Alpha band cortico-muscular coherence occurs in healthy individuals during mechanically-induced tremor.
Alpha band cortico-muscular coherence occurs in healthy individuals during mechanically-induced tremor.
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DOI：
10.1371/journal.pone.0115012
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发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
De Vito G
中科院分区：
文献类型：
--
作者：
Budini F;McManus LM;Berchicci M;Menotti F;Macaluso A;Di Russo F;Lowery MM;De Vito G
本工作旨在研究机械放大震颤对阿尔法频段皮层-肌肉一致性(CMC)的影响。对这一特定波段的CMC的研究特别感兴趣，因为这种一致性在健康个体中通常是缺失的，在受病理性震颤影响的患者中是一种异常特征；因此，了解其机制是重要的。13名健康志愿者(23±4岁)在弹性负荷和20%最大自主等长收缩(MVC)的等长条件下进行肘屈肌持续收缩。选择弹簧刚度来引起拉伸反射伺服回路的不稳定。同时记录的脑电通道、肱二头肌表面肌电信号和肌力。与等长条件相比，对弹簧的收缩导致力信号和肌电幅度的更大波动(p<；0.05)。在等长收缩期间，系统地在β带发现CMC，在α带零星地观察到CMC。然而，在对弹簧负荷的收缩过程中，13名志愿者中有12名在阿尔法频段观察到CMC。部分定向相干(PDC)显示，在阿尔法频段(p<；0.05)，沿EMG到EEG方向的信息流增加。因此，在健康人中，可以通过机械地放大震颤来系统地诱导感觉-运动皮质和二头肌之间的阿尔法频段的一致性。肌电向脑电方向信息流的增加可能反映了肌梭传入活动的增强。这些结果可能有助于理解震颤相关病理中α带CMC的存在，提示这一现象的起源可能不仅发生在皮质水平，还可能受到脊髓回路的影响。
The present work aimed at investigating the effects of mechanically amplified tremor on cortico-muscular coherence (CMC) in the alpha band. The study of CMC in this specific band is of particular interest because this coherence is usually absent in healthy individuals and it is an aberrant feature in patients affected by pathological tremors; understanding its mechanisms is therefore important. Thirteen healthy volunteers (23±4 years) performed elbow flexor sustained contractions both against a spring load and in isometric conditions at 20% of maximal voluntary isometric contraction (MVC). Spring stiffness was selected to induce instability in the stretch reflex servo loop. 64 EEG channels, surface EMG from the biceps brachii muscle and force were simultaneously recorded. Contractions against the spring resulted in greater fluctuations of the force signal and EMG amplitude compared to isometric conditions (p<.05). During isometric contractions CMC was systematically found in the beta band and sporadically observed in the alpha band. However, during the contractions against the spring load, CMC in the alpha band was observed in 12 out of 13 volunteers. Partial directed coherence (PDC) revealed an increased information flow in the EMG to EEG direction in the alpha band (p<.05). Therefore, coherence in the alpha band between the sensory-motor cortex and the biceps brachii muscle can be systematically induced in healthy individuals by mechanically amplifying tremor. The increased information flow in the EMG to EEG direction may reflect enhanced afferent activity from the muscle spindles. These results may contribute to the understanding of the presence of alpha band CMC in tremor related pathologies by suggesting that the origin of this phenomenon may not only be at cortical level but may also be affected by spinal circuit loops.
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影响因子：
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