Project Summary/Abstract The goal of our work is to develop a high-resolution electronic epiretinal implant for treating incurable blindness from retinal degeneration. To further this goal, we propose here to develop novel techniques for adaptive, high-resolution, multi-electrode recording and stimulation of retinal ganglion cells (RGCs) in the isolated macaque and human retina as an experimental lab prototype for the future device. The major goals of this project are to (1) adaptively use current steering with electrode triplets to enhance selective targeting of RGCs, (2) adaptively use spatio-temporal dithering and multiplexing to produce naturalistic activity in large RGC populations that can support high-quality visual coding, and (3) test the fidelity of electrically evoked visual signals in RGCs of the central human retina. Tackling these aims will allow us to emulate the neural code for vision, cell-by-cell and spike-by-spike, over a region of the central retina. Our unique technical approach involves large-scale, high-resolution electrical recording and stimulation, combined with novel computational approaches to adjust device function to the complex circuitry in which it is embedded, including the degenerated retina, and thus to optimize vision restoration.