Neural Transmission & Modulation in the Cerebellum and Vestibuloocular Reflex

Temple University, Philadelphia PA

Investigators

Abstract

LAY ABSTRACT Neural Transmission & Modulation in the Cerebellum and the Vestibulo-ocular Reflex James G. McElligott Operation of the vestibulo-ocular reflex is essential for maintaining clear vision in the presence of head movements. For proper operation of this reflex throughout life, adaptive increases or decreases in the magnitude of this reflex are necessary. This adaptation corrects for alterations in the vestibular and visual system associated with early developmental, age, and injury related events. A simple brain circuit involving the cerebellum and vestibular nucleus controls adaptation of the reflex. Presently, it is not known where in this neuronal circuitry these changes occur. It is also unclear if changes occur by a single common neuronal mechanism or by multiple mechanisms. The purpose of the research is to address these questions. Experiments will be directed towards investigating the involvement of two brain neurotransmitters (glutamate and GABA) and their actions at specific receptors (NMDA for glutamate and GABAa for GABA) within the cerebellar neuronal circuitry. Of particular interest is the glomeruli synapse in the cerebellum where these receptors are present. It is at this unique synapse that mossy fibers, Golgi and granule cells contact each other and interact. Often the brain is compared to a computer in its operation. However, the brain has the ability to repair and to alter its circuitry, a property that the computer lacks. The object of this research is to understand the mechanisms by which the brain produces these alterations or adaptive changes. This knowledge will aid in the development of techniques to facilitate the adaptive process. This knowledge will also have a direct bearing on understanding problems associated with disturbances to the vestibular or balance system. This has an impact on everyday vestibular problems encountered on the earth, as well as the more recently identified vestibular alterations that are associated with extraterrestrial space exploration.