Cochlear outer hair cell electromotility enhances organ of Corti motion on a cycle-by-cycle basis at high frequencies in vivo

• DOI: 10.1073/pnas.2025206118
• Publication Date: 2021-10-22T20:36:30Z
• Authors: James B. Dewey; Alessandro Altoè; Christopher A. Shera; Brian E. Applegate; John S. Oghalai
• Keywords: Male; 0301 basic medicine; 0303 health sciences; Molecular Motor Proteins; Movement; Models, Biological; Vibration; Mice, Mutant Strains; Cochlea; Electrophysiology; Hair Cells, Auditory, Outer; Mice; 03 medical and health sciences; Sound; Acoustic Stimulation; Hearing; Nonlinear Dynamics; Mice, Inbred CBA; Animals; Female; Organ of Corti; Tomography, Optical Coherence

Significance The remarkable high-frequency sensitivity of mammalian hearing depends on the amplification of sound-evoked cochlear vibrations by outer hair cells. One way that outer hair cells are proposed to generate amplifying forces is through voltage-driven changes in cell length. However, it remains unclear whether this electromotility can work fast enough in vivo to provide amplification at the necessary frequencies. Here, we show that sound elicits motions within the living mouse cochlea that are fully consistent with electromotility. These motions are large relative to the motion of the underlying cochlear partition, including at high frequencies. The data therefore suggest that electromotility can indeed provide high-speed amplification in vivo.