Medial olivocochlear efferent inhibition of basilar-membrane responses to clicks: Evidence for two modes of cochlear mechanical excitation
Medial olivocochlear efferent inhibition of basilar-membrane responses to clicks: Evidence for two modes of cochlear mechanical excitation
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DOI：
10.1121/1.2949435
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发表时间：
2008-08-01
影响因子：
2.4
通讯作者：
Cooper, Nigel P.
中科院分区：
文献类型：
--
作者：
Guinan, John J., Jr.;Cooper, Nigel P.
哺乳动物耳蜗力学的概念是基于基底膜（BM）行波，这些行波沿耳蜗长度随频率缩放，由外毛细胞（ohc）放大，并以简单的方式激发内毛细胞和听神经（AN）纤维。然而，最近的实验工作表明，AN对点击的反应的中耳蜗（MOC）抑制并不符合这一图景。为了验证这种ANIP抑制可能是由行波的未知方面引起的，还是由MOC引起的抑制引起的，我们测量了MOC对豚鼠和栗鼠耳蜗基底转动时脑损伤反应的影响。MOC刺激对BM点击反应的抑制呈时间依赖性和水平依赖性。抑制作用在反应的前半个周期中未见，但逐渐增强，最终增加了反应的衰减率。MOC刺激在响应波形中也产生了小的相导联，但对瞬时频率和响应的起伏影响不大。这些数据，加上最近的AN数据，支持了moc诱发的行波抑制和ANIP反应是不同现象的假设，并表明OHCs可以影响哺乳动物耳蜗中至少两种不同的兴奋模式。(c) 2008年美国声学学会。
Conceptualizations of mammalian cochlear mechanics are based on basilar-membrane (BM) traveling waves that scale with frequency along the length of the cochlea, are amplified by outer hair cells (OHCs), and excite inner hair cells and auditory-nerve (AN) fibers in a simple way. However, recent experimental work has shown medial-olivocochlear (MOC) inhibition of AN responses to clicks that do not fit with this picture. To test whether this AN-initial-peak (ANIP) inhibition might result from hitherto unrecognized aspects of the traveling-wave or MOC-evoked inhibition, MOC effects on BM responses to clicks in the basal turns of guinea pig and chinchilla cochleae were measured. MOC stimulation inhibited BM click responses in a time and level dependent manner. Inhibition was not seen during the first half-cycle of the responses, but built up gradually, and ultimately increased the responses' decay rates. MOC stimulation also produced small phase leads in the response wave forms, but had little effect on the instantaneous frequency or the waxing and waning of the responses. These data, plus recent AN data, support the hypothesis that the MOC-evoked inhibitions of the traveling wave and of the ANIP response are separate phenomena, and indicate that the OHCs can affect at least two separate modes of excitation in the mammalian cochlea. (c) 2008 Acoustical Society of America.