Broad nonlinearity in reticular lamina vibrations requires compliant organ of Corti structures.
Broad nonlinearity in reticular lamina vibrations requires compliant organ of Corti structures.
复制标题
网状层振动的广泛非线性需要柯蒂结构的柔顺器官。
DOI：
10.1016/j.bpj.2023.01.029
复制
发表时间：
2023
影响因子：
3.4
通讯作者：
Meaud,Julien
中科院分区：
文献类型：
--
作者：
Samaras,George;Wen,Haiqi;Meaud,Julien
在哺乳动物耳蜗体中，基底膜(BM)的每个纵向位置在与位置相关的最大响应频率(BF)附近具有有限的频率范围内的非线性振动响应，称为最佳频率(BF)。这种非线性反应是由外毛细胞的机电反馈引起的。然而，最近的活体测量表明，即使在显著低于BF的频率下，其他器官的Corti(OOC)结构的机械反应(如网状板(RL))和OHC的电反应(以局部耳蜗微音管[LCM]测量)也是非线性的。在这项工作中，一个生理激励的沙土鼠耳蜗模型被用来证明BM，RL和LCM非线性的频率范围之间的差异的来源是在OHC顶部的结构中更大的顺应性。预测的BM、RL和LCM对纯音和双音刺激的反应与实验结果一致。模拟表明，RL中的亚BF非线性要求OHC顶部的结构比BM更具柔顺性。同样的条件对于BF附近的最佳增益也是必要的，即与实验相符的高放大。这表明，OHC在BF下最佳运行的条件不可避免地会在较宽的频率范围内产生RL响应的非线性。
In the mammalian cochlea, each longitudinal position of the basilar membrane (BM) has a nonlinear vibratory response in a limited frequency range around the location-dependent frequency of maximum response, known as the best frequency (BF). This nonlinear response arises from the electromechanical feedback from outer hair cells (OHCs). However, recent in vivo measurements have demonstrated that the mechanical response of other organ of Corti (OoC) structures, such as the reticular lamina (RL), and the electrical response of OHCs (measured in the local cochlear microphonic [LCM]) are nonlinear even at frequencies significantly below BF. In this work, a physiologically motivated model of the gerbil cochlea is used to demonstrate that the source of this discrepancy between the frequency range of the BM, RL, and LCM nonlinearities is greater compliance in the structures at the top of the OHCs. The predicted responses of the BM, RL, and LCM to pure tone and two-tone stimuli are shown to be in line with experimental evidence. Simulations then demonstrate that the sub-BF nonlinearity in the RL requires the structures at the top of the OHCs to be significantly more compliant than the BM. This same condition is also necessary for "optimal" gain near BF, i.e., high amplification that is in line with the experiment. This demonstrates that the conditions for OHCs to operate optimally at BF inevitably yield nonlinearity of the RL response over a broad frequency range.