ACTIVE AND NONLINEAR MODELS FOR COCHLEAR MECHANICS

为了更好地理解听觉过程，已经在耳蜗建模和生理测量方面进行了许多努力。 了解正常听觉功能的过程有助于确定听力损失和耳鸣的原因。了解每个组件的形态和功能可以为开发更好的人工耳蜗和非侵入性疾病诊断过程开辟道路。非听觉系统的语音识别和信号处理的生物启发设计也是可能的，并且可能对听觉以外的应用产生重大影响。目前耳蜗力学的研究集中在确定在体内测量中看到的增强滤波和非线性压缩的来源。 自1948年首次提出有源放大过程是增强滤波源的假设以来，已经被广泛研究。 本研究提出一种全面、有效的非线性主动宏观耳蜗力学数值方法。 通过这种能力，将开发一个虚拟实验室模型测试，能够纳入最一般的非线性模型的活动和几何不均匀性。 使用混合分析和数值方法的Corti器官的微观力学，特别是外毛细胞及其连接结构，将被包括在全球响应建模。将这些预测与从生理实验获得的体内数据进行比较。 实验验证是这一建模工作的中心焦点。 与生理测量的紧密联系对于验证建模参数是重要的，最重要的是假设的转导模型与耳蜗内电位（或电流）的关系。 受控实验将用于识别换能器模型参数（例如，增益）和验证/无效的假设。

In order to better understand the hearing process, numerous efforts in cochlear modeling and physiological measurement have been undertaken. Understanding the process of normal auditory function holds the significant promise of assisting in the determination of the causes of hearing loss and tinnitus. Understanding the morphology and function of each component can lead the way to the development of better cochlear prostheses and diagnostic processes for noninvasive determination of disease. Biologically inspired designs for speech recognition and signal processing of non--auditory systems are also possible and could have a significant impact for applications other than hearing. Current research in cochlear mechanics is focussed on determining the source of the enhanced filtering and nonlinear compression seen in in vivo measurements. The hypothesis that an active amplification process is the source of the enhanced filtering has been studied widely since first proposed in 1948. In this grant a comprehensive, efficient numerical strategy for nonlinear and active macroscopic cochlear mechanics is proposed. Through this capability, a virtual laboratory for model testing will be developed capable of incorporating the most general nonlinear models for activity and geometric nonuniformity. Using a hybrid analytic and numeric approach the micromechanics of the Organ of Corti, especially the outer hair cells and their connecting structures, will be included in the global response modeling. These predictions will be compared to in vivo data obtained from physiological experiments. Experimental validation is a central focus of this modeling effort. Close ties to the physiological measurements is important to validate modeling parameters, most importantly the relation of the hypothesized transductions models to the endocochlear potential (or current). Controlled experiments will be used to both identify transducer model parameters (e.g., gains) and to validate/invalidate the hypothesis.