Dual contribution to amplification in the mammalian inner ear

Abstract

The inner ear achieves a wide dynamic range of responsiveness by mechanically amplifying weak sounds. The enormous mechanical gain reported for the mammalian cochlea, which exceeds a factor of 4,000, poses a challenge for theory. Here we show how such a large gain can result from an interaction between amplification by low-gain hair bundles and a pressure wave: hair bundles can amplify both their displacement per locally applied pressure and the pressure wave itself. A recently proposed ratchet mechanism, in which hair-bundle forces do not feed back on the pressure wave, delineates the two effects. Our analytical calculations with a WKB approximation agree with numerical solutions.

4 pages, 4 figures

References in corpus (4)

• The Active Traveling Wave in the Cochlea
• The Cochlear Tuning Curve
• Two adaptation processes in auditory hair cells together can provide an active amplifier
• A ratchet mechanism for amplification in low-frequency mammalian hearing

Cited by in corpus (4)

• The physics of hearing: fluid mechanics and the active process of the inner ear
• Redundancy and cooperativity in the mechanics of compositely crosslinked filamentous networks
• Waves on Reissner's membrane: a mechanism for the propagation of otoacoustic emissions from the cochlea
• Unidirectional mechanical amplification as a design principle for an active microphone