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Updated: Jan 29, 2026

Stereocilia Bundle Imaging with Nanoscale Resolution in Live Mammalian Auditory Hair Cells
Published on: January 21, 2021
Nanoscale Poroelasticity of the Tectorial Membrane Determines Hair Bundle Deflections
Jonathan B Sellon1, Mojtaba Azadi2,3,4, Ramin Oftadeh3,4
1Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Abstract:
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.
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