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[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] 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)

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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.


[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: meng poon wireless power transfer date: 03-07-2012 22:23 gmt revision:0 [head]

IEEE-4353634 (pdf) Optimal Operating Frequency in Wireless Power Transmission for Implantable Devices

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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.


[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)

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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.


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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


[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: 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.


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: 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.


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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.


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


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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.


[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.


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: 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: 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.


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: 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.


[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: 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


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)

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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.


[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)

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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??


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)

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ref: YaoHong-2009.1 tags: wireless transmitter modulator QPSK date: 01-03-2012 00:56 gmt revision:2 [1] [0] [head]

IEEE-5256305 (pdf) A 200-pJ/b MUX-Based RF Transmitter for Implantable Multichannel Neural Recording

  • 400Mhz band
  • 17Mbps
  • 0.18um CMOS process, 1.2-1.8V, 2.9mA, -8dbM output power.
  • 0.2 nJ/bit
  • 1.2mm^2
  • no receiver, though a COTS one could probably be purchased.
  • O-QPSK (offset quadrature phase shift keying)
  • VCO operates at 2x the output frequency.
  • No IF.
  • PSK > FSK.
  • Measured error vector magnitude (EVM), which is approx 8% over the data rate.
    • This due to phase noise in the LO & phase mismatch.
    • Typical O-QPSK requires 23% EVM for a BER of 10^-4
  • Almost as good as UWB.


Yao-Hong Liu and Cheng-Lung Li and Tsung-Hsien Lin A 200-pJ/b MUX-Based RF Transmitter for Implantable Multichannel Neural Recording Microwave Theory and Techniques, IEEE Transactions on 57 10 2533 -2541 (2009)

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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.


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)

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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 (?)


[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)

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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}


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)

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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.


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)

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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.


[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)

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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.


[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)

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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.


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ref: Arfin-2009.07 tags: ICMS birdsong wireless stimulation ARfin 2009 MIT date: 12-16-2011 04:21 gmt revision:1 [0] [head]

PMID-19386759[0] Wireless neural stimulation in freely behaving small animals.

  • Made a custom ASIC for delivering bipolar, biphasic current pulses.
  • 32 output channels.
  • Powered by small batteries
  • device in sleep state when not in use
  • controlled by inductive radio transfer with PWM modulation scheme.
  • Tested in Zebra finches, HVC: terminates song in all birds tested.
  • Impressive bit of engineering!


[0] Arfin SK, Long MA, Fee MS, Sarpeshkar R, Wireless neural stimulation in freely behaving small animals.J Neurophysiol 102:1, 598-605 (2009 Jul)

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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]


[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)

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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.

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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!


[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)

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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.


[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).


[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: 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: notes-0 tags: wireless spectrum FCC regulation nytimes date: 10-13-2008 22:52 gmt revision:0 [head]

My comments on this blog post, preseved here for posterity:

I agree with William’s first point, spectrum is ‘owned’ by everybody; the government’s only purpose is to regulate it so that it remains an effective communication medium. Like the bandwidth that it uses, the communication system is optimally owned by users, hence it is a bad idea to auction off segments of spectrum for exclusive use by corporations.

Examine at what happened to the 2.4 GHz band, an area where water absorption is high and most households have a 1kw noise generator (microwave oven): EVERYONE USES IT because it is FREE and OPEN, no licenses required. Just look at all the innovation created for this band: 802.11, bluetooth, ZigBee, cordless phones, wireless remotes, and others. If 802.11 was in the 700-1GHz band someone or a company could easily make long-distance wireless repeaters & mesh-network nodes, sell them to consumers, and everyone could SIP for FREE without paying Verizon / ATT etc. This could set it up as a pyramid scheme, where to get on the network you simply have to buy a mesh node repeater, and with it became part of the ‘corporation’ which provided your wireless services. A certain part of the purcase & access price would, of course, need to go to pay for backbone connections, service, matenance and extending connection to remote areas, but this too can be solved and managed efficiently with something like 1 phone = 1 share.

With coprotations, you either have redundancy (two networks w/ twice as many cell towers) or a monopoly; neither are economically efficient. A re-allocation of prime wireless spectrum back to the correct owners - the citizens - would spur American Innovation greatly and simultaneously cut communication costs. The technology is changing, and the policy should too!

Anyway, i’m sick of paying $0.10 for 100 bytes of data (txt messages) when audio data costs ~1/500th that.

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ref: notes-0 tags: telecommunications FCC wireless regulation government date: 02-26-2008 04:18 gmt revision:2 [1] [0] [head]


  • quote: Further loosening of the regulatory grip would stimulate investment and innovation in high-tech market segments, providing a long-term, sustainable boost for the American economy.
  • exactly! 2.4 Ghz, the 'junk' band, is TOO CROWDED. more open spectrum => more products and services => greater tax revenue (which would be >> revenue gained from stupid, greedy FCC auctions).
    • This revenue is passed onto the consumers. Think about it .. companies pay $20B for wireless, which they must pass on to the consumers, say 100M => an implicit $200 governmental 'tax' on something that should be free and clear. The government should just tax corporations & consumers directly, and not force companies to shoulder huge debts and risks. These debts put a very high bar for entering the competitive field .. which limits competition & technological advance.
  • however ... The author does not want to impose net neutrality. WHAT???? That means that corporations can effectively regulate information consumption. We are not just consumers, Mr. Randolph May.
    • eh.. I guess they already do this, e.g. Fox News. All the more reason to change the system.
    • Provided there is some choice in the marketplace, consumers will be able to reject any offensive limitation imposed by one 'provider', so perhaps it will work.

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ref: bookmark-0 tags: ECG wireless nordic quasar date: 12-07-2007 21:13 gmt revision:2 [1] [0] [head]

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ref: bookmark-0 tags: emate wireless date: 11-09-2007 17:02 gmt revision:0 [head]

http://geektechnique.org/projectlab/669/getting-your-emate-wireless -- self-explanatory. now, all i need to do is get a waveLAN card (as well as reinstall classic on my g4)

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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)