectrode arrays is increased when the device is tethered to the skull.

  • Good, convincing, figures.

____References____

[0] Biran R, Martin DC, Tresco PA, The brain tissue response to implanted silicon microelectrode arrays is increased when the device is tethered to the skull.J Biomed Mater Res A 82:1, 169-78 (2007 Jul)

{1040}
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ref: Du-2011.01 tags: Harrison recording electrode MEA Blanche date: 01-04-2013 02:43 gmt revision:3 [2] [1] [0] [head]

PMID-22022568[0] Multiplexed, High Density Electrophysiology with Nanofabricated Neural Probes

  • The number of single-units possible to record doubles every 7 years [5].
  • Electrodes must be within 100um of soma to relaibly detect extracellular action potentials.
  • Existing Michigan arrays have trace features around >=1 um; here they use E-beam lithography to decrease the probe width dramatically.
    • Their wire widths are 290 nm. Still bigger than 40nm process (?)
  • Seem to use Reid Harrison's ASIC RHA22132 design.
  • noise of electrodes progressively decreased with consecutive gold electroplating cycles. Plating makes the electrodes rough, and decreases their impedance to around 1 M.
    • Electrode contacts are around 10 x 10 um square, 108 um^2 area.
  • Intrinsic noise of the amplifier 1.7 uV RMS.
  • 290 nm wire had an impedance of 9.2 k -- corresponding to 1.0 uV rms noise.
  • able to record from the same neuron from several adjacent electrodes. Spacing ~ 28 um.
  • Detail their process extensively -- 40% of probes survived the process with <= 5 defective channels. THey propose further optimization to the e-beam lithography. Probes took 7 hours to pattern on the lithography machine (!).

____References____

[0] Du J, Blanche TJ, Harrison RR, Lester HA, Masmanidis SC, Multiplexed, high density electrophysiology with nanofabricated neural probes.PLoS One 6:10, e26204 (2011)

{1188}
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ref: -0 tags: flexible micxrowire arrays electrode recording Georgia polymide date: 01-04-2013 00:13 gmt revision:1 [0] [head]

IEEE-906517 (pdf) Flexible microelectrode arrays with integrated insertion devices

  • 2001 MEMS Conference.
  • FMA = flexible microelectrode arrays.
  • Both for nerves (pass-through needle) and cortex (removeable needle).
    • Primarily tested in tissue proxies.
  • Anticipated the utility of photolithography for patterning the electrodes + rigid insertion devices.
  • The elastic modulus of polymers like polymide are two orders of magnitude less than metals, but still six orders of magnitude higher than brain tissue (46kPa).
  • Pass-through needle very similar to the threaded wire idea.
  • removable needle simply stops the thread & drives the needle a bit further to break the attachment site.
    • Did not test removable needle technique (?)
  • Defined electroplating with a thick photoresist mask, as Michel says.
  • Tested FMAs with movement and acceleration vs. rigid arrays. FMAs faired much better, of course!

____References____

' ''' ()

{1178}
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ref: -0 tags: parylene flexible neural recording drug delivery microfluidics 2012 inserter needle release date: 01-02-2013 22:41 gmt revision:1 [0] [head]

PMID-23160191 Novel flexible Parylene neural probe with 3D sheath structure for enhancing tissue integration

  • They seem to think that drugs are critical for success: "These features will enhance tissue integration and improve recording quality towards realizing reliable chronic neural interfaces."
  • Similar to Kennedy: "The sheath structure allows for ingrowth of neural processes leading to improved tissue/probe integration post implantation." 8 electrodes, 4 on the cone interior, 4 on the exterior.
    • opening is 50um at tip, 300 um at base.
  • Used a PEEK-stiffened parylene ZIF connection.
  • Only tested in agarose, but it did properly release from the inserter needle.
  • I wonder if we could use a similar technique..
  • "Lab on a chip" journal (Royal society of Chemistry). nice.

{1187}
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ref: -0 tags: neural recording topologies circuits operational transconductance amplifiers date: 01-02-2013 20:00 gmt revision:0 [head]

PMID-22163863 Recent advances in neural recording microsystems.

  • Decent review. Has some depth on the critical first step of amplification.

{1184}
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ref: -0 tags: optical neural recording photon induced electron transfer date: 01-02-2013 04:25 gmt revision:2 [1] [0] [head]

PMID-22308458 Optically monitoring voltage in neurons by photo-induced electron transfer through molecular wires.

  • Photoinduced electron transfer.
    • About what you would think -- a photon bumps an electron into a higher orbital, and this electron can be donated to another group or drop back down & fluoresce a photon.
  • Good sensitivity: ΔF/F of 20-27% per 100mV, fast kinetics.
  • Not presently genetically targetable.
  • Makes sense in terms of energy: "A 100-mV depolarization changes the PeT driving force by 0.05 eV (one electron × half of 100-mV potential, or 0.05 V). Because PeT is a thermally controlled process, the value of 0.05 eV is large relative to the value of kT at 300 K (0.026 eV), yielding a large dynamic range between the rates of PeT at resting and depolarized potentials.
  • Why electrochromic dyes have plateaued:
    • "In contrast, electrochromic dyes have smaller delta G values, 0.003 (46) to 0.02 (47) eV, and larger comparison energies. Because the interaction is a photochemically controlled process, the energy of the exciting photon is the comparison energy, which is 1.5–2 eV for dyes in the blue-to-green region of the spectrum. Therefore, PeT and FRET dyes have large changes in energy versus their comparison energy (0.05 eV vs. 0.026 eV), giving high sensitivities; electrochromic dyes have small changes compared with the excitation photon (0.003–0.02 eV vs. 2 eV), producing low voltage sensitivity."

{1183}
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ref: -0 tags: optical imaging neural recording diamond magnetic date: 01-02-2013 03:44 gmt revision:0 [head]

PMID-22574249 High spatial and temporal resolution wide-field imaging of neuron activity using quantum NV-diamond.

  • yikes: In this work we consider a fundamentally new form of wide-field imaging for neuronal networks based on the nanoscale magnetic field sensing properties of optically active spins in a diamond substrate.
  • Cultured neurons.
  • NV = nitrogen-vacancy defect centers.
    • "The NV centre is a remarkable optical defect in diamond which allows discrimination of its magnetic sublevels through its fluorescence under illumination. "
    • We show that the NV detection system is able to non-invasively capture the transmembrane potential activity in a series of near real-time images, with spatial resolution at the level of the individual neural compartments.
  • Did not actually perform neural measurements -- used a 10um microwire with mA of current running through it.
    • I would imagine that actual neurons have far less current!

{1182}
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ref: -0 tags: optical recording voltage sensitive dyes redshirt date: 01-02-2013 03:17 gmt revision:3 [2] [1] [0] [head]

PMID-16050036 Imaging brain activity with voltage- and calcium-sensitive dyes.

  • Voltage-sensitive dyes are well suited for measuring synaptic integration, as:
    • Electrodes are too blunt to effectively record these fine, < 1um diameter structures.
    • The surface area to volume ratio is highest in the dendrites
    • Voltage-sensitive dyes also permeate internal membranes not subject to voltage gradients, hence this does not contribute to the signal, leading to a decreased ΔF/F .
  • Dominant experimental noise is shot noise, statistical -- see {1181}.
  • modern dyes and imagers can reliably record single action potentials; spatial averaging yields similar resolution as electrical recording.
  • They performed optical recording of Aplysia sensory ganglia, and discovered following light tail touch: "It is almost as if the Aplysia nervous system is designed such that every cell in the abdominal ganglion cares about this (and perhaps every) sensory stimulus. In addition, more than 1000 neurons in other ganglia are activated by this touch..."
      • These results force a more pessimistic view of the present understanding of the neuronal basis of apparently simple behaviors in relatively simple nervous systems.
  • Used calcium imaging on olfactory glomeruli of mice and turtles; measurements were limited by either shot-noise or heart/breathing artifacts.
  • Confocal and two-photon microscopes, due to their exchange of spatial resolution for sensitivity, are not useful with voltage-sensitive dyes.
    • The generation of fluorescent photons in the 2-photon confocal microscope is not efficient. We compared the signals from Calcium Green-1 in the mouse olfactory bulb using 2-photon and ordinary microscopy. In this comparison the number of photons contributing to the intensity measurement in the 2-photon confocal microscope was about 1000 times smaller than the number measured with the conventional microscope and a CCD camera.
  • By the numbers, quote: Because only a small fraction of the 10e16 photons/ms emitted by a tungsten filament source will be measured, a signal-to-noise ratio of 10e8 (see above) cannot be achieved. A partial listing of the light losses follows. A 0.9-NA lamp collector lens would collect 0.1 of the light emitted by the source. Only 0.2 of that light is in the visible wavelength range; the remainder is infrared (heat). Limiting the incident wavelengths to those, which have the signal means, that only 0.1 of the visible light is used. Thus, the light reaching the
preparation might typically be reduced to 1013 photons/ms. If the light-collecting system that forms the image has high efficiency e.g., in an absorption measurement, about 1013 photons/ms will reach the image plane. (In a fluorescence measurement there will be much less light measured because 1. only a fraction of the incident photons are absorbed by the fluorophores, 2. only a fraction of the absorbed photons appear as emitted photons, and 3. only a fraction of the emitted photons are collected by the objective.) If the camera has a quantum efficiency of 1.0, then, in absorption, a total of 10e13 photoelectrons/ms will be measured. With a camera of 1000 pixels, there will be 10e10 photoelectrons/ms/pixel. The shot noise will be 10e5 photoelectrons/ms/pixel; thus the very best that can be expected is a noise that is 10e−5 of the resting light (a signal-to-noise ratio of 100 db). The extra light losses in a fluorescence measurement will further reduce the maximum obtainable signal-to-noise ratio.

{1181}
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ref: -0 tags: neural imaging recording shot noise redshirt date: 01-02-2013 02:20 gmt revision:0 [head]

http://www.redshirtimaging.com/redshirt_neuro/neuro_lib_2.htm

  • Shot Noise: The limit of accuracy with which light can be measured is set by the shot noise arising from the statistical nature of photon emission and detection.
    • If an ideal light source emits an average of N photons/ms, the RMS deviation in the number emitted is N .
    • At high intensities this ratio NN is large and thus small changes in intensity can be detected. For example, at 10^10 photons/ms a fractional intensity change of 0.1% can be measured with a signal-to-noise ratio of 100.
    • On the other hand, at low intensities this ratio of intensity divided by noise is small and only large signals can be detected. For example, at 10^4 photons/msec the same fractional change of 0.1% can be measured with a signal-to-noise ratio of 1 only after averaging 100 trials.

{1179}
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ref: -0 tags: optical coherence tomography neural recording squid voltage sensitive dyes review date: 12-23-2012 21:00 gmt revision:4 [3] [2] [1] [0] [head]

PMID-20844600 Detection of Neural Action Potentials Using Optical Coherence Tomography: Intensity and Phase Measurements with and without Dyes.

  • Optical methods of recording have been investigated since the 1940's:
    • During action potential (AP) propagation in neural tissue light scattering, absorption, birefringence, fluorescence, and volume changes have been reported (Cohen, 1973).
  • OCT is reflection-based, not transmission: illuminate and measure from the same side.
    • Here they use spectral domain OCT, where the mirror is not scanned; rather SD-OCT uses a spectrometer to record interference of back-scattered light from all depth points simultaneously (Fercher et al., 1995).
    • Use of a spectrometer allows imaging of an axial line within 10-50us, sufficient for imaging action potentials.
    • SD-OCT, due to some underlying mathematics which I can't quite grok atm, can resolve/annul common-mode phase noise for high temporal and Δphase measurement (high sensitivity).
      • This equates to "microsecond temporal resolution and sub-nanometer optical path length resolution".
  • OCT is generally (intially?) used for in-vivo imaging of retinas, in humans and other animals.
  • They present new data for depth-localization of neural activity in squid giant axons (SGA) stained with a voltage-sensitive near-infrared dye.
    • Note: averaged over 250 sweeps.
  • ΔPhase>>ΔIntensity -- figure 4 in the paper.
  • Use of voltage-sensitive dyes improves the resolution of ΔI , but not dramatically --
    • And Δphase is still a bit delayed.
    • Electrical recording is the control.
      • It will take significant technology development before optical methods exceed electrical methods...
  • Looks pretty preliminary. However, OCT can image 1-2mm deep in transparent tissue, which is exceptional.
  • Will have to read their explanation of OCT.
  • Used in a squid giant axon prep. 2010, wonder if anything new has been done (in vivo?).
  • Claim that progress is hampered by limited understanding of how these Δphase signals arise.

{1180}
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ref: -0 tags: optical coherence tomography neural recording aplysia date: 12-23-2012 09:12 gmt revision:2 [1] [0] [head]

PMID-19654752 Detecting intrinsic scattering changes correlated to neuron action potentials using optical coherence imaging.

  • Aplysia, intrinsic imaging of scattering change following electrical stimulation.
    • Why did it take so long for them to get this paper out.. ?
  • Nicolelis first cited author.
  • Quality of recording not necessarily high.
  • quote: "Typical transverse resolutions in OCT (10-20um) are likely insufficient to identify smaller mamallian neurons that are often studied in neuroscience."
    • Solution: optical coherence microscopy (OCM), where a higher NA lens focuses the light to a smaller spot.
    • Expense: shorter depth-of-field.
  • Why does this work? "One mechanism of these optical signals is believed to be a realignment of charged membrane proteins in response to voltage change [6].
  • A delay of roughly 70ms was observed between the change in membrane voltage and the change in scattering intensity.
    • That's slow! Might be due to conduction velocity in Aplysia.
  • SNR of scattering measurement not too high -- the neurons are alive, afterall, and their normal biological processes cause scattering changes.
    • Killing the neurons with KCl dramatically decreased the variance of scattering, consistent with this hpothesis.
  • Birefringence: "Changes in the birefringence of nerves due to electrical activity have been shown to be an order of magnitude larger than scattering intensity changes" PMID-5649693

{1164}
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ref: -0 tags: neural recording McGill Musallam electrodes date: 07-12-2012 22:53 gmt revision:0 [head]

http://www.mdpi.com/1424-8220/8/10/6704/pdf NeuroMEMS: Neuro Probe Microtechnologies

  • Good review (as of 2008) of the many different approaches for nervous system recording.

{307}
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ref: Rousche-1998.07 tags: BMI Utah cat Normann recording electrode MEA histology date: 06-29-2012 01:12 gmt revision:9 [8] [7] [6] [5] [4] [3] [head]

PMID-10223510 Chronic recording capability of the Utah Intracortical Electrode Array in cat sensory cortex.

