Hyperactivity in the dorsal cochlear nucleus after intense sound exposure and its resemblance to tone-evoked activity: a physiological model for tinnitus
Hyperactivity in the dorsal cochlear nucleus after intense sound exposure and its resemblance to tone-evoked activity: a physiological model for tinnitus
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DOI：
10.1016/s0378-5955(99)00197-5
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发表时间：
2000-02-01
期刊：
影响因子：
2.8
通讯作者：
Afman, CE
中科院分区：
文献类型：
--
作者：
Kaltenbach, JA;Afman, CE
强音暴露诱导仓鼠耳蜗背核（DCN）的自发活动增加（多动）。这种增加可能代表噪声引起的耳鸣的重要神经相关性，噪声引起的耳鸣是一种在没有相应的声学刺激的情况下感知到通常具有非常高音调的声音的情况。由于高音调声音被认为是在中央听觉结构中由激活的位置跨越tonotopic阵列表示;因此，高音调的噪声诱导的耳鸣的发生是可能的，因为强烈的声音暴露诱导DCN中的慢性活动过度的tonotopic分布，类似于仅在高频刺激条件下正常诱发的分布。为了研究这种可能性，我们将这种音调诱导的多动症与正常动物中由音调引起的活动进行了比较。这一比较表明，在DCN的活动，已暴露于一个强烈的10 kHz的音调1个月前显示出一个惊人的相似性，在正常动物的DCN的活动，在低到中等水平的音调刺激相同的频率。在这两种测试条件下，相似的模式中看到的地形分布的增加活动沿着tonotopic轴。暴露动物的活动过度的幅度类似于正常DCN中对20 dB SL水平的刺激作出反应的诱发活动。这些结果表明，改变后的DCN强音暴露的生理行为，好像它是在相应的声刺激的情况下，对音调的反应。讨论了这些发现与噪音引起的耳鸣的相关性及其对了解其潜在机制的影响。(C)2000 Elsevier Science B. V.保留所有权利。
Intense tone exposure induces increased spontaneous activity (hyperactivity), in the dorsal cochlear nucleus (DCN) of hamsters. This increase may represent an important neural correlate of noise-induced tinnitus, a condition in which sound, typically of very high pitch, is perceived in the absence of a corresponding acoustic stimulus. Since high pitch sounds are thought to be represented in central auditory structures by the place of activation across the tonotopic array; it is therefore possible that the high pitch of noise-induced tinnitus occurs because intense sound exposure induces a tonotopic distribution of chronic hyperactivity in the DCN similar to that normally evoked only under conditions of high frequency stimulation. To investigate this possibility we compared this tone-induced hyperactivity with the activity evoked in normal animals by presentation of a tone. This comparison revealed that the activity in the DCN of animals which had been exposed to an intense 10 kHz tone 1 month previously showed a striking similarity to the activity in the DCN of normal animals during presentation of low to moderate level tonal stimuli of the same frequency. In both test conditions similar patterns were seen in the topographic distribution of the increased activity along the tonotopic axis. The magnitude of hyperactivity in exposed animals was similar to the evoked activity in the normal DCN responding to a stimulus at a level of 20 dB SL. These results suggest that the altered DCN following intense tone exposure behaves physiologically as though it is responding to a tone in the absence of a corresponding acoustic stimulus. The relevance of these findings to noise-induced tinnitus and their implications for understanding its underlying mechanisms are discussed. (C) 2000 Elsevier Science B.V. All rights reserved.