9309258 Tsuchitani Hearing with two ears (binaural) is much better than with just one (monaural) for detecting and locating sound sources, and understanding speech in a noisy background. Within the mammalian brain, in the brainstem, there is a structure called the superior olivary complex that is the first place in the auditory pathway directly involved in the neural processing that underlies binaural hearing. This complex contains nerve cells formed into groups called nuclei. Two of these are the lateral superior olive nucleus (LSO), and the medial nucleus of the trapezoid body. Both are part of a neural network, the LSO network, that is specifically involved in binaural processing of mid- to high-frequency sounds, those above 1.5kHz. This work is a collaboration between a sensory neurophysiologist and a signal-processing theorist using an interdisciplinary approach. Responses of neurons in the LSO network are recorded for controlled acoustic stimuli which approximate normal "free-field" binaural conditions, and computational models describe how these responses devleop the neural representation of binaural signals. Signal array processing techniques also will be used to determine the consequent contributions of the LSO network to binaural perception. This work will have impact beyond auditory neuroscience to sensory processing in general, to computational modelling of networks, and to devices for aiding or enhancing hearing capabilities. ***
