Molecular architecture of the retina: From model systems to human vision

Summary

Date: 
January 23, 2019 - 12:00pm - 1:00pm
Location: 
Northwest Building, Room 243
About the Speaker
Name: 
Yirong Peng
Speaker Title: 
Postdoctoral Fellow
Speaker Affiliation: 
Sanes Lab

Visual processing begins in the retina—a thin neural structure at the back of the eye. The retina does not transmit visual information passively; rather, it consists of three neuronal layers that perform extensive analysis of visual scenes. Photoreceptors (rods and cones) first capture photons and dispense the information to interneurons (horizontal, bipolar, and amacrine cells). Interneurons then compute the information and transmit it to retinal ganglion cells (RGC). Individual RGC types extract salient visual features and parallel convey them to the rest of the brain. The large diversity of retinal cell types enables a complex computational analysis. However, genetic programs that specify diverse neuronal types have not yet been fully uncovered. In addition, visual perception is highly diverse among species despite sharing a basic retinal plan. For instance, primates, including humans, rely on high-acuity vision, which stems from a specialized region called the fovea at the center of the retina. Among mammals, only primates have a fovea. Thus, it is not well understood the extent to which neuronal cell types are shared between the fovea and the rest of the primate retina and the extent to which neuronal cell types are shared among species. My research uses genetic tools and transcriptomic methods in mouse and non-human primates to address these abovementioned questions. My results are: 1) In the mouse retina, we discovered two cell-type specific transcription factors that encode cellular identities from one retinal circuit. 2) Using high-throughput single-cell RNA-seq of 165,000 cells from both macaque fovea and the peripheral retina, we showed that more than 80% of >65 cell types match between the two regions, but exhibit substantial differences in proportions and gene expression, some of which we relate to functional differences. 3) Comparison of macaque retinal types with those of mice reveals that interneuron types are tightly conserved, but that projection neuron types and programs diverge, despite conserved transcription factor codes.