Project Summary/Abstract The long-term objectives of my research are to understand the visual signaling function of the retina and to exploit this knowledge for the treatment of blindness. The major goal of the proposed work is to develop techniques for precise, patterned multi-electrode stimulation of the retina, with the purpose of advancing the development of high-resolution retinal prosthetic devices to replace the function of retinas damaged by degeneration. The specific aims involve (1) evoking electrical activity in the major high-resolution ganglion cell types of the primate retina, as well as several ganglion cell types in the degenerating rat retina, (2) selectively stimulating individual cells to achieve the elementary spatial and temporal resolution of normal visual signals transmitted to the brain while avoiding stimulation of axons, over a range of retinal eccentricities, and (3) evoking spatial and spatiotemporal patterns of activity in populations of ganglion cells that can mimic the complex visual signals normally transmitted to the brain. We will apply our unique technology to simultaneously and independently stimulate and record from many ganglion cells in vitro, using an array of electrodes comparable to but much smaller and denser than those used in current retinal prosthetics. We will exploit this technology to develop new methods for focal and patterned stimulation to mimic visual signals, including development of novel technologies to target the central retina. We will also leverage our experience with the primate retina and the P23H mutant rat model of retinal degeneration to maximize the relevance of the findings for treating blindness. Our vision is that the work will aid the design of the next generation of retinal prosthetic devices to support advanced visual functions such as object recognition and motion sensing in human patients.