  • Focus on (surprisingly) chronic recording from the utah array: they want to demonstrate that it works.
  • Platinum coating.
  • insulated with 2-3um polymide.
  • 10 cats, 12 arrays: 2 in S1, 8 in auditory ctx, 2 V1.
  • 11 electrodes connected in each array.
  • After a 6-month implant period, 60% of implanted arrays could still record 'some type of activity'.
  • They were completely targeting neuroprostheses.
    • But acknowledge that 'the presence of fibrous encapsulation and chronic astrogliosis suggests that more research is necessary before the UIEA can be uses as a cornerstone of a neuroprosthetic device for human use.
      • And yet they went through with the human trials?
  • Electrode impedance gave no hint as to the ability of a given electrode to record neural units: many electrodes with average impedance could not record neural activity.
  • Impedances generally decreased , which is not unusual (Schmidt and Bak, 1976).
    • Likely that the polymide had become permeated with water vapor to and equilibrium point. (rather than pinhole leaks or water permeation).
  • Quiet amplifiers: 2uv pk-pk.
  • No significant trend in background activity was noted over the implant durations.
  • In nearly every cat, the dura above the electrode array adhered to the bone flap, and the electrode array adhered to the dura. Therefore, when the bone flap was removed, the UIEA was concurrently explanted from the cortex.
    • Similar to Hoogerwerf and Wise 1994 {1025}
    • The explanted UIEAs typically had become encapsulated, the encapsulation was the cause of the cortical depression.
    • Only 1 did not become encapsulated in dura.
    • This encapsulation explains the gradually varying recording properties -- the electrodes were moving out of the brain.
    • "The capsule which formed around the substrate of the UIEA was usually continuous with the dura, which was enmeshed directly to the overlying skull. The encapsulated array therefore had no freedom of movement with respect to the skull, and this may have caused local trauma which reduced the possibility of recording neural activity. This relative micromovement between the fixed array and the ‘floating’ cortical tissue may also be responsible for sustaining continued growth of the encapsulation as described above."
    • Have tried putting teflon on the top of the Utah array -- did this work?
  • Two UIEAs were not found near the cortical surface -- these two arrays were totally removed from the leptomeningeal space. although originally implanted into the cortex beneath the dura, at the time of sacrafice these arrays were found above the repaired dura, and the implanted cortex showed no evicence of cortical implant.
  • Some electrodes healthy; other showed chronic inflammation.
  • General and intense inflamation in the upper layers of cortex even on their best-performing array; no guarantee that this ctx was working properly, as it is heavily compressed with fibroblasts.
  • Regarding vascluature, see {1024}.
  • Say that the largest impediment is the formation of a capsule around the implant. (Do not mention issue of infection; I guess cats have strong immune systems as well?)
  • Rather good biological discussion and conclusion. worth a re-read. "We currently recommend that the UIEA be used for acute and short-term applications."
    • Not too many follow-ups re teflon or fixing the encapsulation problem: See {1026}
      • Indeed, {1027} doesn't even cite this! Too disastrous?

____References____

{828}
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ref: RodriguezOroz-2001.09 tags: STN SNr parkinsons disease single unit recording spain 2001 tremor oscillations DBS somatotopy organization date: 02-22-2012 18:24 gmt revision:12 [11] [10] [9] [8] [7] [6] [head]

PMID-11522580[0] The subthalamic nucleus in Parkinson's disease: somatotopic organization and physiological characteristics

  • Looks like they discovered exactly what we have discovered ... only in 2001. This is both good and bad.
    • From the abstract: "Neurones responding to movement were of the irregular or tonic type, and were found in the dorsolateral region of the STN. Neurones with oscillatory and low frequency activity did not respond to movement and were in the ventral one-third of the nucleus. Thirty-eight tremor-related neurones were recorded."
  • Again, from the abstract: "The findings of this study indicate that the somatotopic arrangement and electrophysiological features of the STN in Parkinson's disease patients are similar to those found in monkeys."
  • It may be that we want to test differential modulation / oscillation: look for differences between rest and activity, if there is sufficient support for both these in the files we have.
  • These people were much, much more careful about localization of their single-electrode tracks. E.g. they calculated electrode location relative the DBS electrode stereotatically, and referenced this to the postoperative MRI location of the treatment electrode.
  • Many more (32% of 350 neurons) responded to active or passive movement.
  • Of this same set, 15% (31 neurons) had a firing rate with rhythmical activity; 38 neurons had rhythmic activity associated with oscillatory EMG, but most of these were responsive to passive stimulation.
  • Autocorrelation of the neuronal bursting and tremor peaked at mean 7Hz, while autocorr. of EMG peaked at mean 5Hz.
  • This whole paragraph is highly interesting: ''The neuronal response associated with active movements was studied by simultaneous recording of neuronal EMG activity of the limbs. Five tremor-related neurons, recorded while a voluntary movement was performed, were available for analysis. Voluntary activation of a particular limb segment arrested the tremor. This was associated with a change in the discharges of the recorded neuron, which fired at a slower rate and in synchrony with the voluntary movement. On occasions, freezing of the voluntary movement ensued and tremor reappeared, changing the neuronal activity back to the typical 4-5Hz tremor-related activity. The cross-correlation analysis of two such neurons showed a peak frequency of 4.63 and 4.88 Hz for tremor-related activity, and 1.5 to 1.38 Hz during voluntary movement. Whether neuronal discharges in the STN preceded or followed EMG activity of the limbs could not be precisely established under the present conditions.
  • Somatotopic representation in the STN is expected from normal and MTPT-treated monkeys. Indeed, somatotopy is enhanced int he GPm of MTPT-treated monkeys.
    • This somatotopy is likely to result from organized afferent from the primary motor cortex (M1) to dorsolateral STN; this is the target of DBS treatment. Ventral and medial STN seems to project to associative and limbic cortical regions.
    • It seems they think the STN is generally not diseased, it is just a useful target for stimulating without evoked movement as in M1. This is consistent with optogenetic studies by Deisseroth [1].
    • Supporting this: "DBS of STN in Parkinson's disease improves executive motor functions, but aggravates conditional associative learning.
  • Interesting: In Parkinson's disease patients with tremor, Levy and colleagues found synchronization and a high firing rate (>10Hz) while recording pairs of neurons >600um apart.
  • Recordings of cortical activity through EEG and STN LFP showed significant coherence in the beta and gamma frequency bands during movement - consistent with corticosubthalamic motor projection. ... and suggest that the STN neurons involved in parkinsonian tremor are the same as the ones ativated during the performance of a voluntary movement. (! -- I agree with this.)
  • More: The reciprocal inhibitory-excitatory connections tightly linking the GPe and the STN may generate self-perpetuating oscillations.

Old notes:

  • this paper concentrates on STN electrophysiology in PD.
    • has a rather excellent list of references.
  • found a somatotopic organization in the STN, with most motor-related units more irregular and in the dorsolateral STN.
  • found a substantial fraction of tremor-synchronized neurons.
  • conclude that the somatotopic organization is about the same as in monkeys (?) (!)
  • M1 projects to STN, as verified through anterograde tracing studies. [1] These neurons increase their firing rate in response to passive movements.
  • there appears to be a relatively-complete representation of the body in the dorsolateral STN.

____References____

[0] Rodriguez-Oroz MC, Rodriguez M, Guridi J, Mewes K, Chockkman V, Vitek J, DeLong MR, Obeso JA, The subthalamic nucleus in Parkinson's disease: somatotopic organization and physiological characteristics.Brain 124:Pt 9, 1777-90 (2001 Sep)
[1] Gradinaru V, Mogri M, Thompson KR, Henderson JM, Deisseroth K, Optical deconstruction of parkinsonian neural circuitry.Science 324:5925, 354-9 (2009 Apr 17)

{1116}
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ref: Snow-2006.02 tags: electrode insertion sharp recording tissue surrogate date: 02-10-2012 18:56 gmt revision:4 [3] [2] [1] [0] [head]

IEEE-1580838 (pdf) Microfabricated cylindrical multielectrodes for neural stimulation.

  • Used optical fiber as the substrate.
  • sharpened using a Dicing saw.
  • polymide insulatino removed by placing fiber tip next to a white-hot platinum filament.
  • cylindrical lithography system using a He-Cd laser.
  • tissue surrogate: two layers of 20um Saran Wrap over tofu. (!!!) -- see also {212}

____References____

Snow, S. and Jacobsen, S.C. and Wells, D.L. and Horch, K.W. Microfabricated cylindrical multielectrodes for neural stimulation Biomedical Engineering, IEEE Transactions on 53 2 320 -326 (2006)

{1113}
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ref: -0 tags: neural recording doubling Stevenson Kording date: 02-08-2012 04:28 gmt revision:0 [head]

PMID-21270781 How advances in neural recording affect data analysis

  • Number of channels recorded doubles every 7 years.
  • This extrapolated from the past 50 years of growth.

{1056}
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ref: Nordhausen-1996.07 tags: Normann Utah array recording date: 02-06-2012 21:37 gmt revision:3 [2] [1] [0] [head]

PMID-8836553[0] Single unit recording capabilities of a 100 microelectrode array. Nordhausen CT, Maynard EM, Normann RA.

  • Used the Utah array in visual stimulus-evoked response in cats.
  • 58.6% of electrodes in the array recorded neural activity.
  • The density of the electrodes in the UIEA makes it impossible to simply push the needles into the cortex with forceps. This only results in surface dimpling, incomplete insertion, and possible cortical damage.
    • We have instead designed a high speed pneumatic insertion tool which takes advantage of viscoelectric properties of the cortical tissue by advancing the electrodes into the tissue at very high velocity.

____References____

[0] Nordhausen CT, Maynard EM, Normann RA, Single unit recording capabilities of a 100 microelectrode array.Brain Res 726:1-2, 129-40 (1996 Jul 8)

{1109}
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ref: -0 tags: Cogan 2008 electrodes recording stimulation date: 02-05-2012 00:21 gmt revision:0 [head]

PMID-18429704 Neural stimulation and recording electrodes.

  • Electrical stimulation of nerve tissue and recording of neural electrical activity are the basis of emerging prostheses and treatments for spinal cord injury, stroke, sensory deficits, and neurological disorders. An understanding of the electrochemical mechanisms underlying the behavior of neural stimulation and recording electrodes is important for the development of chronically implanted devices, particularly those employing large numbers of microelectrodes. For stimulation, materials that support charge injection by capacitive and faradaic mechanisms are available. These include titanium nitride, platinum, and iridium oxide, each with certain advantages and limitations. The use of charge-balanced waveforms and maximum electrochemical potential excursions as criteria for reversible charge injection with these electrode materials are described and critiqued. Techniques for characterizing electrochemical properties relevant to stimulation and recording are described with examples of differences in the in vitro and in vivo response of electrodes.

{891}
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ref: Bonfanti-0 tags: wireless neural recording wireless italy date: 01-20-2012 05:30 gmt revision:3 [2] [1] [0] [head]

PMID-21096380[0] "A multi-channel low-power system-on-chip for single-unit recording and narrowband wireless transmission of neural signal."

  • Use Manchester-encoded FSK, with 20-sample spike extraction feeding 2kb RAM.
  • Feature sub-threshold biased transistors on input stage for low noise, and MOS-bipolar pseudo-resistors + 0.15pf caps as filter elements. see schematic.
  • 105uW / channel with the PA amplifier disabled.
    • Only 4uA/channel consumed in the input stage.
    • DSP consumes 400uA
    • VCO 400uA, PLL 300uA.
  • Has a brief but useful review of the other wireless neural recorders in this field -- including ultrawideband.

____References____

[0] Bonfanti A, Ceravolo M, Zambra G, Gusmeroli R, Spinelli AS, Lacaita AL, Angotzi GN, Baranauskas G, Fadiga L, A multi-channel low-power system-on-chip for single-unit recording and narrowband wireless transmission of neural signal.Conf Proc IEEE Eng Med Biol Soc 2010no Issue 1555-60 (2010)

{214}
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ref: Harrison-2003.06 tags: CMOS amplifier headstage electrophysiology neural_recording low_power chopper Reid Harrison date: 01-16-2012 04:43 gmt revision:12 [11] [10] [9] [8] [7] [6] [head]

IEEE-1201998 (pdf) A low-power low-noise CMOS amplifier for neural recording applications

  • detail novel MOS-bipolar pseudoresistor element to permit amplification of low-frequency signals down to milihertz range.
  • 80 microwatt spike amplifier in 0.16mm^2 silicon with 1.5 um CMOS, 1 microwatt EEG amplifier
  • input-referred noise of 2.2uV RMS.
  • has a nice graph comparing the power vs. noise for a number of other published designs
  • i doubt the low-frequency amplification really matters for neural recording, though certainly it matters for EEG.
    • they give an equation for the noise efficiency factor (NEF), as well as much detailed background.
    • NEF better than any prev. reported. Theoretical limit is 2.9 for this topology; they measure 4.8
  • does not compare well to Medtronic amp: http://www.eetimes.com/news/design/showArticle.jhtml?articleID=197005915
    • 2 microwatt! @ 1.8V
    • chopper-stabilized
    • not sure what they are going to use it for - the battery will be killed it it has to telemeter anything!
    • need to find the report for this.
  • tutorial on chopper-stabilized amplifiers -- they have nearly constant noise v.s. frequency, and very low input/output offset.
  • References: {1056} Single unit recording capabilities of a 100 microelectrode array. Nordhausen CT, Maynard EM, Normann RA.
  • [5] see {1041}
  • [9] {1042}
  • [12] {1043}
____References____

Harrison, R.R. and Charles, C. A low-power low-noise CMOS amplifier for neural recording applications Solid-State Circuits, IEEE Journal of 38 6 958 - 965 (2003)

{814}
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ref: Zhang-2009.02 tags: localized surface plasmon resonance nanoparticle neural recording innovative date: 01-15-2012 23:00 gmt revision:4 [3] [2] [1] [0] [head]

PMID-19199762[0] Optical Detection of Brain Cell Activity Using Plasmonic Gold Nanoparticles

  • Used 140 nm diameter, 40 nm thick gold disc nanoparticles set in a 400nm array, illuminated by 850nm diode laser light.
    • From my reading, it seems that the diameter of these nanoparticles is important, but the grid spacing is not.
  • These nanoparticles strongly scatter light, and the degree of scattering is dependent on the local index of refraction + electric field.
  • The change in scattering due to applied electric field is very small, though - ~ 3e-6 1/V in the air-capacitor setup, ~1e-3 in solution when stimluated by cultured hippocampal neurons.
  • Noteably, nanoparticles are not diffraction limited - their measurement resolution is proportional to their size. Compare with voltage-sensitive dyes, which have a similar measurement signal-to-noise ratio, are diffraction limited, may be toxic, and may photobleach.

