Intracochlear Scala Media Pressure Measurement: Implications for Models of Cochlear Mechanics
Intracochlear Scala Media Pressure Measurement: Implications for Models of Cochlear Mechanics
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DOI：
10.1016/j.bpj.2015.10.052
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发表时间：
2015-12-15
影响因子：
3.4
通讯作者：
Olson, Elizabeth S.
中科院分区：
文献类型：
--
作者：
Kale, Sushrut S.;Olson, Elizabeth S.
主动耳蜗的模型建立在潜在的被动力学的基础上。被动耳蜗力学基于耳蜗的物理和几何特性以及耳蜗分区与周围流体之间的流体-组织相互作用。虽然在主动和被动耳蜗中已经探索了基底膜和鼓阶（ST）中的液体之间的液体-组织相互作用，但是没有关于分隔的中阶（SM）侧的液体-组织相互作用的实验数据。为了这个目的，我们测量声诱发颅内压SM接近分区使用微压传感器。所有SM压力数据均来自被动耳蜗，可能是因为SM耳蜗造口术导致耳蜗内电位丧失。因此，这些实验是被动耳蜗力学的研究。靠近组织的SM压力显示出峰和凹口的模式，这可以解释为快和慢之间的相互作用（即，行波）压力模式。在几只动物中，在同一耳蜗中测量SM和ST压力。与以前的研究类似，ST压在测量位置的最佳频率附近的刺激频率处由慢行波模式主导，并且由高于最佳频率的快模式主导。SM和ST之间的反对称压力支持经典的单分区耳蜗模型，或分区之间具有紧密耦合的双分区模型。根据SM和ST压力，我们计算了慢模式和快模式，并根据主动ST压力，我们将被动结果外推到主动情况。从SM和ST数据估计的被动慢模式本质上是低通的，如耳蜗模型所预测的。
Models of the active cochlea build upon the underlying passive mechanics. Passive cochlear mechanics is based on physical and geometrical properties of the cochlea and the fluid-tissue interaction between the cochlear partition and the surrounding fluid. Although the fluid-tissue interaction between the basilar membrane and the fluid in scala tympani (ST) has been explored in both active and passive cochleae, there was no experimental data on the fluid-tissue interaction on the scala media (SM) side of the partition. To this aim, we measured sound-evoked intracochlear pressure in SM close to the partition using micropressure sensors. All the SM pressure data are from passive cochleae, likely because the SM cochleostomy led to loss of endocochlear potential. Thus, these experiments are studies of passive cochlear mechanics. SM pressure close to the tissue showed a pattern of peaks and notches, which could be explained as an interaction between fast and slow (i.e., traveling wave) pressure modes. In several animals SM and ST pressure were measured in the same cochlea. Similar to previous studies, ST-pressure was dominated by a slow, traveling wave mode at stimulus frequencies in the vicinity of the best frequency of the measurement location, and by a fast mode above best frequency. Antisymmetric pressure between SM and ST supported the classic single-partition cochlear models, or a dual-partition model with tight coupling between partitions. From the SM and ST pressure we calculated slow and fast modes, and from active ST pressure we extrapolated the passive findings to the active case. The passive slow mode estimated from SM and ST data was low-pass in nature, as predicted by cochlear models.