Frequency-dependent enhancement of basilar membrane velocity during olivocochlear bundle stimulation
作者:
David F. Dolan,
Meng He Guo,
Alfred L. Nuttall,
期刊:
The Journal of the Acoustical Society of America
(AIP Available online 1997)
卷期:
Volume 102,
issue 6
页码: 3587-3596
ISSN:0001-4966
年代: 1997
DOI:10.1121/1.421008
出版商: Acoustical Society of America
数据来源: AIP
摘要:
Basilar membrane (BM) velocity responses were measured in the presence of olivocochlear bundle (OCB) stimulation. Frequency threshold tuning curves (FTCs) were derived from tone-evoked input–output (I/O) functions. Efferent nerve activation produced decreases in velocity amplitude for frequencies around best frequency (BF) at low stimulus levels with little or no effect for stimuli well below the BF. A level-dependent efferent reduction/enhancement of BM velocity was found for certain stimulus frequencies above the BF. Efferent activation either had no effect or caused small reductions in the velocity response produced by low level sound, whereas, at higher stimulus levels, efferent activationincreasedthe velocity response. The derived FTCs, therefore, showed criterion-dependent changes with efferent activation. For low BM criterion velocities, FTCs showed the classic desensitization of the tip region without a shift of BF. Some BM velocity criterion values showed FTCs with an expanded high-frequency response area, also without a shift of BF. The results suggest that the effect of OCB activation changes the gain of the voltage-dependent outer hair cell motility such that BM velocity response near BF is decreased while increasing the response for tones well above BF.
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