Investigating the spatial representation and plasticity rules of a cortically dri

描述(申请人提供)：人类有能力学习和执行一系列复杂的运动行为，这些行为是日常生活中不可或缺的，从弹钢琴到说话，但人们对这些行为在大脑中是如何表现的知之甚少。许多跨物种的研究试图阐明前脑运动中心的回路组织，但用于解决这一问题的行为范围仅限于先天的和相对简单的运动。鸣禽提供了一个很好的实验模型来研究复杂的习得运动行为背后的已识别皮质回路的组织。鸣禽大脑中不同的运动区已经被发现，它们在歌唱的产生中起着至关重要的作用。其中一个区域是HVC核(专有名称)，它被证明是歌曲运动序列产生的地方。HVC中的前运动神经元在歌唱时非常微弱地放电，在每次演唱歌曲的单个精确时刻都会显示出短暂的动作电位爆发。在歌曲中，不同的神经元在不同的时间爆发，这表明这些神经元形成了对时间的稀疏表示。虽然据估计，在歌曲演唱过程中的任何时刻，大约有200个神经元同时处于活跃状态，但实际上，对于这个运动前神经元网络在大脑中是如何组织的，以及这种组织所固有的可塑性水平，我们一无所知。这两个具体的 本提案中讨论的目标旨在解决这些问题。利用双光子显微镜显示活体HVC神经元网络，我们将研究SONG环路的时空组织，并对SONG相关活动进行纵向研究。特别是，目标1将解决是否存在用于歌曲表演的通用运动图，从而使核团特定区域的细胞总是与相似的时间相关 一群人的财产。它还将根据个体内的相邻神经元的时间特性来确定是否形成集群。目标2将测试这些运动前神经元的时间特性是否会随着时间的推移而改变，以及该网络固有的可塑性程度。这些实验将首次检验控制大脑中熟练运动行为的空间表征的规则，以及这个运动前网络随时间变化的程度。

DESCRIPTION (provided by applicant): Humans have the ability to learn and execute a wide range of complex motor behaviors that are integral to everyday life, from playing the piano to speaking, but little is known about how these behaviors are represented within the brain. A number of studies across species have attempted to elucidate the circuit organization of forebrain motor centers, but the range of behaviors used to address this issue has been limited to innate and relatively simple movements. Songbirds offer an excellent experimental model to study the organization of identified cortical circuits underlying a complex learned motor behavior. Distinct motor regions of the songbird brain have been identified that play an essential role in song production. One of these areas is the nucleus HVC (proper name), which has been shown to be the site of motor sequence generation for the song. Premotor neurons in HVC fire very sparely during singing, exhibiting a short burst of action potentials at a single precise moment within each rendition of the song. Different neurons burst at different times in the song, suggesting that these neurons form a sparse representation of time. Although it has been estimated that a group of approximately 200 neurons are simultaneously active at any moment during the song, practically nothing is known of how this network of premotor neurons is organized in the brain and the level of plasticity inherent in this organization. The two specific aims discussed in this proposal seek to address these issues. Using two-photon microscopy to visualize the network of HVC neurons in vivo, we will investigate the spatiotemporal organization of the song circuit and conduct a longitudinal study of song-related activity. In particular, Aim 1 will address whether there is a universal motor map for song performance, such that cells in specific regions of the nucleus are invariantly associated with similar temporal properties across a population of individuals. It will also determine whether neighboring neurons within an individual form clusters based on their temporal properties. Aim 2 will test whether the temporal properties of these premotor neurons shift over time, and the degree of plasticity inherent in the network. These experiments will be the first to examine the rules governing the spatial representation of a skilled motor behavior in the brain and the extent to which this premotor network changes over time.