____References____

[0] Zhang J, Atay T, Nurmikko AV, Optical detection of brain cell activity using plasmonic gold nanoparticles.Nano Lett 9:2, 519-24 (2009 Feb)

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ref: Mohseni-2005.09 tags: recording telemetry radio Najafi wireless date: 01-15-2012 22:22 gmt revision:3 [2] [1] [0] [head]

PMID-16200750[0] Wireless Multichannel Biopotential Recording Using an Integrated FM Telemetry Circuit Pedram Mohseni, Khalil Najafi, Steven Eliades, Xiaoquin Wang.

____References____

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ref: Kawano-2010.03 tags: mEA recording VLS silicon original date: 01-15-2012 22:11 gmt revision:3 [2] [1] [0] [head]

PMID-20089393[0] Electrical interfacing between neurons and electronics via vertically integrated sub-4 microm-diameter silicon probe arrays fabricated by vapor-liquid-solid growth.

  • The probe arrays can be fabricated on a silicon (1 1 1) substrate by selective VLS growth using catalytic-gold (Au) dots and a disilane (Si2H6) gas source, allowing precise control of probe position, diameter and length, as well as on-chip interconnections/integrated circuits (ICs) ( [Wagner and Ellis, 1964], [Ishida et al., 1999] and [Kawano et al., 2002])
  • maximum length 120 um (or so)

____References____

[0] Kawano T, Harimoto T, Ishihara A, Takei K, Kawashima T, Usui S, Ishida M, Electrical interfacing between neurons and electronics via vertically integrated sub-4 microm-diameter silicon probe arrays fabricated by vapor-liquid-solid growth.Biosens Bioelectron 25:7, 1809-15 (2010 Mar 15)

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ref: Kim-2009.04 tags: Utah ASIC recording 2009 date: 01-15-2012 22:08 gmt revision:1 [0] [head]

PMID-19067174[0] Integrated wireless neural interface based on the Utah electrode array

  • Describes their fully integrated 100 site Utah probe.
  • "A planar power receiving coil fabricated by patterning electroplated gold films on polyimide substrates was connected to the IC by using a custom metallized ceramic spacer and SnCu reflow soldering. The SnCu soldering was also used to assemble SMD capacitors on the UEA. "

____References____

[0] Kim S, Bhandari R, Klein M, Negi S, Rieth L, Tathireddy P, Toepper M, Oppermann H, Solzbacher F, Integrated wireless neural interface based on the Utah electrode array.Biomed Microdevices 11:2, 453-66 (2009 Apr)

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ref: Holleman-2007.08 tags: amplifier recording NEF low noise original date: 01-15-2012 22:08 gmt revision:1 [0] [head]

IEEE-4353193 (pdf) A Sub-Microwatt Low-Noise Amplifier for Neural Recording

  • 0.805 uA from a 1V supply, gain of 36dB and 44db.
  • open loop amplfier, pass band between 0.3 and 4.7 kHz.
  • 3.5 uV rms input referred noise.
  • NEF 1.8

____References____

Holleman, J. and Otis, B. Engineering in Medicine and Biology Society, 2007. EMBS 2007. 29th Annual International Conference of the IEEE 3930 -3933 (2007)

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ref: Farshchi-2006.07 tags: recording COTS date: 01-15-2012 22:08 gmt revision:1 [0] [head]

IEEE-1643411 (pdf) A TinyOS-enabled MICA2-BasedWireless neural interface

  • six channels, 9.6 kbps, 66 mW power.
  • TinyOS based.

____References____

Farshchi, S. and Nuyujukian, P.H. and Pesterev, A. and Mody, I. and Judy, J.W. A TinyOS-enabled MICA2-BasedWireless neural interface Biomedical Engineering, IEEE Transactions on 53 7 1416 -1424 (2006)

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ref: Sodagar-2009.09 tags: ASIC recording Najafi spike sorting date: 01-15-2012 22:07 gmt revision:4 [3] [2] [1] [0] [head]

IEEE-5226763 (pdf) An Implantable 64-Channel Wireless Microsystem for Single-Unit Neural Recording

  • Spike sorting (thresholding) on 64 channels, 8 bit digitization, 62.5 ks/sec, 60dB gain, 14.4 mW at 1.8V.
  • 1.4 by 1.55 cm.

____References____

Sodagar, A.M. and Perlin, G.E. and Ying Yao and Najafi, K. and Wise, K.D. An Implantable 64-Channel Wireless Microsystem for Single-Unit Neural Recording Solid-State Circuits, IEEE Journal of 44 9 2591 -2604 (2009)

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ref: Obeid-2004.02 tags: Obeid multichannel telemetry wireless recording date: 01-15-2012 22:06 gmt revision:3 [2] [1] [0] [head]

PMID-14757342[0] A multichannel telemetry system for single unit neural recordings

  • 16 channels; only transmit 12.
  • 45 minute battery life, 4W power consumption.
  • Uses a 486 index-card sized PC running DOS.
    • TCP/IP connection from host PC to wearable computer; UDP transmission of neural data.
  • 802.11b via a WAN ethernet card
  • 235g
  • AFE see [1]
  • 100mW radiated power.
  • Latency 680us input to output.
  • Did not notice any problems due to multipath.
  • See also PMID-17945926[2] for similar work

____References____

[0] Obeid I, Nicolelis MA, Wolf PD, A multichannel telemetry system for single unit neural recordings.J Neurosci Methods 133:1-2, 33-8 (2004 Feb 15)
[1] Obeid I, Nicolelis MA, Wolf PD, A low power multichannel analog front end for portable neural signal recordings.J Neurosci Methods 133:1-2, 27-32 (2004 Feb 15)
[2] Parthasarathy J, Hogenson J, Erdman AG, Redish AD, Ziaie B, Battery-operated high-bandwidth multi-channel wireless neural recording system using 802.11b.Conf Proc IEEE Eng Med Biol Soc 1no Issue 5989-92 (2006)

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ref: Maschietto-2009.07 tags: recording ASIC surface recording date: 01-15-2012 22:06 gmt revision:1 [0] [head]

IEEE-5230909 (pdf) A High Resolution Bi-Directional Communication through a Brain-Chip Interface

  • 1000 channels, 10um pitch if thin-film transistors.
  • innovative!
  • EOSFET - electrolyte oxide semiconductor field effect transistor.

____References____

Maschietto, M. and Mahmud, M. and Stefano, G. and Vassanelli, S. Advanced Technologies for Enhanced Quality of Life, 2009. AT-EQUAL '09. 32 -35 (2009)

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ref: Wattanapanitch-2007 tags: recording tech amplifier cascode MOS-bipolar pseudoresistor MIT date: 01-15-2012 18:13 gmt revision:5 [4] [3] [2] [1] [0] [head]

IEEE-4358095 (pdf) An Ultra-Low-Power Neural Recording Amplifier and its use in Adaptively-Biased Multi-Amplifier Arrays.

  • images/729_1.pdf -- copy, just in case.
  • Masters thesis - shows the development of, as the title explains, an ultra low power neural amplifier.
  • Probably the best amplifier out there. NEF 2.67; theoretical limit 2.02.
  • Final design uses folded cascode operational transconductance amplifier (OTA)
    • Design employs a capacitor-feedback gain stage of 40db followed by a lowpass stage.
    • Majority of the current is passed through large subthreshold PMOS input transistors.
      • PMOS has lower noise than NMOS in most processes.
      • Subthreshold has the highest transconductance-to-current ratio. (ratio of a ratio)
    • Cascode transistors self-shunt their own current noise sources.
    • Design takes 0.16 mm^2 in 0.5 um AMI CMOS process, uses 2.7 uA from a ~2.8V supply, input referred noise of 3 uVrms
    • Thesis gives all design parameters for the transistors.
    • Input is AC coupled, DC path through gigaohm MOS-bipolar psudoresistor.
      • this path gracefully decays to diode-connected MOS or bipolar transistors if the voltage is high.
    • images/729_1.pdf
  • Last chapter details the use of envelope detection to adaptively change the bias current of the input stage
    • That is, if an electrode is noisy, the bias current is decreased!

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ref: Hoogerwerf-1994.12 tags: Wise Michigan array MEA recording 3D date: 01-15-2012 07:12 gmt revision:4 [3] [2] [1] [0] [head]

IEEE-335862 (pdf) A three-dimensional microelectrode array for chronic neural recording.

  • see {995} for reasonable photos (they don't show up in the black and white IEEE scan).
  • 16-channel, 4 shanks.
  • 3D : 16 shanks, 64 channels, includes a 16:1 MNOS mux on the attached micromachined silicon platform.
  • Nickel plated lead stransfers (90 deg) see figure 6 electroplating current.
    • This was a point of difficulty, it seems.

____References____

Hoogerwerf, A.C. and Wise, K.D. A three-dimensional microelectrode array for chronic neural recording Biomedical Engineering, IEEE Transactions on 41 12 1136 -1146 (1994)

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ref: BeMent-1986.02 tags: Najafi Michigan probe recording silicon MEA date: 01-15-2012 06:59 gmt revision:6 [5] [4] [3] [2] [1] [0] [head]

PMID-3957372[0] Solid-state electrodes for multichannel multiplexed intracortical neuronal recording.

  • 1986 (!!) - but same basic technology for manufacture of these devices. Modern Michigan probes are much smaller, though - this paper uses 6um feature sizes. It seems like the rate-limiting step for a lot of this is marketization/selling it & getting the money for further R&D.
  • Mention closed-loop neuroprotheses ... 26 years ago. Why do we not have this yet? This is a really important question!
  • 12 channel on-chip analog processing, G=100, bandwidth 100-6kHz.
  • Mention that they think most of the current has to flow around other cells (glia), which makes it possible to record considerably further from the soma (ref [1],); see also PMID-14490040 which through modeling claims much smaller spread of current.
  • Electrode sites are highly capacitive, phase angle 80 deg.
  • 8 um interconnect leads.
  • Enhancement-mode LOCOS NMOS process.

____References____

[0] BeMent SL, Wise KD, Anderson DJ, Najafi K, Drake KL, Solid-state electrodes for multichannel multiplexed intracortical neuronal recording.IEEE Trans Biomed Eng 33:2, 230-41 (1986 Feb)

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ref: Vibert-1979.08 tags: spike sorting recording depth extracellular glass electrodes active feedback original date: 01-15-2012 06:46 gmt revision:3 [2] [1] [0] [head]

PMID-95711[0] Spike separation in multiunit records: A multivariate analysis of spike descriptive parameters

  • Glass coated tungsten microeletrodes have high capacitance; they compensate for this by spraying colloidal silver over the outside sheath of the glass, insulating that with varnish, and driving the shield in a positive-feedback way (stabillized in some way?) This negates the capacitance. 'low impedance capacitance compensated'.
    • Capacitance compensation really matters!!
  • Were able to record from single units for 40-100um range (average: 50um) with SNRs 2:1 to 7:1.
    • Some units had SNRs that could reach 15:1 (!!!), these could be recorded for 600 um of descent.
    • more than 3 units could usually be recognized at each recording point by visual inspection of the oscilloscope, and in some cases up to 6 units could be distinguished
    • Is there some clever RF way of neutralizing the capacitance of everything but the electrode tip? Hmm. Might as well try to minimize it.
  • Bandpass 300 Hz - 10 kHz.
  • When the signal crossed the threshold level, it was retained and assumed to be a spike if the duration of the first component was between 70 and 1000 us.
    • This 70 us lower limit was determined on a preliminary study as a fairly good rise time threshold for separation of fiber spikes from somatic or dendritic spikes.
    • I really need to do some single electrode recordings. Platt?
  • Would it be possible to implement this algorithm in realtime on the DSP?
  • Describe clustering based on PCA.
  • Programming this computer (PDP-12) must have been crazy!
  • They analyzed 20k spikes. Mango gives billions.
  • First principal component (F1) represented 60-65% of total information was based mostly on amplitude
  • Second principal component, 15-20% of total information represented mainly time parameters.
  • Suggested 3 parameters: Vmax, Vmin, and T3 (time from max to min).
  • Maybe they don't know what they are talking about:

____References____

[0] Vibert JF, Costa J, Spike separation in multiunit records: a multivariate analysis of spike descriptive parameters.Electroencephalogr Clin Neurophysiol 47:2, 172-82 (1979 Aug)

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ref: Olsson-2005.12 tags: recording Olsson Wise sorting date: 01-15-2012 06:04 gmt revision:3 [2] [1] [0] [head]

IEEE-1546254 (pdf) A three-dimensional neural recording microsystem with implantable data compression circuitry

  • quite a bit of engineering in this one!
  • 256 site
  • spike detection ASIC which transmits a parameterized version of the threshold crossings.
  • Only consumes 5.4mW total. wow.
  • outgoing bandwidth 2.5 Mb/sec.
  • Only allows spike detection on 32 of these sites
    • The mux is also limited to common groups to minimize consumed space.
  • 5 bit spike detection ADC.
  • 12.6uV RMS noise.
  • Unidirectional link -- sets threshold automatically.
  • 8:1 channel mux changes on both positive and negative clocks, which prevents clock transitions in the middle of the sampling window.
    • Measure crosstalk 6% or less -- really?
  • Vibert [16] evaluated neural spike separation baseed on eight parameters and concluded that using three parameters, Vmax (the maximum positive spike amplitude), Vmin (the minimum negative spike amplitude) and T (the time between Vmax and Vmin) not only adequately sorted spikes but was superior to separation using more parameters. Other parameters were found to be correlated with Vmax, Vmin, and T, whereas Vmax Vmin and T were uncorrelated.

____References____

Olsson, R.H., III and Wise, K.D. A three-dimensional neural recording microsystem with implantable data compression circuitry Solid-State Circuits, IEEE Journal of 40 12 2796 - 2804 (2005)

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ref: Dorman-1985.12 tags: recording ASIC wireless date: 01-15-2012 05:35 gmt revision:2 [1] [0] [head]

IEEE-1052457 (pdf) A monolithic signal processor for a neurophysiological telemetry system

    • 8 channels.
    • 11 mW.
    • 12 cm^3 volume.
    • 900 pF or nitride-dielectric capacitance.
  • FM telemetry. consumes 75% of the system power in high bandwidth mode.
    • 8 cm^3 2.5 AH LiIon.
    • Some very clever stuffs with forward-biased diodes (picoamps, 10^10 ohms) to get the filtering...
    • Abstract: A micropower signal-processor IC is the key component of an implantable telemetry system for neurophysiology. The bipolar/JFET/I/SUP 2/L chip uses digital and low-noise analog circuitry to amplify, filter, and multiplex eight channels of neutral, electrogram, and temperature data from unanesthetized and freely moving animals. Fully integrated continuous-time bandpass amplifiers incorporate a frequency-sensitive feedback network to prevent the amplification of input offset voltage. The system can telemeter data for over 500 h, permitting long-term neurophysiological investigations.

