Much of the hospital's success in identifying and treating children with hearing loss is the result of the rapid transfer of research findings from laboratories to clinic and bedside.
Areas of Research - Neurobiological Studies of Hearing - Communication Engineering Laboratory
Outer Hair Cell Motility
The following animated cartoons illustrate the motility of outer hair cells (OHC) in three scenes. The OHC is shown in isolation, as it would be observed in vitro.
In the first scene, the hair bundles are being deflected, but there is no change in the length of the cell. When a voltage difference is present between the top and sides of the cell, deflection of the hair bundles modulates an electrical current passing through the cell.
In the second scene, the cell contracts in-phase with deflection of the hair bundle toward the tallest stereocilia. The current through the cell increases with deflection in this direction. If the current is modulated slowly (compared to 1 kHz), then the voltage across the lateral membrane will be in-phase with the current. Conformational changes in many voltage sensitive molecules situated within the lateral membrane cause the length of the cell to change. The diameter of the cell increases slightly as the cell contracts to maintain constant cell volume.
In the third scene , the contraction lags by 90 degrees (or one-quarter of a cycle) behind hair bundle deflection. When the voltage and current are out of phase, the cell length changes with the voltage instead of the current.