Effect of volitional relaxation and motor imagery on F wave and MEP: Do these tasks affect excitability of the spinal or cortical motor neurons?
Effect of volitional relaxation and motor imagery on F wave and MEP: Do these tasks affect excitability of the spinal or cortical motor neurons?
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DOI：
10.1016/j.clinph.2010.12.041
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发表时间：
2011-07-01
影响因子：
4.7
通讯作者：
Tani, T.
中科院分区：
文献类型：
--
作者：
Fujisawa, R.;Kimura, J.;Tani, T.
目的：方法：10名健康受试者接受两个独立的实验，每个实验包括连续三个阶段记录拇短展肌（APB）的F波和MEP：（1）基线，（2）固定APB 3 h后，（3）短暂肌肉运动后。实验1（放松任务）在制动过程中，被试自主放松APB，实验2（想象任务）在不运动的情况下，在心理上模拟拇指外展。运动想象减少了这种抑制，恢复F波几乎完全（94%）和MEP只有部分（77%）。因此，休息引起的MEP下降部分是由于皮层调制。与此相反，统计分析显示，无论是F波或MEP评估的图像诱导的运动神经元兴奋性的恢复没有差异。因此，脊髓运动神经元的兴奋性增加负责F-波的变化也占复苏的MEP.Conclusions：意志放松抑制脊髓和皮层运动神经元，而心理模拟柜台休息引起的抑制主要是通过恢复脊髓excitability.Significance：本研究结果有助于阐明生理机制的运动图像。(C)2010年国际临床神经生理学联合会。由Elsevier爱尔兰有限公司出版。保留所有权利。
Objective: To test if simple motor imagery, like thumb abduction, preferentially influences the excitability of the spinal or cortical motoneurons.Methods: Ten healthy subjects underwent two separate experiments, each consisting of recording F waves and MEPs from abductor pollicis brevis (APB) in three consecutive sessions: (1) baseline, (2) after immobilizing APB for 3 h, and (3) after brief muscle exercise. During the immobilization, the subjects were instructed to volitionally relax APB in experiment 1 (relaxation task), and mentally simulate thumb abduction without actual movement in experiment 2 (imagery task).Results: Relaxation task suppressed both MEPs and F waves. Motor imagery reduced this suppression, restoring F waves nearly completely (94%) and MEPs only partially (77%). Hence, the rest-induced decline of MEPs in part results from cortical modulation. In contrast, statistical analysis revealed no differences in imagery-induced recovery of motoneuron excitabilities whether assessed by F wave or MEP. Thus, increased excitability of spinal motoneurons responsible for F-wave changes also accounts for recovery of MEPs.Conclusions: Volitional relaxation depresses the spinal and cortical motoneurons, whereas mental simulation counters rest-induced suppression primarily by restoring spinal excitability.Significance: The present findings help elucidate physiologic mechanisms underlying motor imagery. (C) 2010 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.