____References____

Dorman, M.G. and Prisbe, M.A. and Meindl, J.D. A monolithic signal processor for a neurophysiological telemetry system Solid-State Circuits, IEEE Journal of 20 6 1185 - 1193 (1985)

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ref: Ji-1992.03 tags: recording ASIC Michigan date: 01-15-2012 05:32 gmt revision:1 [0] [head]

IEEE-121568 (pdf) An implantable CMOS circuit interface for multiplexed microelectrode recording arrays

  • 15 uV RMS input-referred noise (high!), 8 channels, AC gain 300 15Hz - 7kHz, 2.5 mW, 3um feature size.
  • Self-test features.

____References____

Ji, J. and Wise, K.D. ''An implantable CMOS circuit interface for multiplexed microelectrode recording arrays'' Solid-State Circuits, IEEE Journal of 27 3 433 -443 (1992)

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ref: Dagtekin-2001 tags: recording chopper asic date: 01-15-2012 05:32 gmt revision:3 [2] [1] [0] [head]

IEEE-1019051 (pdf) A multi channel chopper modulated neural recording system

  • Presented herein is a fully integrated low-noise CMOS multi-channel amplifier for neural recording applications. The circuit employs the chopper modulation technique to reduce the effect of flicker noise and DC offset. A reduced area design implementation is achieved by trading off the increased noise margin performance of the chopper modulator for minimal amplifier area and analog multiplexing of the recording sites. A fully differential topology is used for the signal path to improve noise immunity. The analog amplifier exhibits 56 dB of gain with a 115 kHz bandwidth and a common mode rejection ratio (CMRR) of 80 dB. Simulation results show a total input referred noise less than 16 nV/√Hz. The system power consumption is approximately 750 μWatts. The fully integrated system was designed in ABN 1.6-μm single poly n-well CMOS process.

____References____

Dagtekin, M. and Wentai Liu and Bashirullah, R. Engineering in Medicine and Biology Society, 2001. Proceedings of the 23rd Annual International Conference of the IEEE 1 757 - 760 vol.1 (2001)

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ref: Guillory-1999.09 tags: recording spike sorting Utah date: 01-15-2012 05:32 gmt revision:2 [1] [0] [head]

PMID-10522821[0] A 100-channel system for real time detection and storage of extracellular spike waveforms.

  • Large, non-wireless, 100 channel recording system.
  • Spike snippet extraction
  • Base 5 multiplexing (??)
  • 1uv input-referred noise.
  • also 88 instructions per sample with their 66Mhz DSP.
  • Windows GUI. all of this much like my work, actually. except not wireless.
  • 1999. hard to remember that a 200 Mhz PC was state of the art back then (!!)

____References____

[0] Guillory KS, Normann RA, A 100-channel system for real time detection and storage of extracellular spike waveforms.J Neurosci Methods 91:1-2, 21-9 (1999 Sep 15)

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ref: Obeid-2003.02 tags: Obeid integrated circuits recording Morizio Nicolelis date: 01-15-2012 04:35 gmt revision:2 [1] [0] [head]

IEEE-1185151 (pdf) Two multichannel integrated circuits for neural recording and signal processing

  • pretty basic, nothing tricky. Actually, they are rather scarce with the details -- Morizio?
  • all 16 capacitors are placed off chip; on chip capacitors are only 950e-18 F/um^2 or 0.001pF/um^2 in the process they use.
  • designs with this circuit topology were rejected for noise concerns, as they would require resistors as large as 10G for to realize gain and filter cutoff.
    • and yet Reid's chips seem to be working fine without external capcitors ...
  • have variable gain (but not AGC).
  • 5uV RMS input noise; 3.5uV for the plexon headstage.

____References____

Obeid, I. and Morizio, J.C. and Moxon, K.A. and Nicolelis, M.A.L. and Wolf, P.D. Two multichannel integrated circuits for neural recording and signal processing Biomedical Engineering, IEEE Transactions on 50 2 255 -258 (2003)

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ref: Mojarradi-2003.03 tags: MEMS recording telemetry Normann Andersen wireless date: 01-15-2012 04:29 gmt revision:2 [1] [0] [head]

PMID-12797724[0] A miniaturized neuroprosthesis suitable for implantation into the brain.

  • Standard tricks: cascode configuration, deep-ohmic PMOS Devices for resistive feedback, wide PMOS weak-inversion input stage for good transconductance and low noise.
  • Varaible power for variable noise levels & bandwidths.
  • Wireless transceiver and power stage are in early concept stages.

____References____

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ref: Song-2009.08 tags: wireless neural recording RF Brown laser optical Donoghue date: 01-15-2012 00:58 gmt revision:6 [5] [4] [3] [2] [1] [0] [head]

IEEE-5067358 (pdf) Wireless, Ultra Low Power, Broadband Neural Recording Microsystem

  • 16 channels.
  • Use a VCSEL (vertical cavity surface emission laser) to transmit data through the skin.
  • Nice design, and they claim to have made recordings for 1 month already.
  • One PCB, kapton substrate reinforced with alumina where needed.
  • Custom 12mW neural amplifier.

____References____

Song, Y.-K. and Borton, D.A. and Park, S. and Patterson, W.R. and Bull, C.W. and Laiwalla, F. and Mislow, J. and Simeral, J.D. and Donoghue, J.P. and Nurmikko, A.V. Active Microelectronic Neurosensor Arrays for Implantable Brain Communication Interfaces Neural Systems and Rehabilitation Engineering, IEEE Transactions on 17 4 339 -345 (2009)

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ref: Santhanam-2007.11 tags: HermesB Shenoy continuous neural recording Utah probe flash wireless date: 01-09-2012 00:00 gmt revision:4 [3] [2] [1] [0] [head]

PMID-18018699[0] HermesB: a continuous neural recording system for freely behaving primates.

  • saved the data to compact flash. could record up to 48 hours continuously.
  • recorded from an acceleromter, too - neuron changes were associated with high head accelerations (unsurprisingly).
  • also recorded LFP, and were able to tell with some accuracy what behavioral state the monkey was in.
  • interfaces to the Utah probe
  • not an incredibly small system, judging from the photos.
  • 1600maH battery, 19 hour life @ 2/3 recording duty cycle -> current draw is 120mA, or 450mW.
    • can only record from two channels at once!
    • amplifier gain 610.
    • used ARM microcontroller ADUC2106

____References____

{779}
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ref: Song-2005.06 tags: recording wireless silicon utah probe Donoghue 2005 date: 01-08-2012 23:24 gmt revision:3 [2] [1] [0] [head]

PMID-16003903[0] Development of a chipscale integrated microelectrode/microelectronic device for brain implantable neuroengineering applications.

-- second from this

  • They have mated a 16-channel silicon microprobe to a low-power (50uW/channel) VLSI chip, including a CMOS amplifier.
    • Epoxy ball-bond.
    • 7mW total power.
  • Suggest photovoltaic power using GaAs/AlGaAs photodiodes. 3 in series yielding 3V at about 20% efficiency. Not bad! Then they can use the fiber to get data out, too.

____References____

[0] Song YK, Patterson WR, Bull CW, Beals J, Hwang N, Deangelis AP, Lay C, McKay JL, Nurmikko AV, Fellows MR, Simeral JD, Donoghue JP, Connors BW, Development of a chipscale integrated microelectrode/microelectronic device for brain implantable neuroengineering applications.IEEE Trans Neural Syst Rehabil Eng 13:2, 220-6 (2005 Jun)

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ref: Bossetti-2004.06 tags: Bossetti wolf Carmena Nicolelis latency wireless BMI recording date: 01-08-2012 21:16 gmt revision:2 [1] [0] [head]

IEEE-1300783 (pdf) Transmission latencies in a telemetry-linked brain-machine interface

  • quote: "examines the relationships between the ratio of output to average input bandwidth of an implanted device and transmission latency and required queue depth".
  • can use to explain why I decided on the fixed-bandwidth method. must measure the latency on my system .. how?
  • firing bursts results in high latencies in a variable-bandwidth queued system.
  • Tested in 32-neuron ensemble.
  • require output bandwidth / input bandwidth to be at least 4 to get sub-10ms max latency.

____References____

Bossetti, C.A. and Carmena, J.M. and Nicolelis, M.A.L. and Wolf, P.D. Transmission latencies in a telemetry-linked brain-machine interface Biomedical Engineering, IEEE Transactions on 51 6 919 -924 (2004.06)

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ref: Kipke-2003.06 tags: Michigan rat Kipke recording electrode MEA date: 01-08-2012 03:34 gmt revision:5 [4] [3] [2] [1] [0] [head]

IEEE-1214707 (pdf) Silicon-substrate intracortical microelectrode arrays for long-term recording of neuronal spike activity in cerebral cortex.

  • 4 of the 6 implants (66%) remaining functional for more than 28 weeks (7 mo)
  • Recording sites separated by 100um; at this site separation, adjacent sites may sometimes record the same unit.
  • It is notable that in each case in this series was terminated due to reasons other than the microelectrode not recording unit activity. (SC LIn agrees, pc).
  • around 80% of sites recorded neural activity.

____References____

{997}
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ref: Najafi-1985.07 tags: Najafi original silicon michigan recording array 1985 MEA date: 01-06-2012 05:27 gmt revision:10 [9] [8] [7] [6] [5] [4] [head]

IEEE-1484848 (pdf) A high-yield IC-compatible multielectrode recording array.

  • Already talks about closed-loop control of a neuroprosthesis.
  • Started testing on-chip NMOS amplifiers.
  • tantalum and polysilicon conductors. some resistivity, but much less than the electrode interface.

____References____

Najafi, K. and Wise, K.D. and Mochizuki, T. A high-yield IC-compatible multichannel recording array Electron Devices, IEEE Transactions on 32 7 1206 - 1211 (1985)

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ref: Olds-1967.01 tags: Olds 1967 limbic system operant conditioning recording rats electrophysiology BMI date: 01-06-2012 03:59 gmt revision:2 [1] [0] [head]

PMID-6077726[0] The limbic system and behavioral reinforcement

  • Can't seem to find Olds 1965, as was a conference proceeding .. this will have to do, despite the lack of figures. images/966_1.pdf
  • First reference I can find of chronic (several weeks) (4-9 microelectrodes, single) recording from the rat.
  • Basically modern methods: commutator + solid state preamplifiers mounted to a counterbalanced slack-relieving arm.
    • If unit responses were observed in recordings from a given probe a week after surgery they were usually recordable indefinitely. 44 years later ...
  • Used a primitive but effective analog spike discriminator based on:
    • minimum amplitude
    • maximum amplitude
    • minimum fall time
    • maximum fall time.
  • Also had a head movement artifact detector, which blanked the recordings (stopped the paper roll) for 2 sec.
  • Reinforced on 'bursting', threshold sufficiently high that it only occurred once every 5-15 minutes.
  • Food reinforcement or 1/4 second train of brain stimulation (30ua, 60Hz, sine, in hypothalamus).
  • Reinforcement was conditioned on an 'acquisition' signal, which is visual (?) Bursting is rewarded for 2 minutes, ignored for 8 minutes.
  • Also recorded control neurons.
  • (they were looking at these things as though anew!) "The most striking aspect of the records so formed [on sheets of paper] was that all discriminators at one time or another exhibited rate changes that had the appearance of waves with a period of 10 to 20 minutes. Waves between units in the same animal were to some degree synchronized." Then describes a ramp ..
  • Longer term variations: FR would vary by a factor of 2-5 over a period of several hours.
    • This would make negatively correlated neurons (on a short time scale) appear positively correlated over long time scales (have to fix this in the BMI!)
  • As this was a conditional reinforcement task, they unexpectedly found that the acquisition periods were systematically different than extinction periods
    • More like pavlovian conditioning, esp in the hippocampus, where a conditioned response was also reflected on a control neuron.
    • Even when the light was lit throughout the acquisition period was replaced by a bell at the beginning of the acq. period, there was still a sustained change in FR.
      • Then during the extinction period: it appeared from the record of responses that a definite operant behavior was tried several times and then stopped altogether."
  • In the pontine nucleus (relay from M1 to cerebellum, v. roughly), judging from the control responses, all were conditioned.
    • Pontine responses seem to correspond with movement of the eyes or head that did not set off the movement detector/blanker.
  • Saw brief and very fast bursts during the extinction periods of the kind that Evarts found to characterize pyramical neurons during sleep.
  • When units shifted from food reward to ICS reward, units became undiffarentiated, and within a day they would be reconditioned.
  • Also tried paralyzing the animal to see if it could still generate operant responses; the animal died, results inconclusive.
  • Flood lights made it hard for the rats to produce the operant behavior.

____References____

[0] Olds J, The limbic system and behavioral reinforcement.Prog Brain Res 27no Issue 144-64 (1967)

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ref: notes-2000.09 tags: BMI recording technology Chapin Nicolelis battery Wolf date: 01-06-2012 03:09 gmt revision:4 [3] [2] [1] [0] [head]

from the book "Neural Prostheses for Restoration of Sensory and Motor Function" edited by John Chapin and Karen Moxon.

Phillip Kennedy's one-channel neurotrophic glass electrode BMI (axons apparently grew into the electrode, and he recorded from them)

Pat Wolf on neural amplification / telemetry technology

battery technology for powering the neural telemetry

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ref: Towe-2007.05 tags: RF recording passive backscatter variactors date: 01-06-2012 02:56 gmt revision:3 [2] [1] [0] [head]

IEEE-4227238 (pdf) Passive Backscatter Biotelemetry for Neural Interfacing

  • ahaha. Someone else had the same idea, about at the same time. And they got it to work!

IEEE-5993487 (pdf) A Fully Passive Wireless Microsystem for Recording of Neuropotentials Using RF Backscattering Methods

  • Still not that sensitive -- about an order of magnitude too coarse.
  • Also, no multiplexing.
  • But: there is room, I think this technology has potential.
  • range only 1.5cm.
  • suggest performance can be improved by increasing the nonlinearity of the variactors.
  • Other papers by the author feature ultrasound-powered microstimulation. He's clearly into alternative approaches.

____References____

Towe, B.C. Neural Engineering, 2007. CNE '07. 3rd International IEEE/EMBS Conference on 144 -147 (2007)

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ref: Porada-2000.01 tags: electrodes recording oblique inverted MEA arrays Kruger date: 01-05-2012 23:07 gmt revision:3 [2] [1] [0] [head]

PMID-10776811[0] More than a year of recording with up to 64 microelectrodes

  • for more than a year action potentials of good quality were obtained from most electrodes!
  • used 60mm-long, 12.5um Ni-Cr-Al (Isaohm) wire, polyimide insulated, soldered to microconnectors. Tips purely ('primitively') cut after bonding them to a piece of photographic film substrate.
  • implanted in the rabbit and marmoset V1 cortex from afar.
  • with the 8 rabbits they used a magnetic release to prevent excessive force from removing the implant.
  • used small sections of thicker wire to individually label the electrodes for x-ray; thusly could reconstruct the electrode positions. electrodes in the white matter were silent mais or menos.
  • the autocorrelation functions of the neurons generally look good; some of them do not have a refractory period though.
  • in GFAP-stained sections a single electrode track appeared as a hole of about 28 um wide. The outer diameter of the wire insulation as 18um. electrode tracts were not visible in cresyl violet tracts. the neurones near the electrode tips appeared normal.
  • we recorded signals for up to 711 days, during which time the recording quality did not degrade. nice, nice!
  • they think that the large length of free wire, running about 5mm through the brain provides a sufficient degree of friction so that locally the tissue is prevented from moving relative to the electrodes. They did not need to use microstimulation to improve recording quality.

