Mengotti Paola, Ripamonti Enrico, Pesavento Valentina, Rumiati Raffaella Ida
Neuroscience Area, SISSA, Trieste, Italy.
Department of Economics, Management and Statistics, Statistical Section, University of Milan-Bicocca, Milan, Italy.
Neuropsychologia. 2015 Dec;79(Pt B):256-71. doi: 10.1016/j.neuropsychologia.2015.06.038. Epub 2015 Jul 2.
Imitation is a sensorimotor process whereby the visual information present in the model's movement has to be coupled with the activation of the motor system in the observer. This also implies that greater the similarity between the seen and the produced movement, the easier it will be to execute the movement, a process also known as ideomotor compatibility. Two components can influence the degree of similarity between two movements: the anatomical and the spatial component. The anatomical component is present when the model and imitator move the same body part (e.g., the right hand) while the spatial component is present when the movement of the model and that of the imitator occur at the same spatial position. Imitation can be achieved by relying on both components, but typically the model's and imitator's movements are matched either anatomically or spatially. The aim of this study was to ascertain the contribution of the left and right hemisphere to the imitation accomplished either with anatomical or spatial matching (or with both). Patients with unilateral left and right brain damage performed an ideomotor task and a gesture imitation task. Lesions in the left and right hemispheres gave rise to different performance deficits. Patients with lesions in the left hemisphere showed impaired imitation when anatomical matching was required, and patients with lesions in the right hemisphere showed impaired imitation when spatial matching was required. Lesion analysis further revealed a differential involvement of left and right hemispheric regions, such as the parietal opercula, in supporting imitation in the ideomotor task. Similarly, gesture imitation seemed to rely on different regions in the left and right hemisphere, such as parietal regions in the left hemisphere and premotor, somatosensory and subcortical regions in the right hemisphere.
模仿是一种感觉运动过程，通过该过程，模型动作中呈现的视觉信息必须与观察者运动系统的激活相耦合。这也意味着，所见动作与所产生动作之间的相似性越高，执行该动作就越容易，这一过程也被称为观念运动兼容性。有两个因素会影响两个动作之间的相似程度：解剖学因素和空间因素。当模型和模仿者移动相同的身体部位（如右手）时，解剖学因素起作用；而当模型和模仿者的动作在相同的空间位置发生时，空间因素起作用。模仿可以通过依赖这两个因素来实现，但通常模型和模仿者的动作在解剖学上或空间上相匹配。本研究的目的是确定左半球和右半球对通过解剖学匹配或空间匹配（或两者兼具）完成的模仿的贡献。患有单侧左脑和右脑损伤的患者执行了一项观念运动任务和一项手势模仿任务。左半球和右半球的损伤导致了不同的表现缺陷。左半球有损伤的患者在需要解剖学匹配时表现出模仿能力受损，而右半球有损伤的患者在需要空间匹配时表现出模仿能力受损。病变分析进一步揭示了左、右半球区域（如顶叶岛盖）在支持观念运动任务中的模仿方面的不同参与情况。同样，手势模仿似乎依赖于左、右半球的不同区域，如左半球的顶叶区域和右半球的运动前区、体感区和皮层下区域。
