EXPOSING MECHANICAL IMPEDANCE OF THE COCHLEAR PARTITION

耳蜗对个别频率的声压是有选择性的，如 在物理限制允许的情况下敏感，并即时适应广泛的 刺激水平的范围。人工耳蜗术的基础必须在于 耳蜗板的机械和机电性能， 但人们对此知之甚少。拟议中的工作试图描绘出 隔板的机械性能，特别是当它们与 频率调谐和耳蜗运动的灵敏度。实验性的 蒙古沙鼠的动物意志，它的解剖允许0.5毫米 耳蜗区的纵向范围将通过 圆形窗户打开。 将执行两组测量，均旨在确定 隔板的机械阻抗，其定义为 穿过隔板对隔板运动的压力或力。在……里面 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 将在横跨隔板的九个径向位置处测量阻抗， 以及在超过0.5 mm的两到三个纵向位置。振动 频率将在100至1000赫兹之间变化。中的径向变化 阻抗将直接与分区解剖相关，表明 这些分隔元件对阻抗有很大的贡献。这个 将分析阻抗的纵向变化 基于隔板宽度纵向变化的预测变化 和特征频率。第二组测量图 鼓阶内压的三维变化。鼓阶 压力将通过圆窗开口测量，靠近 在通过特征频率(30)的频率处的耳蜗区 -40千赫(在该地区)。鼓阶压力将参考 前庭阶内某一点的压力，相对远离前庭 分区。与空间、水平和频率相关的变化 压力将通过限制耳蜗模型的形式来通知耳蜗模型 分区阻抗，并解决了主动与被动耳蜗的问题 手术。对这两套衡量标准的协调分析将 提出隔板运动的方式及其微观力学基础 动议。 耳蜗是一个独特的器官，但它的非线性、动态运行 反映了信号检索、分类的一般原则和策略 和转导。这些测量的目标是了解 耳蜗的复杂工作方式，这超出了它的内在价值，是 对了解生理系统的基本价值，以及 总体上是假肢和传感系统设计的延伸。

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.