Figure 5.

NLC has two frequency components whose kinetics limits Q_p frequency response. Average responses from 21 cells. A, Magnitude–frequency plot of average NLC at V_h. A dual-Lorentzian fit reveals slow and fast components (A₁: 0.2453; τ₁: 1.12 ms; A₂: 0.7469; τ₂: 32.6 μs). NLC is plotted relative to values at lowest frequency, which is NLC determined from step-induced (DC) transients (Huang and Santos-Sacchi, 1993) during changes in command holding potential. Error bars indicate SE. Dotted green line is plot of faster component. B, Relationship between clamp τ and Q_p τ for three two-state models of differing rate constants, illustrating that regressions to zero clamp τ can identify each model's characteristic time constant. C, Similarly, regressions on OHC Q_p provide a limiting time constant approaching the fast τ component of NLC. D, a–d, Five cell-binned averages computed and plotted, illustrating the enhanced frequency response as clamp τ decreases (a: 153.0 ± 1.75 μs; b: 100.9 ± 1.2 μs; c: 70.9 ± 1.4 μs; d: 55.7 ± 1.9 μs. Q_p Lorentzian fits data and model are from 100 to 3200 Hz. E, Plot of Q_p at an offset voltage of 30 mV from V_h, showing that τ_Qp decreases at voltages away from V_h (with gain–bandwidth tradeoffs). Five millivolt peak AC stimulation. See text for Boltzmann mean (SE).