title: How close should the outer hair cell RC roll-off frequency be to the characteristic frequency?
abstract: Recent experiments have shown a much larger conductance in outer hair cells, the central components of the mammalian cochlear amplifier. The report used only the cell's linear capacitance, which together with increased conductance, raised the cell's RC corner frequency so that voltage-dependent motility was better able to amplify high-frequency sounds. We construct transfer functions for a simple model of a high characteristic frequency (CF) local cochlear resonance. These show that voltage roll-off does not occur above the RC corner. Instead, it is countered by high-pass filtering that is intrinsic to the mammal's electromechanical resonance. Thus, the RC corner of a short outer hair cell used for high-frequency amplification does not have to be close to the CF, but depending on the drag, raised only above 0.1 CF. This high-pass filter, built in to the mammalian amplifier, allows for sharp frequency selectivity at very high CF.
authors: mospeck@yahoo.com
authors: Mark
authors: M
authors: Ospeck
authors: Kuni H
authors: KH
authors: Iwasa
mesh_terms: D001696:Biomechanical Phenomena; D004553:Electric Conductivity; D018072:Hair Cells, Auditory, Outer / Q000166:cytology* / Q000502:physiology; D008954:Models, Biological; D013997:Time Factors