Acoustic sensitivity and frequency selectivity of the guinea pig inner ear after total destruction of cochlear hair cells Free

After selective destruction of all cochlear hair cells and preservation of vestibular hair cells in guinea pigs treated with massive doses of the aminoglycosidic antibiotic amikacin, acoustic stimuli can still evoke a series of neural responses recordable from the inner ear up to the auditory cortex [Y. Cazals et al., Science 210, 183–186 (1980)]. The responses present equivalent absolute thresholds from 63 Hz to 16 kHz and exhibit well defined tuning curves of a low‐pass filter type which make them akin to responses from hearing organs. Complete or partial destruction of the vestibule combined with a complete cochlear destruction demonstrate that such responses originate from the inner ear and most likely from the saccule. These results support the hypothesis of a hearing function of the saccule in a mammal, a role already demonstrated for lower vertebrates. The tuning properties could originate from the coupling of the ciclia with the otolithic membrane. [Work supported by Inserm grant 8‐ASR‐6 and DGRST grant DN/80.7.0233.]