Nanoscale Poroelasticity of the Tectorial Membrane Determines Hair Bundle Deflections

Stereociliary imprints in the tectorial membrane (TM) have been taken as evidence that outer hair cells are sensitive to shearing displacements of the TM, which plays a key role in shaping cochlear sensitivity and frequency selectivity via resonance and traveling wave mechanisms. However, the TM is...

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Bibliographic Details
Main Authors: Nia, Hadi Tavakoli, Sellon, Jonathan Blake, Azadi Sohi, Mojtaba, Oftadeh, Ramin, Ghaffari, Roozbeh, Grodzinsky, Alan J, Freeman, Dennis M
Other Authors: Massachusetts Institute of Technology. Department of Biological Engineering
Format: Article
Language:English
Published: American Physical Society 2019
Online Access:http://hdl.handle.net/1721.1/120106
https://orcid.org/0000-0003-0622-1333
https://orcid.org/0000-0003-3369-5067
https://orcid.org/0000-0002-4942-3456
https://orcid.org/0000-0001-6309-0910
Description
Summary:Stereociliary imprints in the tectorial membrane (TM) have been taken as evidence that outer hair cells are sensitive to shearing displacements of the TM, which plays a key role in shaping cochlear sensitivity and frequency selectivity via resonance and traveling wave mechanisms. However, the TM is highly hydrated (97% water by weight), suggesting that the TM may be flexible even at the level of single hair cells. Here we show that nanoscale oscillatory displacements of microscale spherical probes in contact with the TM are resisted by frequency-dependent forces that are in phase with TM displacement at low and high frequencies, but are in phase with TM velocity at transition frequencies. The phase lead can be as much as a quarter of a cycle, thereby contributing to frequency selectivity and stability of cochlear amplification.