FIG. 2.

Matched coronal sections of brain tissue from wild-type (A, E, and I), FGF1 null (FGF1 KO) (B, F, and J), FGF2 null (FGF2 KO) (C, G, and K), and double-knockout (Double KO) (D, H, and L) mice were microscopically analyzed. Sections were stained for Nissl substance (A to D) or analyzed by immunohistochemical techniques using antibodies against parvalbumin (E to H) or calbindin (I to L). No differences between the brains of wild-type and FGF1^−/− mice were noted. Brains of FGF2^−/− mice show a thickening of the motor cortex (C) and a decrease in the number of parvalbumin (G)- and calbindin (K)-positive cells. No significant further thickening of the cortex (D) or decrease in neuronal subpopulations (H and L) was apparent in the brains of FGF1^−/− FGF2^−/− mice.