The general objective of our research program continues to be the development of a comprehensive and systematic study of the neuronal organization of the cerebellar-brain stem system and its relation to the coordination of movement. The basic philosophy of the overall experimental design is, fundamentally, a multidisciplinary one; different techniques and areas of knowledge will be amalgamated to determine the morphological and functional properties of single cells, their neuronal circuits, and their ionic microenvironment. Different electrophysiological and biophysical techniques include intra- and extracellular recordings of single cell activity (both in vivo and in vitro) field potential and current density analysis, ion-sensing electrode techniques and intracellular marking with different dyes. Physiological stimuli (visual, vestibular and joint movement) will be utilized in most paradigms. The morphological studies will utilize light and electron microscopy and computer-aided reconstruction. Quantitative analysis of the ultrastructural matrix of given cells will be utilized in defining general properties of morphogenesis. The electrophysiological and morphological data will be combined to generate computer models in order to further relate the functional properties of single cells to their actual structure and their relation to the properties of neuronal circuits. Eye movement-related experiments will be performed in both anethetized and unanesthetized preparations. Special computer techniques will be used to relate particular parameters of these movements to the activity of the above circuits. Pharmacological tools will be used to assess the ionic permeability changes underlying both synaptic and electroresponsive properties of single CNS cells.