EXPOSING MECHANICAL IMPEDANCE OF THE COCHLEAR PARTITION

耳蜗对声压的各个频率具有选择性， 敏感的物理限制允许，并立即适应广泛的 刺激水平的范围。耳蜗手术的基础必须在于 耳蜗分区的机械和机电特性， 但人们对此知之甚少。拟议的工作旨在描述 分区的机械性能，特别是当它们涉及到 频率调谐和耳蜗运动的灵敏度。实验 蒙古沙鼠的动物意志，其解剖结构允许0.5mm 耳蜗分区的纵向范围将通过 圆窗开 将进行两组测量，均旨在确定 隔板的机械阻抗，其定义为 通过隔板的压力或力传递给隔板的运动。在 在第一组测量中，阻抗将直接在 一个点作为局部振动隔板所需的力。点 将在跨越隔板的九个径向位置处测量阻抗， 并且在两个到三个纵向位置处超过0.5 mm。 频率将从100到1000 Hz变化。的径向变化 阻抗将与分区解剖结构直接相关，表明 这些分隔元件基本上对阻抗有贡献。的 阻抗的纵向变化将相对于 预测变化，基于分区宽度的纵向变化 特征频率。第二组测量图 鼓阶颅内压三维测量。鼓阶 压力将通过圆窗开口测量，靠近 耳蜗分区，在通过特征频率（30 - 40 kHz）。鼓阶压力将参考 压力在前庭阶的一个点，相对远离 分区空间，水平和频率依赖的变化， 压力将通过限制耳蜗的形状来通知耳蜗模型。 分区阻抗，并解决主动与被动耳蜗的问题 操作对这两组测量结果的协调分析将 提出了分区运动的模式，以及其微观力学基础 议案 耳蜗是一个独特的器官，但它的非线性，动态运作 反映了信号检索、排序和分类的一般原则和策略 和转导。这些测量的目的是了解 耳蜗的复杂工作，这超出了其内在价值， 对理解生理系统的基本价值， 延伸到一般的假肢和传感系统的设计。

The cochlea is selective to individual frequencies of sound pressure, as sensitive as physical limits allow, and instantaneously adaptive to a wide range of stimulation levels. The basis for cochlear operation must lie in the mechanical and electromechanical properties of the cochlear partition, but is poorly understood. The proposed work seeks to characterize mechanical properties of the partition, especially as they relate to the frequency tuning and sensitivity of cochlear motion. The experimental animal will of the Mongolian gerbil, whose anatomy allows a 0.5mm longitudinal extent of the cochlear partition to be accessed through the round window opening. Two sets of measurements will be performed, both directed at determining the partition's mechanical impedance, which is defined as the ratio of pressure or force across the partition to the motion of the partition. In the first set of measurements, the impedance will be directly measured at a point as the force required to locally vibrate the partition. Point impedance will be measured at nine radial positions spanning the partition, and at two to three longitudinal positions over 0.5 mm. Vibration frequencies will vary from 100 to 1000 Hz. The radial variation in impedance will be directly related to the partition anatomy, indicating which partition elements contribute substantially to the impedance. The longitudinal variation in impedance will be analyzed with respect to the predicted variation, based on longitudinal variations in partition width and characteristic frequency. The second set of measurements map intracochlear pressure in scala tympani in three dimensions. Scala tympani pressure will be measured through the round window opening, close to the cochlear partition, at frequencies through the characteristic frequency (30 - 40 kHz in this region). Scala tympani pressure will be referenced to pressure at one point in scala vestibuli, relatively remote from the partition. The spatial, level, and frequency dependent variations in pressure will inform cochlear models by constraining the form of the partition impedance, and addressing the issue of active-vs-passive cochlear operation. The concerted analysis of the two sets of measurements will suggest modes of partition motion, and the micromechanical basis for that motion. The cochlea is a unique organ, but its nonlinear, dynamic operation reflects general principles and strategies for signal retrieval, sorting and transduction. The goal of these measurements is to understand the complex workings of the cochlea, which, beyond its intrinsic value, is of fundamental value to the understanding of physiological systems, with extension to the design of prosthetics and sensing systems in general.