Filtering of Acoustic Signals within the Hearing Organ
Filtering of Acoustic Signals within the Hearing Organ
复制标题
听觉器官内声音信号的过滤
DOI：
10.1523/jneurosci.0722-14.2014
复制
发表时间：
2014-07-02
影响因子：
5.3
通讯作者：
Fridberger, Anders
中科院分区：
文献类型：
--
作者：
Ramamoorthy, Sripriya;Zha, Dingjun;Fridberger, Anders
哺乳动物的听觉器官对声音的探测涉及到不同细胞类型之间复杂的机械相互作用。内毛细胞是主要的感官感受器，受到整个科尔蒂器官结构振动的刺激。外毛细胞被认为调节这些声音诱发的振动，以提高听力敏感度和频率分辨率，但目前尚不清楚其他结构是否也有助于频率调谐。在本研究中，用光学相干断层扫描干涉法测量了活体麻醉豚鼠内、外毛细胞及其周围支持细胞立体纤毛侧的声诱发振动。我们的测量表明，存在多种振动模式，以及不同类型的细胞在频率调谐和响应相位上的显著差异。特别是，内毛细胞的频率调谐不同于其他类型的细胞，导致与外毛细胞相比，内毛细胞最大激活的轨迹向耳蜗尖移动。这些观察表明，在内毛细胞兴奋之前，对声音信号的额外处理和过滤发生在Corti器官内，这与既定的理论背道而驰。
The detection of sound by the mammalian hearing organ involves a complex mechanical interplay among different cell types. The inner hair cells, which are the primary sensory receptors, are stimulated by the structural vibrations of the entire organ of Corti. The outer hair cells are thought to modulate these sound-evoked vibrations to enhance hearing sensitivity and frequency resolution, but it remains unclear whether other structures also contribute to frequency tuning. In the current study, sound-evoked vibrations were measured at the stereociliary side of inner and outer hair cells and their surrounding supporting cells, using optical coherence tomography interferometry in living anesthetized guinea pigs. Our measurements demonstrate the presence of multiple vibration modes as well as significant differences in frequency tuning and response phase among different cell types. In particular, the frequency tuning at the inner hair cells differs from other cell types, causing the locus of maximum inner hair cell activation to be shifted toward the apex of the cochlea compared with the outer hair cells. These observations show that additional processing and filtering of acoustic signals occur within the organ of Corti before inner hair cell excitation, representing a departure from established theories.