Behavioral and Neural Analysis of Vocal Plasticity

描述（由申请人提供）：鸣禽的声乐学习为研究神经系统如何使用基于表现的反馈来校准和维持运动技能提供了一个有用的模型，特别是与人类语言相关。伯德桑提供了一个很好的描述和可量化的行为的优势，这种行为是由一组离散的和广泛研究的大脑区域提供的。歌曲学习分为两个阶段，这两个阶段都主要依赖于听力[17,18]。首先，在感官学习期间，幼鸟会听并记住成年“导师”的歌曲。然后，在一段感觉运动学习期间，他们使用听觉反馈来逐渐完善自己最初杂乱无章的发声，使它们逐渐像以前记忆的导师歌曲一样。正常的歌曲学习需要在早期发育的敏感时期有适当的经验，也依赖于成年期的听觉反馈来维持精确校准的声音输出[4]。歌曲和语言在依赖听觉反馈方面的相似性表明，对歌曲学习的调查可能会为控制声音运动学习的行为和神经机制提供更全面的见解。此外，我们对鸟类基底神经节-前脑回路（前前脑通路或“AFP”）在声乐学习中的功能特别感兴趣。这个回路在幼鸟和成年鸟的依赖反馈的鸣叫学习中起着核心作用。因为AFP可以在定义良好的行为背景下进行机械研究，它可能被证明是一个特别容易处理的模型，可以更普遍地理解基底神经节的功能。在这里，我们建议使用我们在上一个资助周期下开发的听觉反馈操作技术来扩展我们对鸣禽的发声行为如何由经验塑造的研究（目标1），确定驱动学习的信号如何在大脑中表示（目标2）以及它们如何参与基底神经节回路来改变歌曲（目标3）。我们将重点关注孟加拉雀，一种表现出声音学习的一般特性的物种，但似乎特别强烈地依赖于听觉反馈。鸣禽提供了一种模型，在这种模型中，基于表现的反馈对定义良好且可量化的行为的影响可以在机制层面上被理解。这样的理解将提供对正常学习过程的基本洞察，特别是与语言相关的学习过程，并有助于我们预防和纠正由这些过程功能障碍引起的残疾。我们将使用鸣禽来研究听觉反馈对成人声乐学习影响的神经机制。这些研究将为正常的学习过程，特别是与人类语言相关的学习过程提供基本的见解，并有助于我们预防和纠正由这些过程功能障碍引起的残疾。由于声乐学习在很大程度上依赖于广泛保守的基底神经节-前脑回路，该系统也可能被证明是一个特别容易处理的系统，用于研究这种回路在运动控制和学习中的一般功能，以及在基底神经节疾病条件下出现的缺陷。

DESCRIPTION (provided by applicant): Vocal learning in songbirds provides a useful model for studying how performance-based feedback is used by the nervous system in calibrating and maintaining motor skills, with particular relevance to human speech. Birdsong offers the advantages of a well-described and quantifiable behavior that is subserved by a discrete and extensively investigated set of brain regions. Song learning proceeds in two stages, both of which depend critically on hearing [17, 18]. First, during a period of sensory learning, young birds listen to and memorize the song of an adult 'tutor'. Then, during a period of sensorimotor learning, they use auditory feedback to gradually refine their own initially rambling vocalizations so that they progressively resemble the previously memorized tutor song. Normal song learning requires appropriate experience during a sensitive period in early development, and also relies on auditory feedback in adulthood to maintain precisely calibrated vocal output [4]. The similarities between song and speech in their reliance on auditory feedback suggest that investigations of song learning may provide more general insights into the behavioral and neural mechanisms that govern vocal-motor learning. In addition, we are especially interested in the function of an avian basal ganglia-forebrain circuit (the anterior forebrain pathway or 'AFP') in vocal learning. This circuit plays a central role in feedback-dependent song learning in juvenile and adult birds. Because the AFP can be studied mechanistically in the context of well-defined behavior it may prove to be a particularly tractable model for understanding basal ganglia function more generally. Here, we propose to use the techniques for auditory feedback manipulation that we developed under the previous grant cycle to extend our studies of how vocal behavior in songbirds is shaped by experience (aim 1), determine how the signals that drive learning are represented in the brain (Aim 2) and how they engage basal ganglia circuitry to change song (Aim 3). We will focus on the Bengalese finch, a species that exhibits general properties of vocal learning, but appears to rely particularly strongly on auditory feedback. Songbirds provide a model where the influence of performance-based feedback on a well-defined and quantifiable behavior can be understood at a mechanistic level. Such an understanding will provide basic insight into normal learning processes, with particular relevance to speech, and contribute to our ability to prevent and correct disabilities that arise from dysfunction of these processes. PUBLIC HEALTH RELEVANCE We will use songbirds to investigate the neural mechanisms that underlie the influence of auditory feedback on adult vocal learning. Such investigations will provide basic insight into normal learning processes, with particular relevance to human speech, and contribute to our ability to prevent and correct disabilities that arise from dysfunction of these processes. Because vocal learning depends crucially on widely conserved basal ganglia-forebrain circuits, this system additionally may prove an especially tractable one for investigating the general functioning of such circuits in motor control and learning and the deficits that arise under conditions of basal ganglia disease.