Supplementary Figure 4: The role of novel motor activity in stimulating OP differentiation.
From: Rapid production of new oligodendrocytes is required in the earliest stages of motor-skill learning
OPs are continuously cycling in the young adult CNS in response to mitogenic growth factors such Pdgf. After division one or both daughter OPs can rest in the G1 phase of the cell cycle, sometimes for days or weeks, before either differentiating or entering another division cycle3,4,7,9,31. Our data suggest that electrical activity in axon(s) cans stimulate OPs that are paused in G1 to differentiate - losing Pdgfra expression and expressing Enpp6, Mbp and other myelin gene products instead. The newly-differentiating oligodendrocytes have a distinctive spidery morphology in vivo; they remain like this for several days in vivo in rodents31 before down-regulating Enpp6 (faint pink line) and assuming the typical morphology of mature myelinating oligodendrocytes. The Enpp6high early-differentiating oligodendrocytes and Enpp6low myelinating oligodendrocytes probably contribute to improving circuit performance in the early and late stages of motor learning, respectively.
