The prime objective of the core grant proposal is to provide common facilities for morphological, biochemical and physiological studies of the visual system. The research encompassed in the proposal deals with cellular mechanisms in the visual process. The main emphasis in several studies is on the structure and function of single neurons and on the interaction between cells at various levels in the visual pathway. Analysis of receptive field properties of single cells and the functional architecture of the mammalian visual pathways are central problems in the proposal. Single cell studies will be complemented by the use of various anatomical techniques, including new tracer methods already employed successfully. Neuronal structure and connectivity in the retina and visual cortex will be studied using intracellular recordings and histochemical markers to visualize the dendritic and axonal arborization of functionally identified neurons. The synaptic morphology at various levels in the visual pathway will be studied using light and electron microscopic techniques. Anatomical and physiological studies will be done in monkeys, cats and mice raised under various conditions of visual deprivation to learn about the relative role of innate and environmental influences during development. The availability of mammalian visual mutants makes it possible to study the nature of neuronal specificity and related developmental problems. The identity and localization of neurotransmitters will be examined in the retina and in central visual pathways. This work will be carried out in vivo and in vitro preparations. The physiological properties of retinal cells isolated by mild enzymatic dissociation will be studied in tissue culture. A study will be made of synapse formation and transmission between isolated and identified retinal cells. Finally the cell surface specificity of visual cells will be examined using monoclonal antibodies and other immunological and biochemical techniques.