Siegel J H, Kim D O
Hear Res. 1982 Feb;6(2):171-82. doi: 10.1016/0378-5955(82)90052-1.
We confirm the report of Mountain (Mountain, D.C. (1980): Science 210, 77-72) that stimulating the crossed olivocochlear bundle (COCB) can change the magnitude of the distortion product (f2-f1) in the ear-canal sound pressure. Our results are extended to include (2f1-f2) as well as (f2-f1) from anesthetized chinchillas with both middle-ear muscles sectioned. In contrast to Mountain's report, the polarity of the change can be either positive, negative or absent, depending on the choice of two-tone stimulus frequencies. The influence of two-tone stimulus level is also complex, but we have not yet seen the polarity of the COCB effect change with stimulus level. The magnitude and polarity of the change in (2f1-f2) are not simply related to those for (f2-f1). The effect of COCB stimulation is abolished when scala tympani is perfused with artificial perilymph containing 10(-5) M d-tubocurarine. These results demonstrate that the COCB effect is postsynaptic, probably mediated by outer hair cells. We suggest that the normal cochlea contains an active biomechanical mechanism which reduces the damping of the cochlear-partition motion and is modulated by activating the efferents. It is thus possible that the central nervous system may be able to control the dynamics of the motion of the cochlear partition.
我们证实了芒廷（Mountain, D.C. (1980): Science 210, 77 - 72）的报告，即刺激交叉橄榄耳蜗束（COCB）可改变耳道声压中畸变产物（f2 - f1）的大小。我们的研究结果进一步扩展至包括双侧中耳肌肉切断的麻醉栗鼠的（2f1 - f2）以及（f2 - f1）。与芒廷的报告不同，根据双音刺激频率的选择，变化的极性可以是正向、负向或无变化。双音刺激强度的影响也很复杂，但我们尚未观察到COCB效应的极性随刺激强度而改变。（2f1 - f2）变化的大小和极性与（f2 - f1）的大小和极性并非简单相关。当鼓阶灌注含10⁻⁵ M d - 筒箭毒碱的人工外淋巴时，COCB刺激的效应被消除。这些结果表明，COCB效应是突触后效应，可能由外毛细胞介导。我们认为，正常耳蜗包含一种活跃的生物力学机制，该机制可降低耳蜗隔运动的阻尼，并通过激活传出神经进行调节。因此，中枢神经系统有可能能够控制耳蜗隔运动的动力学。
