Current Biology.：镜像神经系统具有双重作用

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Current Biology.：镜像神经系统具有双重作用 人类大脑存在一种由马达神经细胞构成的镜像神经系统（mirrorneuronsystem），它能激活一种马达路径（motorpathways），从而使人类具有了模仿所见动作的能力。那么如果身体无法模仿所见动作又会怎样？发表于7月12日《现代生物学》上的一篇论文称，在这种情况下，人类大脑会激活一种替代路径以期达到模仿目的。这表明大脑马达系统的运作不仅仅是“复制”所见动作，更主要的是为了达到某个目的。该
  生物谷：人类大脑存在一种由马达神经细胞构成的镜像神经系统（mirror neuron system），它能激活一种马达路径（motor pathways），从而使人类具有了模仿所见动作的能力。那么如果身体无法模仿所见动作又会怎样？发表于7月12日《现代生物学》上的一篇论文称，在这种情况下，人类大脑会激活一种替代路径以期达到模仿目的。这表明大脑马达系统的运作不仅仅是“复制”所见动作，更主要的是为了达到某个目的。

  该项研究由来自荷兰、意大利、法国的科学家联合小组完成。他们向16个正常测试者和2个身体有障碍（无手臂）的测试者放映一般需要用手完成的简单动作（比如抓取杯子）的录像，同时应用核磁共振成像技术（MRI）观测他们的脑部活动。

  研究人员发现，在观看录像的时候，所有正常的测试者大脑均激活了能让他们抓取杯子的马达路径，而无手臂者大脑则激活了能让他们移动脚的马达路径。论文高级作者、荷兰格罗宁根大学的神经科学家Christian Keysers教授认为，这一结果强调了镜像神经系统的运作并不是简单的模仿，而是有着特定的目的。无手臂者认为他们能够用脚抓起杯子，所以他们的大脑就有了反应。

  美国加州大学洛杉矶分校的神经学家Marco Iacoboni认为，这一研究向我们清楚地展示了镜像神经元的作用在于模仿人而不仅仅是动作。但是他同时强调，两组测试者脑部活动的水平和区域存在很大的差异，今后还需要花大力气深入研究。（科学网）

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Aplasics Born without Hands Mirror the Goal of Hand Actions with Their Feet
Valeria Gazzola,1 Henk van der Worp,2 Theo Mulder,2,3 Bruno Wicker,4 Giacomo Rizzolatti,5 and Christian Keysers1,

1 BCN Neuroimaging Center, University Medical Center Groningen, University of Groningen, A. Deusinglaan 2, 9713AW Groningen, The Netherlands
2 Center for Human Movement Sciences, University Medical Center, University of Groningen, 9700 AD Groningen, The Netherlands
3 Royal Netherlands Academy of Arts and Sciences, Kloveniersburgwal 29, 1011 JV Amsterdam, The Netherlands
4 Institut de Neurosciences Cognitives de la Méditerranée, Centre National de la Recherche Scientifique 31, Chemin Joseph Aiguier, 13009 Marseille, France
5 Dipartimento di Neuroscienze, Universita di Parma, Via Volturno, 43100 Parma, Italy


Corresponding author
Christian Keysers
c.m.keysers@rug.nl

The premotor and parietal mirror neuron system (MNS) is thought to contribute to the understanding of observed actions by mapping them onto “corresponding” motor programs of the observer [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24], but how would the MNS respond to the observation of hand actions if the observer never had hands? Would it not show changes of blood-oxygen-level dependent (BOLD) signal, because the observer lacks motor programs that can resonate [12, 25, 26], or would it show significant changes because the observer has motor programs for the foot or mouth with corresponding goals [15, 17, 19, 27, 28]? We scanned two aplasic subjects, born without arms or hands, while they watched hand actions and compared their brain activity with that of 16 control subjects. All subjects additionally executed actions with different effectors (feet, mouth, and, for controls, hands). The BOLD signal of aplasic individuals within the putative MNS was augmented when they watched hand actions, demonstrating the brain's capacity to mirror actions that deviate from the embodiment of the observer by recruiting voxels involved in the execution of actions that achieve corresponding goals by different effectors. This sheds light on the functional organization of the MNS and predominance of goals in imitation.