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.

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

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.