Noise trauma induced plastic changes in brain regions outside the classical auditory pathway.
Noise trauma induced plastic changes in brain regions outside the classical auditory pathway.
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DOI：
10.1016/j.neuroscience.2015.12.005
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发表时间：
2016-02-19
期刊：
影响因子：
3.3
通讯作者：
Salvi R
中科院分区：
文献类型：
--
作者：
Chen GD;Sheppard A;Salvi R
强噪声暴露对经典听觉通路的影响已经得到了广泛的研究，但关于噪声引起的听力损失对大脑非经典听觉区域如杏仁外侧核(LA)和纹状体(STR)的影响却知之甚少。为了解决这个问题，我们比较了噪声在LA和STR的多单位簇(MUC)自发和音调诱发反应(MUC)中的变化与在听觉皮质(AC)的变化。高频倍频程频带噪声(10-20 kHz)和窄带噪声(16-20 kHz)在噪声频带内和以上的高频引起永久性阈值漂移(PTS)，而在低频不引起永久性阈值漂移。噪声损伤后AC的自发放电频率(SR)显著增加，而LA和STR的SR在所有频率下仅略有增加。高频噪声创伤以频率和时间依赖的方式影响音调诱发的放电频率，并且这种变化似乎与噪声创伤的严重程度有关。在LA，高频(创伤区)的纯音诱发放电频率降低，而低频或边缘频率的放电频率增强，这取决于高频听力损失的严重程度。发射率的时间分布从一个宽阔的平台变成了一个尖锐的、延迟的峰值。在AC中，音频诱发的放电率在高频时受到抑制，在低频时增强，而放电率的时间分布明显变得更宽。相反，STR的放电率普遍降低，放电率的时间曲线变得更具阶段性和较少的延长。高频听力损失引起的低频放电频率和模式的改变可能会产生感知后果。低频MUC的纯音诱发多动可表现为听觉亢进，而放电模式的改变可影响时间分辨和整合。
The effects of intense noise exposure on the classical auditory pathway have been extensively investigated; however, little is known about the effects of noise-induced hearing loss on non-classical auditory areas in the brain such as the lateral amygdala (LA) and striatum (Str). To address this issue, we compared the noise-induced changes in spontaneous and tone-evoked responses from multiunit clusters (MUC) in the LA and Str with those seen in auditory cortex (AC). High-frequency octave band noise (10–20 kHz) and narrow band noise (16–20 kHz) induced permanent thresho ld shifts (PTS) at high-frequencies within and above the noise band but not at low frequencies. While the noise trauma significantly elevated spontaneous discharge rate (SR) in the AC, SRs in the LA and Str were only slightly increased across all frequencies. The high-frequency noise trauma affected tone-evoked firing rates in frequency and time dependent manner and the changes appeared to be related to severity of noise trauma. In the LA, tone-evoked firing rates were reduced at the high-frequencies (trauma area) whereas firing rates were enhanced at the low-frequencies or at the edge-frequency dependent on severity of hearing loss at the high frequencies. The firing rate temporal profile changed from a broad plateau to one sharp, delayed peak. In the AC, tone-evoked firing rates were depressed at high frequencies and enhanced at the low frequencies while the firing rate temporal profiles became substantially broader. In contrast, firing rates in the Str were generally decreased and firing rate temporal profiles become more phasic and less prolonged. The altered firing rate and pattern at low frequencies induced by high frequency hearing loss could have perceptual consequences. The tone-evoked hyperactivity in low-frequency MUC could manifest as hyperacusis whereas the discharge pattern changes could affect temporal resolution and integration.