Different vibration modes of the Organ of Corti due to mechanical and electrical stimuli

The organ of Corti complex (OCC) is highly organized with structurally significant matrices such as the tectorial and basilar membranes and cells such as the pillar cells, Deiters cells and outer hair cells. It is getting clearer that the fine structures in the OCC vibrates out of phase under certain conditions. The functional consequence of the complex vibration modes is unclear. We present our computational and experimental results on different vibration modes of the OCC. Using a custom-fabricated micro-chamber, the vibrations of isolate OCC due to mechanical and an electrical impulse were measured. The same conditions were simulated with a computer model. When there is no outer hair cell feedback, the OCC fine structures vibrate in phase upon a mechanical impulse. With the outer hair cell feedback, initial response is similar to the passive case, but after first couple of oscillatory cycles, the top and bottom surfaces of the OCC vibrate out of phase, similar to the response to an electrical impulse. O...