The Physics & Astronomy Colloquium Series presents Alexander Neiman of Ohio University on “Nonlinear dynamics of noisy hair cells” on Friday, Nov. 6, at 4:10 p.m. in Walter 245.
Abstract: Perception of sound by living organisms relies on active mechanisms at work, resulting in observed high sensitivity, sharp frequency response and wide dynamic range. Hair cells are mechanoreceptors transducing mechanical vibrations to electrical signals in the senses of hearing and balance in vertebrates. Somatic cell motility and active motility of the hair bundle, mechanically sensitive structure on the hair cell apex, are two main mechanisms by which hair cells can amplify mechanical stimuli. In amphibians and some reptiles active processes in hair cells result in noisy mechanical oscillation of hair bundles, which may lead to frequency selective amplification. Yet, the same cells demonstrate spontaneous electrical oscillation of their somatic potentials, a signature of another amplification mechanism. Functional role of voltage oscillation is not well understood. We use computational modeling to address intriguing questions of how the interaction of two distinct oscillations, mechanical and electrical, affect spontaneous dynamics, battle noise, and shapes sensitivity of amphibian hair cells to external mechanical signals.
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