The specific aim of the present proposal is to study, in the rat, the cerebellar dentate nucleus pathways linking important oculomotor and accessory oculomotor centers with those mediating visual, vestibular and neck information. The long-term goal of these experiments is to understand better the role of the neocerebellum and dentate nucleus in visually guided behavior, particularly during hand-eye coordination involving head movements. The experiments outlined under SPECIFIC AIMS will examine the oculomotor projections of denate neurons, and their response properties to specific stimulation of visual, vestibular, and nuchal receptors. A combined physiological and anatomical approach is planned. Standard electrophysiological intra- and extracellular recording techniques will be used to study single antidromicall identified dentate neurons during electrical stimulation of these afferent systems. Subsequently, their responses and functional interaction during natural stimulation of the visual, vestibular, and neck receptors will be examined. Moephological studies including lesions, intracellular injections of horseradish peroxidase and autoradiography are planned to demonstrate the mediating pathways and the intrinsic organization of those portions of the nucleus receiving inputs from these sensory modalities. As outlined, the studies will provide important information on the organization, mediating pathways, and functional interaction between visual, vestibular and nuchal inputs to the limb musculature-related portions of the neocerebellum, thereby increasing the understanding of the role of the cerebellum in hand-eye coordination.