Candidi Matteo, Urgesi Cosimo, Ionta Silvio, Aglioti Salvatore M
Universita di Roma "La Sapienza", Rome, Italy.
Soc Neurosci. 2008;3(3-4):388-400. doi: 10.1080/17470910701676269.
Single-pulse transcranial magnetic stimulation (TMS) studies show that action observation facilitates the onlooker's cortico-spinal system supporting the notion of motor mirroring. Repetitive transcranial magnetic stimulation (rTMS) over ventral premotor cortex (vPMc) impairs visual discrimination of body actions. Although studies suggest that the action observation-execution matching system may map only actions that belong to the observer's motor repertoire, we demonstrated comparable motor and premotor facilitation during observation of biomechanically possible as well as impossible actions. It has also been shown that seeing impossible body movements activates the extrastriate body area (EBA). Using event-related rTMS, we sought to determine whether vPMc and EBA are actively involved in the visual discrimination of actions performed through biomechanically possible or impossible kinematics and of their biomechanical plausibility. Stimulation of vPMc impaired discrimination of possible actions while leaving intact the discrimination of biomechanically impossible actions and of biomechanical plausibility. No effect of EBA rTMS on any type of action processing was found. Thus, vPMc is crucial for discrimination of the goal of actions that can be actually performed suggesting that this area is involved in the visual processing of goal-directed actions.
单脉冲经颅磁刺激（TMS）研究表明，动作观察有助于旁观者的皮质脊髓系统，支持运动镜像的概念。对腹侧运动前皮质（vPMc）进行重复经颅磁刺激（rTMS）会损害对身体动作的视觉辨别。尽管研究表明动作观察-执行匹配系统可能仅映射属于观察者运动技能库的动作，但我们发现在观察生物力学上可能以及不可能的动作期间，运动和运动前促进作用具有可比性。研究还表明，看到不可能的身体动作会激活纹外身体区域（EBA）。我们使用事件相关rTMS，试图确定vPMc和EBA是否积极参与对通过生物力学上可能或不可能的运动学所执行动作及其生物力学合理性的视觉辨别。刺激vPMc会损害对可能动作的辨别，而对生物力学上不可能的动作及其生物力学合理性的辨别则不受影响。未发现EBA rTMS对任何类型的动作处理有影响。因此，vPMc对于辨别实际可执行动作的目标至关重要，这表明该区域参与了目标导向动作的视觉处理。
