Borroni Paola, Montagna Marcella, Cerri Gabriella, Baldissera Fausto
Dipartimento di Medicina, Chirurgia e Odontoiatria, Università degli Studi di Milano, Via A.di Rudinì 8, 20142 Milano, Italy.
Eur J Neurosci. 2008 Oct;28(7):1427-35. doi: 10.1111/j.1460-9568.2008.06458.x.
In humans, observation of movement performed by others evokes a subliminal motor resonant response, probably mediated by the mirror neurone system, which reproduces the motor commands needed to execute the observed movement with good spatial and temporal fidelity. Motor properties of the resonant response were here investigated with the ultimate goal of understanding the principles operating in the transformation from observation to internal reproduction of movement. Motor resonance was measured as the modulation of excitability of spinal motoneurones, evoked by the observation of a cyclic flexion-extension of one hand. The first two experiments showed that the observation of a one-hand movement always evoked a bimanual resonant response independent of which hand was observed and that these bilateral responses were consistently phase-linked. H-reflexes simultaneously recorded in right and left flexor carpi radialis muscles were always modulated 'in-phase' with each other. The goal of the third experiment was to define the role of primary motor cortex in the bilateral resonant response. Bilateral H-reflexes were recorded during a temporary inactivation induced by transcranial magnetic stimulation over the left cortical hand motor area of observers. The finding that such cortical depression abolished the H-reflex modulation of only the right flexor carpi radialis motoneurones, leaving it unchanged on the left side, suggested that both primary motor areas were activated by the premotor cortex and transmit the resonant activation through crossed corticospinal pathways. The data provide further evidence that the subliminal activation of motor pathways induced by movement observation is organized according to general rules shared with the control of voluntary movement.
在人类中，观察他人进行的动作会引发一种潜意识的运动共振反应，这可能由镜像神经元系统介导，该系统能以良好的空间和时间保真度再现执行所观察动作所需的运动指令。本文研究了共振反应的运动特性，最终目的是理解从动作观察到内部动作再现过程中起作用的原理。通过观察一只手的周期性屈伸来测量运动共振，即测量脊髓运动神经元兴奋性的调制。前两个实验表明，观察单手动作总会引发双手共振反应，且与观察哪只手无关，并且这些双侧反应始终存在相位关联。同时记录右侧和左侧桡侧腕屈肌中的H反射，它们总是相互“同相”调制。第三个实验的目的是确定初级运动皮层在双侧共振反应中的作用。在对观察者左侧皮质手部运动区进行经颅磁刺激诱导的暂时失活期间，记录双侧H反射。结果发现，这种皮质抑制仅消除了右侧桡侧腕屈肌运动神经元的H反射调制，而左侧保持不变，这表明两个初级运动区均由运动前皮层激活，并通过交叉的皮质脊髓通路传递共振激活。这些数据进一步证明，动作观察诱导的运动通路潜意识激活是根据与自主运动控制共有的一般规则进行组织的。
