Animal movement is controlled by motor neurons (MNs), which project out of the central nervous system to activate muscles¹. MN activity is coordinated by complex premotor networks that facilitate the contribution of individual muscles to many different behaviours^2,3,4,5,6. Here we use connectomics⁷ to analyse the wiring logic of premotor circuits controlling the Drosophila leg and wing. We find that both premotor networks cluster into modules that link MNs innervating muscles with related functions. Within most leg motor modules, the synaptic weights of each premotor neuron are proportional to the size of their target MNs, establishing a circuit basis for hierarchical MN recruitment. By contrast, wing premotor networks lack proportional synaptic connectivity, which may enable more flexible recruitment of wing steering muscles. Through comparison of the architecture of distinct motor control systems within the same animal, we identify common principles of premotor network organization and specializations that reflect the unique biomechanical constraints and evolutionary origins of leg and wing motor control.

动物的运动由运动神经元 (MN) 控制，运动神经元从中枢神经系统伸出来激活肌肉 ¹ 。 MN 活动由复杂的运动前网络协调，促进个体肌肉对许多不同行为的贡献 ^2,3,4,5,6 。在这里，我们使用连接组学 ⁷ 来分析控制果蝇腿和翅膀的运动前电路的接线逻辑。我们发现这两个前运动网络都聚集成模块，将神经支配肌肉的 MN 与相关功能联系起来。在大多数腿部运动模块中，每个前运动神经元的突触权重与其目标 MN 的大小成正比，为分层 MN 招募建立了电路基础。相比之下，机翼前运动网络缺乏成比例的突触连接，这可能使得机翼转向肌肉能够更灵活地募集。通过比较同一动物内不同运动控制系统的体系结构，我们确定了运动前网络组织和专业化的共同原则，反映了腿部和翅膀运动控制的独特生物力学约束和进化起源。