Central nervous system myelination increases action potential conduction velocity. However, it is unclear how myelination is coordinated to ensure the temporally precise arrival of action potentials and facilitate information processing within cortical and associative circuits. Here, we show that myelin sheaths, supported by mature oligodendrocytes, remain plastic in the adult mouse brain and undergo subtle structural modifications to influence action potential conduction velocity. Repetitive transcranial magnetic stimulation and spatial learning, two stimuli that modify neuronal activity, alter the length of the nodes of Ranvier and the size of the periaxonal space within active brain regions. This change in the axon-glial configuration is independent of oligodendrogenesis and robustly alters action potential conduction velocity. Because aptitude in the spatial learning task was found to correlate with action potential conduction velocity in the fimbria-fornix pathway, modifying the axon-glial configuration may be a mechanism that facilitates learning in the adult mouse brain.

中枢神经系统髓鞘形成增加动作电位传导速度。然而，目前尚不清楚如何协调髓鞘形成以确保动作电位在时间上精确到达并促进皮层和联想电路内的信息处理。在这里，我们展示了由成熟少突胶质细胞支持的髓鞘在成年小鼠大脑中保持可塑性，并进行细微的结构修改以影响动作电位传导速度。重复经颅磁刺激和空间学习，两种改变神经元活动的刺激，改变 Ranvier 节点的长度和活跃大脑区域内的轴突周围空间的大小。轴突-神经胶质结构的这种变化独立于少突胶质细胞生成，并且强烈地改变了动作电位传导速度。