____References____

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ref: QingBai and Wise-2001.08 tags: Bai Wise buffered MEA recording electrodes Michigan date: 01-05-2012 04:53 gmt revision:5 [4] [3] [2] [1] [0] [head]

IEEE-936367 (pdf) Single-unit neural recording with active microelectrode arrays

  • Design neural probes with on-chip unity-gain amplifiers. Proven to not degrade recordings (indeed, it should help!)
  • 200ohm output impedance
  • 11uV RMS noise, 100Hz-10kHz.
  • Multiplexer adds 8uV rms noise. noise from clock transitions 2ppm.
  • Also built amplifiers with 40db voltage gain (100x).

____References____

Qing Bai and Wise, K.D. Single-unit neural recording with active microelectrode arrays Biomedical Engineering, IEEE Transactions on 48 8 911 -920 (2001)

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ref: Najafi-1986.12 tags: Najafi implantable wired recording Michigan array multiplexing silicon boron MEA date: 01-05-2012 03:07 gmt revision:8 [7] [6] [5] [4] [3] [2] [head]

IEEE-1052646 (pdf) An implantable multielectrode array with on-chip signal processing

  • "The major reason for the slow progress in the understanding of neural circuits has been the lack of adequate instrumentation."
  • previous photolithographic: [4],[5]. Their first publication: [7].
  • Kensall Wise, not Stephen.
  • Single shank
  • 10 recording sites spaced at 100um
  • Amplifying 100x, b/w 15kHz., multiplexing.
  • width: 15um near tip, 160um at base.
  • 3 leads (!) power, ground, data.
  • 6um LOCOS enhancement and depletion NMOS technology -- not CMOS. (latter is prone to latch-up)
  • 5mW power.
  • boron dope silicon, etch back non doped portion with ethylenediamine-pyrocatechol (EDP) water solution.
  • must not have any substrate bias!

____References____

Najafi, K. and Wise, K.D. An implantable multielectrode array with on-chip signal processing Solid-State Circuits, IEEE Journal of 21 6 1035 - 1044 (1986)

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ref: Nicolelis-2003.09 tags: nicolelis recording electrode monkeys MEA date: 01-04-2012 01:23 gmt revision:3 [2] [1] [0] [head]

PMID-12960378 Chronic, multisite, multielectrode recordings in macaque monkeys.

  • max 412 neurons, snr 5
  • up to 18 months, with precipitous decline
  • Miguel is the first author. well, that only makes sense.

____References____

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ref: Sodagar-2007.06 tags: neural recording telemetry Wise Najafi mulitichannel electrophysiology Michigan ASIC date: 01-03-2012 23:07 gmt revision:4 [3] [2] [1] [0] [head]

PMID-17554826[0] A fully integrated mixed-signal neural processor for implantable multichannel cortical recording.

  • document is rich in details! looks pretty well designed, too.
  • Michigan 3-d electrodes
  • inductively powered, 2Mbps output
  • 64 channels
  • 18b/spike for 64 channels in scan mode, continuous waveforms on 2 channels in monitor mode
  • programmable analog spike detection. resolution: 5 bits.
  • no timestamps - send them out as they come in, with a clock rate fast enough so that this does not matter.
    • temporary storage in SRAM
    • time compression and buffering is somewhat complex (?)
  • only transmit threshold crossings, positive, negative, and both.
    • they do not detail how the signal is telemetered - perhaps this is for another publication.
  • fabricated chip occupies 3.5 x 2.7 mm. 0.5um process.
  • fabricated chip has a power of 200uw @ 1.8V. that's 6.4mW altogether! I need to get down to this figure! (well..)

____References____

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ref: Najafi-1990.05 tags: Najafi Michigan probe silicon strength electrodes recording MEA date: 01-03-2012 22:45 gmt revision:5 [4] [3] [2] [1] [0] [head]

PMID-2345003[0] Strength characterization of silicon microprobes in neurophysiological tissues.

  • These active (with amplification/buffering circuitry) electrodes were around since 1990! It's been a while, and at least the devices are commercially available now.
  • Show that thin-film silicon is remarkably flexible and tough - about six times as strong as bulk silicon.
  • Have developed a silicon probe with an integrated phosphorous-doped polysilicon strain guague - nice.

____References____

[0] Najafi K, Hetke JF, Strength characterization of silicon microprobes in neurophysiological tissues.IEEE Trans Biomed Eng 37:5, 474-81 (1990 May)

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ref: Tian-2010.08 tags: nanowire nanoprobe silicon FET doping cis trans extracellular intracellular recording neuro MEA date: 01-03-2012 16:35 gmt revision:4 [3] [2] [1] [0] [head]

PMID-20705858[0] Three-Dimensional, Flexible Nanoscale Field-Effect Transistors as Localized Bioprobes

  • Made a silicon nanowire with 60 deg. kinks via trans/cis manipulation.
  • Doped one part of the N nanowire P to make a 200nm long FET whose gate is simply the surface of the nanowire (I think, have to check the refs)
  • Attached the nanoprobe / nanowire to flexible PMMA / SM-8 support which, due to interfacial stress, rose off the substrate (clever!)
  • Coated tip with phospholipid layers -> better cell attachment / penetration.
    • Possible to have the cell pull the nanoprobe in via endocytic pathways.
  • Were able to record intracellular and extracellular AP from rabbit cardiocytes. (!!!)

____References____

[0] Tian B, Cohen-Karni T, Qing Q, Duan X, Xie P, Lieber CM, Three-dimensional, flexible nanoscale field-effect transistors as localized bioprobes.Science 329:5993, 830-4 (2010 Aug 13)

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ref: Dabrowski-2003.1 tags: ASIC neural recording poland neuroplat pseudoresistor date: 01-03-2012 15:24 gmt revision:4 [3] [2] [1] [0] [head]

IEEE-1351853 (pdf) Development of integrated circuits for readout of microelectrode arrays to image neuronal activity in live retinal tissue

  • Use miller effect to increas capacitance for HPF.
  • resistors are long channel PMOS 3um / 500um, biased in linear region @ 0V.
    • Transistors must be in linear region: implement gate following of input signal. By varying this gate voltage, can change the filter characteristics.
  • Amplifier looks rather clever.
  • 7uV RMS input-referred noise.

____References____

Dabrowski, W. and Grybos, P. and Hottowy, P. and Skoczen, A. and Swientek, K. and Bezayiff, N. and Grillo, A.A. and Kachiguine, S. and Litke, A.M. and Sher, A. Nuclear Science Symposium Conference Record, 2003 IEEE 2 956 - 960 Vol.2 (2003)

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ref: Delgado-1964 tags: Delgado wireless stimulation record stimoceiver rhesus monkey date: 01-03-2012 07:07 gmt revision:5 [4] [3] [2] [1] [0] [head]

bibtex: delgado-1964 Personality, education, and electrical stimulation of the brain

  • images/977_1.pdf
  • "Is it conceivable that behavior or the psyche can be related to electronics? Before answering these questions, we should ask one more: what is the main difference between primitive tribesmen still living in the jungle and the civilized human beings so well represented by this audience?" Education.
  • Kinda a ramble saying how education and understanding the brain is essential to our future.
  • Against atomic deterrence, unsurprisingly.
    • We are in the precarious race between the acquisition of many megatons of destructive power and the development of intelligent human beings who will make wise use of the forces at our disposal"
  • Radio receiver on a belt.
  • Elicited very complex movements from stimulating the thalamus, including walking from one side of the cage to the other, including avoiding the boss monkey!
    • He calls this 'electrical stimulation of the will'.
  • stimulate nucleus postero-ventralis induces targeted, well-directed attacks against other males of the group.
  • Stimulation of the caudate-septal lobes, just behind the frontal lobes, causes the boss monkey to become tame / tolerant / less aggressive.
  • When this function was enabled by pressing a button in the monkeys cage, the monkey most harrassed learned to press the button to halt the boss's aggressive behavior.
  • Regarding patients: "some of these patients have undergone testing for weeks or months, and lead a nearly normal life wthile 10, 20 or even more fine wires were present, in different cerebral areas and ready for stimulation from outside the scalp."
    • For example, in one patient, who spike a mean of 8.5 words per minute, by means of stimulation to the second temporal column increased his conversation to 44 words per minute." Menwhile, the number of friendly remarks increased by a factor of 9.
  • "Knowledge of the human mind may be decisive for our pursuit of happiness and for the very existence of mankind"

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ref: Pearce-2004.01 tags: neural recording microfluidics in-vitro MEA date: 01-03-2012 06:53 gmt revision:4 [3] [2] [1] [0] [head]

PMID-17271187[0] Dynamic control of extracellular environment in in vitro neural recording systems.

  • they show how to create microfluidic channels on top of in-vitro microfluidic arrays.
  • used dorsal root ganglion cells.
  • key aspect:
    • make a thin cavity/space between two polycarbonate panes.
    • fill the cavity with liquid-phase isobornyl acrylate
    • cover the panes with a high-resolution mask
    • upon exposure to UV light the isobornyl polymerizes.
    • did this on top of a MEA-60
  • looks like they can very accurately deliver pulses and streams of fluid.

____References____

[0] Pearce T, Oakes S, Pope R, Williams J, Dynamic control of extracellular environment in in vitro neural recording systems.Conf Proc IEEE Eng Med Biol Soc 6no Issue 4045-8 (2004)

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ref: Blum-2007.12 tags: stimulation recording Blum integrated circuit ASIC date: 01-03-2012 03:26 gmt revision:8 [7] [6] [5] [4] [3] [2] [head]

IEEE-4358608 (pdf) An Integrated System for Simultaneous, Multichannel Neuronal Stimulation and Recording

  • Use capacitor-feedback amplifier with a seperate feedback amp to provide a DC path.
  • Input amplifier is disabled during stimulation (hopefully without blowing out gate oxide..)
  • Charge stored in the feedback caps acts as a S/H. clever!
  • Due to topology, noise increases with bias current of feedback amp.
  • Stimluation was a measly 9ua.
  • Use a feedback amplifier to actively discharge the electrode after stimulation.
  • Generally a well-though-out, informative paper, with insight as to the design compromises.

Blum RA, Ross JD Brown EA and DeWeerth SP (2007) An Integrated System for Simultaneous, Multichannel Neuronal Stimulation and Recording IEEE Trans. Circuits Syst. I. Regular Pap 54, 2608-2618

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ref: WISE-2004.01 tags: wireless electrodes silicon Michigan Kipke Najafi recording MEA date: 01-03-2012 03:23 gmt revision:12 [11] [10] [9] [8] [7] [6] [head]

IEEE-01258173 (pdf) Wireless implantable microsystems: high-density electronic interfaces to the nervous system - January 2004.

  • very impressive!
  • based on the old / well established beam-lead technology (see the image of the paper at the bottom of that page).
    • required 20 years of development to create an etching process with sufficient yield, though. Microprobes have been in development since 1966.
    • Silicon is slowly attacked by saline; however, the use of a boron etch-stop to define the substrate virtually eliminates such erosion.
    • Silicon dioxide is known to slowly hydrate in water, but this can be mitigated by CVD of silicon nitride / silicon oxide stacks. Polysilicon can be used too, since it forms a tight bond with silicon oxide, keeping water out.
      • Why don't they just seal it with a known impermeable plastic/epoxy/whatever? (They do, later) Utah probe is sealed in parylene.
    • Shunt capacitance is negligible compared to site capacitance; heavy substrate doping minimizes electrical or optically induced noise & virtually eliminates crosstalk.
    • (Of course) Silicon allows amplifiers and circuitry to be formed at/near the electrode, eliminating the need for (some) interconnects.
    • Silicon ribbon connectors cannot be made much longer than a few centimeters. 4um thick silicon cables are 100x more flexible than a 25um gold wire (!!) - but that is out-of-plane; they are relatively weak for in-plane stress.
  • Gold has a maximum charge delivery of 20uC/cm^2 ; platinum, 75 uC/cm^2 ; iridium oxide, 3000 uC/cm^2.
  • Glass can be hermetically bonded to silicon if both flat clean surfaces are put in opposition with a high voltage (1500V) placed across the interface at an elevated temperature (400C). These packages have been shown to be stable and inert in guinea pigs.
    • Silicon nitride, thin metal films, and metal films over polymers are all attractive coatings for probes (with no mention of biocompatibility); they last decades in salt water, and eventually succumb to pinholes.
  • Silicon probes outperform microwire arrays by a factor of (up to) 50 in terms of volume of tissue displaced / recording site. Michigan probes are typically 15um thick x 60um in cross section.
  • they tend to use many more recording sites than recording channels, hence, have a low expected yield. e.g. they have a 1024 site electrode (see the cool figures!), and can record from the best 128 of those. good idea, reasonable strategy, I guess.
    • they demonstrate that it is not too hard to remove the artifact of multiplexing on their systems - the multiplexing noise is below electrode noise.
  • talk about spongifying their iridium electrodes using current pulses in a PBS solution to (apparently) lower electrode impedance.
  • talk about drug delivery too
  • describe the exact manufacturing procedures that the Michigan arrays are created, including the critical back-etch (which i don't exactly understand).
  • describe the circuits used to amplify low-level neural signals.
  • Their charge-redistribution ADC is okay - 250ksps, 9b resolution, 1.4mW from a 3v source. Commercial ADCS are better - AD7467 is 0.6mw, 200ksps, 10bits. (though it scales up to 1.3mW @ 3V, 200ksps ; 0.36mW @1.8V - so the devices are comparable.)
  • some of the (very tiny) electrodes have 'holes' (!)
  • also have wireless microstimulators.
  • demonstrate long-term recording: 383days post implant in a rat & there are still many cells (though the figure is not that great, it is easy to understand) (this might be an exemplar)
  • associated website?
  • (quote:) "For ranges of a few centimeters, the high attenuation of RF signals in biological tissue dictates carrier frequencies below 10Mhz." Their solution is to use FSK with octave jumps in freqency & modulation rates up to 60% that of the carrier frequency.

