Expression of Smad3 at different stages of neuronal precursor maturation. (A) In the prevailing model of AHN, quiescent radial glia-like cells (RGL or Type-1 cells) generate proliferative precursors known as intermediate progenitors cells (Type-2 cells), which give rise to neuroblasts (Type-3 cells), then to immature neurons and finally generating mature granule neurons. The identification of the different type of cells is based on the expression of specific precursors and lineage markers. Confocal microscopy images of (B) Nestin/Smad3, (C) Sox2/Smad3, (D) GFAP/Smad3, (E) Mash1/Smad3, (F) DCX/Smad3 double-labeled cells with no dendrite maturation, indicative of Type 2b or neuroblast cells, and (G) with dendrite maturation indicative of immature neurons. Scale bar 10 μm.