Fig. 10.

Summary diagram of OL lineage progression in human cerebral white matter during the latter half of gestation. Note that the high-risk period for PVL coincides with the developmental epoch when the white matter is mostly populated by O4+O1− pre-OLs that also label with NG2. O4+O1+ immature OLs are a minor population until ∼30 weeks (dotted line) when they undergo a marked expansion. This expansion in the immature OL population is accompanied by the appearance in the periventricular white matter of MBP+ mature OLs. Hence the decline in incidence of PVL at ∼32 weeks coincides with OL maturation in the periventricular white matter.wks, Weeks.