Yao Jun, Carmona Carolina, Chen Albert, Kuiken Todd, Dewald Julius
Physical Therapy and Human Movement Sciences Department, Northwestern University, Chicago, IL 60611, USA.
Annu Int Conf IEEE Eng Med Biol Soc. 2011;2011:1065-8. doi: 10.1109/IEMBS.2011.6090248.
This case study demonstrates the ability of sensory cortical representations to remap following arm amputation and subsequent targeted reinnervation (TR). Previous human studies have demonstrated functional plasticity in the primary sensory cortex months or years after amputation of the upper arm, forearm, the hand or a single finger, or after subsequent replantation. Targeted reinnervation, a surgical procedure that re-routes inactive, residual sensorimotor nerves previously responsible for innervating the missing limb to alternative muscle groups and skin areas [1-3], has shown the ability to restore a subject's sensation in the reinnervated skin areas. Whether this new technique causes analogous cortical remapping in a similar timeframe as following hand replantation is still unknown. In order to answer this question, high-density electroencephalography was used to study whether the original sensory cortical territory was regained after TR. Before TR, we found that the cortical response to sensory electrical stimulation in the residual limb showed a diffuse bilateral pattern without a clear focus in either the time or spatial domain, Two years after TR, the sensory map of the reinnervated median nerve shifted back to a close-to-normal, predominantly contralateral pattern. The overall trend of TR-induced sensory remapping is similar to previous reports related to hand replantation but occurs over a slower timeframe. This relatively slower progress after TR as compared to after hand replantation could be because TR is performed months or even years after amputation, while hand replantation was performed immediately after the injury. This work provides new evidence for long term plasticity in the human brain.
本案例研究展示了感觉皮层表征在手臂截肢及随后的靶向再植（TR）后重新映射的能力。先前的人体研究表明，在上臂、前臂、手部或单个手指截肢后数月或数年，或在随后的再植术后，初级感觉皮层存在功能可塑性。靶向再植是一种外科手术，将先前负责支配缺失肢体的无活性残余感觉运动神经重新路由至替代肌肉群和皮肤区域[1 - 3]，已显示出能够恢复受试者在再植皮肤区域的感觉。这项新技术是否会在与手部再植类似的时间范围内引起类似的皮层重新映射尚不清楚。为了回答这个问题，采用高密度脑电图来研究TR后原始感觉皮层区域是否恢复。在TR之前，我们发现残肢对感觉电刺激的皮层反应在时间或空间域均呈现出双侧弥漫性模式，无明显焦点。TR两年后，再植正中神经的感觉图谱恢复到接近正常的、主要为对侧的模式。TR诱导的感觉重新映射的总体趋势与先前有关手部再植的报道相似，但发生时间框架较慢。与手部再植后相比，TR后进展相对较慢可能是因为TR在截肢数月甚至数年之后进行，而手部再植是在受伤后立即进行。这项工作为人类大脑的长期可塑性提供了新证据。
