Temporal control of muscle synergies is linked with alpha-band neural drive.
Temporal control of muscle synergies is linked with alpha-band neural drive.
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肌肉协同作用的时间控制与α波段神经驱动有关。
DOI：
10.1113/jp281232
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发表时间：
2021-07
影响因子：
5.5
通讯作者：
Valero-Cuevas, Francisco J.
中科院分区：
文献类型：
--
作者：
Laine, Christopher M.;Cohn, Brian A.;Valero-Cuevas, Francisco J.
在运动过程中，神经系统可以将肌肉群作为一个适应性强的功能实体或“协同作用”来共同控制。控制人类自愿行为何时（或是否）发生这种情况的规则尚不清楚，至少部分是因为协同作用通常是由肌肉活动的相关模式定义的，而不考虑其神经控制的基本结构。在这项研究中，我们研究了肌肉输出的共调制（即肌电图振幅的相关性）在多大程度上意味着肌肉共享肌间神经输入（通过肌电图-肌电图一致性分析进行评估）。我们首先检查了从事手臂骑行任务的成对上肢肌肉之间的这种关系。然后，我们应用了一种新颖的多维肌电图-肌电图一致性分析，允许在共享神经驱动的基础上表征协同作用。我们发现 α 波段相干性 (8-16 Hz) 与整体肌肉活动水平随时间的相关程度有关。这种一致性分析的扩展描述了α带驱动的跨肌肉分布和时间调制，揭示了与传统定义的肌肉协同作用的时间和结构特征的密切匹配。有趣的是，一致性衍生的神经驱动与 EMG 振幅的变化呈负相关，并且先于 EMG 振幅的变化约 200 毫秒。我们对α带神经驱动如何在肌肉之间动态分布的新颖表征是理解神经起源和肌肉协同作用的相关性的基本一步。
During movement, groups of muscles may be controlled together by the nervous system as an adaptable functional entity, or ‘synergy’. The rules governing when (or if) this occurs during voluntary behavior in humans are not well understood, at least in part because synergies are usually defined by correlated patterns of muscle activity without regard for the underlying structure of their neural control. In this study, we investigated the extent to which comodulation of muscle output (i.e., correlation of EMG amplitudes) implies that muscles share intermuscular neural input (assessed via EMG-EMG coherence analysis). We first examined this relationship among pairs of upper limb muscles engaged in an arm cycling task. We then applied a novel multidimensional EMG-EMG coherence analysis allowing synergies to be characterized on the basis of shared neural drive. We found that alpha-band coherence (8–16 Hz) is related to the degree to which overall muscle activity levels correlate over time. The extension of this coherence analysis to describe the cross-muscle distribution and temporal modulation of alpha-band drive revealed a close match to the temporal and structural features of traditionally-defined muscle synergies. Interestingly, the coherence-derived neural drive was inversely associated with, and preceded, changes in EMG amplitudes by ~200ms. Our novel characterization of how alpha-band neural drive is dynamically distributed among muscles is a fundamental step forward in understanding the neural origins and correlates of muscle synergies.