Schady W, Braune S, Watson S, Torebjörk H E, Schmidt R
Department of Clinical Neurology, Manchester Royal Infirmary, England.
Ann Neurol. 1994 Jul;36(1):68-75. doi: 10.1002/ana.410360114.
We studied the responsiveness of the somatosensory system in humans after prolonged deprivation of peripheral input. Eight patients with traumatic transection of the median or ulnar nerve and 6 patients with amputation of a finger or hand underwent microneurography and intraneural stimulation. Bundles of nerve fibers were electrically stimulated through a microelectrode placed in the affected nerve proximally to the site of damage or in the case of amputees, in a nerve fascicle supplying the stump. During intraneural stimulation the subjects with nerve injuries reported distinct percepts in the hypoesthetic skin. Their projections were usually confined to the territory of a single or two adjacent palmar digital nerves, similar to the fascicular territories of healthy nerves in control subjects, but there was much less microneurographically recordable afferent activity than in normal subjects. In amputees intraneural stimulation evoked sensations in a phantom digit or digits in over three fourths of the fascicles studied. We conclude that (1) the somatosensory system remains able to process information from a nerve fascicle that has lost its cutaneous territory, and (2) somatosensory localization remains accurate despite the presumed central reorganization that takes place after nerve division or amputation. This lack of functional adaptation has important implications with regard to our understanding of human central nervous system plasticity.
我们研究了在长期外周输入剥夺后人类体感系统的反应性。8例正中神经或尺神经创伤性横断患者以及6例手指或手部截肢患者接受了微神经图检查和神经内刺激。通过置于受损神经近端损伤部位的微电极对神经纤维束进行电刺激，对于截肢患者，则是在供应残端的神经束中进行刺激。在神经内刺激期间，神经损伤的受试者在感觉减退的皮肤中报告了明显的感觉。它们的投射通常局限于一条或两条相邻掌侧指神经的区域，类似于对照受试者中健康神经的束状区域，但与正常受试者相比，微神经图可记录的传入活动要少得多。在截肢患者中，神经内刺激在超过四分之三的研究神经束中诱发了幻指的感觉。我们得出结论：（1）体感系统仍然能够处理来自失去其皮肤区域的神经束的信息，（2）尽管在神经分割或截肢后可能发生中枢重组，但体感定位仍然准确。这种缺乏功能适应性对于我们理解人类中枢神经系统可塑性具有重要意义。
