Interactive Organ of Corti Mechanics
A Visual C++ routine created by R.Nobili
A Visual C++ routine created by R.Nobili
The viscosity of the Deiters' cell coupling is documented by the movie shown in the left panel, which was kindly provided by Fabio Mammano. One outer hair cell was electrically stimulated by a patch-clamped pipette vaguely visible on the top-right side of the movie. The outer hair cell base is attached to the peer-shaped Deiters' cell, which stretches considerably under the action of the cell motor contraction.
The model affords an example of a sort of organ of Corti motion that is capable of undamping the oscillations of the basilar membrane. The structure formed by the triangle of Corti and the reticular lamina is assumed rigid, whilst the basilar membrane is assumed elastic. It is generally believed that the distortion of an organ of Corti segment is bimodal, as shown in the following figure:
Mode 1 follows the action of the fluid pressure difference at the opposite sites of the basilar membrane.
The effect produced by a change in the resting length of the outer hair cells is a combination of modes 1 and 2. The fast motility of the outer hair cells is responsible for the generation of a force that works so as to amplify the oscillation of the basilar membrane and the surrounding fluid.
Despite its simplicity, the model accounts well for the response of the structure to step-wise changes of outer hair cell lenght, as detected by experiments. The figure hereafter summarizes the facts:
The figure shows the extents of the basilar membrane (BM) and reticular lamina (RL) motion under the action of a current step causing a sudden contraction of the outer hair cells.
Hereafter is a view of the similar phenomenon as reproduced by the visual programme CORTI.EXE
