Neural processing and perception of complex sounds

描述（由申请人提供）：拟议研究的长期目标是加深我们对复杂声音处理的机械理解，并将皮层神经表征与听觉感知联系起来。为此，我建议研究复杂的声音处理的中央听觉回路的一个物种，丰富的声乐交流行为-听觉前脑鸣禽。鸣禽提供了一个很好的模型，研究一般原则的高层次的声音处理，因为它们面临的复杂的听觉任务。此外，它们拥有一个有助于这些任务的听觉区域的层次网络，包括相当于初级听觉皮层的鸟类区域L。我最近发现，在现场有一个简单的时间和光谱感受野的有序组织。这种有组织的声音特征表示提供了一个框架，研究复杂的声音皮层处理。在拟议的实验中，我将进一步研究在单个神经元水平上的代表性，通过探测自然发声刺激和映射非线性感受野，使用基于信息论的技术称为最大信息维度。为了开始讨论产生这种表征的回路机制，我将再次绘制L场的感受野，同时选择性地使L场的不同子区域失活。最后，我将测试这一假设，即场L分区与不同的tning属性差异有助于感知复杂的声音，失活的场L分区，而鸟类执行操作性歌曲的歧视任务。这项研究的结果不仅将进一步加深我们对频谱时间感受野如何通过神经回路产生以及它们如何与感知相关的基本理解，而且还将对治疗听觉障碍产生重要影响。

DESCRIPTION (provided by applicant): The long-term objective of the proposed study is to deepen our mechanistic understanding of complex sound processing and to relate cortical neural representations to auditory perception. To this end, I propose to study complex sound processing in a central auditory circuit of a species with rich vocal communication behavior - the auditory forebrain of songbirds. Songbirds provide an excellent model for studying general principles of higher-level sound processing, because of the complex auditory tasks they face. Moreover, they possess a hierarchical network of auditory areas that subserve these tasks, including the avian equivalent of primary auditory cortex, field L. I recently found that in field there is an orderly organization of simple temporal and spectral receptive fields. This organized representation of sound features provides a framework for investigating cortical processing of complex sounds. In the proposed experiments, I will further investigate the representation at the single neuron level, by probing with natural vocalization stimuli and by mapping nonlinear receptive fields, using an information theory-based technique called maximally informative dimensions. To begin to address the circuit mechanisms that give rise to the representation, I will then map the receptive fields in field L again while selectively inactivating different subregions of field L. Finally, I will test the hypothesis that field L subregions with different tning properties differentially contribute to perception of complex sounds, by inactivating subregions of field L while birds perform operant song discrimination tasks. The outcome of the proposed study will not only further our basic understanding of how spectrotemporal receptive field arise through neural circuits and how they relate to perception, but will also have important implications for treating auditory disorders.