Fig. 5.

Despite low-pass filtering, cycle-by-cycle deformations of the OHC region are large relative to the motion of the underlying BM at all frequencies. (A and B) Average vector difference between RL and OHC-DC displacements, normalized to BM displacement, for 70-dB SPL tones swept in frequency (A) or 9-kHz tones swept in level (B). The vector difference approximates the net deformation within the OHC region induced by electromotility. Despite the steep drop in deformation magnitude (re BM) for 70-dB SPL tones above ∼2 kHz, the deformations were still ∼2× as large as the BM displacement near the CF. At low stimulus levels, deformations were ∼4× as large as BM displacements.