Computational study on the mechano-transduction in the organ of Corti

Wenxiao Zhou, PhD Defense, Advised by Professor Jong-Hoon Nam

Wednesday, December 9, 2020
2 p.m.

The cochlea encodes acoustical stimulations into neural signals. The auditory sensory epithelium in the cochlea, called the organ of Corti, consists of sensory receptor cells and supporting cells. Hair cell mechano-transduction has been studied extensively because it is the central function of the cochlea. However, some of its basic properties such as sensitivity are still poorly defined. Outer hair cell’s electromotility is required for cochlear amplification. Finding of outer hair cell motility cast doubt on the long-held assumption that the organ of Corti is a rigid scaffold to hold the hair cells. More and more observations revealed that vibrations in the organ of Corti are complicated. The backbone of modern cochlear physics is the traveling waves. In the cochlea, sounds are transmitted as slow traveling waves as opposed to fast compressive waves, yet existence of the standing wave is still possible in the cochlea and has its own functional importance. With a detailed nonlinear time-domain model and available experimental data, we investigated cochlear biophysics in three aspects: 1) using two-tone suppression to estimate mechano-transduction sensitivity, 2) deriving hair bundle kinematic gain from passive and active vibration modes, and 3) exploring the existence of standing waves through the onset latency.