Investigating the spatial representation and plasticity rules of a cortically dri

描述（由申请人提供）：人类有能力学习和执行各种复杂的运动行为，这些行为是日常生活中不可或缺的，从弹钢琴到说话，但人们对这些行为如何在大脑中表现出来知之甚少。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隐藏在复杂习得运动行为之下的已识别皮层回路的组织。鸣禽大脑中不同的运动区域在鸣叫过程中起着至关重要的作用。其中一个区域是核HVC（专有名称），它已被证明是歌曲运动序列产生的位置。HVC的前运动神经元在唱歌过程中很少放电，在每次演唱的特定时刻表现出短暂的动作电位爆发。不同的神经元在歌曲的不同时间爆发，这表明这些神经元形成了一个稀疏的时间表征。尽管据估计，在唱歌的任何时候，大约有200个神经元同时处于活动状态，但实际上，人们对大脑中这种前运动神经元网络的组织方式以及这种组织中固有的可塑性水平一无所知。两个具体的

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.