____References____

WISE, K.D. and ANDERSON, D.J. and HETKE, J.F. and KIPKE, D.R. and NAJAFI, K. Wireless implantable microsystems: high-density electronic interfaces to the nervous system Proceedings of the IEEE 92 1 76 - 97 (2004)

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ref: Csicsvari-2003.08 tags: recording michigan silicon electrodes Buzsaki MEA date: 01-03-2012 03:23 gmt revision:4 [3] [2] [1] [0] [head]

PMID-12904510[0] Csicsvari 2003 Massively parallel recording of unit and local field potentials with silicon-based electrodes

  • What's so massive? 64 or 96 channel Michigan probes.
  • Motivation: recording local connections and interactions requires precise knoledge of the location of your recording sites.
  • Some classic refs on cortical building blocks.
  • Optical recording: Mao et al 2001 PMID-11738033.
  • Wired recording:, Chicurel 2001; Deadwyler and Hampson 1995 PMID-7481817; Evarts 1968; {994}
  • Tetrodes: Drake 1988, Gray 1995, McNaughton et al 1983; Recce and O'Keefe 1989.
  • on-chip active circuitry (simple voltage feedback op-amp - without reference electrodes!) reduces microphone artifact. 6mm 'antenna'.
    • refs: Bai and Wise 2001 {995}; Olsson et al. 2002
    • also Najafi and Wise 1986 {996}; Wise and Najafi 1991 .
  • Stored wideband data; sorted via KlustaKwik.
  • Total recording area 1.6mm deep by 1.8mm wide. Shanks separated by 300um ; recordings sites separated by 100um; shanks 12um thick.
    • Made via double-sided deep reactive reactive ion etching (DRIE).
  • stimulated the entorhinal cortex & recorded in the hippocampus; used the precise spatial layout of the micromachined silicon electrodes to map out the evoked potentials.
  • figure 3 shows that they can record the 'same' neuron from multiple 100um-spaced sites on a given shank. Some of this is due to the physically large extent of the hippocampal cells which they recorded; spike propagate both down the axon and back into the soma, and by using Current Source Density maps, they could estimate some of spatio-temporal characterisics of the AP.
    • CSD is the second spatial derivtive of the local field potentials.
    • Could measure forward and back-propagation of APs to the dendrites (!)
  • quote: in contrast to wire tetrodes with blunt cute ends, it was possible to record from the same cell layer numerous times after moving the probe up and subsequently back to the previous recording location.
    • size of the electrode shanks: 62um wide x 12um thick at top of recording site of 12 site shank; 82um wide at top of 16 site shank.
    • Top 4 recording sites' recording quality deteriorated with multiple penetrations.
  • good place-cell map; cells were discriminated based on a PCA across both time and electrode.

____References____

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ref: Delgado-1968.1 tags: Delgado wireless stimulation recording electrode date: 01-03-2012 03:22 gmt revision:3 [2] [1] [0] [head]

PMID-5683678[0] Intracerebral radio stimulation and recording in completely free patients.

  • images/978_1.pdf
  • See: The cordoba bull ranch experiment (youtube).
  • "This paper reports instrumentation used and clinical application in four patients with psychomotor epilepsy in whom electrodes had been implanted in the temporal lobes. To our knowledge, this is the first clinical use of intracerebral radio stimulation and recording in man. "
  • Electrode: 1.2mm plastic stylus, 15 stainless steel 3mm wide contacts attached at 3mm intervals.
  • Implanted in the anterior medial amygdala.
  • The receiver-stimulator which is carried by the subject, measures 3.7cm x 3.0cm x 1.4cm, and weighs 20g. The solid-state circuitry is encapsulated in epoxy resin which provides it with very good mechanical strength and makes it waterproof. Space for the 7-volt Mercury battery is included in the size mentioned above.
  • 3 channels stim, individual pulse intensity, same pulse duration and repetition for all 3 channels.
    • Operating range 100ft.
    • max current 2uA.
  • 216Mhz IRIG EEG transimtter, FM modulated.
    • The size of the three-channel unit, including the battery, is 4.5cm x 4.5cm x 1.5cm, and it weighs 50g.
    • Input-referred noise: 5uV.
  • Remarkable: one cerebral contact could be shared by recording and stimulating units. (2MOhm input impedance in the EEG amps)
  • Radio stimulation of different points in the amygdala and hippocampus in the four patients produced a variety of effects including pleasant sensations, elation, deep, thoughtful, concentration, odd feelings , super relaxation, colored visions, and other responses.
  • Extensive information has been published about different systems for radio telemetry in biological studies (Barwick & Fullagar, 1967; Caceres, 1965; Geddes, 1962; Slater, 1963). The disparity between the large number of technical papers and the few reports of results indicates the existence of methodological problems.
    • Recall that cardiac pacemakers were by this time in common use.

____References____

[0] Delgado JM, Mark V, Sweet W, Ervin F, Weiss G, Bach-Y-Rita G, Hagiwara R, Intracerebral radio stimulation and recording in completely free patients.J Nerv Ment Dis 147:4, 329-40 (1968 Oct)

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ref: Otto-2006.02 tags: electrophysiology recording rejuvenation stimulation MEA date: 01-03-2012 03:21 gmt revision:3 [2] [1] [0] [head]

PMID-16485763[0] Voltage pulses change neural interface properties and improve unit recordings with chronically implanted microelectrodes.

  • stimulation protocol: 1.5 volts, cortical electrode positive, 4 seconds, DC, current measured.
  • results: 10% mean improvement in SNR (not that great, oh well)
    • however, some effects were really profound: complete rejuvenation of the recordings!
  • result: 67% lower impedance.

____References____

[0] Otto KJ, Johnson MD, Kipke DR, Voltage pulses change neural interface properties and improve unit recordings with chronically implanted microelectrodes.IEEE Trans Biomed Eng 53:2, 333-40 (2006 Feb)

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ref: Kennedy-1989.09 tags: Kennedy neurotrophic electrode recording fabrication 1989 electrophysiology date: 01-03-2012 03:21 gmt revision:2 [1] [0] [head]

PMID-2796391[0] The cone electrode: a long-term electrode that records from neurites grown onto its recording surface.

  • A piece of the sciatic nerve is placed in the glass cone before implantation in the cortex of a rat.
  • A neurite can be an axon or dendrite.

____References____

[0] Kennedy PR, The cone electrode: a long-term electrode that records from neurites grown onto its recording surface.J Neurosci Methods 29:3, 181-93 (1989 Sep)

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ref: Williams-1999.12 tags: recording microwire guinea kipke MEA Michigan date: 01-03-2012 03:18 gmt revision:2 [1] [0] [head]

PMID-10592339[0] Long term neural recording characteristics of wire microelectrode arrays implanted in cerebral cortex

  • details the williams microwire array assembly protocol - basically the same as what gary does here in the nicolelis lab, only written up nicely and for guinea pigs not rhesus macaques.
  • references miguel's book on multielectrode recordings

____References____

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ref: Rolston-2009.01 tags: ICMS artifacts stimulation Rolston Potter recording BMI date: 01-03-2012 02:38 gmt revision:3 [2] [1] [0] [head]

PMID-19668698[0] A low-cost multielectrode system for data acquisition enabling real-time closed-loop processing with rapid recovery from stimulation artifacts

  • Well written, well tested, but fundamentally simple system - only two poles active high-pass, one pole low-pass.
  • With TBSI headstages the stimulation artifact is brief - figure 8 shows < 4ms.
  • Includes NeuroWriter software, generously open-sourced (but alas windows only - C#).

____References____

[0] Rolston JD, Gross RE, Potter SM, A low-cost multielectrode system for data acquisition enabling real-time closed-loop processing with rapid recovery from stimulation artifacts.Front Neuroengineering 2no Issue 12 (2009)

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ref: Darmanjian-2005.03 tags: recording wifi 802.11 DSP BMI Principe date: 01-03-2012 02:13 gmt revision:2 [1] [0] [head]

IEEE-1419566 (pdf) A Portable Wireless DSP System for a Brain Machine Interface

  • 1400Mw (yuck!!), large design, PCMCIA 802.11 card @ 1.8 Mbps, external SRAM for models
  • implemented LMS and as expected it's faster on the Texas Instruments C33 floating-point DSP.

____References____

Darmanjian, S. and Morrison, S. and Dang, B. and Gugel, K. and Principe, J. Neural Engineering, 2005. Conference Proceedings. 2nd International IEEE EMBS Conference on 112 -115 (2005)

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ref: Mohseni-2004.05 tags: recording amplifier biopotential Mohseni Najafi date: 01-03-2012 01:09 gmt revision:2 [1] [0] [head]

PMID-15132510[0] A fully Integrated Neural Recording Amplifier with DC Input Stabilization

  • The DC stabilization is the interesting part - use subthreshold PMOS transistors.
  • NEF not so good on this one - about 10. {729} much better.

____References____

[0] Mohseni P, Najafi K, A fully integrated neural recording amplifier with DC input stabilization.IEEE Trans Biomed Eng 51:5, 832-7 (2004 May)

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ref: Perelman-2007.01 tags: Technion recording silicon date: 01-03-2012 01:07 gmt revision:2 [1] [0] [head]

PMID-17260864[0] An integrated system for multichannel neuronal recording with spike/LFP separation, integrated A/D conversion and threshold detection.

  • Use an RC filter (5MOhm resistor (polysilicon) + 160pf cap (gate oxide)) to split spike and LFP signals.
  • Weak-inversion MOS transistor to vary the high-pass pole. This can be varied over several orders of magnitude with a DAC (and can be varied to compensate for process variation).
  • Have some good debugging notes on their chip - how the weak inversion MOS transistors leaked more current than expected.

____References____

[0] Perelman Y, Ginosar R, An integrated system for multichannel neuronal recording with spike/LFP separation, integrated A/D conversion and threshold detection.IEEE Trans Biomed Eng 54:1, 130-7 (2007 Jan)

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ref: Merletti-2009.02 tags: surface EMG multielectrode recording technology italy date: 01-03-2012 01:07 gmt revision:2 [1] [0] [head]

PMID-19042063[0] Technology and instrumentation for detection and conditioning of the surface electromyographic signal: state of the art

  • good background & review of surface EMG (sEMG) - noise levels, electrodes, electronics. eg. Instrumentation amplifiers with an input resistance < 100MOhm are not recommended, and the lower the input capacitance, the better: the impedance of a 10pf capacitor at 100hz is 160MOhm.
  • Low and balanced input impedances are required to reduce asymmetric filtering of common-mode power-line noise.

____References____

[0] Merletti R, Botter A, Troiano A, Merlo E, Minetto MA, Technology and instrumentation for detection and conditioning of the surface electromyographic signal: state of the art.Clin Biomech (Bristol, Avon) 24:2, 122-34 (2009 Feb)

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ref: Grutzendler-2011.09 tags: two-photon imaging in-vivo neurons recording dendrites spines date: 01-03-2012 01:02 gmt revision:3 [2] [1] [0] [head]

PMID-21880826[0] http://cshprotocols.cshlp.org/content/2011/9/pdb.prot065474.full?rss=1

  • Excellent source of information and references. Go CSH!
  • Possible to image up to 400um deep. PMID-12490949[1]
  • People have used TPLSM imaging for years in mice. PMID-19946265[2]

____References____

[0] Grutzendler J, Yang G, Pan F, Parkhurst CN, Gan WB, Transcranial two-photon imaging of the living mouse brain.Cold Spring Harb Protoc 2011:9, no Pages (2011 Sep 1)
[1] Grutzendler J, Kasthuri N, Gan WB, Long-term dendritic spine stability in the adult cortex.Nature 420:6917, 812-6 (2002 Dec 19-26)
[2] Yang G, Pan F, Gan WB, Stably maintained dendritic spines are associated with lifelong memories.Nature 462:7275, 920-4 (2009 Dec 17)

{894}
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ref: Bonfanti-2010.09 tags: neural recording wireless manchester 2010 Italy date: 01-03-2012 01:02 gmt revision:2 [1] [0] [head]

IEEE-5619710 (pdf) A Multi-Channel Low-Power IC for Neural Spike Recording with Data Compression and Narrowband 400-MHz MC-FSK Wireless Transmission

  • Good 64-channel wireless neurochip with LNA, variable gain and filtering, spike extraction.
  • ~300uW/channel realized.
  • 2.7x3.1mm

____References____

Bonfanti, A. and Ceravolo, M. and Zambra, G. and Gusmeroli, R. and Borghi, T. and Spinelli, A.S. and Lacaita, A.L. ESSCIRC, 2010 Proceedings of the 330 -333 (2010)

{910}
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ref: Lemon-1976.1 tags: Lemon motor recording afferent input date: 01-03-2012 01:01 gmt revision:1 [0] [head]

PMID-11491[0] Afferent input to movement-related precentral neurones in conscious monkeys.

  • Trained monkeys to make both a stereotyped movement and respond passively and calmly to external stimulation.
  • Most cells recorded responded to joint velocity; none to joint position.
  • A smaller subset responded to muscle palpitation
  • Cells were tuned to similar things as their neighbors, though sometimes they responded to markedly different stimuli. Consistent with Wyler.

____References____

[0] Lemon RN, Porter R, Afferent input to movement-related precentral neurones in conscious monkeys.Proc R Soc Lond B Biol Sci 194:1116, 313-39 (1976 Oct 29)

{665}
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ref: Cho-2007.03 tags: SOM self organizing maps Prinicpe neural signal reconstruction recording compression date: 01-03-2012 00:59 gmt revision:2 [1] [0] [head]

PMID-17234384[0] Self-organizing maps with dynamic learning for signal reconstruction.

  • They use a dynamically-learning self-organizing map to compress (encode) continuous neural signals so they can be sent over a wireless link. In this way, you do not have to sort and bin on the device (but this is relatively easy; it seems that their SOM is more computationally expensive than simple thresholding.) Nonetheless, it is an interesting approach.

____References____

[0] Cho J, Paiva AR, Kim SP, Sanchez JC, Príncipe JC, Self-organizing maps with dynamic learning for signal reconstruction.Neural Netw 20:2, 274-84 (2007 Mar)

{937}
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ref: Rizk-2009.04 tags: Rizk neural recording Wolf Nicolelis turner FPGA wireless date: 01-03-2012 00:58 gmt revision:2 [1] [0] [head]

PMID-19255459[0] A fully implantable 96-channel neural data acquisition system.

  • also performs spike detection and extraction within the body.
  • Inductively powered.
  • 960Mhz data band, link up to 2m.
  • First fully implantable system aimed at BMI; however, fully implantable low channel-count have already been deployed.

____References____

[0] Rizk M, Bossetti CA, Jochum TA, Callender SH, Nicolelis MA, Turner DA, Wolf PD, A fully implantable 96-channel neural data acquisition system.J Neural Eng 6:2, 026002 (2009 Apr)

{982}
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ref: Verloop-1984.08 tags: recording electrode arrays MEA epoxy teflon simple mold slice cultures date: 01-03-2012 00:57 gmt revision:2 [1] [0] [head]

PMID-6492861[0] A simple method for the construction of electrode arrays.

