Histochemistry was performed as described previously [89], with the following exceptions: Coronal 70- to 100-μm vibratome slices were used for immunohistochemistry with GluR-B (1:60, polyclonal; Chemicon, Temecula, California, United States), GFP (1:8,000, polyclonal; MobiTech, Göttingen, Germany), and Cre (1:8,000, polyclonal; BAbCO, Berkeley, California, United States) primary antibodies, and FITC-coupled (1:200; Dianova, Hamburg, Germany) and peroxidase-coupled (1:600; Vector, Burlingame, California, United States) secondary goat anti-rabbit antibodies.