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Why does bending stereocilia in the opposite direction inhibit a hair cell?

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Diagram showing auditory mechanisms in insects, including labeled illustrations of a scolophore organ, the mosquito ear with antenna shaft and scolophores, the cicada ear with auditory capsule and tympanic membrane, and the grasshopper ear with sensory body and tympanic membrane. — sound reception Auditory mechanisms in insects. (Left) A scolophore organ. (Top right) The mosquito ear. (Centre right) The ear of the cicada *Magicicada septendecim*. (Bottom right) The ear of the grasshopper.

In the context of sound reception, the inhibition of a hair cell occurs because of the mechanical regulation of ion channels located on the stereocilia.

When stereocilia are deflected in the direction of increasing length, these ion channels open, allowing potassium ions to flow into the cell, which depolarizes and excites the hair cell. Conversely, when the stereocilia are bent in the opposite direction—away from the direction of increasing length or away from the kinocilium—the ion channels are physically shut. This closure prevents the influx of potassium ions, leading to the hyperpolarization, or inhibition, of the hair cell.12