Figure 2.

Time-course of various oligodendrocyte lineage markers expression in the human forebrain. (A) Early oligodendrocyte precursor cells appear around 9 gw in the ganglionic eminence, and during the next few weeks spread to cortex. Late oligodendrocyte precursors appear in modest numbers around 15 gw. MBP⁺ cells with typical oligodendrocyte morphology are very sparse at midgestation, but their population steadily enlarges. The first myelin sheaths can be demonstrated by MBP staining at 18 gw in thalamus, and around 21 gw in the internal capsule. During the whole period of our observation (up to 24 gw) cortical white matter was not myelinated, i.e. not “white”. (B–E) Examples of 3D reconstructions from serial confocal sections stained with anti-PDGFRα (B), anti-NG2 (C), anti-O4 (D) and anti-MBP (E) monoclonal antibodies. Image on panel B was taken from ganglionic eminence subventricular zone at 15 gw, panels (C) and (D) from cortical subplate zone at 22 gw and panel (E) from internal capsule, 24 gw. Scale bar: 20 μm.