Amygdala hyperactivity and tonotopic shift after salicylate exposure.
Amygdala hyperactivity and tonotopic shift after salicylate exposure.
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DOI：
10.1016/j.brainres.2012.03.016
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发表时间：
2012-11-16
期刊：
影响因子：
2.9
通讯作者：
Salvi R
中科院分区：
文献类型：
--
作者：
Chen GD;Manohar S;Salvi R
杏仁核在形成和储存令人厌恶的事件的记忆方面很重要，被认为在使人衰弱的耳鸣和听觉过敏中起主要作用。为了探讨这一假设，我们记录了侧杏仁核（LA）和听觉皮层（AC）之前和之后的水杨酸盐剂量，诱导耳鸣和hyperacusis样行为的大鼠。水杨酸盐意外增加了LA中局部场电位（LFP）的幅度，使其对≥60 dB SPL的声音过度活跃。频率感受野（FRF）的多单元（MU）集群在LA也显着改变水杨酸。在低强度下，低于10 kHz和高于20 kHz频率的神经元活动受到抑制，但在10和20 kHz之间（水杨酸诱导的大鼠耳鸣音调附近的频率）的刺激下，神经元活动大大增强。这些频率依赖性变化导致许多LA神经元的FRF向10-20 kHz迁移，从而放大了该区域的活动。为了确定水杨酸诱导的仅限于LA的变化是否会远程影响AC的神经活动，我们使用微量移液管将水杨酸（20 μl，2.8 mM）注入杏仁核。局部递送水杨酸到杏仁核显著增加AC中记录的LFP的幅度，并选择性地增强AC神经元在中频（10-20 kHz）的神经元活性，所述中频与耳鸣音高相关。综上所述，这些结果表明，全身水杨酸治疗可以诱导扁桃体的活动过度和音调移位，将水杨酸注入扁桃体可以深刻地增强AC中的声音诱发活动，这些变化可能会增加耳鸣和响亮声音的感知和情绪显着性。
The amygdala, important in forming and storing memories of aversive events, is believed to play a major role in debilitating tinnitus and hyperacusis. To explore this hypothesis, we recorded from the lateral amygdala (LA) and auditory cortex (AC) before and after treating rats with a dose of salicylate that induces tinnitus and hyperacusis-like behavior. Salicylate unexpectedly increased the amplitude of the local field potential (LFP) in the LA making it hyperactive to sounds ≥60 dB SPL. Frequency receptive fields (FRF) of multiunit (MU) clusters in the LA were also dramatically altered by salicylate. Neuronal activity at frequencies below 10 kHz and above 20 kHz was depressed at low intensities, but was greatly enhanced for stimuli between 10 and 20 kHz (frequencies near the pitch of the salicylate-induced tinnitus in the rat). These frequency-dependent changes caused the FRF of many LA neurons to migrate towards 10-20 kHz thereby amplifying activity from this region. To determine if salicylate-induced changes restricted to the LA would remotely affect neural activity in the AC, we used a micropipette to infuse salicylate (20 µl, 2.8 mM) into the amygdala. Local delivery of salicylate to the amygdala significantly increased the amplitude of the LFP recorded in the AC and selectively enhanced the neuronal activity of AC neurons at the mid-frequencies (10-20 kHz), frequencies associated with the tinnitus pitch. Taken together, these results indicate that systemic salicylate treatment can induce hyperactivity and tonotopic shift in the amygdala and infusion of salicylate into the amygdala can profoundly enhance sound-evoked activity in AC, changes likely to increase the perception and emotional salience of tinnitus and loud sounds.