Pre-motor neural circuits enable versatile and sequential limb movements

摘要 运动是神经系统的可测量输出，简单的运动可以 组合成复杂的行为。我们使用肢体追踪， 连接体分析绘制控制基本腿的神经回路 果蝇梳理毛发的动作前运动网络的组织 先天的，顺序的行为将显示一个复杂的运动控制的成功解决方案 问题，并揭示可推广的连接图案，其计算功能 可以通过实验来测试。 从详细了解这种行为的时间模式开始，我们将 确定最简单的运动子程序，可以组合起来组装 全部曲目产生这些运动的电路位于 启动它们的命令样神经元和执行它们的运动神经元子集 他们利用我们对指令神经元和新电子的遗传筛选结果， 果蝇腹神经索的显微镜数据，我们将追踪神经元 连接，以揭示完整的前运动网络，显示哪些组 肌肉通过共同的兴奋性和抑制性连接共同工作， 它们的运动神经元。 前运动连接体允许我们通过建模来测试可能的电路功能。 我们将研究是否命令神经元诱导梳理序列与 共享的运动集中到共同的前运动节点或保持独立 控制路径。通过绘制抑制性连接，我们将确定这些 增加灵活性，以有效地修改元素移动的各个方面：例如，如果腿 延伸是一个构建块，它可以指向头部进行扫掠或指向 通过增加和减少一些额外运动神经元， 瞄准更近端的电梯肌肉运动前区的解剖学连接体 电路限制了关于电路功能的假设，导致了意想不到的发现， 高度连接的节点，并指导未来的实验来测量神经元活动 和行为后果。

Abstract Movements are measurable outputs of the nervous system and simple movements can be combined to compose complicated behaviors. We use limb tracking and connectome analyses to map the neural circuits controlling the elemental leg movements in Drosophila grooming. The organization of the pre-motor networks for this innate, sequential behavior will show a successful solution for a complex motor control problem and reveal generalizable connectivity motifs whose computational functions can be experimentally tested. Starting from a detailed understanding of the temporal patterns in this behavior, we will identify the simplest movement subroutines that can be combined to assemble the whole repertoire. The circuits that produce these movements lie between the command-like neurons that initiate them and subsets of motor neurons that execute them. Using the results of our genetic screens for command neurons and new electron microscopy data for the Drosophila ventral nerve cord, we will trace neuronal connections to uncover the complete pre-motor network, showing which groups of muscles are bound to work together by common excitatory and inhibitory connections to their associated motor neurons. The pre-motor connectome allows us to test possible circuit functions through modeling. We will investigate whether command neurons that induce grooming sequences with shared movements converge onto common pre-motor nodes or maintain independent control pathways. By mapping inhibitory connections, we will determine whether these add flexibility to efficiently modify aspects of elemental movements: for example, if leg extension is a building block, it could be directed toward the head for a sweep or toward the contralateral leg for a rub by adding and subtracting a few additional motor neurons targeting more proximal elevator muscles. The anatomical connectome for pre-motor circuits constrains hypotheses about circuit function, leads to unexpected discoveries of highly connected nodes, and guides future experiments to measure neuronal activity and behavioral consequences.