The mammalian cochlea relies on the active forcing of sensory outer hair cells (OHCs) to amplify traveling wave responses along the basilar membrane. These forces are the result of electromotility, wherein current through the OHCs leads to conformational changes in the cells that provide stresses on surrounding structures. OHC transducer current can be detected via the voltage in the scala tympani (the cochlear microphonic, CM), and the CM can be used as an indicator of healthy cochlear operation. The CM represents a summation of OHC currents (the inner hair cell contribution is known to be small) and to use CM to probe the properties of OHC transduction requires a model that simulates that summation. We developed a finite element model for that purpose. The pattern of current generators (the model input) was initially based on basilar membrane displacement, with the current size based on in vitro data. The model was able to reproduce the amplitude of experimental CM results reasonably well when the input tuning was enhanced slightly (peak increased by ∼6 dB), which can be regarded as additional hair bundle tuning, and with a current/input value of 200–260 pA/nm, which is ∼4 times greater than the largest in vitro measures.

哺乳动物耳蜗依靠感觉外毛细胞 (OHC) 的主动强迫来放大沿基底膜的行波响应。这些力是电动力的结果，其中通过 OHC 的电流导致细胞中的构象变化，从而为周围结构提供应力。OHC 换能器电流可以通过鼓阶（耳蜗微音器，CM）中的电压来检测，CM 可以作为健康耳蜗运行的指标。CM 表示 OHC 电流的总和（已知内部毛细胞的贡献很小），并且使用 CM 来探测 OHC 转导的特性需要一个模拟该总和的模型。为此，我们开发了一个有限元模型。电流发生器的模式（模型输入）最初基于基底膜位移，电流大小基于体外数据。当输入调谐略微增强（峰值增加~6 dB）时，该模型能够很好地再现实验CM结果的幅度，这可以被视为额外的毛束调谐，并且电流/输入值为200- 260 pA/nm，比最大的体外测量值高 4 倍。