Outer Hair Cell Electromotility & the Cochlear Amplifier

Outer hair cells (OHCs) do something no other mammalian cell does: their lateral-wall motor protein, prestin, changes the cell's own length tens of thousands of times per second, in step with sound. This simulator renders a local patch of the organ of Corti — a row of OHCs sitting between the basilar and tectorial membranes — and drives each cell's receptor potential through a real RC low-pass filter before feeding it into a prestin length-change model. The resulting electromotile force is fed back into the basilar membrane's vibration, visually reproducing the cochlear amplifier's boost in gain and its well-known rolloff once the stimulus frequency climbs past the membrane's own RC corner frequency. Live readouts track the filtered receptor potential, the cell's contraction amplitude in nanometers, and the resulting amplification in decibels relative to a passive (non-motile) cochlea.