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.
Our research goal is to determine the factors that instruct the development of visual responses in the mammalian retina. In particular, we are studying the circuits that enable the retina to detect the direction of motion of an object in a visual scene. Or work will determine what role visual experience plays in wiring up these direction-selective circuits and what forms the cellular and synaptic basis of these developmental processes.
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