Ullén Fredrik
Neuropediatric Research Unit Q2:07, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.
Neuron Glia Biol. 2009 May;5(1-2):29-34. doi: 10.1017/S1740925X09990330. Epub 2009 Sep 29.
Studies on various animal models have established that neuronal activity can influence the myelination process. Are such mechanisms present in humans, and do they mediate experience-driven white matter plasticity not only during early development but also in adolescents and adults? While there is as yet no direct evidence for this, a number of findings - reviewed here - are consistent with this idea. First, postmortem and neuroimaging studies show that the human white matter development is a protracted process that continues well into adulthood. Second, developmental changes and individual differences in white matter structure are related to differences in neural activity and behavior. Finally, studies on effects of long-term training, in particular in musicians, show strong relations between training and white matter structure. I conclude by briefly discussing possible types of white matter plasticity that could underlie these findings, emphasizing a distinction between indirect myelination plasticity, where the myelin sheath grows in parallel with the axon itself, and direct myelination plasticity, where the myelin sheath thickness is modulated independently of axonal diameter.
对各种动物模型的研究已经证实，神经元活动能够影响髓鞘形成过程。人类中是否存在这样的机制，它们是否不仅在早期发育阶段，而且在青少年和成年人中，介导经验驱动的白质可塑性？虽然目前尚无直接证据支持这一点，但这里回顾的一些研究结果与这一观点是一致的。首先，尸检和神经影像学研究表明，人类白质发育是一个长期的过程，会持续到成年期。其次，白质结构的发育变化和个体差异与神经活动和行为的差异有关。最后，对长期训练影响的研究，特别是对音乐家的研究，表明训练与白质结构之间存在密切关系。我通过简要讨论这些发现可能基于的白质可塑性的可能类型来结束本文，强调间接髓鞘形成可塑性（髓鞘鞘膜与轴突本身平行生长）和直接髓鞘形成可塑性（髓鞘鞘膜厚度独立于轴突直径进行调节）之间的区别。
