Receptive Field Correlates of Starling Song Recognition Behavior

描述(申请人提供)：大脑中声音处理的关键方面之一是分离识别单个说话者或定义的听觉对象(如元音和辅音)的听觉特征。损害这一能力的听力损害不能通过传统手段补救；特别是在生命早期发生的听力损失导致无法形成适当的声音处理机制，这些机制及其发育都不是很好的了解。鸣禽使用发声来识别个体，许多物种可以在一生中继续学习新的联系。欧洲八哥的歌曲识别行为受到了特别的关注，它们的社会性使它们更容易受到操作条件范式的影响，在这些范式中，被试学习区分不同个体的歌曲。最近的发现已经确定了一个前脑区域，尾侧中脑系膜(CMM)，它包含对在训练过程中学习的歌曲产生选择性的神经元。因此，八哥是研究这种选择性如何产生的一个有吸引力的系统，这项研究的长期目标是建立CMM感受野(RFs)的严格统计模型。这些模型将阐明听觉处理背后的神经元电路和机制，以及动物如何使用听觉信息的神经元表征来做出决定。这项提案的具体目的是通过研究八哥歌唱的两个不同元素如何影响歌曲识别行为来支持这一目标。八哥歌声由一系列被称为主题的离散的刻板印象元素组成，这些主题是以非随机的模式演唱的，而个别的主题是由独特的频谱特征组合组成的。这一建议描述了在以下假设下检验序列和特征组合的相对贡献的实验：(1)主题选择性在行为和生理水平上都发生在对特定特征的组合的敏感性上；(2)在行为和生理水平上的主题选择性对时间语境敏感。这项研究将通过加深我们对大脑如何处理复杂感觉信息的理解，为听力损失和语言障碍的治疗做出贡献。它开发的分析听觉信号的方法也可能对制造听觉假体设备有用。

DESCRIPTION (provided by applicant): One of the crucial aspects of vocal processing in the brain is the isolation of auditory features that identify an individual speaker or defined auditory objects like vowels and consonants. Hearing damage that compromises this ability cannot be remedied through traditional means; in particular, hearing loss that occurs early in life leads to a failure to develop the appropriate mechanisms for vocal processing, and neither those mechanisms nor their development is well understood. Songbirds use vocalizations to identify individuals, and many species can continue to learn new associations throughout life. Song recognition behavior has received particular attention in European starlings (Sturnus vulgaris), whose social nature makes them amenable to operant conditioning paradigms in which subjects learn to distinguish between songs from different individuals. Recent findings have identified a forebrain region, the caudomedial mesopallium (CMM), which contains neurons that develop selectivity for songs learned in the training procedure. Thus, starlings represent an attractive system in which to study how such selectivity arises, and the long-term objective of this research is to develop rigorous statistical models of CMM receptive fields (RFs). These models will shed light on the neuronal circuitry and mechanisms underlying auditory processing, and on how neuronal representations of auditory information are used by animals in making decisions. The specific aims of this proposal support this goal by examining how two distinct elements of starling song contribute to song recognition behavior. Starling songs comprise a series of discrete stereotyped elements called motifs that are sung in a non-random pattern, and individual motifs are composed of a unique combination of spectrotemporal features. This proposal describes experiments that test the relative contributions of sequence and feature composition under the hypotheses that (1) motif selectivity arises at both the behavioral and physiological level from sensitivity to a combination of specific features and (2) motif selectivity at the behavioral and physiological level is sensitive to temporal context. This research will contribute to treatments for hearing loss and language deficits by deepening our understanding of how the brain processes complex sensory information. The methods it develops for analyzing auditory signals may also be useful in the creation of auditory prosthetic devices.