Raisman G
Ann Neurol. 1978 Feb;3(2):101-6. doi: 10.1002/ana.410030203.
The consequences of axonal injuries in the adult nervous system depend on the location of the axons: complete anatomical and functional repair can occur in the peripheral but not the central nervous system. A quantitative electron microscopical comparison of the reactions to axonal injuries in a peripheral site (the superior cervical sympathetic ganglion) and in a central site (the septal nuclei) in adult rats shows that in both cases the denervated postsynaptic sites are reinnervated by new formation of synapses. However, in the ganglion it is the originally severed axons which form the new synapses (regeneration), whereas in the septum the new synapses arise from local, undamaged axons and the cut axons do not reestablish their original contacts. Failure of regeneration in the central site is probably due to the fact that the growing axon sprouts are incapable of finding a pathway to the denervated tissues. Since the observations indicate that the neuropil of the central nervous system is capable of highly efficient synapse formation after injury, true repair of central nervous system damage might be possible if methods could be devised for dealing with the "pathway" problem.
在周围神经系统中可实现完全的解剖和功能修复，而在中枢神经系统中则不然。对成年大鼠周围部位（颈上神经节）和中枢部位（隔核）轴突损伤反应的定量电子显微镜比较表明，在这两种情况下，失神经支配的突触后位点都是通过新突触的形成来重新获得神经支配的。然而，在神经节中，是最初被切断的轴突形成新的突触（再生），而在隔区，新突触则来自局部未受损的轴突，切断的轴突不会重新建立其原来的联系。中枢部位再生失败可能是因为生长的轴突发芽无法找到通往失神经支配组织的路径。由于观察结果表明中枢神经系统的神经毡在损伤后能够高效地形成突触，因此，如果能够设计出解决“路径”问题的方法，中枢神经系统损伤的真正修复或许是有可能的。
