Development of direction selectivity in retina

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 DESCRIPTION (provided by applicant): Direction-selective ganglion cells respond strongly to an image moving in the preferred direction and weakly to an image moving in the opposite, or null direction. Direction-selective ganglion cells are critical for driving ocular-motor reflexes tat stabilize images on the retina as we move through a visual scene as well as for sensing the movement of objects within the visual scene. The preferred directions of direction- selective ganglion cells cluster along the cardinal directions (up, down, left and right). The predominant model for the generation of direction selectivity in the retina is that a particular class of interneurons forms inhibitory synapses on the null side of the dendritic tree of direction-selectiv ganglion cells. The mechanisms that instruct the emergence of preferred directions and the circuits that underlie these mechanisms during development are unknown. Here we propose to use a combination of state-of-the-art electrophysiological, two- photon imaging and optogenetic techniques to determine the mechanisms that underlie the development of two essential features of direction-selectivity - the emergence of preferred directions, and the circuits that create null side inhibition. In particular, we will determine if visual experience plays a criticalrole in the formation of these circuits.