Subcutaneous Transmitter


System Description

Subcutaneous Transmitters: Detailed description of the telemetry system.

Papers and Posters: List of paper and posters describing studies done with the telemetry system.

Example Recordings: A selection of recordings made with our subcutaneous transmitters.

Parts and Prices: A list of devices and their prices in various quantities.

Testimonials: Comments from Subcutaneous Transmitter (SCT) users.

News Group: Private news group for subcutaneous transmitter users to discuss implantation and analysis.

Circuit Manuals

Subcutaneous Transmitter (A3028): Single or dual channel EEG and EMG monitor. Available in dual-channel, 15-day mouse version, single-channel, 25-day mouse version, dual-channel 79-day rat version, single-channel 133-day rat version, and other versions smaller and larger. Replaces all versions of the A3019.

Antenna (A3015): An antenna stand made out of a circuit board and angle brackets that connects via BNC cable to the receiver.

Faraday Enclosures: Faraday enclosures to block ambient interference and increase transmitter operating range.

Octal Data Receiver (A3027): Message receiver with eight independent antennas. Replaces A3018. (In development.)

LWDAQ Driver (A2071E): Provides power and control to the Data Receiver, acts as a TPCIP server on the Internet for data acquisition.

RF Spectrometer (A3008): Measures RF power from 850 MHz to 1050 MHz.

Software Guides

LWDAQ Software: Software that runs on a Windows, MacOS, or Linux computer to perform data acquisition over the Internet.

Recorder Instrument: The LWDAQ Instrument that uploads data from the Data Receiver (A3018) through the LWDAQ Driver over the Internet.

Neuroarchiver Tool: The LWDAQ Tool that processes and stores Recorder Instrument data.

Application Notes

Encapsulation: Development of a rugged, water-proof encapsulation procedure for small subcutaneous transmitters.

Flexible Wires: Search for flexible, corrosion-resistant leads for subcutaneous transmitters.

Electrodes: Termination of the analog pickup leads.

Reception: Measurements of radio-frequency reception reliability.

Seizure Detection: Development of automatic seizure detection procedure for use with SCT system.

Mains Hum: The origin of the 50-Hz and 60-Hz noise we observe in laboratories.

The Source of EEG: The origin of the EEG signal we record with our SCT electrodes.

Papers and Posters

Biochemical autoregulatory gene therapy for focal epilepsy (2018) Leib et al., Nature Medicine. doi:10.1038/s41591-018-0103-x.

Epilepsy gene therapy using non-integrating lentiviral delivery of anengineered potassium channel gene (2018) Snowball et al., bioRxiv 298588; doi: 10.1101/298588.

Semiology, clustering, periodicity and natural history of seizures in an experimental visual cortical epilepsy model (2018) Chang et al., bioRxiv 289256; doi: 10.1101/289256.

KEAP1 inhibition is neuroprotective and suppresses the development of epilepsy (May 2018) Shekh-Ahmad et al., Brain. 2018 May 1;141(5):1390-1403.

Circadian and Brain State Modulation of Network Hyperexcitability in Alzheimer's Disease (Apr 2018) Brown et al., eNeuro, ENEURO.0426-17.2018.

Carvacrol after status epilepticus (SE) prevents recurrent SE, early seizures, cell death, and cognitive decline (Jan 2017) Khalil et al., Epilepsia, 58(2):263-273, 2017, doi:10.1111/epi.13645.

The Development of Nociceptive Network Activity in the Somatosensory Cortex of Freely Moving Rat Pups (Oct 2016) Chang et al., Oxford Journal Cerebral Cortex, Volume 26 Issue 11, doi: 10.1093/cercor/bhw330.

Epileptogenic effects of NMDAR antibodies in a passive transfer mouse model (Aug 2015) Wright et al., BRAIN Journal of Neurology, Oxford University Press, 138(9).

Chemical-genetic attenuation of focal neocortical seizures (April 2014) Kaetzel et al., Nature Communications 5, Article number: 3847, doi:10.1038/ncomms 4847.

Ceftriaxone Treatment after Traumatic Brain Injury Restores Expression of the Glutamate Transporter, GLT-1, Reduces Regional Gliosis, and Reduces Post-Traumatic Seizures in the Rat (August 2013) Goodrich et al., Journal of Neurotrauma, 30(16): 1434-1441.

