Yu Xiao Jing, He Hong Jian, Zhang Qiao Wei, Zhao Feng, Zee Chi Shing, Zhang Shi Zheng, Gong Xiang Yang
Department of Radiology, Sir Run Run Shaw Hospital Affiliated to Medical College of Zhejiang University, Hangzhou 310016, Zhejiang Province, China.
Center for Brain Imaging Science and Technology, Department of BME, Zhejiang University, Hangzhou 310027, Zhejiang Province, China.
Brain Res. 2014 Feb 10;1546:9-17. doi: 10.1016/j.brainres.2013.12.025. Epub 2013 Dec 27.
Bilateral arm amputees usually are excellent foot users. To explore the plasticity of the primary motor cortex in upper-extremities amputees and to determine if the acquisition of special foot movement skill is related with the bilateral hand amputation, we studied the primary motor cortex by using combined task and resting state functional magnetic resonance imaging (fMRI). We investigated 6 bilateral arm amputees with or without special foot movement skill. In the task fMRI study, we found that toe tapping of all the amputees activated the bilateral hand area, including cases without special foot skill. In addition, cases without special foot skill mainly activated the precentral gyrus, which differed from those with more adept foot motor skill who activated both the precentral and postcentral gyri. To further understand the plasticity of the hand area, the resting state functional connectivity was investigated between the foot and hand regions. One-tailed two-sample t-test suggested that the connections between two areas became significantly stronger in the amputee group. Our study demonstrates that hand region of the cortex does not remain 'silent' after bilateral arm amputation, but rather is recruited by other modalities such as adjacent or nonadjacent cortexes to process motor information in a functionally relevant manner. From the data presented, it seems that the bilateral arm amputees have a strong potential to develop new skills in their remaining extremities and practice may further enhance this potential.
双侧上肢截肢者通常是出色的足部使用者。为了探究上肢截肢者初级运动皮层的可塑性，并确定特殊足部运动技能的习得是否与双侧手部截肢有关，我们使用联合任务和静息态功能磁共振成像（fMRI）对初级运动皮层进行了研究。我们调查了6名有或没有特殊足部运动技能的双侧上肢截肢者。在任务fMRI研究中，我们发现所有截肢者的脚趾轻敲都激活了双侧手部区域，包括没有特殊足部技能的病例。此外，没有特殊足部技能的病例主要激活中央前回，这与具有更熟练足部运动技能的病例不同，后者同时激活了中央前回和中央后回。为了进一步了解手部区域的可塑性，我们研究了足部和手部区域之间的静息态功能连接。单尾双样本t检验表明，截肢者组中两个区域之间的连接明显增强。我们的研究表明，双侧上肢截肢后，皮层的手部区域并非保持“沉默”，而是被其他模态（如相邻或不相邻的皮层）以功能相关的方式招募来处理运动信息。从所呈现的数据来看，双侧上肢截肢者似乎有很大的潜力在其剩余肢体中发展新技能，而练习可能会进一步增强这种潜力。
