NEURAL ANALYSIS OF VOCAL LEARNING

描述(改编自申请者摘要)：长期目标是 了解学习和记忆的神经基础，特别是如何 大脑存储和表示复杂的感觉信息，以及它如何使用 用于指导运动行为学习的感官信息。中国的声乐学习 歌鸟为研究这些问题提供了一个有用的系统。鸟群 从成人“家教”那里学歌分两个不同的阶段，这两个阶段 依靠听觉经验和反馈。第一，在关键时期 对于感官学习，幼鸟听到导师的歌声，并记住一个 这首歌的内部表示，或“模板”。然后，在一次 感觉运动学习期间，它们使用来自自己的听觉反馈 声音，以逐渐改进他们的声音输出，使其与存储的 辅导模板。此外，鸟类有专门的大脑结构专门致力于 到歌曲学习，其中许多重要的神经变化很可能 才会发生。最后，因为歌曲学习有许多具体的特点 与语音获取一样，它可以提供对以下方面的特殊见解 人类发声学习的机制和语言的关键期 发展。 已知歌唱系统的前前脑(AF)通路发挥着 它在歌曲学习中的关键作用，但其确切功能尚不清楚。 这条通路中的神经元对声音做出反应，投射到发声运动 途径，成年后发展出高度选择性的听觉 对鸟儿自己的歌声的反应。这些特性表明，房颤 神经元可能参与感觉学习过程中感觉的储存。 歌曲模板，然后，在感觉运动学习期间，提供听觉 反馈到运动通路，以指导发声的精炼。这个 拟议中的实验将检验这些假设。首先，研究了 幼龄雀类感觉关闭时的房颤通路神经元 句号，将准确地决定何时出现歌曲选择性。第二 在学习过程中对动物发声的处理将澄清 这些房颤神经元的选择性是否受感觉经验的影响 家教的反馈，动物自己的声音反馈，或者两者兼而有之。在这些 实验中，鸟类的发声(塑料歌声)也将 定量分析，并与新出现的调谐特性进行比较 它们的房颤神经元，以增加我们对神经元如何编码和 辨别这种复杂的刺激。最后，AF提供的想法是 对发声运动通路的关键感觉反馈将通过 评估房颤输入对靶区神经反应的贡献 宋代运动核，处于几个不同的学习阶段。

DESCRIPTION (Adapted from applicant's abstract): The long term goal is to understand the neural basis of learning and memory, particularly how the brain stores and represents complex sensory information, and how it uses sensory information to guide learning of motor behaviors. Vocal learning in songbirds provides a useful system for studying these questions. Birds learn their song from adult "tutors" in two distinct stages, both of which depend on auditory experience and feedback. First, during a critical period for sensory learning, young birds hear the tutor song, and memorize an internal representation, or "template", of this song. Then, during a sensorimotor learning period, they use auditory feedback from their own voice to gradually refine their vocal output so that it matches the stored tutor template. Moreover, birds have specialized brain structures devoted to song learning, in which many of the important neural changes are likely to occur. Finally, because song learning has a number of specific features in common with speech acquisition, it may provide particular insight into mechanisms underlying human vocal learning and critical periods for language development. The anterior forebrain (AF) pathway of the song system is known to play a critical role in song learning, but its exact function remains unclear. Neurons in this pathway respond to sounds, project to the vocal motor pathway, and by adulthood have developed highly selective auditory responsiveness to the bird's own song. These properties suggest that AF neurons might be involved during sensory learning in storage of the sensory template for song, and then, during sensorimotor learning, provide auditory feedback to the motor pathway to guide refinement of vocalizations. The proposed experiments will test these hypotheses. First, study of the neurons of the AF pathway in young finches, at the close of the sensory period, will determine exactly when song selectivity emerges. Second manipulations of the animal's vocalizations during learning will clarify whether the selectivity of these AF neurons is shaped by sensory experience of the tutor, feedback from the animal's own voice, or both. In these experiments, birds' developing vocalizations (plastic song) will also be quantitatively analyzed, and compared to the emerging tuning properties of their AF neurons, to increase our understanding of how neurons encode and discriminate such complex stimuli. Finally, the idea that the AF provides crucial sensory feedback to the vocal motor pathway will be tested by assessing the contribution of AF inputs to neural responses in its target song motor nucleus, at several different stages of learning.