  • It is simple!
  • of note: "Therefore arrays of equidistant electrodes have been developed for superficial and depth recording. During the last decade the construction of many of these multiple electrodes for in vivo and in vitro measurements is based o n thin film techniques (Wise a n d Angell, 1975; Pickard, 1979; Pochay et al., 1979; Prohaska et al., 1979; Kuperstein and Whittington, 1981).
    • Have to go back and check these thin-film attempts.
  • See also: PMID-7248818[1] A flexible high density multi-channel electrode array for long-term chronic implantation. (surface recording).

____References____

[0] Verloop AJ, Holsheimer J, A simple method for the construction of electrode arrays.J Neurosci Methods 11:3, 173-8 (1984 Aug)
[1] Weissman AD, Schwartz EL, A flexible high density multi-channel electrode array for long-term chronic implantation.Brain Res Bull 6:6, 543-6 (1981 Jun)

{986}
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ref: Nicolelis-2002.1 tags: Nicolelis MEA electrodes recording date: 01-03-2012 00:57 gmt revision:1 [0] [head]

PMID-12367642[0] Multielectrode recordings: the next steps.

  • Ensemble recordings have actually been around for a long time -- Schmidt, at least.
    • 100s of electrodes, however, have not.
  • Predicted the death of single unit recordings and the emergence of 1000s of channels with indefinite longevity.
  • Also talk about gene arrays & antisense RNA & cre/loxP. Oldish.

____References____

[0] Nicolelis MA, Ribeiro S, Multielectrode recordings: the next steps.Curr Opin Neurobiol 12:5, 602-6 (2002 Oct)

{994}
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ref: Wilson-1993.08 tags: Wilson McNaughton 1993 sleep hippocampus array recording date: 01-03-2012 00:57 gmt revision:2 [1] [0] [head]

PMID-8351520[0] Dynamics of the hippocampal ensemble code for space.

  • 73-148 neurons.
  • Could accurately decode the rat's movement through space.
  • "The parallel recording methods outlined here make possible the study of the dynamics of neuronal interactions during unique behavioral events."

PMID-8036517[1] Reactivation of hippocampal ensemble memories during sleep.

  • "Information acquired during active behavior is thus re-expressed in hippocampal circuits during sleep, as postulated by some theories of memory consolidation."

____References____

[0] Wilson MA, McNaughton BL, Dynamics of the hippocampal ensemble code for space.Science 261:5124, 1055-8 (1993 Aug 20)
[1] Wilson MA, McNaughton BL, Reactivation of hippocampal ensemble memories during sleep.Science 265:5172, 676-9 (1994 Jul 29)

{741}
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ref: Sodagar-2006.31 tags: Najafi michigan probe silicon recording 2006 date: 01-03-2012 00:56 gmt revision:5 [4] [3] [2] [1] [0] [head]

IEEE-4463150 (pdf) A neural signal processor for an implantable multi-channel cortical recording microsystem

  • Full 64 ch NPU (neural processing unit). The 'competition'.
    • Scan mode: all 64 channels are searched for the occurence of neural spikes. Addresses with neural activity are sorted, packed, and sent to the outside world.
      • Each channel can be individually set to +, -, or +- spikes. (no templates).
    • monitor mode: 2 channels of broadband transmission.
  • ref [3] claims 100 channels integrated.
  • inductive bidirectional wireless link.
  • Hierarchical design: 64 channels = 2 32 channel master/slave NPUs, each 4 8-channel modules.
  • External 8-bit A/D converter.
  • One 32-ch NPU in 0.5um AMI N-well CMOS process, 3.5mm x 2.7mm.
  • channel scan rate 64ksample/sec; 64 kspikes/sec, typical 8:1 data compression.
  • 2mbps output rate.
  • see also {393} and {149} - they report the same results, perhaps in more detail.

____References____

Sodagar, A.M. and Wise, K.D. and Najafi, K. Engineering in Medicine and Biology Society, 2006. EMBS '06. 28th Annual International Conference of the IEEE 5900 -5903 (2006)

{1001}
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ref: Gregory-2009.09 tags: wireless recording FM modulation COTS Najafi date: 01-03-2012 00:56 gmt revision:3 [2] [1] [0] [head]

IEEE-5335132 (pdf) Low-cost wireless neural recording system and software

  • COTS design, using the USRP!
    • have a bootable Fedora system with the client s/w. I should do this as well.
  • 15-channel FM transmitter
  • only 6.3g
  • Only 10mW!
  • 24 hour transmission over a range of 3m
  • 25uV in-vivo noise floor.
  • about 2% cross-talk, due to limited b/w.
  • Parts:
    • AD8609 input amplifier (50uA/amp). Only 2 poles high a lowpass (?)
    • ADG706 Mux (low sw power, 1.8V supply)
    • MSP430F20xx uC
    • AD8541 mux buffer into VCO -- 1Mhz b/w, 45ua/amplifier.
    • MAX2608 VCO. No PA required. 6-pin SOT23.
  • Much lighter design than mine. Perhaps not so much filtering is required??

____References____

Gregory, J.A. and Borna, A. and Roy, S. and Xiaoqin Wang and Lewandowski, B. and Schmidt, M. and Najafi, K. Engineering in Medicine and Biology Society, 2009. EMBC 2009. Annual International Conference of the IEEE 3833 -3836 (2009)

{873}
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ref: Szuts-2011.02 tags: wireless neural recording Szuts Meister TDM FM spy camera date: 01-03-2012 00:55 gmt revision:4 [3] [2] [1] [0] [head]

PMID-21240274[0] A wireless multi-channel neural amplifier for freely moving animals.

  • 60 meters!
  • 64 channels!
  • < 4uV RMS input referred noise over 80-2.3Khz BW.
  • Mounted on a backpack. Seems reasonable.
  • Uses a http://www.spystuff.com/ RF transmitter for home video surveillance
    • BW: 8Mhz.
  • presently used with tetrode microdrive.
  • Use a 'neuroplat' AFE, ref [10] {1004}.
    • AC coupling, relatively narrow passband - 80 - 2.3kHz.
    • Channels are oversampled: 20kHz.
  • High power:
    • Neuroplat 165mW,
    • Transmitter 200mW,
    • Headboard circuitry 100mW,
    • Voltage regulators 180mW.
    • Total: 545mW. That does not match with Table 1, which is 345mw. ??
  • RX = http://ve6atv.sbszoo.com/platinum/docs/13cmRxDwg.pdf
    • rather direct TDM decoding scheme (each channel is a pulse; receiver oversamples by 6x & weights these samples; apply HP emphasis filter to individual samples. )
    • probably could get a more efficient RF encoding if they chose not to use the video link, but hey.
  • Some behavioral experiments .. not interesting (?)

____References____

[0] Szuts TA, Fadeyev V, Kachiguine S, Sher A, Grivich MV, Agrochão M, Hottowy P, Dabrowski W, Lubenov EV, Siapas AG, Uchida N, Litke AM, Meister M, A wireless multi-channel neural amplifier for freely moving animals.Nat Neurosci 14:2, 263-9 (2011 Feb)

{1002}
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ref: Fan-2011.01 tags: TBSI wireless recordings system FM modulation multiplexing poland date: 01-03-2012 00:55 gmt revision:5 [4] [3] [2] [1] [0] [head]

PMID-21765934[0] A wireless multi-channel recording system for freely behaving mice and rats.

  • Light enough that rats can use it: 4.5g
  • 15 or 32 channels.
  • Good list of the competiton; they note Szuts et al [31], [1], {1003}, [2], {1004}, {1005}
  • Why are there so many authors?
  • Morizio and Henry Yin last authors.

____References____

[0] Fan D, Rich D, Holtzman T, Ruther P, Dalley JW, Lopez A, Rossi MA, Barter JW, Salas-Meza D, Herwik S, Holzhammer T, Morizio J, Yin HH, A wireless multi-channel recording system for freely behaving mice and rats.PLoS One 6:7, e22033 (2011)
[1] no Title no Source no Volume no Issue no Pages no PubDate
[2] Szuts TA, Fadeyev V, Kachiguine S, Sher A, Grivich MV, Agrochão M, Hottowy P, Dabrowski W, Lubenov EV, Siapas AG, Uchida N, Litke AM, Meister M, A wireless multi-channel neural amplifier for freely moving animals.Nat Neurosci 14:2, 263-9 (2011 Feb)

{1003}
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ref: Ming-2009.09 tags: wireless neural recording Ghovanloo NCSU PWM date: 01-03-2012 00:55 gmt revision:3 [2] [1] [0] [head]

IEEE-5333227 (pdf) In vivo testing of a low noise 32-channel wireless neural recording system

  • 32 channels.
  • Unique feature: analog-to-time PWM; digitization ciruitry is hence on the receiver.
  • Even with this, 4.9 uV rms input-referred noise 1Hz-10kHz. Good!
  • Another ASIC.
  • 5.6mW at +- 1.5V, 3.3 x 3.0 mm^2.
  • 1 bit adjustable gain; total gain 67 or 77dB.
  • analog-to-time PWM just uses rail-to-rail comparators, activated by a circulating register.
    • During each comparison, there is no digital transition anywhere on the chip, reducing substrate noise.
  • this 640kHz TDM signal feeds a VCO -> FSK or OOK modulation.
  • Custom receiver. USB.
  • Need to measure THD & input referred noise on mine.
  • -33dB crosstalk.
  • Ghovanloo seems pretty good at citing himself.

____References____

Ming Yin and Seung Bae Lee and Ghovanloo, M. Engineering in Medicine and Biology Society, 2009. EMBC 2009. Annual International Conference of the IEEE 1608 -1611 (2009)

{1005}
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ref: Miranda-2010.06 tags: Meng Shenoy Hermes wireless neural recording digital COTS date: 01-03-2012 00:55 gmt revision:2 [1] [0] [head]

IEEE-5471737 (pdf) HermesD: A High-Rate Long-Range Wireless Transmission System for Simultaneous Multichannel Neural Recording Applications

  • 32 channels broadband 12 b/sample, FSK modulation of 3.7-4.1 carrier
  • 142mW lasts 33h using two 3.6V/1200maH LiSOCl2 batteries.
  • Circuarly polarized patch antenna + 13dBi circular horn antenna
  • -83dbM with a BER of 10^-9
  • Can easily be scaled up in terms of # of channels and bit rate to accomidate future systems.
  • they think that thresholding / compression / low bit-rate is dumb.
  • Cite Rizk and Obeid, and carefully review other work wrt saying that their present is the best (fair..)
  • [6][7] employ spike sorting -- have to check these.
    • "but the resources are usually too scarce to provide high-quality spike classification on a large number of channels simultaneously, with a reasonably low power-budged (false!)
  • My design is smaller.
  • Use utah array.
  • possible to have 6 receivers simultaneously.
  • 3.7-4.1Ghz good choice for transmission in terms of regulation / availability.
  • Transmission in cages below 1Ghz severly attenuated ; cages relatively transparent to anything above 4Ghz.
  • Used Intans RHA1016.
  • Input-referred noise 3.2uV; lsb value = 1.5uV, and spike amplitudes can be 6.3mV before clipping occurs.
  • CPLD packetizer.
  • FSK built around SMV3895A from Z-communications.
    • No PLL, as this consumes power, and both the room and the animal are temperature-controlled; temp drive 0.44Mhz/C
    • Only works for wideband systems: a 3.2Ghz signal with a b/w of only 10kHz is impractical without frequency stability mechanisms. finding a needle in a haystack..
  • Reciver and antenna use right-hand circular polarization (RHCP), which attenuates multipath.
    • The first and all odd ordered bounce reflections arrive at the reciever have their polarization reversed since their incidence angles are below the pseudo-brewster angle 60-70deg.
  • Receiver complicated to track variations in transmitter freq.
    • Use a transmission line to delay the FM signal @ IF for discrimination. (This is a noncoherent modulation technique).
    • Colpitts oscillator clock recovery. Clock storage time of about 30b!
    • Receiver sensitivity level -83 dBm.
  • set threshold at 3x RMS value of spike traces.
  • [11] Reid Harrison presents an 100 ch integrated amp with a total power consumption of only 3.5mW. {1006}

____References____

Miranda, H. and Gilja, V. and Chestek, C.A. and Shenoy, K.V. and Meng, T.H. HermesD: A High-Rate Long-Range Wireless Transmission System for Simultaneous Multichannel Neural Recording Applications Biomedical Circuits and Systems, IEEE Transactions on 4 3 181 -191 (2010)

{1006}
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ref: Harrison-2009.08 tags: low power ASIC wireless neural recording Reid Harrison Shenoy date: 01-03-2012 00:55 gmt revision:2 [1] [0] [head]

IEEE-5061585 (pdf) Wireless Neural Recording With Single Low-Power Integrated Circuit

  • 100 channels, with threshold spike extraction.
  • 900Mhz FSK transmit coil.
  • Inductive power and data link.

____References____

Harrison, R.R. and Kier, R.J. and Chestek, C.A. and Gilja, V. and Nuyujukian, P. and Ryu, S. and Greger, B. and Solzbacher, F. and Shenoy, K.V. Wireless Neural Recording With Single Low-Power Integrated Circuit Neural Systems and Rehabilitation Engineering, IEEE Transactions on 17 4 322 -329 (2009)

{365}
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ref: Akin-1995.06 tags: Najafi neural recording technology micromachined digital TETS 1995 PNS schematics date: 01-01-2012 20:23 gmt revision:8 [7] [6] [5] [4] [3] [2] [head]

IEEE-717081 (pdf) An Implantable Multichannel Digital neural recording system for a micromachined sieve electrode

  • Later pub: IEEE-654942 (pdf) -- apparently putting on-chip isolated diodes is a difficult task.
  • 90mw of power @ 5V, 4x4mm of area (!!)
  • targeted for regenerated peripheral neurons grown through a micromachined silicon sieve electrode.
    • PNS nerves are deliberately severed and allowed to regrow through the sieve.
  • 8bit low-power current-mode ADC. seems like a clever design to me - though I can't really follow the operation from the description written there.
  • class e transmitter amplifier.
  • 3um BiCMOS process. (you get vertical BJTs and Zener diodes)
  • has excellent schematics. - including the voltage regulator, envelop detector & ADC.
  • most of the power is dissipated in the voltage regulator (!!) - 80mW of 90mW.
  • tiny!
  • rather than using pseudoresistors, they use diode-capacitor input filter which avoids the need for chopping or off-chip hybrid components.
  • can record from any two of 32 input channels. I think the multiplexer is after the preamp - right?

____References____

Akin, T. and Najafi, K. and Bradley, R.M. Solid-State Sensors and Actuators, 1995 and Eurosensors IX.. Transducers '95. The 8th International Conference on 1 51 -54 (1995)

{663}
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ref: Thorbergsson-2008.01 tags: recording nordic wireless neural date: 01-01-2012 19:05 gmt revision:2 [1] [0] [head]

PMID-19162894[0] Implementation of a telemetry system for neurophysiological signals.

