Power Efficiency of Outer Hair Cell Somatic Electromotility
Figure 4
Displacement gain vs. cell length.
Sinusoidal control of the extracellular voltage around the base of OHCs (microchamber configuration) evokes movment proportional to the voltage and dependent upon cell length. Symbols show microchamber data from Frank et al. [48] in comparison to the prediction of the present model (solid black curve, Eq. 18 at base). The same model simulated for voltage clamp conditions (solid blue curve, Eq. 17 at base) predicts voltage clamp data from Ashmore [15] and Santos-Sacchi, [62]. Also shown is the model prediction after increasing the basal membrane conductance by 2.2× (dashed curve, low Zb) to simulate application of Ach in the microchamber configuration. Hence, efferent action lowering Zb is predicted to increase OHC movement gain in the microchamber, but sharply attenuate the gain under physiological stimulation due to short circuit of the base of the cell.