In the forebrain, three regionally distinct sources have been shown to generate OPCs sequentially. OPCs first originate from Nkx2.1-expressing cells in the ventricular zone of the medial ganglionic eminence. Some OPCs are also generated from multipotent progenitors in the subventricular zone (SVZ). These cells migrate into the olfactory bulb. Depending on their origin in the SVZ, these progenitors give rise to either OPCs or astrocytes. Typically, cells originating from the posterior and dorsomedial SVZ produce more oligodendrocytes owing to increased exposure to posterior Shh signaling and dorsal Wnt signaling which favors OPC specification, in contrast to ventral Bmp signaling which inhibits it.
