Mouse brains were isolated and fixed in 4% PFA in 0.1 M PB (0.019 M NaH2PO4, 0.089 M Na2HPO4, pH 7.4) overnight, and then washed with 0.1 M PB twice. The fixed brains were kept in 0.1 M PB with 1% ProClin 200 in 4 °C until sectioned by vibrating microtome. Soft agar-embedded mouse brains were cut into 50 μm sections and subjected to immunostaining as previously described . Briefly, brain slices were incubated with blocking buffer (10% fetal bovine serum and 0.1% Triton-X-100 in 0.1 M PB) for 1 h at room temperature, and then incubated at 4 °C overnight with primary antibodies diluted in blocking buffer. After washing three times with PB, samples were incubated at room temperature for 1 h with Alexa-488 or −594 secondary antibody, and then washed and mounted on adhesion microscope slides (CITOTEST) with fluorescent mounting medium. For co-immunostaining, samples were incubated with the second primary antibody the next morning for 1 h at room temperature before staining with the secondary fluorescence antibodies. Images were taken by a Zeiss LSM710 confocal microscope with exactly same scanning conditions for paired experiments, and analyzed by Image J.