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，特别是大脑如何 存储和表示复杂的感官信息，以及它如何使用感官 指导学习运动行为的信息。鸣禽的发声学习 为研究这些问题提供了一个有用的系统。鸟儿学会歌唱 在两个不同的阶段，这两个阶段都依赖于听觉 体验和反馈。第一，在感官的关键时期 学习时，小鸟听到家教的歌声，记住了内心的声音 这首歌的表现形式，或“模板”。然后，在感觉运动过程中 在学习期间，他们使用来自自己声音的听觉反馈逐渐 优化他们的声音输出，使其与存储的导师模板相匹配。 此外，鸟类有专门的大脑结构专门用于歌曲学习，在 许多重要的神经变化很可能会发生。最后， 因为歌曲学习与语言学习有许多共同之处 收购，它可能提供对潜在机制的特殊洞察 人类发声学习和语言发展的关键时期。 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，投射到发声运动通路， 成年后发展出高度选择性听觉反应 鸟儿自己的歌声。这些特性表明，房颤神经元可能是 在存储歌曲的感觉模板的感觉学习期间涉及， 然后，在感觉运动学习期间，向运动提供听觉反馈 指导发音精炼的途径。拟议中的实验将 检验这些假设。第一，青少年房颤通路神经元的研究 在感觉期结束时，雀类会准确地决定什么时候歌唱 选择性出现了。动物发声的二次操控 将阐明这些房颤神经元的选择性是否 由导师的感官经验塑造，来自动物自己的反馈 声音或者两者兼而有之。在这些实验中，鸟类的发声 (塑料歌曲)也将被定量分析，并与 他们的房颤神经元的新调谐特性，以增加我们的理解 神经元如何编码和辨别这种复杂的刺激。最后， 认为房颤为发声运动通路提供关键的感觉反馈 将通过评估房颤输入对神经反应的贡献进行测试 在其靶曲运动核中，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.