Perceptual gap detection is mediated by gap termination responses in auditory cortex.
Perceptual gap detection is mediated by gap termination responses in auditory cortex.
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DOI：
10.1016/j.cub.2014.05.031
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发表时间：
2014-07-07
期刊：
影响因子：
--
通讯作者：
Wehr M
中科院分区：
文献类型：
--
作者：
Weible AP;Moore AK;Liu C;DeBlander L;Wu H;Kentros C;Wehr M
随着年龄的增长，在有背景噪音的情况下理解讲话往往变得越来越困难。这些与年龄相关的语言处理缺陷反映了时间敏锐度的损害。间隙检测是语音处理中时间敏锐度的一个模型，在这个模型中，插入白噪声中的间隙作为一个线索，减弱随后的惊吓反应。损伤研究表明，听觉皮层对短暂间隙的检测是必要的，听觉皮层神经元对间隙的结束做出反应，产生一种称为间隙终止反应（GTR）的特征性尖峰爆发。然而，尚不清楚GTR是否或如何在间隙检测中起因果作用。在间隙检测方案的特定时期，我们通过光遗传学抑制行为小鼠听觉皮层中表达生长抑素或细小蛋白的抑制性中间神经元或表达camkii的兴奋性神经元的活性来验证这一点。抑制中间神经元在间隙后的活动增强了间隙检测。在这段时间内抑制兴奋性细胞会减弱间隙检测。在间隔之前抑制活动会产生相反的行为效果，而在两个间隔中延长抑制对间隔检测没有影响。除了确认皮层参与外，我们还首次证明了间隙后神经活动与感知间隙检测之间的因果关系。此外，我们的结果表明，间隙检测涉及到间隙前后尖峰活动的持续比较。最后，我们提出了一个简单的，但生物学上合理的神经回路，它可以复制这些神经和行为的结果。
Understanding speech in the presence of background noise often becomes increasingly difficult with age. These age-related speech processing deficits reflect impairments in temporal acuity. Gap detection is a model for temporal acuity in speech processing, in which a gap inserted in white noise acts as a cue that attenuates subsequent startle responses. Lesion studies have shown that auditory cortex is necessary for the detection of brief gaps, and auditory cortical neurons respond to the end of the gap with a characteristic burst of spikes called the gap termination response (GTR). However, it remains unknown whether or how the GTR plays a causal role in gap detection. We tested this by optogenetically suppressing the activity of somatostatin- or parvalbumin-expressing inhibitory interneurons, or CaMKII-expressing excitatory neurons, in auditory cortex of behaving mice during specific epochs of a gap detection protocol. Suppressing interneuron activity during the post-gap interval enhanced gap detection. Suppressing excitatory cells during this interval attenuated gap detection. Suppressing activity preceding the gap had the opposite behavioral effects, whereas prolonged suppression across both intervals had no effect on gap detection. In addition to confirming cortical involvement, here we demonstrate for the first time a causal relationship between post-gap neural activity and perceptual gap detection. Furthermore, our results suggest that gap detection involves an ongoing comparison of pre- and post-gap spiking activity. Finally, we propose a simple, yet biologically plausible neural circuit that reproduces each of these neural and behavioral results.
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