Helm F, Marinovic W, Krüger B, Munzert J, Riek S
Neuromotor Behavior Laboratory, Justus-Liebig-University Giessen, Germany.
School of Human Movement Studies, The University of Queensland, Brisbane, Australia; School of Psychology, The University of Queensland, Brisbane, Australia.
Neuroscience. 2015 Apr 2;290:398-405. doi: 10.1016/j.neuroscience.2015.01.050. Epub 2015 Jan 30.
Research on motor imagery and action observation has become increasingly important in recent years particularly because of its potential benefits for movement rehabilitation and the optimization of athletic performance (Munzert et al., 2009). Motor execution, motor imagery, and action observation have been shown to rely largely on a similar neural network in motor and motor-related cortical areas (Jeannerod, 2001). Given that motor imagery is a covert stage of an action and its characteristics, it has been assumed that modifying the motor task in terms of, for example, effort will impact neural activity. With this background, the present study examined how different force requirements influence corticospinal excitability (CSE) and intracortical facilitation during motor imagery and action observation of a repetitive movement (dynamic force production). Participants were instructed to kinesthetically imagine or observe an abduction/adduction movement of the right index finger that differed in terms of force requirements. Trials were carried out with single- or paired-pulse transcranial magnetic stimulation. Surface electromyography was recorded from the first dorsal interosseous (FDI) and the abductor digiti minimi (ADM). As expected, results showed a significant main effect on mean peak-to-peak motor-evoked potential (MEP) amplitudes in FDI but no differences in MEP amplitudes in ADM muscle. Participants' mean peak-to-peak MEPs increased when the force requirements (movement effort) of the imagined or observed action were increased. This reveals an impact of the imagined and observed force requirements of repetitive movements on CSE. It is concluded that this effect might be due to stronger motor neuron recruitment for motor imagery and action observation with an additional load. That would imply that the modification of motor parameters in movements such as force requirements modulates CSE.
近年来，运动想象和动作观察的研究变得越来越重要，特别是因为其对运动康复和运动表现优化具有潜在益处（Munzert等人，2009年）。运动执行、运动想象和动作观察已被证明在很大程度上依赖于运动及与运动相关的皮质区域中相似的神经网络（Jeannerod，2001年）。鉴于运动想象是动作的一个隐蔽阶段及其特点，人们认为例如在努力程度方面改变运动任务会影响神经活动。在此背景下，本研究考察了在重复运动（动态力量产生）的运动想象和动作观察过程中，不同的力量要求如何影响皮质脊髓兴奋性（CSE）和皮质内易化。参与者被指示通过动觉想象或观察右手食指的外展/内收运动，这些运动在力量要求方面有所不同。试验采用单脉冲或双脉冲经颅磁刺激进行。从第一背侧骨间肌（FDI）和小指展肌（ADM）记录表面肌电图。正如预期的那样，结果显示对FDI中平均峰峰值运动诱发电位（MEP）幅度有显著的主效应，但ADM肌肉中MEP幅度没有差异。当想象或观察动作的力量要求（运动努力程度）增加时，参与者的平均峰峰值MEP增加。这揭示了重复运动的想象和观察到的力量要求对CSE的影响。得出的结论是，这种效应可能是由于在额外负荷下，运动想象和动作观察中运动神经元募集更强。这意味着在诸如力量要求等运动参数方面的改变会调节CSE。
