Electrical imaging of axonal stimulation in the retina

Stimulation of axons or its avoidance plays a central role for neuroprosthetics and neural-interfaces research. One peculiar example constitutes retinal implants. Retinal implants aim to artificially activate retinal ganglion cells (RGCs) via electrical stimulation. Such stimulation, however, often generates undesired stimulation of RGC axon bundles, which leads to distorted visual percepts. In order to establish stimulation strategies avoiding axonal stimulation it is necessary to image the evoked activity in single axons. In this work we electrically imaged axonal stimulation in ex vivo mouse retina using a high-density CMOS-based microelectrode array. We demonstrate signal propagation tracking via stimulus triggered average during high frequency (100 Hz) sinusoidal electrical stimulation.