科学家发现，在经过双手移植之后，左手比右手更快地与大脑建立了联系。此前的研究表明和手的控制有关的大脑区域与负责手臂以及面部肌肉的皮层区域相邻。这些大脑区域在一只手或双手被切断之后会进行相当多的重新连接，而面部和手臂的运动皮层代表区可能蔓延到原来被手支配的区域。
Angela Sirigu及其同事利用经颅磁刺激方法监视了两个双手移植受试者（最初惯用右手）手臂和手的肌肉电脉冲。经颅磁刺激是一种用脉冲磁场刺激皮层神经元的方法。这组科学家证明了恢复的进程对于一个人的左手和右手并不相同。根据受试者的大脑活动测定，左手在手术后10个月重新获得了显著的存在，而右手用了26个月，而且需要对大脑更强的刺激才能发现。这组作者说，这些结果提示移植患者可以重新激活他们的双手在运动皮层上的原始代表区。（生物谷Bioon.com）
生物谷推荐原始出处：
PNAS April 6, 2009, doi: 10.1073/pnas.0809614106
Re-emergence of hand-muscle representations in human motor cortex after hand allograft
Claudia D. Vargasa,1, Antoine Aballéaa, érika C. Rodriguesa,1, Karen T. Reillya, Catherine Merciera,2, Palmina Petruzzob, Jean M. Dubernardb and Angela Sirigua,3
The human primary motor cortex (M1) undergoes considerable reorganization in response to traumatic upper limb amputation. The representations of the preserved arm muscles expand, invading portions of M1 previously dedicated to the hand, suggesting that former hand neurons are reassigned to the control of remaining proximal upper limb muscles. Hand allograft offers a unique opportunity to study the reversibility of such long-term cortical changes. We used transcranial magnetic stimulation in patient LB, who underwent bilateral hand transplantation 3 years after a traumatic amputation, to longitudinally track both the emergence of intrinsic (from the donor) hand muscles in M1 as well as changes in the representation of stump (upper arm and forearm) muscles. The same muscles were also mapped in patient CD, the first bilateral hand allograft recipient. Newly transplanted intrinsic muscles acquired a cortical representation in LB's M1 at 10 months postgraft for the left hand and at 26 months for the right hand. The appearance of a cortical representation of transplanted hand muscles in M1 coincided with the shrinkage of stump muscle representations for the left but not for the right side. In patient CD, transcranial magnetic stimulation performed at 51 months postgraft revealed a complete set of intrinsic hand-muscle representations for the left but not the right hand. Our findings show that newly transplanted muscles can be recognized and integrated into the patient's motor cortex.
