Université de Bourgogne, Unité de Formation et de Recherche en Sciences et Techniques des Activités Physiques et Sportives, Campus Universitaire, Dijon, France;
J Neurophysiol. 2013 Dec;110(12):2887-94. doi: 10.1152/jn.00123.2013. Epub 2013 Oct 2.
Although plentiful data are available regarding mental states involving the dominant-right arm, the evidence for the nondominant-left arm is sparse. Here, we investigated whether right-handers can generate accurate predictions with either the right or the left arm. Fifteen adults carried out actual and mental arm movements in two directions with varying inertial resistance (inertial anisotropy phenomenon). We recorded actual and mental movement times and used the degree of their similarity as an indicator for the accuracy of motor imagery/prediction process. We found timing correspondences (isochrony) between actual and mental right arm movements in both rightward (low inertia resistance) and leftward (high inertia resistance) directions. Timing similarities between actual and mental left arm movements existed for the leftward direction (low inertia resistance) but not for the rightward direction (high inertia resistance). We found similar results when participants reaching towards the midline of the workspace, a result that excludes a hemispace effect. Electromyographic analysis during mental movements showed that arm muscles remained inactivate, thus eliminating a muscle activation strategy that could explain intermanual differences. Furthermore, motor-evoked potentials enhancement in both right and left biceps brachii during mental actions indicated that subjects were actively engaged in mental movement simulation and that the disadvantage of the left arm cannot be attributed to the nonactivation of the right motor cortex. Our findings suggest that predictive mechanisms are more robust for the right than the left arm in right-handers. We discussed these findings from the perspective of the internal models theory and the dynamic-dominance hypothesis of laterality.
尽管有大量关于涉及优势右臂的心理状态的数据，但关于非优势左臂的证据却很少。在这里，我们研究了右利手是否可以用右臂或左臂进行准确的预测。15 名成年人在两种方向上进行了实际和心理手臂运动，同时施加了不同的惯性阻力（惯性各向异性现象）。我们记录了实际和心理运动的时间，并使用它们之间的相似程度作为运动意象/预测过程准确性的指标。我们发现，在向右（低惯性阻力）和向左（高惯性阻力）方向上，实际和心理右臂运动之间存在时间对应关系（等时性）。在向左方向（低惯性阻力）上，实际和心理左臂运动之间存在时间相似性，但在向右方向（高惯性阻力）上则没有。当参与者向工作空间的中线伸展手臂时，我们得到了类似的结果，这排除了半空间效应。在心理运动期间的肌电图分析表明，手臂肌肉仍然处于静止状态，从而排除了可以解释手间差异的肌肉激活策略。此外，在心理动作中，双侧肱二头肌的运动诱发电位增强表明，受试者积极参与心理运动模拟，并且左臂的劣势不能归因于右运动皮层的非激活。我们的研究结果表明，在右利手中，预测机制对于右臂比对左臂更稳健。我们从内部模型理论和侧性的动态优势假说的角度讨论了这些发现。
