Center for Perceptual Systems Seminar Series
Mon, October 1, 2012 • 12:00 PM - 1:00 AM • SEA 4.244
"The Processing of Binaural Information in the Auditory System: Some Surprises Revealed by In-Vivo Whole Cell Recordings "
George D. Pollak, Ph.D. Section of Neurobiology, Center for Perceptual Systems and Institute for Neuroscience The University of Texas at Austin
Bag Lunch Talk
Find information about current and upcoming talks at CPS on our website: http://www.utexas.edu/cola/centers/cps/events/upcoming.php
Abstract: My research is concerned with the processing of acoustic signals in the auditory system and the circuits, both excitatory and inhibitory, that we deduce from the patterns of EPSPs and IPSPs evoked by monaural and binaural stimuli that we record in vivo with whole cell recordings in awake animals. What we focus on it how the circuits shape and create functionally relevant response properties in the auditory midbrain, the inferior colliculus. Specifically, the studies that I will describe are concerned with the coding of interaural intensity disparities (IIDs), the cues animals use to localize high frequency sounds. I will discuss how IIDs are initially processed in the lateral superior olive, the second synaptic station in the auditory system, and the pathways by which the information in the lateral superior olive is distributed to higher order nuclei, all of which ultimately converge in the inferior colliculus. By determining the spikes, post-synaptic potentials and conductances that generate both the responses evoked by sound presented to each ear and by sound presented binaurally. I will show that there are several types of neurons in the inferior colliculus processes IIDs, each distinguished by the complement of inputs it receives from lower auditory centers. I will then show how the inputs operate cooperatively to generate the particular response property expressed by each type. Finally, I will show how the inputs to these cells could encode not only the IID generated by a single sound in space, but also how they could derive selective response properties for sounds moving in space or for multiple sounds that occur in more complex acoustic environments.