Center for Magnetoencephalography, University of Nebraska Medical Center (UNMC), 988422 Nebraska Medical Center, Omaha, NE, 68198-8422, USA.
Department of Neurological Sciences, UNMC, Omaha, NE, USA.
Brain Struct Funct. 2017 Sep;222(7):3075-3086. doi: 10.1007/s00429-017-1387-1. Epub 2017 Mar 24.
Shortly after movement termination, there is a strong increase or resynchronization of the beta rhythm (15-30 Hz) across the sensorimotor network of humans, known as the post-movement beta rebound (PMBR). This response has been associated with active inhibition of the motor network following the completion of a movement, sensory afferentation of the sensorimotor cortices, and other functions. However, studies that have directly probed the role of the PMBR in movement execution have reported mixed results, possibly due to differences in the amount of total motor output and/or movement complexity. Herein, we used magnetoencephalography during an isometric-force control task to examine whether alterations in the timing of motor termination demands modulate the PMBR, independent of differences in the motor output itself. Briefly, we manipulated the amount of time between the cue to initiate the force and the cue to terminate the force, such that participants were either forced to terminate quickly or slowly. We also performed a control experiment to test for temporal predictability effects. Our results indicated that the PMBR was stronger immediately following movement termination in the prefrontal cortices, supplementary motor area, left postcentral gyrus, paracentral lobule, and parietal cortex when participants were forced to terminate more quickly. These results were not attributable to the temporal predictability of each condition. These findings support the notion that the PMBR response at least partially serves motor inhibition, independent of the parameters within the motor output itself, and that particular nodes of the motor network may be differentially modulated by motor termination.
运动终止后不久，人类感觉运动网络中的β节律（15-30 Hz）会强烈增加或重新同步，即运动后β反弹（PMBR）。这一反应与运动完成后的运动网络主动抑制、感觉传入感觉运动皮质以及其他功能有关。然而，直接探测 PMBR 在运动执行中的作用的研究报告结果不一，这可能是由于总运动输出量和/或运动复杂性的差异造成的。在此，我们在等长力控制任务中使用脑磁图来检查运动终止要求的定时改变是否会调制 PMBR，而不考虑运动输出本身的差异。简而言之，我们操纵启动力的提示和终止力的提示之间的时间量，使参与者被迫快速或缓慢地终止。我们还进行了控制实验以测试时间可预测性效应。结果表明，当参与者被迫更快地终止时，前额叶皮质、辅助运动区、左侧后中央回、旁中央小叶和顶叶皮质中的 PMBR 在运动终止后立即更强。这些结果不是由于每个条件的时间可预测性造成的。这些发现支持这样一种观点，即 PMBR 反应至少部分地服务于运动抑制，而与运动输出本身的参数无关，并且运动网络的特定节点可能会被运动终止以不同的方式调节。
