Enhanced representation of spectral contrasts in the primary auditory cortex.
Enhanced representation of spectral contrasts in the primary auditory cortex.
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DOI：
10.3389/fnsys.2013.00021
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发表时间：
2013
影响因子：
3
通讯作者：
Noreña AJ
中科院分区：
文献类型：
--
作者：
Catz N;Noreña AJ
早期听觉处理的作用可能是从声学混合物中提取一些基本特征，以便组织听觉场景。为了完成该任务，中央听觉系统可以依赖于感觉对象通常由频谱边缘组成的事实，即，刺激能量随频率突然变化的区域。声学刺激的处理可能会受益于增强频谱边缘内部表示的机制。虽然视觉系统被认为严重依赖于这种机制（增强空间边缘），但仍不清楚相关过程是否在听觉中起着重要作用。我们研究了频谱边缘的皮层表示，使用由多音点组成的声学刺激，其时间平均频谱包络包含抑制或增强区域。重要的是，刺激被设计成使得神经反应特性可以被评估为刺激呈现期间刺激频率的函数。我们的研究结果表明，声学频谱边缘的代表性增强的听觉皮层，这种增强是敏感的频谱对比度曲线的特点，如深度，锐度和宽度。光谱边缘被最大程度地增强，以获得鲜明的对比度和大的深度。在抑制区域内的频率下，皮层活动也受到抑制。值得注意的是，在抑制区域的下边缘附近的频率处，对放电的抑制比上边缘处的抑制更大。总体而言，本研究提供了关键的见解，在听觉系统的频谱对比度的处理。
The role of early auditory processing may be to extract some elementary features from an acoustic mixture in order to organize the auditory scene. To accomplish this task, the central auditory system may rely on the fact that sensory objects are often composed of spectral edges, i.e., regions where the stimulus energy changes abruptly over frequency. The processing of acoustic stimuli may benefit from a mechanism enhancing the internal representation of spectral edges. While the visual system is thought to rely heavily on this mechanism (enhancing spatial edges), it is still unclear whether a related process plays a significant role in audition. We investigated the cortical representation of spectral edges, using acoustic stimuli composed of multi-tone pips whose time-averaged spectral envelope contained suppressed or enhanced regions. Importantly, the stimuli were designed such that neural responses properties could be assessed as a function of stimulus frequency during stimulus presentation. Our results suggest that the representation of acoustic spectral edges is enhanced in the auditory cortex, and that this enhancement is sensitive to the characteristics of the spectral contrast profile, such as depth, sharpness and width. Spectral edges are maximally enhanced for sharp contrast and large depth. Cortical activity was also suppressed at frequencies within the suppressed region. To note, the suppression of firing was larger at frequencies nearby the lower edge of the suppressed region than at the upper edge. Overall, the present study gives critical insights into the processing of spectral contrasts in the auditory system.