Bell Andrew, Fletcher Neville H
Research School of Biological Sciences, Australian National University, Canberra 0200, Australia.
J Acoust Soc Am. 2004 Aug;116(2):1016-24. doi: 10.1121/1.1766053.
This paper draws attention to symmetric Lloyd-Redwood (SLR) waves-known in ultrasonics as "squirting" waves-and points out that their distinctive properties make them well-suited for carrying positive feedback between rows of outer hair cells. This could result in standing-wave resonance-in essence a narrow-band cochlear amplifier. Based on known physical properties of the cochlea, such an amplifier can be readily tuned to match the full 10-octave range of human hearing. SLR waves propagate in a thin liquid layer enclosed between two thin compliant plates or a single such plate and a rigid wall, conditions found in the subtectorial space of the cochlea, and rely on the mass of the inter-plate fluid interacting with the stiffness of the plates to provide low phase velocity and high dispersion. The first property means SLR wavelengths can be as short as the distance between rows of outer hair cells, allowing standing wave formation; the second permits wide-range tuning using only an order-of-magnitude variation in cochlear physical properties, most importantly the inter-row spacing. Viscous drag at the two surfaces potentially limits SLR wave propagation at low frequencies, but this can perhaps be overcome by invoking hydrophobic effects.
本文关注对称劳埃德 - 雷德伍德(SLR)波——在超声学中被称为“喷射”波——并指出其独特性质使其非常适合在成排的外毛细胞之间传递正反馈。这可能导致驻波共振——本质上是一种窄带耳蜗放大器。基于耳蜗已知的物理特性,这样的放大器可以很容易地进行调谐,以匹配人类听力的整个10倍频程范围。SLR波在夹于两个薄柔性板之间或单个这样的板与刚性壁之间的薄液层中传播,这是在耳蜗的盖膜下空间发现的条件,并且依赖于板间流体的质量与板的刚度相互作用以提供低相速度和高色散。第一个特性意味着SLR波长可以短至外毛细胞排之间的距离,从而允许形成驻波;第二个特性允许仅使用耳蜗物理特性(最重要的是排间距)的一个数量级变化进行宽范围调谐。两个表面的粘性阻力可能会在低频时限制SLR波的传播,但这或许可以通过引入疏水效应来克服。