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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] Hochberg LR, Serruya MD, Friehs GM, Mukand JA, Saleh M, Caplan AH, Branner A, Chen D, Penn RD, Donoghue JP, Neuronal ensemble control of prosthetic devices by a human with tetraplegia.Nature 442:7099, 164-71 (2006 Jul 13)

[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] 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] Serruya MD, Hatsopoulos NG, Paninski L, Fellows MR, Donoghue JP, Instant neural control of a movement signal.Nature 416:6877, 141-2 (2002 Mar 14)

{1163}
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ref: Schmidt-1993.11 tags: Normann utah array histology silicon electrode array cats date: 02-23-2017 22:03 gmt revision:4 [3] [2] [1] [0] [head]

PMID-8263001[0] Biocompatibility of silicon-based electrode arrays implanted in feline cortical tissue.

  • Tried two different times:
    • one day before euthanasia
    • 6 month implant.
  • Tried three different implants:
    • Uncoated silicon,
    • polymide coating
    • polymide coating with SiO2 adhesion layer / primer.
  • The last was the worst in terms of histopathological response.
  • Chronic implants showed relatively restrained immune response,
    • Gliosis was found around all tracks, 20-40um.
  • Encapsulation was less than 9um.
  • Edema and hemorrhage was minor but present on a subset of all implants.
  • Acute (24h) hemorrhage was more severe -- ~ 60%; edema ~ 20%.
  • Chronic histology revealed considerable macrophages w/ hemosiderin (a complex including ferritin)
  • See also [1]

____References____

[0] Schmidt S, Horch K, Normann R, Biocompatibility of silicon-based electrode arrays implanted in feline cortical tissue.J Biomed Mater Res 27:11, 1393-9 (1993 Nov)
[1] Jones KE, Campbell PK, Normann RA, A glass/silicon composite intracortical electrode array.Ann Biomed Eng 20:4, 423-37 (1992)

{1328}
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ref: -0 tags: alumina utah array electrode parylene encapsulation date: 10-23-2015 21:28 gmt revision:1 [0] [head]

Utah/blackrock group has been working on improving the longevity of their parlyene encapsulation with the addition of ~50nm Al2O3.

  • PMID-24771981 '''Self-aligned tip deinsulation of atomic layer deposited Al2O3 and parylene C coated Utah electrode array based neural interfaces
    • Process:
      • Normal Utah array dicing saw / glass frit / thinning and etch fabrication for the Utah probe.
      • Sputtered Ti, Sputtered Pt. (not sure how they mask this?)
      • Sputtered iridium oxide (SIROF, sputtered in an Ar + O2 plasma) electrode tips (again, not sure about the mask..)
      • ALD Al2O3 passivation, 50nm. Cambridge Fiji system, same as nanolab. Must take a long time!
      • A-174, aka 3-Methacryloxypropyltrimethoxysilane adhesion promoter (which presumably acts by pulling hydroxy groups off the alumina substrate; Al-O bonds have higher energy than Si-O)
      • 6um parylene.
      • Laser ablation of tips with 1000 pulses from KrF 5ns 100Hz excimer laser. Works much better than poking the electrode tips through thin aluminum foil.
      • O2 plasma descum / removal of carbon residues.
      • BOE removal of Al2O3 above the SIROF
    • Of note, ALD Al2O3 has included hydroxy bonds, which means that it gradually etches in PBS. (Pure Al2O3, as passivates aluminum parts exposed to seawater, does not?)
    • PBS also etches Si3N4, and crystaline Si.
  • IEEE-6627006 (pdf) Bi-layer encapsulation of utah array based neural interfaces by atomic layer deposited Al2O3 and parylene C
    • Atomic layer deposited (ALD) alumina is an excellent moisture barrier with WVTR at the order of ~ 10e-10 g·mm/m2·day [10-13]. But alumina alone is not suitable for encapsulation since it dissolves in water [14].
    • Demonstrated stable power-up of RF encapsulated devices for up to 600 equivalent days in 37C PBS.
      • Actual testing carried out at 57C, 4x accelerated.
  • PMID-24658358 Long-term reliability of Al2O3 and Parylene C bilayer encapsulated Utah electrode array based neural interfaces for chronic implantation.
    • Demonstrated good barrier longevity with wired Utah probes, active probes with flip-chip (Au/Sn eutectic reflow) record/stimulate circuits, and ones with bonded RF stimulation chips, INIR-6. (6th version!)
    • PBS etching of Si lead to undercutting & eventual flake-off of the SIROF, leading to dramatic impedance increase. (Figure 5 and 7).
      • no Pt under the SIROF?