Optogenetic and Potassium Channel Gene Therapy in a Rodent Model of Focal Neocortical Epilepsy (Nov 2012) Wykes et al., Science Translational Medicine, DOI: 10.1126/scitranslmed.3004190.

A Novel Telemetry System for Recording EEG in Small Animals: description of the subcutaneous transmitter system (September 2011) Chang et al., Journal of Neuroscience, 201(1): 106-115.

Using Open Source Instruments wireless telemetry devices and software to monitor and analyze seizure activity in rodents: Poster, Wykes et al., 2014.

Autoantibodies to the N-methyl-D-aspartate receptor and seizure susceptibility in mice: Poster, Wright et al., 2014.

Older Documents

Antenna Combiner (A3021): Amplifier and four-way antenna combiner.

Subcutaneous Transmitter (A3019): Transmitter with a single input, made as a 25-day, 512 SPS mouse version or 133-day, 512 SPS rat version.

Data Receiver (A3018): Combination of Demodulating Receiver (A3017), Saw Oscillator (A3016SO), and Data Recorder (A3007C) into one box with BNC connection for an RF Antenna (A3015).

Demodulating Receiver (A3017): Used in the Data Receiver. Replaces the A3005.

RF Tester (A3014): Test circuits preparing for next receiver design. Includes a SAW Oscillator used in the Data Receiver., a Modulating Transmitter, a Demodulating Receiver, and a TQFP-48 programmer.

Subcutaneous Transmitter (A3013): The original transmitter with a single differential input, now obsolete.

Test Transmitter (A3020): Combination of the A3019 circuit, a SAW oscillator, and an attempted SAW VCO.

RF Combo (A3016): Combines three circuits in one board: a new RF Spectrometer, a new SAW Oscillator, and a new Demodulating Receiver.

Data Transmission and Reception Circuits, Part Two: Describes the Subcutaneous Transmitter (A3009A), Demodulating Receiver (A3005C), Data Recorder (A3007B), and the combination of A3005C with A3007B in a single enclosure which we call the Data Receiver (A3010A).

Demodulating Receiver (A3005C): A 902-928 MHz ISM-band FM receiver.

Programmer (A3011): Programmer and test circuit for A3009 transmitters.

Data Receiver (A3010): Combination of A3005C and A3007B in a single enclosure, with one antenna sticking out. Provides a cable for power and signals.

Subcutaneous Transmitter (A3009): Transmitter with programmable center frequency and modulation width. Programming connector eliminates programming extension board used with previous circuits.

Data Transmission and Reception Circuits, Part One: Describes the failure of the Subcutaneous Transmitter (A3006A) with Demodulating Receiver (A3005A) and Data Recorder (A3007A).

Data Recorder (A3007): Takes output of A3005A as its input, detects A3006 transmissions, and stores them in its 512-KByte memory along with time stamps. For use with the Recorder instrument.

Subcutaneous Transmitter (A3006): Battery, 950-MHz oscillator, magnetic power switch, 32-kHz oscillator, programmable logic chip, sixteen-bit analog-to-digital converter, x10 differential input amplifier, 160-Hz low-pass filter, 1.6-Hz high-pass filter.

Dummy Transmission Circuits: Performance of the Transmitter with Logic Chip (A3004) together in combination with the Demodulating Receiver (A3005), showing that the two circuits meet or exceed our expectations.

Receiver (A3005): 50-Ohm antenna input, SAW (surface acoustic wave) filter, 1000-MHz local oscillator, 95-MHz intermediate frequency low-pass filter, 60-db limiting amplifier, full-wave rectifying demodulator, 20-MBPS 1-V logic output for oscilloscope viewing.

Transmitter with Logic Chip (A3004): Battery, 950-MHz oscillator, magnetic power switch, 32-kHz oscillator, and programmable logic chip.

Transmitter with On-Off Switch (A3002): Battery, 950-MHz oscillator, and magnetic power switch.

Technical Proposal: Proposal to develop and build subcutaneous transmitters, addressed to Dr. Walker of the Institute of Neurology, London.

Test Circuits (A3001): User manual for feasability test circuits.

Modulating Transmitter: Feasability study using our Modulating Transmitter test circuit.

Downshifting Receiver: Feasability study using our Downshifting Receiver test circuit.

Miniature Transmitter: Feasability study using our Miniature Transmitter test circuit.