Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA.
Committee on Computational Neuroscience, University of Chicago, Chicago, IL 60637, USA.
Neuron. 2020 May 6;106(3):526-536.e4. doi: 10.1016/j.neuron.2020.02.011. Epub 2020 Mar 6.
Voluntary movement initiation involves the modulations of large groups of neurons in the primary motor cortex (M1). Yet similar modulations occur during movement planning when no movement occurs. Here, we show that a sequential spatiotemporal pattern of excitability propagates across M1 prior to the movement initiation in one of two oppositely oriented directions along the rostro-caudal axis. Using spatiotemporal patterns of intracortical microstimulation, we find that reaction time increases significantly when stimulation is delivered against, but not with, the natural propagation direction. Functional connections among M1 units emerge at movement that are oriented along the same rostro-caudal axis but not during movement planning. Finally, we show that beta amplitude profiles can more accurately decode muscle activity when they conform to the natural propagating patterns. These findings provide the first causal evidence that large-scale, propagating patterns of cortical excitability are behaviorally relevant and may be a necessary component of movement initiation.
自愿运动启动涉及初级运动皮层（M1）中大量神经元的调制。然而，在没有运动发生时，在运动规划期间也会发生类似的调制。在这里，我们表明兴奋性的顺序时空模式在沿前后轴的两个相反方向之一的运动起始之前在 M1 中传播。使用皮层内微刺激的时空模式，我们发现当刺激与自然传播方向相反而不是顺行时，反应时间会显著增加。在运动期间，M1 单元之间出现的功能连接与自然传播方向一致，但在运动规划期间没有出现。最后，我们表明，当β振幅曲线符合自然传播模式时，它们可以更准确地解码肌肉活动。这些发现提供了第一个因果证据，表明皮层兴奋性的大规模传播模式与行为相关，并且可能是运动启动的必要组成部分。
