The frequency limit of outer hair cell motility measured in vivo

eLife

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[1] Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands;

关键词: Mongolian gerbil;    outer hair cells;    electromotility;    cochlear amplifier;    cochlear mechanics;    hearing;    Other;   

DOI  :  10.7554/eLife.47667

来源: publisher

【 摘 要 】

10.7554/eLife.47667.001Outer hair cells (OHCs) in the mammalian ear exhibit electromotility, electrically driven somatic length changes that are thought to mechanically amplify sound-evoked vibrations. For this amplification to work, OHCs must respond to sounds on a cycle-by-cycle basis even at frequencies that exceed the low-pass corner frequency of their cell membranes. Using in vivo optical vibrometry we tested this theory by measuring sound-evoked motility in the 13–25 kHz region of the gerbil cochlea. OHC vibrations were strongly rectified, and motility exhibited first-order low-pass characteristics with corner frequencies around 3 kHz– more than 2.5 octaves below the frequencies the OHCs are expected to amplify. These observations lead us to suggest that the OHCs operate more like the envelope detectors in a classical gain-control scheme than like high-frequency sound amplifiers. These findings call for a fundamental reconsideration of the role of the OHCs in cochlear function and the causes of cochlear hearing loss.

【 授权许可】

CC BY