Lyu Yuanyuan, Guo Xiaoli, Bekrater-Bodmann Robin, Flor Herta, Tong Shanbao
School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Department of Cognitive and Clinical Neuroscience, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim 68169, Germany.
Sci Rep. 2016 Feb 16;6:21100. doi: 10.1038/srep21100.
A potential contributor to impaired motor imagery in amputees is an alteration of the body schema as a result of the presence of a phantom limb. However, the nature of the relationship between motor imagery and phantom experiences remains unknown. In this study, the influence of phantom limb perception on motor imagery was investigated using a hand mental rotation task by means of behavioral and electrophysiological measures. Compared with healthy controls, significantly prolonged response time for both the intact and missing hand were observed specifically in amputees who perceived a phantom limb during the task but not in amputees without phantom limb perception. Event-related desynchronization of EEG in the beta band (beta-ERD) in central and parietal areas showed an angular disparity specifically in amputees with phantom limb perception, with its source localized in the right inferior parietal lobule. The response time as well as the beta-ERD values were significantly positively correlated with phantom vividness. Our results suggest that phantom limb perception during the task is an important interferential factor for motor imagery after amputation and the interference might be related to a change of the body representation resulting from an unnatural posture of the phantom limb.
截肢者运动想象受损的一个潜在因素是幻肢的存在导致身体图式的改变。然而，运动想象与幻肢体验之间关系的本质仍不清楚。在本研究中，通过行为和电生理测量，利用手部心理旋转任务研究了幻肢感知对运动想象的影响。与健康对照组相比，在任务期间感知到幻肢的截肢者中，无论是健全手还是缺失手，反应时间都显著延长，而在没有幻肢感知的截肢者中则未观察到这种情况。中央和顶叶区域脑电图β频段的事件相关去同步化（β-ERD）在有幻肢感知的截肢者中显示出角度差异，其来源定位于右侧顶下小叶。反应时间以及β-ERD值与幻肢生动程度显著正相关。我们的结果表明，任务期间的幻肢感知是截肢后运动想象的一个重要干扰因素，这种干扰可能与幻肢不自然姿势导致的身体表征变化有关。
