Motor facilitation while observing hand actions: Specificity of the effect and role of observer's orientation
Motor facilitation while observing hand actions: Specificity of the effect and role of observer's orientation
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DOI：
10.1152/jn.00773.2000
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发表时间：
2002-03-01
影响因子：
2.5
通讯作者：
Pascual-Leone, A
中科院分区：
文献类型：
--
作者：
Maeda, F;Kleiner-Fisman, G;Pascual-Leone, A
动作观察增强皮质脊髓兴奋性。在这里，我们测试了这种效应的特异性和观察者的方向所起的作用。10名正常受试者观察了右手在两个不同方向（远离，即，从观察者面向外的自然手取向;或朝向，即，不自然的面向观察者的手定向）。用经颅磁刺激（TMS）记录拇短展肌（APB）和第一骨间背侧肌（FDI）的运动诱发电位（MEP）。使用力传感器记录食指的运动方向。促进MEP的大小显着更大的APB在观察拇指运动和FDI在观察食指运动。当屏幕上呈现的手从观察者的手面向外并与观察者的手相对应（远离方向）时，MEP大小的促进作用显著更大。经颅磁刺激诱发的食指运动方向与观察到的运动相匹配，向伸展/屈曲方向移动，而不是向外展/内收方向移动。我们的研究结果提供了进一步的证据表明，运动的观察增强了运动中所涉及的肌肉的运动输出，并促进了观察到的动作。此外，我们提供了新的证据，这种观察引起的运动皮层调制的高度特异性。调制的程度取决于手的方向。当观察到的动作对应于观察者的方向时，调制是最大的。
Action observation enhances cortico-spinal excitability. Here we tested the specificity of this effect and the role played by the orientation of the observer. Ten normal subjects observed video clips of right hand performing three different finger movements (thumb ab-/adduction, index ab-/adduction, index extens-/flexion) in two different orientations (Away, i.e., natural hand-orientation facing out from the observer; or Toward, i.e., unnatural hand-orientation facing toward the observer). Motor-evoked potentials (MEPs) induced by transcranial magnetic stimulation (TMS) were recorded from the abductor pollicis brevis (APB) and the first dorsal interosseus (FDI) muscles. Movement direction of the index finger was recorded using force transducers. Facilitation of MEP size was significantly greater for APB during observation of thumb movements and for FDI during observation of index finger movements. Facilitation of MEP size was significantly greater when the hand presented on screen was facing out from and corresponding to that of the observer (Away orientation). The direction of the index finger movement evoked by TMS shifted toward extension/flexion versus ab-/adduction matching the observed movement. Our results give further evidence that observation of a movement enhances motor output to the muscles involved in the movement and facilitates the observed action. In addition, we provide novel evidence about the high degree of specificity of this observation-induced motor cortical modulation. The degree of modulation depends on hand orientation. The modulation is maximal when the observed action corresponds to the orientation of the observer.