Tuning, spontaneous activity and tonotopic map in chicken cochlear ganglion neurons following sound-induced hair cell loss and regeneration
Tuning, spontaneous activity and tonotopic map in chicken cochlear ganglion neurons following sound-induced hair cell loss and regeneration
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DOI：
10.1016/0378-5955(96)00086-x
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发表时间：
1996-09-01
期刊：
影响因子：
2.8
通讯作者：
Salvi, RJ
中科院分区：
文献类型：
--
作者：
Chen, L;Trautwein, PG;Salvi, RJ
将成年鸡暴露于525 Hz， 120 dB声压级的噪声下48 h，沿基底乳头神经外边缘的月牙形斑块上的毛细胞和被膜被破坏。暴露后0-1、5、14和28天分别对耳蜗神经节神经元进行单单元记录，以确定耳蜗损伤对神经放电模式的影响，以及放电模式是否完全恢复。暴露后，调谐曲线非常宽，CF阈值升高30-40 dB。此外，具有首选间隔的峰间直方图神经元的平均自发率和百分比也大大降低。暴露后5 d，调节曲线和自发活动开始恢复；然而，此时观察到一些w形的调谐曲线，具有两个不同的尖端和一个超敏感的尾部。暴露后14 ~ 28 d， w型调谐曲线消失，自发活动恢复正常。但大多数敏感神经元的CF阈值仍略高，低于CF的调谐曲线斜率较正常浅，调谐曲线低频尾的阈值往往超敏感。这些功能缺陷与被膜上部纤维层的残余损伤密切相关。为了确定耳蜗病变是否改变了耳蜗的频率位置图，在暴露后5天，用生物细胞素标记4个具有生理特征的神经元。标记神经元的CFs与正常频位图一致（Chen et al. (1994) Hearing Research 81, 130-136），表明张力位图没有改变。
Adult chickens were exposed for 48 h to a 525 Hz, 120 dB SPL tone that destroyed the hair cells and tectorial membrane in a crescent-shaped patch along the abneural edge of the basilar papilla. Single-unit recordings were obtained from cochlear ganglion neurons 0-1, 5, 14 and 28 days post-exposure to determine what effect the cochlear lesion had on neural discharge patterns and if the discharge patterns fully recovered. Immediately after exposure, the tuning curves were extremely broad and CF thresholds were elevated by 30-40 dB. In addition, the average spontaneous rate and percentage of neurons with interspike interval histograms with preferred intervals were greatly reduced. Tuning curves and spontaneous activity started to recover by 5 days post-exposure; however, some W-shaped tuning curves with two distinct tips and a hypersensitive tail were observed at this time. W-shaped tuning curves disappeared and spontaneous activity recovered to normal levels 14-28 days post-exposure. However, the CF thresholds of the most sensitive neurons were still slightly elevated, tuning curve slopes below CF were shallower than normal, and thresholds in the low-frequency tail of the tuning curves were often hypersensitive. These functional deficits were most closely associated with residual damage to the upper fibrous layer of the tectorial membrane. To determine if the cochlear frequency-place map was altered by the cochlear lesion, four physiologically characterized neurons were labeled with biocytin at 5 days post-exposure. The CFs of the labeled neurons were consistent with the normal frequency-place map (Chen et al. (1994) Hearing Research 81, 130-136) indicating that the tonotopic map was not altered.