(A) Experimental design showing that the OLIG2+ cells at day 24 are further cultured for 12 days in the presence of purmorphamine or FGF2 alone, or in a combination of purmorphamine and FGF2 or EGF. (B) FGF2, but not EGF, blocks HB9 expression (column 2). (C) In the presence of purmorphamine, FGF2 but not EGF increases the proportion of OLIG2+ cells by ∼50% and decreases the HB9+ population to less than 5%, whereas EGF moderately decreases HB9+ cells. (D) Neither FGF2 nor EGF selectively alters the Ki67+ proportion in OLIG2+ cells. (E) There is a moderate increase in Ki67+ cells in FGF2-treated (for 10 days) cultures. *P<0.05 between the paired groups. Scale bar: 50 μm.