[Electromechanical transduction: influence of the outer hair cells on the motion of the organ of Corti].

BACKGROUND

The somatic electromotility of the outer hair cells can be induced by an extracellular electrical field. This enables us to investigate the electromechanically induced motion of the organ of Corti.

METHODS

The electrically induced motion of the guinea-pig organ of Corti was measured with a laser Doppler vibrometer in three cochlear turns at ten radial positions on the reticular lamina (RL) and six on each of the upper and lower surfaces of the tectorial membrane (TM).

RESULTS AND CONCLUSIONS

We found a complex vibration pattern of the RL and TM, leading to a stimulus synchronous modulation of the depth of the subtectorial space in the region of the inner hair cells (IHCs). This modulation causes radial fluid motion inside the space up to at least 3 kHz. This motion is capable of deflecting the IHC stereocilia and provides an amplification mechanism additional to that associated with basilar-membrane motion.