Henson O W, Xie D H, Keating A W, Henson M M
Department of Cell Biology and Anatomy, University of North Carolina at Chapel Hill 27599, USA.
Hear Res. 1995 Jun;86(1-2):111-24. doi: 10.1016/0378-5955(95)00061-8.
In the unanesthetized mustached bat, stimulation of the ear with an acoustic transient produces damped oscillations which are evident in the cochlear microphonic potential. In this report we demonstrate how the decay time of these oscillations is affected by broadband noise presented to the contralateral ear (CLN). In the absence of CLN, the mean decay time was 1.94 +/- 0.23 ms, but during the presentation of CLN the decay time consistently decreased. The changes were finely graded, the higher the CLN, the greater the change. The effect could be maintained at a constant level for extended periods of time and this was evident when the CLN exceeded 40 dB SPL. The latency of the reflex for 64 dB noise was about 11 ms and near maximum changes occurred within 15 ms of CLN onset. Sectioning medial efferent nerve fibers in the floor of the fourth ventricle or the administration of a single dose of gentamicin eliminated changes produced by CLN. The prominence of CM responses to damped oscillations and the robust changes in response to CLN make the mustached bat an excellent model for studying the influence of the medial efferent system on cochlear mechanics.
在未麻醉的有须蝙蝠中，用声瞬变刺激耳朵会产生阻尼振荡，这在耳蜗微音器电位中很明显。在本报告中，我们展示了这些振荡的衰减时间是如何受到施加于对侧耳朵的宽带噪声（CLN）影响的。在没有CLN的情况下，平均衰减时间为1.94±0.23毫秒，但在呈现CLN期间，衰减时间持续下降。变化是精细分级的，CLN越高，变化越大。当CLN超过40 dB SPL时，这种效应可以在很长一段时间内保持在恒定水平，这很明显。64 dB噪声的反射潜伏期约为11毫秒，在CLN开始后15毫秒内发生了接近最大的变化。切断第四脑室底部的内侧传出神经纤维或单次注射庆大霉素消除了CLN产生的变化。CM对阻尼振荡反应的突出以及对CLN反应的强烈变化，使有须蝙蝠成为研究内侧传出系统对耳蜗力学影响的优秀模型。
