DIRECTIONALLY SENSITIVE INPUT TO OCULOMOTOR PATHWAYS

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Funds are requested for an ADAMHA RSDA Level II to enable the principle investigator (P.I.) to investigate the functional role that directionally sensitive (DS) cells play in visually evoked behaviors. The P.I. is in his 4th yr. as an Asst. Professor following 4 yrs. as a Postdoctoral Fellow. Now that his laboratory is established, the constraints of academia slow his immediate experimental goals as well as his long-term professional growth. This award will free the P.I. from other commitments to allow for the development of unique neuroscience approaches to the understanding of information processing and sensory-motor integration. The research goals of the P.I. and the Department of Behavior Neuroscience are directed towards an understanding of the brain's control of behavior by using current neuroscience approaches. The P.I. will draw upon the considerable neuroscience expertise of his department and the University of Pittsburgh at large to development techniques of in vitro brain neurophysiology and combine them with his approaches of pharmacology and receptive field analysis of an intact system. DS retinal ganglion cells are output neurons of the eye that respond selectively to stimuli moving only in one direction. They will be studied as a possible input to a complex brain system which stabilizes images on the retina by controlling eye position. The P.I. is currently funded to perform experiments which compare neuronal responses in the anaesthetized animal to optokinetic nystagmus (OKN) in the awake animal. Recently though, an in vitro preparation using the turtle is being developed for oculomotor research. This preparation has the unique advantage that the entire system remains intact and viable, so that DS cells in the extracorporeal brain respond to visual stimuli projected onto the attached eyes. The development of in vitro approaches to the study of these reflex behaviors require new skills for the P.I. Perfecting these techniques will produce new tools to use in investigations of the brain's control over behavior. These experiments can then involve sensory-motor integration from the cellular basis of sensory feature extraction to the convergence of sensory pathways onto motor output pathways. Stabilization of the visual image by OKN is a simple model of a sensory- motor behavior. In humans, a disorder of a related eye movement function is an indication of schizophrenia. Knowledge of oculomotor control may further OKN's diagnostic usefulness by differentiating between retinal and central control of eye movement behaviors in normal and disease states.