Spontaneous Otoacoustic Emissions in Mice Reflect Changes in Cochlear Amplification and How It Is Controlled by the Tectorial Membrane
Spontaneous Otoacoustic Emissions in Mice Reflect Changes in Cochlear Amplification and How It Is Controlled by the Tectorial Membrane
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DOI：
10.1523/eneuro.0314-18.2018
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发表时间：
2018-11-01
期刊：
影响因子：
3.4
通讯作者：
Richardson, Guy P.
中科院分区：
文献类型：
--
作者：
Cheatham, Mary Ann;Zhou, Yingjie;Richardson, Guy P.
在没有声音的情况下从耳道记录的自发耳声发射（SOAE）反映耳蜗放大，这是哺乳动物听觉的非凡灵敏度和频率选择性所需的外毛细胞（OHC）过程。虽然野生型小鼠很少发射，但那些影响盖膜（TM）的突变显示SOAE的发生率与人类相似。在这份报告中，我们的特点是小鼠错义突变Tecta，一个基因所需的核心内的TM的条纹片矩阵的形成。Y1870 C突变的杂合子小鼠（Tecta（Y1870 C/+））是多产的发射体，尽管有中度听力损失。此外，木村的膜，其中的OHC静纤毛插入，分离的主体TM，除了在顶端耳蜗位置。在Tecta（Y1870 C/+）小鼠中也观察到多模态SOAE，其中能量的频率是低频SOAE（主要）的整数倍。二次谐波SOAE的频率是较低频率的主要频率的两倍，是最常见的。这些次级SOAE出现在刺激诱发的OAE较小的空间区域或噪声基底中。在初级SOAE频率之上引入高电平抑制器可以减少或消除初级和二次谐波SOAE。相比之下，二次谐波SOAE不受抑制剂的影响，无论是高于或低于二次谐波SOAE频率，即使它们的振幅大得多。因此，二次谐波SOAE似乎没有空间上分离，从他们的主要，一个发现，耳蜗力学和TM结构的变化的后果的影响。
Spontaneous otoacoustic emissions (SOAEs) recorded from the ear canal in the absence of sound reflect cochlear amplification, an outer hair cell (OHC) process required for the extraordinary sensitivity and frequency selectivity of mammalian hearing. Although wild-type mice rarely emit, those with mutations that influence the tectorial membrane (TM) show an incidence of SOAEs similar to that in humans. In this report, we characterized mice with a missense mutation in Tecta, a gene required for the formation of the striated-sheet matrix within the core of the TM. Mice heterozygous for the Y1870C mutation (Tecta(Y1870C/+)) are prolific emitters, despite a moderate hearing loss. Additionally, Kimura's membrane, into which the OHC stereocilia insert, separates from the main body of the TM, except at apical cochlear locations. Multimodal SOAEs are also observed in Tecta(Y1870C/+) mice where energy is present at frequencies that are integer multiples of a lower-frequency SOAE (the primary). Second-harmonic SOAEs, at twice the frequency of a lower-frequency primary, are the most frequently observed. These secondary SOAEs are found in spatial regions where stimulus-evoked OAEs are small or in the noise floor. Introduction of high-level suppressors just above the primary SOAE frequency reduce or eliminate both primary and second-harmonic SOAEs. In contrast, second-harmonic SOAEs are not affected by suppressors, either above or below the second-harmonic SOAE frequency, even when they are much larger in amplitude. Hence, second-harmonic SOAEs do not appear to be spatially separated from their primaries, a finding that has implications for cochlear mechanics and the consequences of changes to TM structure.