Pyramidal tract neurons (PTNs) within macaque rostral ventral premotor cortex (F5) and (M1) provide direct input to spinal circuitry and are critical for skilled movement control. Contrary to initial hypotheses, they can also be active during action observation, in the absence of any movement. A population-level understanding of this phenomenon is currently lacking. We recorded from single neurons, including identified PTNs, in (M1) (n = 187), and F5 (n = 115) as two adult male macaques executed, observed, or withheld (NoGo) reach-to-grasp actions. F5 maintained a similar representation of grasping actions during both execution and observation. In contrast, although many individual M1 neurons were active during observation, M1 population activity was distinct from execution, and more closely aligned to NoGo activity, suggesting this activity contributes to withholding of self-movement. M1 and its outputs may dissociate initiation of movement from representation of grasp in order to flexibly guide behaviour.

中文翻译：

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前运动和初级运动皮层镜像神经元的运动启动和抓握表征

猕猴头侧腹侧运动前皮层 (F5) 和 (M1) 内的锥体束神经元 (PTN) 为脊髓回路提供直接输入，对于熟练的运动控制至关重要。与最初的假设相反，在没有任何运动的情况下，它们也可以在动作观察期间处于活动状态。目前缺乏对这种现象的人口层面的理解。我们在 (M1) (n = 187) 和 F5 (n = 115) 中记录了单个神经元，包括已识别的 PTN，因为两只成年雄性猕猴执行、观察或拒绝 (NoGo) 伸手抓握动作。F5 在执行和观察期间保持了类似的抓取动作表示。相比之下，尽管许多个体 M1 神经元在观察期间处于活跃状态，但 M1 群体活动与执行不同，并且与 NoGo 活动更接近，表明这项活动有助于抑制自我运动。M1 及其输出可以将运动的启动与抓握的表示分离，以便灵活地指导行为。