High-fidelity restoration of visual signals by electrical stimulation in the central primate retina

Electrical stimulation of retinal ganglion cells (RGCs) with electronic implants provides rudimentary artificial vision to people blinded by retinal degeneration, but cannot reproduce the neural code of the retina. Recent work has demonstrated more precise activation of RGCs using focal electrical stimulation in the peripheral macaque retina, but high-resolution vision requires the central retina. This work probes the effectiveness of focal epiretinal stimulation in the central macaque retina, using large-scale recording and stimulation ex vivo. The functional organization of the major RGC types was similar between the peripheral and central retina, and these cell types could be distinguished by their electrical properties. Electrical stimulation revealed similar RGC activation thresholds and reduced axon bundle activation in the central retina, but diminished stimulation selectivity. However, a novel stimulation algorithm revealed higher expected acuity in the central retina. These results support the possibility of reproducing high-acuity vision in the central retina with an epiretinal implant.