Date on Master's Thesis/Doctoral Dissertation
12-2019
Document Type
Doctoral Dissertation
Degree Name
Ph. D.
Department
Anatomical Sciences and Neurobiology
Degree Program
Anatomical Sciences and Neurobiology, PhD
Committee Chair
Borghuis, Bart
Committee Member
Bickford, Martha
Committee Member
Guido, William
Committee Member
Leonardo, Anthony
Committee Member
McCall, Maureen
Author's Keywords
retina; systems neuroscience; imaging; electrophysiology
Abstract
Phototransduction, transmission of visual information down the optic nerve incurs delays on the order of 50 – 100ms. This implies that the neuronal representation of a moving object should lag behind the object’s actual position. However, studies have demonstrated that the visual system compensates for neuronal delays using a predictive mechanism called phase advancing, which shifts the population response toward the leading edge of a moving object’s retinal image. To understand how this compensation is achieved in the retina, I investigated cellular and synaptic mechanisms that drive phase advancing. I used three approaches, each testing phase advancing at a different organizational level within the mouse retina. First, I studied phase advancing at the level of ganglion cell populations, using two-photon imaging of visually evoked calcium responses. I found populations of phase advancing OFF-type, ON-type, ON-OFF type, and horizontally tuned directionally selective ganglion cells. Second, I measured synaptic current responses of individual ganglion cells with patch-clamp electrophysiology, and I used a computational model to compare the observed responses to simulated responses based on the ganglion cell’s spatio-temporal receptive fields. Third, I tested whether phase advancing originates presynaptic to ganglion cells, by assessing phase advancing at the level of bipolar cell glutamate release using two-photon imaging of the glutamate biosensor iGluSnFR expressed in the inner plexiform layer. Based on the results of my experiments, I conclude that bipolar and ganglion cell receptive field structure generates phase advanced responses and acts to compensate for neuronal delays within the retina.
Recommended Citation
DePiero, Victor Julian, "Understanding object motion encoding in the mammalian retina." (2019). Electronic Theses and Dissertations. Paper 3323.
https://doi.org/10.18297/etd/3323
Included in
Biology Commons, Computational Neuroscience Commons, Molecular and Cellular Neuroscience Commons, Systems Neuroscience Commons
