IBN-9728933 Spirou In the brainstem, which is the part of the brain just above the spinal cord, are centers involved in early processing of auditory information. These cell groups, called nuclei, show different kinds of physiological specialization, and receive and send projections to several other parts of the brainstem and higher centers. One of these centers is called the medial superior olivary nucleus (MSO), from its location and shape. The MSO is thought to have a major role in the ability to localize sounds in space, by analyzing the time of arrival of signals coming from the two ears. Part of this specialized processing is done by converging excitatory nerve inputs, but an important and largely unknown role is played by inhibitory signals that also converge on single cells in the MSO. This project uses physiological recording from an isolated brain slice to study activity produced in the MSO by inputs from the two sides of the brainstem; to establish basic information about the structure, pharmacology and kinetic properties of inhibitory inputs to MSO; and to study the sensitivity of the MSO cells to small differences in arrival time of signals from the two sides. Results will be important to understanding how temporal processing of high resolution occurs in the auditory system, and will also lead to better computational models of how sound localization is done. Such models may be applied to design of instruments with improved ability to discriminate sounds in complex environments.
