Outer Hair Cell Electromotility & the Cochlear Amplifier (2D)

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 2D simulator models a full row of basilar-membrane segments, each with its own characteristic frequency and its own local OHC, and integrates a genuine closed feedback loop frame by frame — local BM motion drives a mechanotransduction receptor potential, an RC membrane filter shapes it, a saturating prestin motor converts it into a length change, and that length change is fed straight back into the very same segment's equation of motion, in phase with the traveling wave. The live envelope plot compares this active, electromotility-boosted response against a passive reference computed with the identical stimulus and zero feedback, while sliders for incoming sound amplitude and prestin function let you dial the cochlear amplifier from fully healthy down to the flattened, desensitized tuning of real prestin-dependent hearing loss.