Dynamics of cochlear nonlinearity: Automatic gain control or instantaneous damping?
Dynamics of cochlear nonlinearity: Automatic gain control or instantaneous damping?
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DOI：
10.1121/1.5014039
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发表时间：
2017-12-01
影响因子：
2.4
通讯作者：
Shera, Christopher A.
中科院分区：
文献类型：
--
作者：
Altoe, Alessandro;Charaziak, Karolina K.;Shera, Christopher A.
基底膜运动的测量表明，耳蜗力学响应的压缩非线性不是瞬时现象。由于这个原因，耳蜗放大器被认为包含一个以有限反应时间为特征的自动增益控制（AGC）机制。本文研究了瞬态非线性阻尼对振动系统响应的影响。主要结果是：(i)瞬时非线性阻尼产生的非瞬时增益控制明显不同于典型的AGC策略；（ii）有限反应时间所隐含的压缩非线性动力学与沙鼠基底膜上测量的非线性动力学不一致；（iii）相反，这些非线性动力学可以使用具有瞬时非线性阻尼的谐振子来再现。此外，现有的包括瞬时增益控制机制的耳蜗模型捕获了BM非线性的主要动力学。因此，具有有限反应时间的AGC系统似乎既没有必要也不足以解释耳蜗中的非线性增益控制。(C) 2017年美国声学学会。
Measurements of basilar-membrane (BM) motion show that the compressive nonlinearity of cochlear mechanical responses is not an instantaneous phenomenon. For this reason, the cochlear amplifier has been thought to incorporate an automatic gain control (AGC) mechanism characterized by a finite reaction time. This paper studies the effect of instantaneous nonlinear damping on the responses of oscillatory systems. The principal results are that (i) instantaneous nonlinear damping produces a noninstantaneous gain control that differs markedly from typical AGC strategies; (ii) the kinetics of compressive nonlinearity implied by the finite reaction time of an AGC system appear inconsistent with the nonlinear dynamics measured on the gerbil basilar membrane; and (iii) conversely, those nonlinear dynamics can be reproduced using an harmonic oscillator with instantaneous nonlinear damping. Furthermore, existing cochlear models that include instantaneous gain-control mechanisms capture the principal kinetics of BM nonlinearity. Thus, an AGC system with finite reaction time appears neither necessary nor sufficient to explain nonlinear gain control in the cochlea. (C) 2017 Acoustical Society of America.