Immunocytochemical characterization of cellular phenotypes in the cerebral cortex of Fgf2 exon 3 knockout mice. Coronal sections from the parietal regions of the cerebral cortex (above the dorsal hippocampus, approximately 1 mm caudal from the hippocampal comissure) of wild type (A, C, F) and Fgf2 exon 3 knockout mice (B, D, F) immunostained for Neuronal Antigen (NeuN) (A, B); Glial Fibrillary Acidic Protein (GFAP) counterstained with DAPI (C, D); and TBR-1 (E, F). A though D are images of layers 1–3 and E, F are images of layers 5–6. Arrows point to nuclei of immunostained cells. Note the decrease in cell density in the knockout. Scale bar, 20 μm.