This item is under embargo and not available online per the author's request. For access information, please visit http://libanswers.wustl.edu/faq/5640.

Date of Award

Spring 5-15-2021

Author's School

Graduate School of Arts and Sciences

Author's Department

Biology & Biomedical Sciences (Neurosciences)

Degree Name

Doctor of Philosophy (PhD)

Degree Type

Dissertation

Abstract

The spike trains of retinal ganglion cells (RGCs) are the sole source of visual information to the brain. In mice, more than 40 RGC types send signals to more than 50 brain areas. RGCs that perform nonlinear operations to extract specific visual features (e.g., the motion of an object against a background) are called feature detectors. Those that linearly integrate local changes in light inten-sity are known as pixel encoders. Most mouse RGC types are feature detectors. In the first part of my dissertation, I discovered a pixel encoder RGC type in mice, the PixON-RGC. I revealed how the unique receptive field structure of PixON-RGCs gives rise to their characteristic responses. I showed that PixON-RGC axons project to the dorsal lateral geniculate nucleus (dLGN) of the thal-amus and likely contribute to visual perception.The second part of my thesis examined ipsilateral projecting RGCs (ipsi-RGCs) to charac-terize binocular vision's cellular substrate and understand how it supports specific behaviors, par-ticularly prey capture. By 3D analysis of predator-prey interactions, I found that mice hunt crickets with their binocular visual field. The binocular vision of mammals relies on ipsi-RGCs. Taking ad-vantage of genetic tools available in mice, I showed that ipsi-RGC removal (~2% of RGCs) in the adult retina reduces mice's hunting success drastically without affecting other visual behaviors. I performed large-scale single-cell recordings and morphological reconstructions of ipsi-RGCs, which revealed that only a small subset (9/40+) of RGC types have ipsilateral projections. Of the nine ipsi-RGC types, only five reliably responded to prey-mimetic stimuli that I designed based on my ethological observations. Thus, I found that mice's viewing strategies align with a spatially re-stricted and cell-type-specific set of ipsi-RGCs that supports binocular vision to guide predation.

Language

English (en)

Chair and Committee

Daniel Kerschensteiner Andreas Burkhalter

Committee Members

Andreas Burkhalter, Edward Han, Timothy Holy, Daniel Kerschensteiner,

Available for download on Sunday, May 15, 2022

Share

COinS