{1302}
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ref: -0 tags: kevlar electrodes flexible polymer 12um McNaughton Utah date: 10-11-2014 00:19 gmt revision:0 [head]

PMID-8982987 Metallized polymer fibers as leadwires and intrafascicular microelectrodes

  • McNaughton TG1, Horch KW.
  • Ti/W, Au, Pt metalization via sputtering.
  • 12um core diamater.
  • demonstrate 8 month reliability.
  • 1um dipped silicone elastomer insulation.
  • note difficulty in manufactuing the fibers. No kidding!
  • Tensile strength the same as a 25um Pt-Ir wire, 90x more flexible.

{1292}
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ref: -0 tags: intracortical utah array fabrication MEMS Normann date: 08-14-2014 01:35 gmt revision:5 [4] [3] [2] [1] [0] [head]

PMID-1937509 A silicon-based, three-dimensional neural interface: manufacturing processes for an intracortical electrode array.

  • Campbell PK1, Jones KE, Huber RJ, Horch KW, Normann RA. (1991)
  • One of (but not the) first papers describing their methods / idea (I think).
  • First conf paper: {1294} (1988)
  • later adopted glass frit insulator --

{1294}
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ref: -0 tags: utah array development date: 08-14-2014 01:34 gmt revision:1 [0] [head]

IEEE-94953 (pdf) Silicon based microstructures suitable for intracortical electrical stimulation (visual prosthesis application)

  • Normann, R.A. ; Dept. of Bioeng., Utah Univ., Salt Lake City, UT, USA ; Campbell, P.K. ; Li, W.P.
  • 1988
  • not quite yet there...

{1293}
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ref: -0 tags: utah array development failure mode donoghue date: 08-14-2014 01:30 gmt revision:0 [head]

PMID-24216311 Failure mode analysis of silicon-based intracortical microelectrode arrays in non-human primates

  • Barrese JC, Rao N, Paroo K, Triebwasser C, Vargas-Irwin C, Franquemont L, Donoghue JP. (2013)
  • Most failures (56%) occurred within a year of implantation, with acute mechanical failures the most common class (48%), largely because of connector issues (83%).
  • Among grossly observable biological failures (24%), a progressive meningeal reaction that separated the array from the parenchyma was most prevalent (14.5%).

{1212}
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ref: Nordhausen-1994.02 tags: Utah array electrodes optimization date: 08-14-2014 01:24 gmt revision:2 [1] [0] [head]

PMID-8180807[0] Optimizing recording capabilities of the Utah Intracortical Electrode Array.

  • Nordhausen, Rousch, Normann (1993)
  • Originally it was designed for stimulation in a visual prosthesis.
  • Thought that the large surface area would securely anchor it to the cortex
    • Turns out you need to put gore-tex on top to keep it from being expelled.
  • Varied the exposed electrode tip to determine the optimum area.
  • Oldschool computer plots ...

____References____

[0] Nordhausen CT, Rousche PJ, Normann RA, Optimizing recording capabilities of the Utah Intracortical Electrode Array.Brain Res 637:1-2, 27-36 (1994 Feb 21)

{1247}
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ref: -0 tags: Utah parylene cracking encapsulation electrode date: 06-28-2013 18:26 gmt revision:4 [3] [2] [1] [0] [head]

Characterization of parylene-C film as an encapsulation material for neural interface devices

  • Hsu, Jui-Meia; Kammer, Saschab; Jung, Erikc; Rieth, Lorend; Normann,A. Richarde; Solzbacher, Florianade (Utah)
  • lists Tg 35-80C for parylene-C;
  • 3um films applied.
  • Parylene samples were subjected to accelerated lifetime testing (85 % relative humidity (RH) and 85 ̊C) for 20 days, and the film did not show appearance changes as observed by optical microscopy. However, X-ray diffractograms show that the film crystallinity increased during this test.
  • 120C 100%RH for 2 hours released parylene from the silicon.
  • Soldering @ 350C backside of Utah array caused parylene to crack.
  • X-ray diffraction shows that heat causes parylene to crystalize:

___Low Dielectric Constant Materials for Ic Applications___ edited by Paul Shin Ho, Jihperng Leu, Wei William Lee

  • Aging and annealing increase crystalinity and thus lower the elongation to break and increase the modulus and mechanical strength of the films.
  • parylene-N is considerably more crystaline (57%), Tg 13C. (low!)
  • Bulk barrier properties are among the best of the organic polymeric coatings.

