Neural basis of vocal signal recognition during natural communication

描述(由申请者提供)：人类和非人类灵长类动物通过发声与同种生物交流。为了在这种媒介中成功地进行交流，听众必须能够识别声音信号(例如人类的单词)，并将它们从声学环境中过多的其他生物和非生物声音中解析出来。识别特定物种的声音信号并不是声音信号识别的顶峰，而只是更复杂过程的一部分。与其他对象一样，语音信号包括反映呼叫者的社会维度的多个类别，例如个人身份、性别、方言 由于呼叫者声音的特性，这些社会类别被编码在发声的声学结构中，并且已知在人类和非人类灵长类声音交互中都具有感知意义。虽然语音识别的神经基础已经使用各种神经成像技术和患者进行了广泛的研究，但对其潜在的细胞机制知之甚少。考虑到声音感知的相似性和听觉系统神经解剖学上的同源性，非人灵长类动物是解释灵长类新皮质中声音信号识别的神经机制的极好模型。几乎所有早期对非人类灵长类皮质发声处理的神经研究都涉及将发声样本呈现给受限制的动物的实验。然而，交流是一个内在的互动过程，涉及到同类个体之间的信号交换。这项建议的目的是研究普通绒猴在进行对声叫声时自然行为的声音信号识别，这是一种以发声的相互交换为特征的发声行为。由于绒猴只会对特定的叫声类型做出反声叫声，这种行为代表了一种自然的(即未经训练的)识别系统，特别适合在自然交流过程中探索社会分类的神经基础，原因如下。首先，前人的研究表明，呼叫者的社会类别会影响对音叫声的动态。其次，我们开发了新颖的交互式回放软件，使我们能够在实验条件下引发这种声音反应。第三，我们可以记录受试者自由活动时绒猴前额叶皮质单个神经元的活动。这三个组成部分是实现这项提案的三个目标的一个潜在的强有力的办法。具体目标1是结合单个单位神经生理学和组织学来描述绒猴发声交流额叶皮质的功能神经解剖学特征。这一目标将为所有后续的生理学奠定基础，无论是在这项提议中，还是在未来。特定的 目的2试图通过向受试者呈现综合操纵的发音来广泛地检验社会分类的知觉基础。具体目标3通过使用目标1的神经解剖学位置和目标2的知觉发现来测试对音呼叫过程中社会分类的神经基础，从而建立在本提案的前面目标的基础上。

DESCRIPTION (provided by applicant): Human and nonhuman primates communicate with conspecifics using vocalizations. For communication in this medium to be successful, listeners must be able to recognize vocal signals (e.g. words for humans) and parse them from the plethora of other biotic and abiotic sounds in the acoustic environment. Rather than be the culmination of vocal signal recognition, identifying species-specific acoustic signals is only one part of a more complex process. Like other objects, vocal signals comprise a number of categories that reflect social dimensions of the caller, such as individual identity, sex, dialect, etc. These social categories are encoded in the acoustic structure of the vocalization due to idiosyncrasies in the caller's voice and are known to be perceptually meaningful in both human and nonhuman primate vocal interactions. While the neural basis of speech recognition has been extensively studied using various neuroimaging techniques and patients, much less is known about its underlying cellular mechanisms. Given similarities in vocal perception and homologies in the auditory system neuroanatomy, nonhuman primates represent an excellent model for explicating the neural mechanisms underlying vocal signal recognition in primate neocortex. Nearly all earlier neural studies of vocalization processing in nonhuman primate cortex involve experiments in which vocalization exemplars are presented to restrained animals. Communication, however, is an inherently interactive process involving the exchange of signals between conspecifics. The aim of this proposal is to examine vocal signal recognition in naturally behaving common marmosets while they engage in antiphonal calling, a vocal behavior characterized by the reciprocal exchange of vocalizations. Since marmosets will only produce an antiphonal call in response to a particular call type, this behavior represents a natural (i.e. untrained) recognition system and is uniquely suited to explore the neural basis of social categorization during natural communication for the following three reasons. First, previous work shows that social categories of callers affect the dynamics of antiphonal calling. Second, we developed novel, interactive playback software that allows us to elicit this vocal response under experimental conditions. And third, we can record the activity of single neurons in marmoset prefrontal cortex while subjects are freely-moving. These three components represent a potentially powerful approach to addressing the three aims of this proposal. Specific Aim 1 is to combine single-unit neurophysiology and histology to characterize the functional neuroanatomy of marmoset frontal cortex for vocal communication. This aim will establish a foundation for all subsequent physiology, both in this proposal and further in the future. Specific Aim 2 seeks to extensively test the perceptual basis of social categorization by presenting subjects with synthetically manipulated vocalizations. Specific Aim 3 builds on the preceding aims of this proposal by testing the neural basis of social categorization during antiphonal calling using the neuroanatomical locations of Aim 1 and the perceptual findings of Aim 2.