Bilateral motor unit synchronization of leg muscles during a simple dynamic balance task
Bilateral motor unit synchronization of leg muscles during a simple dynamic balance task
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DOI：
10.1111/j.1460-9568.2008.06584.x
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发表时间：
2009-02-01
影响因子：
3.4
通讯作者：
Beek, Peter J.
中科院分区：
文献类型：
--
作者：
Boonstra, Tjeerd W.;Daffertshofer, Andreas;Beek, Peter J.
为了处理丰富的行为目标，中枢神经系统必须以灵活的方式控制肌肉骨骼系统的许多自由度。如果将肌肉协同作用作为运动性能的受控构建块，而不是个体自由度，那么这个问题可以大大简化。肌肉协同作用被认为是一组肌肉在空间或时间上的一致激活模式，但其形成的神经机制在很大程度上仍然未知。在这里，我们评估的假设，协同作用反映在共同的输入不同的贡献肌肉，并调查调制运动单元（MU）同步的同源肌肉在节奏平衡任务。如果共同的输入与肌肉协同作用有关，那么由此产生的MU同步不应该是静态的，而是依赖于任务的，并且在本上下文中，随时间变化。双侧腿部肌肉表面肌电信号之间的一致性揭示了MU在两个不同频带中的同步。MU同步不是恒定的，而是在运动周期内调制的，其时间过程类似于肌肉的激活模式。这些结果与MU同步和肌肉协同作用之间的联系是一致的，并建议MU同步提供了一种方便的方法，用于研究协同相关的神经机制。
To handle the rich repertoire of behavioural goals, the CNS has to control the many degrees of freedom of the musculoskeletal system in a flexible manner. This problem can be drastically simplified if muscle synergies serve as the to-be-controlled building blocks of motor performance, instead of the individual degrees of freedom. Muscle synergies have been identified as coherent activation patterns of a group of muscles in space or time, but the neural mechanisms underlying their formation remain largely unknown. Here we evaluated the hypothesis that synergies are reflected in common input to different contributing muscles, and investigated modulations in motor unit (MU) synchronization of homologous muscles during a rhythmic balance task. If common input is related to muscle synergies, the resultant MU synchronization should not be static but task dependent and, in the present context, vary in time. Coherence between surface electromyographic signals of bilateral leg muscles revealed MU synchronization in two distinct frequency bands. MU synchronization was not constant but modulated within a movement cycle, and its time course resembled the activation patterns of the muscles. These results are congruent with a linkage between MU synchronization and muscle synergies, and suggest that MU synchronization provides an expedient method for studying synergy-related neural mechanisms.