Unique physiological properties of novel ganglion cell types in primate retina

Project Summary/Abstract The overall objective of this research is to gain a deeper understanding of visual processing in the macaque monkey retina, the most important animal model for understanding human vision, and to leverage that knowledge to treat blindness. The goal of the proposed work is to determine how four poorly understood retinal cell types contribute to visual processing in primates. Many of the retinal amacrine and ganglion cell types that have been characterized in non-primate retinas perform complex and specialized visual computations, extracting information such as motion direction, object orientation, and object versus background motion from visual inputs. Whether similar computations also occur in the primate retina is unclear, because most physiological studies have focused on the role of only five of the ~20 output pathways. We have identified four cell types in the macaque monkey retina that exhibit intriguing differences from the five better-studied cell types in their visual response properties. Our specific aims are to 1) determine how striking waves of activity in the network of A1 amacrine cells network shapes the light response properties of parasol ganglion cells, 2) determine how intrinsic and circuit mechanisms shape the unusual spatial and temporal response properties of broad thorny ganglion cells, and 3) determine how membrane and receptive field properties allow ON- and OFF-type smooth monostratified ganglion cells to signal distinct information to the brain from their parasol cell counterparts. At the conclusion of this work, we expect to have a deeper understanding of the visual computations performed by the primate retina and the neural mechanisms that underlie those computations. Further, this project will shed much needed light on how retinal processing in primates, and by extension humans, relates to that observed in rodents and other animal models.