Noise exposure alters long-term neural firing rates and synchrony in primary auditory and rostral belt cortices following bimodal stimulation
Noise exposure alters long-term neural firing rates and synchrony in primary auditory and rostral belt cortices following bimodal stimulation
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DOI：
10.1016/j.heares.2017.07.004
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发表时间：
2017-12-01
期刊：
影响因子：
2.8
通讯作者：
Basura, Gregory J.
中科院分区：
文献类型：
--
作者：
Takacs, Joseph D.;Forrest, Taylor J.;Basura, Gregory J.
我们以前证明，双峰刺激（三叉神经脊束核[Sp 5]与最佳频率音配对）改变了豚鼠配对后15分钟初级听觉皮层（A1）的神经音诱发和自发放电率（SFR）。根据双峰配对间隔，神经反应被增强（+10 ms）或抑制（0 ms）。在这里，我们调查是否双峰刺激导致长期（长达2小时）的变化，音调诱发和SFR和神经同步性（耳鸣相关），如果长期双峰效应改变噪声暴露。为了验证永久性听力损失对结果的影响，在单侧（左耳）噪声暴露和暂时性阈值偏移后三周测量了放电率和神经同步性。在双峰刺激前后（配对间隔为0 ms;同时Sp 5-音调和+10 ms; Sp 5先于音调），从对侧（噪声）A1和背侧喙带（RB）进行细胞外单单位记录;认为影响A1的关联听觉皮层区域。60和120分钟后，0毫秒配对音调诱发和SFR被抑制在假A1;效果只保留120分钟后配对噪音。在假手术和噪声暴露的A1中，+10 ms刺激仅影响配对后120 min的SFR。在假RB中，0和+10 ms配对持续抑制音调诱发和SFR，而噪声中0 ms配对显著增强音调诱发和SFR长达2 h。总之，这些研究结果表明，双峰刺激在A1中具有持久的影响，也延伸到被噪声改变的关联RB，并且可能对噪声损伤的大脑如何处理多感官信息具有持久的影响。此外，在双峰刺激之前，噪声损伤增加了A1，RB以及A1和RB神经元之间的神经同步性。双模刺激导致持续的变化，在完整的A1和RB的神经同步性，也改变了噪声暴露。考虑到噪声后神经同步性的增加可能与耳鸣发作一致，这些数据暗示A1和RB可能参与幻音感知的病因学。这些数据还表明，噪声改变了双峰刺激对A1和RB神经同步的影响;这种影响也可能导致耳鸣感知的变化。(C)2017爱思唯尔B. V.保留所有权利。
We previously demonstrated that bimodal stimulation (spinal trigeminal nucleus [Sp5] paired with best frequency tone) altered neural tone-evoked and spontaneous firing rates (SFRs) in primary auditory cortex (A1) 15 min after pairing in guinea pigs with and without noise-induced tinnitus. Neural responses were enhanced (+10 ms) or suppressed (0 ms) based on the bimodal pairing interval. Here we investigated whether bimodal stimulation leads to long-term (up to 2 h) changes in tone-evoked and SFRs and neural synchrony (correlate of tinnitus) and if the long-term bimodal effects are altered following noise exposure. To obviate the effects of permanent hearing loss on the results, firing rates and neural synchrony were measured three weeks following unilateral (left ear) noise exposure and a temporary threshold shift. Simultaneous extra-cellular single-unit recordings were made from contra lateral (to noise) A1 and dorsal rostral belt (RB); an associative auditory cortical region thought to influence A1, before and after bimodal stimulation (pairing intervals of 0 ms; simultaneous Sp5-tone and +10 ms; Sp5 precedes tone). Sixty and 120 min after 0 ms pairing tone-evoked and SFRs were suppressed in sham A1; an effect only preserved 120 min following pairing in noise. Stimulation at +10 ms only affected SFRs 120 min after pairing in sham and noise-exposed A1. Within sham RB, pairing at 0 and +10 ms persistently suppressed tone-evoked and SFRs, while 0 ms pairing in noise markedly enhanced tone-evoked and SFRs up to 2 h. Together, these findings suggest that bimodal stimulation has long-lasting effects in A1 that also extend to the associative RB that is altered by noise and may have persistent implications for how noise damaged brains process multi-sensory information. Moreover, prior to bimodal stimulation, noise damage increased neural synchrony in A1, RB and between A1 and RB neurons. Bimodal stimulation led to persistent changes in neural synchrony in intact A1 and RB that were also altered by noise-exposure. Given that increases in neural synchrony following noise may be consistent with tinnitus onset, these data implicate that both A1 and RB may be involved in the etiology of phantom sound perception. These data also suggest that noise alters the effects of bimodal stimulation on neural synchrony in A1 and RB; an effect that may also lead to changes in tinnitus perception. (C) 2017 Elsevier B.V. All rights reserved.