Department of General Psychology, University of Padova, via Venezia 8, 35131 Padova, Italy.
Exp Brain Res. 2011 Jun;211(3-4):557-68. doi: 10.1007/s00221-011-2650-y. Epub 2011 Apr 7.
A large body of research reports that perceiving body movements of other people activates motor representations in the observer's brain. This automatic resonance mechanism appears to be imitative in nature. However, action observation does not inevitably lead to symmetrical motor facilitation: mirroring the observed movement might be disadvantageous for successfully performing joint actions. In two experiments, we used transcranial magnetic stimulation (TMS) to investigate whether the excitability of the corticospinal system was selectively modulated by the social dimension of an observed action. We recorded motor-evoked potentials (MEPs) from right-hand muscles during the observation of an action sequence which, depending on context, might or might not elicit a complementary response. The results demonstrate a differential motor facilitation depending on action context. Specifically, when the context called for a complementary action, the excitability pattern reflected the under-threshold activation of a complementary action, whereas when the context did not imply acting in a complementary manner, the observer's corticospinal activity reflected symmetrical motor resonance. We contend that the mechanisms underlying action observation are flexible and respond to contextual factors that guide the social interaction between individuals beyond emulation.
大量研究报告表明，感知他人的身体动作会激活观察者大脑中的运动表象。这种自动共振机制似乎具有模仿的性质。然而，动作观察并不一定会导致对称的运动促进：模仿观察到的运动对于成功执行联合动作可能是不利的。在两项实验中，我们使用经颅磁刺激（TMS）来研究观察到的动作的社会维度是否会选择性地调节皮质脊髓系统的兴奋性。我们在观察动作序列时记录右手肌肉的运动诱发电位（MEPs），具体取决于上下文，这些动作序列可能会或可能不会引起补充反应。结果表明，运动兴奋性的模式会根据动作的上下文而有所不同。具体来说，当上下文需要补充动作时，兴奋性模式反映了补充动作的未达到阈值的激活，而当上下文不暗示以补充的方式行动时，观察者的皮质脊髓活动反映了对称的运动共振。我们认为，动作观察的机制是灵活的，会对指导个体之间社会互动的上下文因素做出反应，而不仅仅是模仿。
