Immunohistochemistry on free-floating sections was performed using the following primary antibodies and dilutions: GFP (1:1000; rat-IgG; Nakarai Tesque, Inc., Japan and 1:1000; rabbit-IgG; Molecular Probes), PSA-NCAM (1:500; #12E3 mouse-IgM) (Seki and Arai, 1991 and Seki and Arai, 1993), Ki67 (1:200; mouse-IgG; Novocastra, UK), NKCC1 (1:500; rabbit-IgG; Chemicon, Temecula, CA), VGAT (1:500; rabbit-IgG; Synaptic Systems, Germany), NeuroD (1:200; goat-IgG; Santa Cruz Biotechnology, Inc., CA), BrdU (1:200; rat-IgG; Harlan, Leicestershire, UK), calbindin (1:500; rabbit-IgG; Chemicon), or NeuN (1:1000; mouse-IgG; Chemicon).