MECHANICS OF THE ORGAN OF CORTI

目的是了解机械活动的作用 内耳将声音转化为神经信号的过程 刺激. 这将是数学研究的延续 包括适当的波浪分析技术， 流体和固体的基本力学。 这其中的根本 工作是只使用物理参数的数学 模型 我们对曲线拟合练习不感兴趣。 在 在过去的一段时间里，微观力学的研究表明，大多数 流行的模型与解剖学事实相矛盾， 材料性能 然而，人们强烈支持 Pickles及其同事提出的纤毛行为， 与Flock的睫状体硬度测量结果一致， Strelioff，这是，反过来，与已知的属性一致， 肌动蛋白。 结论是尖端纤维屈曲的开始 发生在0.1 nm左右的位移处，这提供了强的 在激励阈值水平下的机械非线性。 一 外毛细胞动电活动的模型， 由Brownell的测量和建议激发，表明 这将是有效的，在高频率，远远超过20千赫。 从而为主动机制和非线性提供了坚实的基础 似乎已经建立。 在下一阶段的努力中，OHC电动力学模型沿着 与戴维斯电池模型的一般电场，将 将其并入三维耳蜗模型中。 非常 重要的是基底膜之间的相位关系 OHC纤毛上的位移和剪切力。 我们有 以前开发的机械逼真的模型 Corti器官的扭曲和振荡， 流体在覆膜下膜区域中的流动。 这些的耦合对于正确的相位关系是必要的。 期望OHC电泳将提供 作用在基底膜上的显著力，因此 生理上脆弱的反应的尖锐化 基底膜和IHC纤毛。 这将被计算为 矩形截面的直耳蜗模型。 同样令人困惑的是， 耳蜗解剖学，迄今为止， 精心分析。 分析的实质性延伸 包括曲率和不连续性影响的能力 弹性组织和耳蜗液都将被带走， 使用非常大的有限元方法。

The objective is to understand the role of the mechanical activity of the inner ear in the transformation of sound into neural stimulation. This will be a continuation of mathematical studies involving appropriate techniques of wave analysis and the fundamental mechanics of fluids and solids. Fundamental to this work is the use of only physical parameters in the mathematical models. We are not interested in curve-fitting exercises. in the past period, a study of the micromechanics indicated that most popular models contradict the facts of anatomy and reasonable material properties. Strong support was found, however, for the behavior of cilia suggested by Pickles and co-workers, which is consistent with the measurements of ciliary stiffness of Flock and Strelioff, which are, in turn, consistent with known properties of actin. A conclusion is that the onset of buckling of the tip fibers occurs at displacements around 0.1 nm, which provides a strong mechanical nonlinearity at threshold levels of excitation. A model for the electrokinetic activity of the outer hair cells, motivated by measurements and suggestion by Brownell, indicates that this will be effective at high frequencies, well over 20 kHz. Thus a substantial basis for an active mechanism and nonlinearity appears to have been established. In the next period of effort, the OHC electrokinetic model along with the Davis battery model for the general electrical fields, will be incorporated into the three dimensional cochlear model. Very important is the phase relation between the basilar membrane displacement and shear force on the OHC cilia. We have previously developed realistic models for the mechanical distortion of the organ of Corti and for the oscillating and streaming flow of the fluid in the sub-tectorial membrane region. The coupling of these is necessary for the correct phase relations. The expectation is that the OHC electrophoresis will provide significant forces acting on the basilar membrane, and thus a physiologically vulnerable sharpening of the response of the basilar membrane and the IHC cilia. This will be computed for the straight cochlear model with rectangular cross section. Equally puzzling are the reasons for various features of the gross cochlear anatomy, which so far have eluded both simple and elaborate analysis. A substantial extension of the analysis capability to include the effect of curvature and discontinuities of both the elastic tissue and the cochlear fluids will be carried out, using the very large finite element approach.