Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford OX1 3UD, United Kingdom.
Neuropsychologia. 2010 Aug;48(10):3173-7. doi: 10.1016/j.neuropsychologia.2010.06.033. Epub 2010 Jul 1.
Viewing another person's hand actions enhances excitability in an observer's left and right primary motor (M1) cortex. We aimed to determine whether viewing communicative hand actions alters this bilateral sensorimotor resonance. Using single-pulse transcranial magnetic stimulation (TMS), we measured excitability in the left and right M1 while right-handed non-signing participants observed bimanual communicative hand actions, i.e., meaningful signs in British Sign Language. TMS-induced motor evoked potentials were recorded from hand muscles during sign observation before and after teaching the participants to associate meanings with half of the signs. Before this teaching, when participants did not know that the presented hand actions were signs, excitability of left and right M1 was modulated equally. After learning the meanings of half the signs, excitability of the left, but not right, M1 was significantly enhanced. This left-lateralized enhancement of M1 excitability occurred during observation of signs with known and unknown meanings. The findings suggest that awareness of the communicative nature of another person's hand actions strengthens sensorimotor resonance in the left M1 cortex and alters hemispheric balance during action observation.
观看他人的手部动作会增强观察者左右初级运动皮层（M1）的兴奋性。我们旨在确定观看交际性手部动作是否会改变这种双侧感觉运动共鸣。使用单次脉冲经颅磁刺激（TMS），我们在右利手非手语参与者观察双手交际性手部动作时，即英国手语中的有意义的手语，测量了左右 M1 的兴奋性。在向参与者教授将一半手语与含义相关联之前和之后，在观察手语期间从手部肌肉记录 TMS 诱导的运动诱发电位。在进行此教学之前，当参与者不知道呈现的手部动作是手语时，左右 M1 的兴奋性被同等调节。在学习了一半手语的含义后，左 M1 的兴奋性显著增强，但右 M1 没有。这种 M1 兴奋性的左侧偏侧增强发生在手语的含义为已知和未知的情况下。这些发现表明，对手部动作的交际性质的认识会增强左 M1 皮层的感觉运动共鸣，并改变动作观察期间的半球平衡。
