Modulation of oligodendrocyte generation during a critical temporal window after NG2 cell division

Oligodendrocytes in the mammalian brain are continuously generated from NG2 cells throughout postnatal life. However it has remained unclear when the decision of NG2 cells to self-renew or differentiate into oligodendrocytes occurs after cell division. Using a combination of in vivo and ex vivo imaging and fate analysis of proliferated NG2 cells in fixed tissue, we demonstrate that in the postnatal developing mouse brain, the majority of divided NG2 cells differentiate into oligodendrocytes during a critical age-specific temporal window of 3–8 days. Importantly, within this time period, myelin and oligodendrocyte damage accelerated oligodendrocyte differentiation from divided cells, while whisker removal decreased the survival of divided cells in the deprived somatosensory cortex. These findings indicate that during the critical temporal window of plasticity, the fate of divided NG2 cells is sensitive to modulation by external signals.