Fig. 1.

Auditory tests in Otog^−/− and Otogl^−/− mice. Results for Otog^−/− (diagrams on the left) and Otogl^−/− (diagrams on the right) mutant mice and for aged-matched Otog^+/− and Otogl^+/− controls are presented in blue and in red/brown, respectively (different shades of blue and red/brown for different ages). The numbers of animals studied for each genotype are indicated in brackets. (A) ABR thresholds (mean ± SD) in response to short tone pips at different frequencies (horizontal axis) and at different ages. (B) Masking tuning curves in P28 mice (mean ± SD) showing the intensity level against frequency of a continuous tone (masker) required for a 50% decrease in amplitude of the CAP produced by a 10-kHz tone pip (test tone) presented at 10 dB above the ABR threshold. (C) Steady-state CM potential recorded in P16 mice with an electrode located at the round window, and produced by a long 5-kHz tone pip at 95 dB SPL. Note the asymmetry and phase shifts of the waveforms in the mutant mice relative to the control mice. (D) DPOAE thresholds (mean ± SD) for 2-tone stimuli (frequencies f₁ and f₂, at equal intensities) across the f₂ frequency in P16 mice. Vertical arrows indicate the absence of DPOAE for the maximal intensity of the stimulus (75 dB SPL).