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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Multiple layers of inhibition in the direction coding circuit in mouse retina

Hoggarth, K. Alex 15 August 2016 (has links)
Local and global forms of inhibition control directionally selective ganglion cells (DSGCs) in the mammalian retina. Specifically, local inhibition arising from GABAergic starburst amacrine cells (SACs) strongly contributes to direction selectivity. In this thesis, I demonstrate that increasing ambient illumination leads to the recruitment of GABAergic wide-field amacrine cells (WACs) endowing the DS circuit with an additional feature: size selectivity. Using a combination of electrophysiology, pharmacology and light/electron microscopy, I demonstrate that WACs predominantly contact presynaptic bipolar cells, which drive direct excitation and feed-forward inhibition (through SACs) to DSGCs, therefore maintaining the appropriate balance of inhibition/excitation required for generating DS. This circuit arrangement permits high-fidelity direction coding over a range of ambient light levels, over which size selectivity is adjusted. Together, these results provide novel insights into the anatomical and functional arrangement of multiple inhibitory interneurons within a single computational module in the retina. / Graduate

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