In situ motions of individual inner-hair-cell stereocilia from stapes stimulation in adult mice

In vertebrate hearing organs, mechanical vibrations are converted to ionic currents through mechanoelectrical-transduction (MET) channels. Concerted stereocilia motion produces an ensemble MET current driving the hair-cell receptor potential. Mammalian cochleae are unique in that the tuning of sensory cells is determined by their mechanical environment and the mode of hair-bundle stimulation that their environment creates. However, little is known about the in situ intra-hair-bundle motions of stereocilia relative to one another, or to their environment. In this study, high-speed imaging allowed the stereocilium and cell-body motions of inner hair cells to be monitored in an ex vivo organ of Corti (OoC) mouse preparation. We have found that the OoC rotates about the base of the inner pillar cell, the hair bundle rotates about its base and lags behind the motion of the apical surface of the cell, and the individual stereocilia move semi-independently within a given hair bundle.

Automated summary

In vertebrate hearing organs, mechanical vibrations are converted to ionic currents through mechanoelectrical-transduction (MET) channels. High-speed imaging in an ex vivo organ of Corti (OoC) mouse preparation revealed how the OoC and hair bundle rotate, and how individual stereocilia move semi-independently within a given hair bundle. This study sheds light on the in situ intra-hair-bundle motions of stereocilia, providing insight into the unique tuning mechanisms of mammalian cochleae.