Subcutaneous Transmitter

System Description

Subcutaneous Transmitters: Detailed description and set-up instructions.
Published Papers: 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 users of our telemetry system.
News Group: Private news group for discussion of implantation and analysis.

Circuit Manuals

Subcutaneous Transmitter (A3028): Single or dual channel EEG, ECG or EMG monitor.
Antenna (A3015C): Antennas with coaxial socket for receiving telemetry signals.
Faraday Enclosure: Faraday enclosures to block ambient interference.
Faraday Enclosure Feedthrough (A3039): Coaxial and ethernet feedthroughs for Faraday enclosures.
Octal Data Receiver (A3027): Message receiver with eight independent antenna inputs.
LWDAQ Driver (A2071E): A TPCIP server and power supply for data acquisition.
Animal Location Tracker (A3038): Combined message receiver, location tracker and TCPIP server.
Battery Charger (A3033): Battery rhargers for rechargeable trabnsmitters.

Software Guides

LWDAQ Software: Data acquisition software, communicates with hardware over TCPIP.
Receiver Instrument: The software instrument that downloads telemetry data.
Neuroarchiver Tool: The software tool that records and processes telemetry data.
PyECoG: EEG viewer with NDF to H5 translation.

Application Notes

The Source of EEG: The origin of the EEG signal we record with our SCT electrodes.
Event Detection: Automatic detection of seizures, spikes, waves, and ripples.
Flexible Wires: Design and selection of leads and antennas for implants.
Electrodes: Design and selection of terminations of leads.
Reception: Measurements of radio-frequency reception reliability.
Mains Hum: The origin of the 50-Hz and 60-Hz noise we observe in laboratories.

Published Papers

Encephalitis patient-derived monoclonal GABAA receptor antibodies cause epileptic seizures (Nov 2021) Kreye et al, J Exp Med, doi: 10.1038/s42003-021-02635-8.
Multimodal electrophysiological analyses reveal that reduced synaptic excitatory neurotransmission underlies seizures in a model of NMDAR antibody- mediated encephalitis (Sep 2021) Wright et al, Commun Biol, doi: 10.1038/s42003-021-02635-8.
Medial septal GABAergic neurons reduce seizure duration upon optogenetic closed-loop stimulation (Mar 2021) Gonzalez-Sulzer et al, Brain, doi.10.1093/brain/awab051.
The matrix metalloproteinase inhibitor IPR-179 has antiseizure and antiepileptogenic effects (Nov 2020) Broekaart et al, J Clin Invest, doi: 10.1172/JCI138332.
Altered Hippocampal-Prefrontal Neural Dynamics in Mouse Models of Down Syndrome (Jan 2020) Chang et al, Cell Rep, doi: 10.1016/j.celrep.2019.12.065.
Combination antioxidant therapy prevents epileptogenesis and modifies chronic epilepsy (Sep 2019) Shekh-Ahmad et al, Redox Biol, doi: 10.1016/j.redox.2019.101278.
Electrical stimulation of the ventral hippocampal commissure delays experimental epilepsy and is associated with altered microRNA expression (Jun 2019) Costart et al, Brain Stimul, doi: 10.1016/j.brs.2019.06.009.
Epilepsy Gene Therapy Using an Engineered Potassium Channel (Feb 2019) Snowball et al, J Neurosci, doi: 10.1523/JNEUROSCI.1143-18.2019.
Semiology, clustering, periodicity and natural history of seizures in an experimental visual cortical epilepsy model (Nov 2018) Chang et al, Dis Model Mech, doi: 10.1242/dmm.036194.
Biochemical autoregulatory gene therapy for focal epilepsy (Jul 2018) Leib et al, Nat Med, doi: 10.1038/s41591-018-0103-x.
KEAP1 inhibition is neuroprotective and suppresses the development of epilepsy (May 2018) Shekh-Ahmad et al, Brain, doi: 10.1093/brain/awy071.
Circadian and Brain State Modulation of Network Hyperexcitability in Alzheimer's Disease (Apr 2018) Brown et al, eNeuro, doi: 10.1523/ENEURO.0426-17.2018.
A microRNA-129-5p/Rbfox crosstalk coordinates homeostatic downscaling of excitatory synapses (May 2017) Rajman et al, EMBO, doi: 10.15252/embj.201695748.
Carvacrol after status epilepticus (SE) prevents recurrent SE, early seizures, cell death, and cognitive decline (Jan 2017) Khalil et al, Epilepsia, 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, Cereb Cortex, doi: 10.1093/cercor/bhw330.
Epileptogenic effects of NMDAR antibodies in a passive transfer mouse model (Aug 2015) Wright et al, Brain, doi: 10.1093/brain/awv257.
Chemical-genetic attenuation of focal neocortical seizures (Apr 2014) Kaetzel et al, Nat Commun, 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 (Aug 2013) Goodrich et al, J Neurotrauma, doi: 10.1089/neu.2012.2712.
Optogenetic and Potassium Channel Gene Therapy in a Rodent Model of Focal Neocortical Epilepsy (Nov 2012) Wykes et al, Sci Transl Med, doi: 10.1126/scitranslmed.3004190.
A Novel Telemetry System for Recording EEG in Small Animals: description of the subcutaneous transmitter system (Sep 2011) Chang et al, J Neurosci Methods, doi: 10.1016/j.jneumeth.2011.07.018.

Older Documents

Prospectus (Updated 2016): Three-page introduction to the SCT system with figures and tables of prices.
Customer Need Flowchart (Updated 2017): Single-page flowchart to help decide which telemetry system will work for your study.
Encapsulation: Development of a rugged, water-proof encapsulation for implants.
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.
RF Spectrometer (A3008): Measures RF power from 850 MHz to 1050 MHz.
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 feasibility test circuits.
Modulating Transmitter: Feasibility study using our Modulating Transmitter test circuit.
Downshifting Receiver: Feasibility study using our Downshifting Receiver test circuit.
Miniature Transmitter: Feasibility study using our Miniature Transmitter test circuit.
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.