End of the road: Astrocyte endfeet regulate OPC migration and myelination

Oligodendrocyte precursor cells (OPCs) use the vasculature as a scaffold for their migration. In this issue of Neuron, Su et al. determine that astrocytic ensheathment of the vasculature mediates OPC detachment from blood vessels via the secretion of semaphorins, regulating the timing of oligodendrocyte differentiation.