(A–D) Immunostaining for NG2 in Nkx2.1-cre-/Rosa-DTA (A1–A2 to C1–C2) and Nkx2.1-cre+/Rosa-DTA (D1–D2 to F1–F2) telencephalic coronal slices at E14.5 (A1–A2, D1–D2), E16.5 (B1–B2, E1–E2) and E18.5 (C1–C2, F1–F2). A2, B2, C2, D2, E2, and D2 are higher power views of the region in A1, B1, C1, D1, E1, and F1, respectively (white arrowheads). At E14.5, there were no significant differences in NG2+ glia observed in the cingulate regionof Nkx2.1-cre+/Rosa-DTA mutant mice (n=3) compared to wild-type mice (n=3) (A1–A2, D1–D2). By contrast, later at E16.5, there was already a drastic loss of NG2+ glia populating the medio-dorsal telencephalon regionsin the Nkx2.1-cre+/Rosa-DTA (n=3) mutant mice compared to control mice (n=3) (B1–B2, E1–E2). This loss was maintained at E18.5 in the Nkx2.1-cre+/Rosa-DTA (n=3) mutant mice compared to control mice (n=3) (C1–C2, F1–F2). Scale bar = 675 µm in A1, B1, C1, D1, E1, and F1; 40 μmin A2, B2, C2, D2, E2, and F2.