Receptive Field Correlates of Starling Song Recognition Behavior

描述（由申请人提供）：大脑中声音处理的一个关键方面是听觉特征的隔离，这些听觉特征可以识别单个说话者或定义听觉对象，如元音和辅音。损害这种能力的听力损伤无法通过传统手段加以补救；特别是，在生命早期发生的听力损失导致无法发展适当的声音处理机制，这些机制及其发展都没有得到很好的理解。鸣禽用叫声来识别个体，许多物种可以在一生中不断学习新的联系。歌曲识别行为在欧洲椋鸟（Sturnus vulgaris）中受到了特别的关注，它们的社会性质使它们服从于操作性条件反射范式，在这种范式中，被试学习区分来自不同个体的歌曲。最近的发现已经确定了一个前脑区域，尾部中膜（CMM），其中包含对训练过程中学习的歌曲产生选择性的神经元。因此，椋鸟代表了一个有吸引力的系统来研究这种选择性是如何产生的，这项研究的长期目标是建立严格的CMM接受野（RFs）统计模型。这些模型将揭示听觉处理的神经回路和机制，以及听觉信息的神经元表征如何被动物用于决策。该提案的具体目的是通过研究椋鸟鸣叫的两个不同元素如何影响鸣叫识别行为来支持这一目标。欧椋鸟的歌曲由一系列离散的刻板元素组成，这些元素被称为母题，它们以非随机的模式演唱，单个母题由光谱时间特征的独特组合组成。本提案描述了在以下假设下测试序列和特征组成的相对贡献的实验：(1)基序选择性在行为和生理水平上都来自对特定特征组合的敏感性；(2)行为和生理水平上的基序选择性对时间背景敏感。这项研究将加深我们对大脑如何处理复杂感觉信息的理解，从而有助于治疗听力损失和语言缺陷。它开发的用于分析听觉信号的方法也可用于听觉假肢装置的创建。

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.