Power Efficiency of Outer Hair Cell Somatic Electromotility
Figure 8
OHC length vs. best frequency.
OHCs vary their length systematically with the place-principle of best frequency sensitivity in the cochlea. A) Anatomical lengths of hair cells in the cochlea (red symbols connected by lines, [78]) are compared to the length predicted by the present model to achieve maximum power conversion efficiency (frequency of peak in Fig. 7). Solid black curves show model predictions for peak efficiencies under control (high Zb) conditions while dashed green curves show predictions during efferent activation (low Zb). B) The model predicts that peak efficiencies vary systematically with OHC length, with cells tuned near 3–4 kHz being the most efficient (B, solid black curve). All cells are predicted to become inefficient when the basal electrical impedance (Zb) is reduced thorough activation of the efferent system (B, dashed green curve).