Zwislocki J J
Hear Res. 1986;22:155-69. doi: 10.1016/0378-5955(86)90091-2.
A large number of experimental results on basilar-membrane vibration, cochlear microphonics, hair-cell receptor potentials, and spike rates in auditory nerve afferents are brought together to arrive at a comprehensive concept of cochlear mechanics, including hair-cell stimulation. Beginning with basilar-membrane tuning curves, we note that some of their most detailed determinations reveal a small notch and a secondary maximum above the best frequency in addition to sharp tuning. These features tend to become more prominent as the sharpness of tuning decreases. They cannot be accounted for on the assumption that the cochlear partition represents a simple second-order system consisting of distributed, elastically suspended mass. A higher order system is required. The cross-sectional structure of the partition suggests a fifth-order system made up of two sets of distributed resonators, one consisting essentially of the distributed mass of the organ of Corti supported by the stiffness of the basilar membrane, the other of the tectorial-membrane mass and its elastic attachment to the spiral limbus. The stiff stereocilia of the outer hair cells appear to serve as the main elastic coupling between the two resonator sets. Interaction of the two resonator sets is brought into evidence particularly clearly by weakening the coupling between the tectorial membrane and the organ of Corti. This can be achieved by manipulating the tectorial membrane with a microelectrode without affecting the endolymphatic potential. The partial decoupling leads to a transformation of a unimodal CM transfer function into a bimodal one. Except for the stiffness of the tectorial-membrane attachment to the limbus, the masses and stiffnesses involved in the two coupled resonator systems can be estimated independently on the basis of available measurements. Their application to an approximate computer model of the cochlea produced a cochlear frequency map consistent with experimental findings. The computer model, whose elements are in one-to-one correspondence with the gross elements of the cochlear partition, reproduces approximately the fundamental amplitude and phase characteristics of the measured basilar-membrane vibration. In particular, it reproduces the notch and the secondary maximum located above the best frequency. Our current computer model is linear and does not reproduce the known cochlear distortion products. Nevertheless, variation of those of its stiffness and resistance elements that correspond to the hair-cell stereocilia has allowed us to reproduce typical changes in basilar-membrane vibration, which accompany changes in sound intensity or cochlear deterioration.(ABSTRACT TRUNCATED AT 400 WORDS)
大量关于基底膜振动、耳蜗微音器电位、毛细胞感受器电位以及听神经传入纤维放电率的实验结果被汇总起来，以形成一个包括毛细胞刺激在内的耳蜗力学的综合概念。从基底膜调谐曲线开始，我们注意到，除了尖锐调谐外，其一些最详细的测定还揭示了一个小凹口以及在最佳频率之上的一个次最大值。随着调谐锐度的降低，这些特征往往会变得更加突出。基于耳蜗隔板代表一个由分布的、弹性悬挂质量组成的简单二阶系统这一假设，无法解释这些特征。需要一个更高阶的系统。隔板的横截面结构表明是一个由两组分布谐振器组成的五阶系统，一组基本上由柯蒂氏器的分布质量组成，由基底膜的刚度支撑，另一组由盖膜质量及其与螺旋缘的弹性附着组成。外毛细胞坚硬的静纤毛似乎是两组谐振器之间的主要弹性耦合。通过削弱盖膜与柯蒂氏器之间的耦合，两组谐振器之间的相互作用特别清晰地显现出来。这可以通过用微电极操纵盖膜而不影响内淋巴电位来实现。部分解耦导致单峰CM传递函数转变为双峰传递函数。除了盖膜与螺旋缘附着的刚度外，两个耦合谐振器系统中涉及的质量和刚度可以根据现有测量独立估计。将它们应用于耳蜗的近似计算机模型，产生了与实验结果一致的耳蜗频率图。该计算机模型的元件与耳蜗隔板的大体元件一一对应，大致再现了测量的基底膜振动的基本幅度和相位特征。特别是，它再现了位于最佳频率之上的凹口和次最大值。我们目前的计算机模型是线性的，不能再现已知的耳蜗畸变产物。然而，改变其与毛细胞静纤毛相对应的刚度和电阻元件，使我们能够再现基底膜振动的典型变化，这些变化伴随着声强变化或耳蜗退化。（摘要截于400字）
