The effect of simultaneous contractions of ipsilateral muscles on changes in corticospinal excitability induced by paired associative stimulation (PAS)
The effect of simultaneous contractions of ipsilateral muscles on changes in corticospinal excitability induced by paired associative stimulation (PAS)
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DOI：
10.1016/j.neulet.2008.08.064
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发表时间：
2008-11-07
影响因子：
2.5
通讯作者：
Carson, Richard G.
中科院分区：
文献类型：
--
作者：
Kennedy, Niarnh C.;Carson, Richard G.
考虑了利用交叉促进现象来提高配对联想刺激（PAS）的可靠性和肌肉特异性的方法。八名参与者完成了三个单独的课程：左手腕以最大自主收缩 (MVC) 的 20% 进行等长屈肌收缩，同时在右侧正中神经和左侧初级运动皮层 (MI) 进行 PAS（间隔 20 秒；持续时间 14 分钟）；仅以 MVC 的 20% 和 PAS 进行等长收缩（14 分钟）。另外八名参与者完成了两次持续时间较长的 PAS（28 分钟）：单独进行或与左手腕的屈曲收缩结合进行。在干预前、干预后立即和干预后 10 分钟，通过对左侧 M1 进行磁刺激，在右侧腕屈肌 (rFCR) 和伸肌 (rECR) 中诱发 30 个运动电位 (MEP)。 14 分钟和 28 分钟的 PAS 和（左腕屈曲）收缩相结合会导致 rFCR MEP 振幅可靠增加，而 rECR 中不存在这种情况。在仅 PAS 条件下，14 分钟的刺激导致 rFCR 和 rECR 中 MEP 振幅不可靠的增加，而 28 分钟的 PAS 仅对 rFCR 引起小（不可靠）的变化。这些结果支持以下结论：PAS 引起的皮质脊髓通路的兴奋性变化与皮质刺激部位同侧肌肉收缩相关的变化相互作用。此外，对侧肢体施加的局部收缩增加了与 PAS 相关的兴奋性变化的程度和肌肉特异性。 (C) 2008 Elsevier Ireland Ltd. 保留所有权利。
Consideration was given to means of increasing the reliability and muscle specificity of paired associative stimulation (PAS) by utilising the phenomenon of crossed-facilitation. Eight participants completed three separate sessions: isometric flexor contractions of the left wrist at 20% of maximum voluntary contraction (MVC) simultaneously with PAS (20s intervals; 14 min duration) delivered at the right median nerve and left primary motor cortex (MI); isometric contractions at 20% of MVC: and PAS only ( 14 min). Eight further participants completed two sessions of longer duration PAS (28 min): either alone or in conjunction with flexion contractions of the left wrist. Thirty motor potentials (MEPs) were evoked in the right flexor (rFCR) and extensor (rECR) carpi radialis muscles by magnetic stimulation of left M1 Prior to the interventions, immediately post-intervention, and 10 min post-intervention. Both 14 and 28 min of combined PAS and (left wrist flexion) contractions resulted in reliable increases in rFCR MEP amplitude, which were not present in rECR. In the PAS only conditions, 14 min of stimulation gave rise to unreliable increases in MEP amplitudes in rFCR and rECR, whereas 28 min of PAS induced small (unreliable) changes only for rFCR. These results support the conclusion that changes in the excitability of the corticospinal pathway induced by PAS interact with those associated with contraction of the muscles ipsilateral to the site of cortical stimulation. Furthermore, focal contractions applied by the opposite limb increase the extent and muscle specificity of the induced changes in excitability associated with PAS. (C) 2008 Elsevier Ireland Ltd. All rights reserved.