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. 2018 Jan 12;7:e30241. doi: 10.7554/eLife.30241

Figure 2. Hearing in RIBEYE knockout mice.

Figure 2.

(A) Distortion products of otoacoustic emissions (DPOAE) show no significant differences in the tested frequency range (4–46 kHz in half-octave increments) between KO (red, n = 30) and WT littermates (blue, n = 22), suggesting normal outer hair cell function. (B) Auditory brainstem response (ABR) measurements in the tested frequency range (4–46 kHz in half-octave increments) reveal a small (≈ 10 dB SPL) but significant threshold shift in KO mice (red, n = 28) over their WT littermates (blue, n = 22) at P21-P22. (C) Mean ABR waveforms to 5 ms tone pips at 23 kHz at 60 dB SPL from KO (red, n = 30) and WT littermates (blue, n = 24) reveal a decrease in amplitude of the first ABR wave in KO. (D) Quantification of peak to peak amplitude (wave I: p1–n1) differences between KO (red) and WT littermates (blue) at 23 kHz were significant over most sound pressure levels (20 dB SPL, p>0.05; 30 and 60 dB SPL, p≤0.01; 40–60 dB SPL, p≤0.001). (E) First peak amplitudes normalized to their respective values at 60 dB SPL. Amplitudes scale with their maximum value in WT and KO. (F) First peak latency (p1) is not significantly altered in KO mice. For wave I amplitude and latency analysis (D–F), the n-number varied between sound pressure levels by a clearly detectable first wave and speaker calibration, n of WT/KO — 20 dB, 11/7; 30 dB, 21/11; 40 dB, 23/22; 50 dB, 23/26; 60 dB, 23/28; 70 dB, 5/6. Boxes represent standard deviations of the mean; whiskers and the shaded line in (C) represent standard errors of the mean. Significance levels of two-tailed unpaired t-tests: n.s., not significant; *p≤0.05; **p≤0.01; ***p≤0.001.