Neural circuitry of retinal receptive fields in primate

The retina contains the first stages of the neural encoding of visual information that begins the generation of our perception of the visual world. The retina contains as many as 70 distinct cell types that interact in specific circuits that process distinct aspects of visual stimuli. The majority of these cell types and circuits are not well understood physiologically and functionally. In this thesis I will describe experiments that examine how specific retinal neurons interact with each other to form their receptive fields and process visual information. In the first chapter I will describe pharmacological and calcium imaging experiments that suggest that AI axon bearing amacrine cell dendrites are input structures and its axons are output structures. In the second chapter I will test the effect of HEPES and other pH buffers on measures of horizontal cell feedback in primate retina and show results that are consistent with horizontal cell feedback requiring local pH changes in the outer retina. In the third chapter I will present evidence that the blue-yellow opponency in the small bistratified ganglion cell is generated predominantly by horizontal cell feedback, not antagonistic ON and OFF pathway inputs, as previously thought.