Professor, Departments of Surgery (Otolaryngology), Cellular and
Molecular Physiology, and Neurobiology; Interdepartmental Neuroscience Program,
Our research efforts are directed at understanding normal peripheral auditory function so that eventually inner ear deafness can be treated effectively.
The exquisite sensitivity and frequency resolving power of the mammalian inner ear depends upon interactions between the two receptor cells of the organ of Corti, inner (IHC) and outer (OHC) hair cells. Whereas inner hair cells appear to function solely as receptors of acoustic information, OHCs function both as receptors and effectors, producing motile responses as a function of transmembrane potential fluctuations. These motile responses are believed to modify the mechanical input to the inner hair cells which receive the majority of afferent innervation, thereby enhancing the gross frequency tuning afforded by basilar membrane mechanics. Currently, we are studying the effector role of the OHC with electrophysiological and displacement measurement techniques using isolated OHCs from the guinea pig. In particular, we use the whole cell voltage clamp to study the voltage dependence of the mechanical response, and the corresponding nonlinear charge associated with the motility voltage sensor. Estimates of the mechanical frequency response are made in order to assess the potential significance of OHC motility in the in vivo feedback scheme. In addition to the work on OHCs, we are also involved with studies on electrical coupling in the supporting cells, as well as characterization of the ionic currents in these cells and in spiral ganglion cells.
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