Improving the Selectivity of Neural Recording and Stimulation Using Electrical Techniques from a Minimally Invasive Implant

Treating symptoms with electrical stimulation is well-established in modern medicine. There is a clear utility in increasing the selectivity of this stimulation. A common limitation is the presence of side effects due to the stimulation activating excessive volumes of neural tissue; the risk of off-target activation or direct damage from the stimulation also prevents the use of electrical techniques some cases where it could be of benefit. Excessive stimulation also decreases the power efficiency of the medical device, with major ramifications for implant feasibility and design.

This project is focussed on improving the selectivity of stimulation from minimally invasive implants of two kinds: epineural cuff electrodes for the peripheral nervous system, and epidural planar electrode arrays for the central nervous system. These were chosen due to their higher chronic tolerance by the body than more invasive systems, which makes them more attractive designs for long-term implants. This project looks at how more complex, non-standard stimulation patterns, such as temporal interference, can improve the stimulation selectivity. Design changes to these platforms that improve their performance when using these non-standard stimulation patterns are also evaluated.

Finally, this project looks at how these implanted platforms can "close the loop" by measuring neural signals. Selective recording methods such as electrical impedance tomography are evaluated for use in the context of a peripheral nerve implant to measure activity at the fascicle level.