Fig. 8.

Auditory brainstem responses in adultfz4(−/−) mice reveal a peripheral hearing defect. Representative ABRs in 11-month-old fz4(+/+) andfz4(−/−) mice are shown. The click stimulus at the indicated sound pressure levels (dB SPL) triggers the line sweep and occurs at the 0 msec position. Each traceis an average of 1000 responses. The fz4(+/+) mouse shows a threshold sensitivity of ∼60 dB SPL, whereas thefz4(−/−) littermate shows no response at any of the stimulus intensities tested. This fz4(−/−) mouse also shows no startle reflex when tested with a stimulus generated by striking two metal rods.