Figure 2. Vibration magnitude spectra of the basilar membrane (BM, -panels a, c) and reticular lamina (RL, -panels b, d) in a sensitive guinea pig cochlea and a postmortem guinea pig cochlea.

Displacement magnitudes of vibration in nm are plotted as a function of stimulus frequency with sound level as the parameter. For these data, an auditory sensitivity loss of 12 dB is caused by the surgical preparation. Numbers against each curve represent sound levels of dB SPL at the eardrum used to stimulate the hearing organ vibration. In living animals (a, b), at 30 dB SPL, the maximum amplitude of BM vibration is 0.05 nm, the maximum displacement amplitude RL of is 0.1 nm at the best frequency of 20 kHz. In the postmortem animal(c, d), at 70 dB SPL, the maximum amplitude of BM vibration is 0.52 nm, the maximum displacement amplitude of the RL is 0.51 nm.