Abstract
Myelination of central nervous system axons increases action potential conduction velocity and increases the speed of information transfer. However, it is unclear whether myelination optimizes action potential conduction to achieve synchronicity and facilitate information processing within cortical and associative circuits. Here we show that myelin sheaths remain plastic in the adult mouse and undergo subtle structural modifications to influence action potential conduction. 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, which is independent of oligodendrogenesis, tunes conduction velocity to increase the synchronicity of action potential conduction.
One Sentence Summary The activity-dependent modulation of nodes of Ranvier and the periaxonal space allows central conduction to be tuned to achieve synchronicity.
