Date of Award

2013

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Graduate Group

Neuroscience

First Advisor

Vijay Balasubramanian

Abstract

Visual scenes in the natural world are highly correlated. To efficiently encode such an environment with a limited dynamic range, the retina ought to reduce correlations to maximize information. On the other hand, some redundancy is needed to combat the effects of noise. Here we ask how the degree of redundancy in retinal output depends on the stimulus ensemble. We find that retinal output preserves correlations in a spatially correlated stimulus but adaptively reduces changes in spatio-temporal input correlations. The latter effect can be explained by stimulus-dependent changes in receptive fields. We also find evidence that horizontal cells in the outer retina enhance changes in output correlations. GABAergic amacrine cells in the inner retina also enhance differences in correlation, albeit to a lesser degree, while gylcinergic amacrine cells have little effect on output correlation. These results suggest that the early visual system is capable of adapting to stimulus correlations to balance the challenges of redundancy and noise.

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