{597}
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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____

{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)

{1027}
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ref: Suner-2005.12 tags: MEA Utah reliability longevity SNR date: 01-25-2013 02:03 gmt revision:7 [6] [5] [4] [3] [2] [1] [head]

PMID-16425835[0] Reliability of signals from a chronically implanted, silicon-based electrode array

  • see {597}
  • Percutaneous connector used pressure-fitted pogo pins, as Gary was thinking of.
  • Utah array coated in parylene for this exp.
    • After implantation, array and cortex was covered in gore-tex (to prevent dura adhesion) -- they do not highlight this fact.
  • polyester insulated 25um gold wires as leads.
  • Reasonable SNR over 82, 172, 154 days.
  • One monkey had an array to 569 days -- 76 electrodes still provided good or fair waveforms.
  • ancilary (?) measure of tuning of the neurons. most neurons were not tuned.
  • SNR calculated as peak-peak of waveform divided by 2x standard deviation of signal.
  • A total of 36 implants in 16 other monkeys, which were not systematically evaluated for reliability here, provided successful recordings for up to 1264 days. Most of these studies ended because of headcap failure.
    • They no longer use dental acrylic -- only titanium bone screws.
  • 50-800K impedance
  • Improvement of the signal quality and increased yield, for which there was no clear trend in the three animals, may result from recovery produced by variations in the initial insertion injury.
  • The cortical capillary bed is densely packed, with spacing on the order of 40um in primate cortical tissue [27] ( vasculature ) -- they suppose that variance may be due to this.

____References____

[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)

{270}
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ref: Hochberg-2006.07 tags: BMI Donoghue Utah probe Nature tetraplegia Hochberg 2006 date: 01-23-2013 18:49 gmt revision:4 [3] [2] [1] [0] [head]

PMID-16838014[] Neuronal ensemble control of prosthetic devices by a human with tetraplegia

  • patient was able to talk?
  • 96-channel microelectrode array implanted in arm/hand knob or right precentral gyrus.
  • around 30 units / day observed.
  • 90% of units showed significantly varied firing rates (K-S test) during imagined movements.
  • 2D control. Good pursuit tracking and center-out performance.
  • Used Wiener filter.
  • also see the technology review

____References____

{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____

{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)

{1048}
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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)

{1044}
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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)

{598}
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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)

{1023}
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ref: Jones-1992.01 tags: Utah MEA original date: 01-05-2012 22:08 gmt revision:2 [1] [0] [head]

PMID-1510294[0] A Glass/silicon Composite Intracortical Electrode Array.

  • Describe fabrication of the Utah probe.
  • Needles 1.5mm long, 80um in diameter at the base, tapered.
  • 10 x 10 array on 400um spacing.
  • Impedance 10T ohm, capacitance 50fF
  • Old array used diamond dicing saw.
    • electrodes were isolated via p-n-p junctions, formed via thermomigration.
    • Too clever! These electrodes leaked & had poor yield.
  • New method: melt glass into shallow saw kerfs on the backside of a p-doped 1.83mm thick wafer, then remove much of the silicon from the top using the same saw. This produces columns of silicon held together at the base by glass.
    • Diamond dicing saw has a kerf of 50um. These things sound awesome.
    • Photopatterned aluminum electrode lands on the back.
    • Points are made by an acid etch.
    • Then plated in metal of some sort
    • Followed by polymide insulation (3-6um thick) (rather round from the SEM).
    • DC resistance of 10 to 20k.

____References____

[0] Jones KE, Campbell PK, Normann RA, A glass/silicon composite intracortical electrode array.Ann Biomed Eng 20:4, 423-37 (1992)

{1031}
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ref: Kelly-2007.01 tags: MEA single electrode comparison CMU Utah date: 01-05-2012 22:07 gmt revision:1 [0] [head]

PMID-17215384[0] Comparison of recordings from microelectrode arrays and single electrodes in the visual cortex.

  • We found that the array yields good recordings on a large number of electrodes, with qualities comparable to those from single electrode recordings. On average, the recording quality is somewhat lower than that of single electrodes, but nonetheless is sufficient for assessing tuning properties such as the spatiotemporal receptive field and orientation tuning.

____References____

[0] Kelly RC, Smith MA, Samonds JM, Kohn A, Bonds AB, Movshon JA, Lee TS, Comparison of recordings from microelectrode arrays and single electrodes in the visual cortex.J Neurosci 27:2, 261-4 (2007 Jan 10)

{1032}
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ref: Dickey-2009.08 tags: Utah probe MEA stability date: 01-05-2012 22:07 gmt revision:1 [0] [head]

PMID-19535480[0] Single-unit stability using chronically implanted multielectrode arrays.

  • We found that 57% of the original units were stable through 7 days, 43% were stable through 10 days, and 39% were stable through 15 days.
  • Still not that good. Actual neurons / synapses last .. well, the lifetime of an individual.

____References____

[0] Dickey AS, Suminski A, Amit Y, Hatsopoulos NG, Single-unit stability using chronically implanted multielectrode arrays.J Neurophysiol 102:2, 1331-9 (2009 Aug)

{293}
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ref: Serruya-2002.03 tags: BMI Donoghue 2002 Hatsopoulos Utah array Serruya date: 09-07-2008 19:08 gmt revision:1 [0] [head]

PMID-11894084[0] Instant neural control of a movement signal.

  • used only a few (7-30) motor cortex neurons
  • this let the monkey immediately manipulate a computer cursor, without extensive training (according to them).

____References____