Fig. 8.

mABR measurements and acoustically-associative freezing behavior of DT-injected Prestin-DTR mice. A Representative example of mABR signals in an injected littermate control mouse. B Representative example of mABR signals in an injected Prestin-DTR/+ mouse. C mABR thresholds in the Prestin-DTR/+ mice (green) and control littermate mice (without Prestin-DTR expression, dark gray). All mice were injected with DT. Note that the injected Prestin-DTR/+ mice show no detectable mABR response at 90 dB SPL at frequencies from 54 kHz to 80 kHz. Control vs injected Prestin-DTR/+, Mann-Whitney test, **P = 0.0012 at 40 kHz, ***P = 0.0006 at other frequencies. D Representative examples of locomotion of control and Prestin-DTR/+ mice before (gray, 30 s), during (red, 10 s), and after (blue, 30 s) the pure-tone sound cue at 90 dB SPL. The mice had been trained to pair either the 16-kHz or the 63-kHz cue with the foot-shock-induced freezing. Dots indicate the location of a mouse every 0.5 s. Injected littermate mice were used as controls. E, F Percentage freezing time with the 16-kHz cue (E) or the 63-kHz cue (F). Pre-cue vs Post-cue, paired t-test, Prestin-DTR/+ mice at 16 kHz, t₆ = 13.81, ****P <0.0001; Control mice at 16 kHz, t₅ = 9.774, ***P = 0.0002; Prestin-DTR/+ mice at 63 kHz, t₈ = 0.1187, P = 0.9094; Control mice at 63 kHz, t₅ = 5.386, **P = 0.003. In (C), (E), and (F), data are presented as the mean ± SD. N numbers are shown in panels. All the mice were ~1 month old.