NEURAL CORRELATES OF VOCAL LEARNING IN SONGBIRDS

这项研究的长期目标是了解 在歌唱学习过程中获得的记忆是如何储存在鸣鸟体内的 大脑；这些记忆如何与听觉体验和 类固醇激素对血管紧张素转换酶反应特性的影响 以及这些反应特性如何反映或决定 一只鸟会唱什么歌，它会对歌声做出怎样的行为反应。 鸟鸣的习得可能是最接近人类语言的动物类比 发展。专门的神经结构已经进化成从属于两者 行为，说话和唱歌都是最容易在早年学会的 易感受期和需要物种-典型的听觉输入和 听觉反馈。此外，在这两种情况下，正常的知觉 发育可能需要获得正常的运动技能。两者的发展 语言和歌曲会受到异常感官体验的损害，比如 由儿童暂时性传导性听力损失引起，或当幼儿 鸟儿被阻止听到适当的歌声模型或其 自己的发声。对歌曲神经基础的再认识 学习可以提供一个模型，说明 专门的行为在运动和知觉中被存储、访问和使用 发展，它还可能揭示导致 不正常的早期感觉体验，限制行为发育。 本研究以歌曲控制核团HVC为研究对象。这 核团对成年鸟类的鸣叫产生和听觉/运动是必需的 在歌曲习得过程中，它内部的相互作用可能很重要。这个 研究的具体目的是：1)确定颈椎的解剖位置 HVC的听觉输入；2)确定内部电路和 核团内各亚类神经元的投射； 进一步研究感觉体验、歌曲制作和类固醇是如何 激素在听觉反应特性的发展中相互作用 HVC中的神经元。这些实验结合了解剖学和 HVC核及其传入和传递的电生理研究 产出。细胞外应用的神经元示踪剂将用于 确定听觉输入的来源、发展和组织 HVC。然后将使用细胞内记录和染料填充来找出 HVC中不同的神经元群体是如何相互联系的 与其他歌唱系统核团中的细胞。方法将被开发为 防止鸟儿在正常的歌唱期间听到自己的歌声 习得与歌唱和选择性听觉的发展 将对HVC的反应进行行为和电生理监测 在这些鸟身上。

The long-term goals of this research are to understand the neural basis of how memories acquired during song learning are stored in the songbird brain; how these memories interact with auditory experience and the influence of steroid hormones to modulate the response properties of auditory neurons; and how these response properties reflect or determine what songs a bird will sing and how it will respond behaviorally to song. Bird song acquisition is probably the closest animal analog of human speech development. Specialized neural structures have evolved to subserve both behaviors, and both speech and song are most easily learned during an early impressionable period and require species-typical auditory input and auditory feedback. Furthermore, in both instances, normal perceptual development may require normal motor acquisition. The development of both speech and song is impaired by abnormal sensory experience, such as that caused by temporary conductive hearing loss in children or when a young bird is prevented from hearing appropriate song models or from hearing its own vocalizations. Further understanding of the neural basis of song learning may provide a model of how the sensory input required for specialized behaviors is stored, accessed, and used in motor and perceptual development, and it may also uncover the cellular mechanisms that cause abnormal early sensory experience to limit behavioral development. The proposed research focuses on the song-control nucleus HVc. This nucleus is necessary for song production in adult birds, and auditory/motor interactions within it are probably important during song acquisition. The specific aims research are: 1) to determine the anatomical locus of auditory input to HVc; 2) to determine the internal circuitry and projections of sub-classes of neurons within this nucleus; and 3) to investigate further how sensory experience, song production, and steroid hormones interact in the development of auditory response properties of neurons in HVc. The experiments combine anatomical and electrophysiological investigations of nucleus HVc, and of its inputs and outputs. Extracellularly applied neuronal tracers will be used to determine the source, development, and organization of auditory inputs to HVc. Intracellular recording and dye-filling will then be used to find out how different populations of neurons in HVc connect with each other and with cells in other song-system nuclei. Methods will be developed to prevent a bird from hearing itself sing during the normal period of song acquisition, and the development of song and of selective auditory responses in HVc will be monitored behaviorally and electrophysiologically in these birds.