Finding the impedance of the organ of Corti.
Finding the impedance of the organ of Corti.
复制标题
求柯蒂氏器的阻抗。
DOI：
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发表时间：
1991
影响因子：
2.4
通讯作者：
George Zweig
中科院分区：
文献类型：
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作者：
George Zweig
基底膜对纯音的非线性响应的测量结果表明，对于中等膜速度，基底膜的非线性响应具有简单的形式：V（x，f; Vu）/Vu近似为[V（x，f）/Vu]v（x，f），f小于或等于fc（x），其中响应V是测量位置x处的膜的速度，Vu是脐速度，f是刺激的频率，并且fc（x）是局部特征频率。从数据中确定函数v（x，f）和V（x，f）的频率依赖性，并且v（x，f）和ln V（x，f）被示出为在复频率平面的下半部分中的解析函数，其中Re [v（x，f）]是f在固定x处的单调递增函数。基底膜运动的线性极限由传递函数T（x，f）=（V/V1）v/（1-v）表征，该传递函数通过将V（x，f;Vu）/Vu外推到小的膜速度V1来估计。T（x，f）和ln T（x，f）在复频率平面的下半部分是解析函数。传递函数的振幅的倒数在f处有一个深的凹陷，近似fc（x），在较低频率处有一个宽的肩部，与神经阈值调谐曲线有着惊人的相似之处。本文利用T（x，f）的函数形式，导出了柯替氏器截面运动的方程。每个部分的行为就像一个负阻尼谐振子稳定在时间t的反馈力成比例的速度在前一个时间t-tau。时间延迟τ与振荡器周期成比例[τ约为1.75/fc（x）]。像激光一样，Corti器官将能量泵入谐波行波。与激光不同，当行波接近最大膜速度点[fc（x）约为f]时，能量流的方向突然反转。所有积累的波能量然后被泵回Corti器官的一小部分，在那里可能发生转导。外毛细胞是耳蜗放大器的负阻尼和负反馈的主动元件。
Measurements of the nonlinear response of the basilar membrane to a pure tone are shown to have a simple form for moderate membrane velocities: V(x,f;Vu)/Vu approximately [V(x,f)/Vu]v(x,f), f less than or equal to fc(x), where the response V is the velocity of the membrane at measurement position x, Vu is the umbo velocity, f is the frequency of the stimulus, and fc(x) is the local characteristic frequency. The frequency dependence of the functions v(x,f) and V(x,f) is determined from the data, and v(x,f) and ln V(x,f) are shown to be analytic functions in the lower half of the complex frequency plane, with Re [v(x,f)] a monotonically increasing function of f at fixed x. The linear limit of basilar membrane motion is characterized by a transfer function T(x,f) = (V/V1)v/(1-v), estimated by extrapolating V(x,f;Vu)/Vu to a small membrane velocity V1.T(x,f) and ln T(x,f) are shown to be analytic functions in the lower half of the complex frequency plane. The inverse of the amplitude of the transfer function, which has both a deep dip at f approximately fc(x) and a broad shoulder at lower frequencies, bears a striking resemblance to the neural threshold tuning curve. The functional form of T(x,f) is used to deduce the equation governing the motion of a section of the organ of Corti. Each section acts like a negatively damped harmonic oscillator stabilized at time t by a feedback force proportional to the velocity at the previous time t-tau. The time delay tau is proportional to the oscillator period [tau approximately 1.75/fc(x)]. Like a laser, the organ of Corti pumps energy into harmonic traveling waves. Unlike the laser, the direction of energy flow abruptly reverses as the traveling wave approaches the point of maximum membrane velocity [fc(x) approximately f]. All accumulated wave energy is then pumped back into a small section of the organ of Corti where transduction presumably occurs. Outer hair cells are conjectured to be active elements contributing to the negative damping and feedback of the cochlear amplifier.