  • used the Nordic chip with a 8051 on-board, along with an OPA348 and ADG804 multiplexer.
  • can only record one channel at at time, at only 3.7ksps.

____References____

[0] Thorbergsson PT, Garwicz M, Schouenborg J, Johansson AJ, Implementation of a telemetry system for neurophysiological signals.Conf Proc IEEE Eng Med Biol Soc 2008no Issue 1254-7 (2008)

{314}
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ref: Obeid-2004.02 tags: Wolf BMI recording electronics telemetry Obeid date: 12-31-2011 18:27 gmt revision:4 [3] [2] [1] [0] [head]

PMID-14757341[1] A low power multichannel analog front end for portable neural signal recordings.

  • have an interesting section on CMRR, quote: Although we use a precision differential amplifier with a CMRR of 110 dB, we were unable, in practice, to measure CMRRs greater than not, vert, similar42 dB. This can be accounted for by the device tolerances in the preamplifier stage; using ±0.1% resistors and ±5% capacitors in the preamplifier, the expected worst case CMRR at 1 kHz is 39.2 dB

____References____

{621}
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ref: Ativanichayaphong-2008.05 tags: wireless neural recording stimulation date: 12-28-2011 21:15 gmt revision:3 [2] [1] [0] [head]

PMID-18262282[0] A combined wireless neural stimulating and recording system for study of pain processing

  • used rather simple unidirectional radio links.
  • provide schematics in the document!
  • one channel record; one-channel stim.
  • VHF bands are presntly open (?) -- perhaps use them?
  • 914 MHz transmit neural, 433Mhz RX stimulus commands.

____References____

{834}
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ref: Brown-2008.03 tags: microstimulation recording artifact supression MEA ICMS date: 12-28-2011 20:43 gmt revision:3 [2] [1] [0] [head]

IEEE-4464125 (pdf) Stimulus-Artifact Elimination in a Multi-Electrode System

  • Stimulate and record on the same electrode within 3ms; record on adjacent electrodes within 500us.
  • Target at MEAs, again.
  • Notes that very small charge mismatches of 1% or less, which is common and acceptable in traditional analog circuit designs, generates an artifact that saturates the neural amp signal chain.
  • for stimulating & recording on the same electrode, the the residual charge must be brought down to 1/1e5 the stimulating charge (or less).
  • paper follows upon {833} -- shared author, Blum -- especially in the idea of using active feedback to cancel artifact charge & associated voltage.
  • target the active feedback for keeping all amplifier out of saturation.
  • vary highpass filter poles during artifact supression (!)
  • bias currents of 1fA on the feedback highpass stage. yikes.

Brown EA, Ross JD, Blum RA, Yoonkey N, Wheeler BC, and DeWeerth SP (2008) Stimulus-Artifact Elimination in a Multi-Electrode System. IEEE TRans. Biomed. Circuit Sys. 2. 10-21

{267}
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ref: Kennedy-1992.08 tags: BMI Kennedy cone electrode electrophysiology recording neurotrophic date: 12-17-2011 01:00 gmt revision:1 [0] [head]

PMID-1407726[] The cone electrode: ultrastructural studies following long-term recording in rat and monkey cortex

  • they placed sciatic nerve inside the glass cone electrode to encourage regrowth.
    • alternatively, they filled the cone electrode with 'matrigel' whatever that 'neurotrophic substance' is.
  • good recordings at 6 months post impantation.
  • virtually no neurons were found in the tissue in any cone
    • however, they saw plenty of mylenated axons. (the mylenation assuredly is good for the quality of recordings hah)
    • in no case was the tissue absent from the glass.

____References____

{65}
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ref: Laubach-2003.03 tags: cluster matlab linux neurophysiology recording on-line data_analysis microstimulation nicolelis laubach date: 12-17-2011 00:38 gmt revision:4 [3] [2] [1] [0] [head]

IEEE-1215970 (pdf)

  • 2003
  • M. Laubach
  • Random Forests - what are these?
  • was this ever used??

follow up paper: http://spikelab.jbpierce.org/Publications/LaubachEMBS2003.pdf

  • discriminant pusuit algorithm & local regression basis (again what are these? lead me to find the lazy learning package: http://iridia.ulb.ac.be/~lazy/

____References____

Laubach, M. and Arieh, Y. and Luczak, A. and Oh, J. and Xu, Y. Bioengineering Conference, 2003 IEEE 29th Annual, Proceedings of 17 - 18 (2003.03)

{921}
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ref: Mavoori-2005.1 tags: Fetz ICMS stim wireless recording flash 2005 date: 12-16-2011 04:21 gmt revision:3 [2] [1] [0] [head]

PMID-16102841[0] An autonomous implantable computer for neural recording and stimulation in unrestrained primates.

  • Pretty basic: AFE + bandpass filter, 11.7ksps ADC, uC spike discriminator, microstimulator, IRDA link, 4Mbit flash (why so small? -- 2005).
  • Device could run for weeks at a time.
  • Used in his Hebbian learning task [1]

____References____

[0] Mavoori J, Jackson A, Diorio C, Fetz E, An autonomous implantable computer for neural recording and stimulation in unrestrained primates.J Neurosci Methods 148:1, 71-7 (2005 Oct 15)
[1] Jackson A, Mavoori J, Fetz EE, Long-term motor cortex plasticity induced by an electronic neural implant.Nature 444:7115, 56-60 (2006 Nov 2)

{839}
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ref: work-0 tags: headstage recording wireless interference stage5 intan date: 08-13-2010 01:16 gmt revision:5 [4] [3] [2] [1] [0] [head]

(I'm posting this here as it's easier than putting a image & text in subversion)

I'm building a wireless headstage for neural recording. Hence, it has sensitive, high-gain amplifiers (RHA2116) pretty close to a wireless transmitter + serial lines. The transmitter operates intermittently to save power, only sending samples from one continuous channel + threshold crossings for all the other channels. 27 byte-wide samples + channel identifier + 4 bytes threshold crossing are sent in one radio packet; as the radio takes some 130us to start up the PLL, 8 of these packets are chunked together into one frame; one frame is transmitted every 144hz (actually, 1e6/(32*27*8)Hz. At the conclusion of each frame, the continuous channel to be transmitted is incremented.

It seems that radio transmission is interfering with the input amplfifiers, as the beginning samples from a frame are corrupted - this is when the previous frame is going out over the air. It could also be noise from the SPI lines, which run under and close to the amplifiers. This may also not be a problem in vivo - it could only be an issue when the input to the amplifiers are floating.

Above, a plot of the raw data coming off the headstage radio. Red trace indicates the channel currently being transmitted; blue are the samples. Note that some chanels do not have the artifact - I presume this is because their input is grounded.

This will be very tricky to debug, as if we turn off the radio, we'll get no data. Checking if it is a SPI problem is possible by writing the bus at a specified time.


Tested with radio PA disabled, it is definitely the SPI bus - routing problem! Stupid.

{805}
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ref: notes-0 tags: ice hydrophones glissando recording sound date: 01-19-2010 16:41 gmt revision:0 [head]

http://silentlistening.wordpress.com/2008/05/09/dispersion-of-sound-waves-in-ice-sheets/ -- amazing!

{783}
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ref: Chae-2009.08 tags: wireless neural recording UWB Chinese ultra-wideband RF date: 10-12-2009 21:07 gmt revision:2 [1] [0] [head]

PMID-19435684[0] A 128-channel 6 mW wireless neural recording IC with spike feature extraction and UWB transmitter.

  • The title basically says it all.
  • Great details - all of the sub-circuits needed.
  • Really impressive work!

____References____

[0] Chae MS, Yang Z, Yuce MR, Hoang L, Liu W, A 128-channel 6 mW wireless neural recording IC with spike feature extraction and UWB transmitter.IEEE Trans Neural Syst Rehabil Eng 17:4, 312-21 (2009 Aug)

{742}
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ref: Rizk-2007.09 tags: Rizk Obeid wolf Duke 96-channel headstage wireless recording date: 05-04-2009 21:16 gmt revision:1 [0] [head]

PMID-17873433[0] A single-chip signal processing and telemetry engine for an implantable 96-channel neural data acquisition system.

  • This document provides many of the details interior to the FPGA for spike detection / data thresholding / channel bandwidth management.
  • Their FPGA uses 100mw of power (20mw static, 10mw / 16 channel processor, 10mw telemetry processing). 6000 lines of code -- uses almost the entire processing capacity of the device.
    • 49% of the FPGA's 10240 flip-flops, 93% of the 10240 4-input LUT, and 100% of the 40x 18-kilobit RAM blocks.
  • At 65 spikes per second per channel, generally every 4th packet indicated dropped spikes. That's not good...
  • They transmit 48 bytes / waveform (1 byte channel, 2byte timestamp, 45 byte waveform). w/ 1Mpbs transceiver. Me: 32 bytes with a 2Mbps transceiver.
  • All things being equal, the power transmitted by a transceiver must increase linearly with the data rate in order to transmit the data the same distance with the same bit error rate. (Wang A Y and Sodini C G 2006 On the energy efficiency of wireless transceivers. ICC 06: IEEE Int. Conf on Communication. 2006 Vol. 8)
    • An 802.11 transmitter would use about the same energy per bit at a maximum rate of 54Mbps - if a small chip can be found which performs this, it may be practical. Their TXRX uses 35mW.

____References____

[0] Rizk M, Obeid I, Callender SH, Wolf PD, A single-chip signal processing and telemetry engine for an implantable 96-channel neural data acquisition system.J Neural Eng 4:3, 309-21 (2007 Sep)

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ref: Darmanjian-2006.01 tags: wireless neural recording university Florida Principe telemetry msp430 dsp nordic date: 04-15-2009 20:56 gmt revision:1 [0] [head]

PMID-17946962[0] A reconfigurable neural signal processor (NSP) for brain machine interfaces.

  • use a Texas instruments TMS320VC33 200MFLOPS (yes floating point) DSP,
  • a nordic NRF24L01,
  • a MSP430F1611x as a co-processor / wireless protocol manager / bootloader,
  • an Altera EPM3128ATC100 CPLD for expansion / connection.
  • uses 450 - 600mW in use (running an LMS algorithm).

____References____

[0] Darmanjian S, Cieslewski G, Morrison S, Dang B, Gugel K, Principe J, A reconfigurable neural signal processor (NSP) for brain machine interfaces.Conf Proc IEEE Eng Med Biol Soc 1no Issue 2502-5 (2006)

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ref: Linderman-2006.01 tags: neural recording technology compact flash stanford Shenoy 2006 date: 04-15-2009 20:55 gmt revision:3 [2] [1] [0] [head]

PMID-17946450[0] An Autonomous, broadband, multi-channel neural recording system for freely behaving primates

  • goal: recording system for freely-behaving animals.
    • problems: battery life, size
    • cannot sample broadband.
    • non autonomous.
  • solution:
    • compact flash, ARM core
    • accelerometer?
    • mounted inside the monkey's skull in the dental cement.
  • specs

____References____

[0] Linderman MD, Gilja V, Santhanam G, Afshar A, Ryu S, Meng TH, Shenoy KV, An autonomous, broadband, multi-channel neural recording system for freely behaving primates.Conf Proc IEEE Eng Med Biol Soc 1no Issue 1212-5 (2006)

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ref: notes-0 tags: wireless nordic headstage bridge neurorecord pictures photo EMG myopen date: 03-12-2009 02:33 gmt revision:4 [3] [2] [1] [0] [head]

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ref: -0 tags: myopen EMG recordings NLMS noise date: 07-29-2008 18:32 gmt revision:2 [1] [0] [head]

Myopen amplifiers & analog/digital filters & NLMS are working properly! Below, a recording from my deltiod as I held my arm up: (only one EMG channel active, ground was my knee))

Yellow traces are raw inputs from ADC, blue are the output from the IIR / adaptive filters; hence, you only see 8 of the 16 channels. Read from bottom to top (need a -1 in some opengl matrix somewhere...) Below, the system with no input except for free wires attached to one channel (and picking up ambient noise). For this channel, NLMS could not remove the square wave - too many harmonics - but for all other channels the algorthim properly removes 60hz interference :)

Now, let me clean this EEG paste off my shoulder & leg ;)

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ref: bookmark-0 tags: neural recording companies electrodes wireless bioamplifier germany date: 10-22-2007 01:39 gmt revision:2 [1] [0] [head]

http://www.neuroconnex.com/ -- looks like they have some excellent products, but not sure how to purchase them.

  • links to specification sheets are broken.
  • they have a closed-loop stimulator for treatment of Parkinsons etc. cool!
also see Mega biomonitor. (14 bit resolution)

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ref: notes-0 tags: recording tech tbsi biosignal telemetry date: 05-20-2007 16:40 gmt revision:1 [0] [head]

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ref: Vyssotski-2006.02 tags: neurologger neural_recording recording_technology EEG SUA LFP electrical engineering date: 02-05-2007 06:21 gmt revision:6 [5] [4] [3] [2] [1] [0] [head]

PMID-16236777[0] Miniature neurologgers for flying pigeons: multichannel EEG and action and field potentials in combination with GPS recording.

Recording neuronal activity of animals moving through their natural habitat is difficult to achieve by means of conventional radiotelemetry. This illustration shows a new approach, exemplified by a homing pigeon carrying both a small GPS path recorder and a miniaturized action and field potential logger (“neurologger”), the entire assembly weighing maximally 35 g, a load carried easily by a pigeon over a distance of up to 50 km. Before release at a distant location, the devices are activated and store both positional and neuronal activity data during the entire flight. On return to the loft, all data are downloaded and can be analyzed using software for path analysis and electrical brain activity. Thus single unit activity or EEG patterns can be matched to the flight path superimposed on topographical maps. Such neurologgers may also be useful for a variety of studies using unrestrained laboratory animals in different environments or test apparatuses. The prototype on the hand-held pigeon records and stores EEG simultaneously from eight channels up to 47 h, or single unit activity from two channels during 9 h, but the number of channels can be increased without much gain in weight by sandwiching several of these devices. Further miniaturization can be expected. For details, see Vyssotski AL, Serkov AN, Itskov PM, Dell Omo G, Latanov AV, Wolfer DP, and Lipp H-P. Miniature neurologgers for flying pigeons: multichannel EEG and action and field potentials in combination with GPS recording. [1]

____References____

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ref: bookmark-0 tags: eeg oss openeeg recording linux date: 0-0-2007 0:0 revision:0 [head]

http://openeeg.sourceforge.net/

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ref: bookmark-0 tags: neural_recording recording_technology electrical engineering DSP date: 0-0-2006 0:0 revision:0 [head]

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ref: bookmark-0 tags: linux command line tips rip record date: 0-0-2006 0:0 revision:0 [head]

http://www.pixelbeat.org/cmdline.html