Wireless, Broadband, Low Power, Neural Recording Systems Development
We have built wireless implantable microelectronic devices for transmitting cortical signals transcutaneously. The devices are aimed at interfacing a microelectrode array to an external computer for neural control applications. Our implantable microsystems presently enable 100-channel broadband neural recording in a non-human primate (and porcine) brain by converting these signals to a digital stream of radio frequency pulses for remote wireless transmission. Two types of devices have been developed within our lab, a fully implantable device encased within a Titanium enclosure, and an externally head mounted device which fits the skull mounted pedestals utilized in primate neuroscientific research today. The (a) implantable unit employs a Titanium can with a sapphire window to allow wireless telecommunication, while (b) the externally mounted device encased within an inert polymer allows for easy battery switching to allow for constant operation with minimal interruption. Both design paradigms have integrated ultra-low power amplification with analog multiplexing, an analog-to-digital converter, a low power digital controller chip, and wireless radio frequency telemetry. Both devices run on Li-Ion batteries, and as its application demands, the fully implantable device also incorporates wireless (inductive) charging through the skin. As of today, the fully implantable device has been tested as a sub-chronic unit in non-human primates (~ 20 months), yielding robust spike and broadband neural data on all available channels.
Externally Mounted Wireless Neural Recording Device
Our research focuses on interfacing wireless technology with current neuroscience research methodologies. Current non-human primates implanted with the Blackrock Microsystems NeuroPort system are bound to utilizing cables to extract their neural data for recording and analysis. We have designed a wireless device to attach to the NeuroPort system to allow wireless recording of non-human primates performing naturalistic behaviors in a freely-moving environment. This device consists of a small battery powering analog data amplifiers, digitizers and a wireless transmitter to send this data out over a few meters to a receiver. This device allows neuroscience research to open up to behavioral, movement kinematics, social interaction, psychological neuroscience and other such fields. Current research on this device aims to extend the battery life, utilize lower power, multiply the number of incoming recording channels, and shrinking the footprint of the device.
Fully Implantable Wireless Neural Recording Device
The fully implantable device is encased within a titanium enclosure for hermeticity and longevity in an implanted environment. This device incorporates the data flow pattern of analog data amplifiers, digitizers and wireless transmitters through radio frequency to send data a few meters out to a receiving antenna. Since this device is fully implanted, it also incorporates a battery which provides a run time of approximately 8 hours. The battery is charged by aligning an inductively coupled coil from the outside to provide wireless power transmitted through the skin and the sapphire window incorporated into the Titanium enclosure. The device is the culmination of years of research on broadband wireless data transmission of neural signals as well as development of implantable biomedical devices that meet industry standards for human clinical use. This device has provided over two years (combined) of implanted non-human primate neural data for research purposes in our (and our collaborators') labs. Current research on this technology focuses on size and power reduction as well as capability enhancement into electrical stimulation as well as other biomedical information collection such as head acceleration/brain or body temperature etc.