Research Project: Effects of Electrical Stimulation on Neural Networks

Principal Investigator: Ethan Cohen

Collaborators: Lee Johnson (Naval Research Laboratory)

In collaboration with Code 5611 (Naval Research Laboratory), we are recording retinal ganglion cells using a novel 80,000 microwire electrode recording array chip. The right panel shows  the time course (vertical) of the electrical signals on  a patch of 256 electrode “pixels” in response to a spot stimulus (shaded region shows spot duration). Many ganglion cell signals can be recorded simultaneously with the chip. The objective of this project will be to examine how the ganglion cell network responds to electrical stimulation pulses from large stimulus electrodes, and to optimize stimulation patterns.  Multi-neuron recordings will provide the center with a better understanding of how stimulation pulses by retinal prostheses activate different ganglion cells and propagate spatially across the tissue.

Naval Research Lab microwire glass recording array bonded to a camera readout chip.

Raster plot image of retinal ganglion cell spike activity  recorded by the NRL array to a full field light flash (shaded region). Different pixels (a,b,c) show the light-evoked firing patterns of individual retinal ganglion cells sampled by single electrodes.