Neuronal cells were defined as cells, which stained positive for Tuj1and had a process at least 3 times longer than the cell body. For immunofluorescence staining, cells were washed with PBS and then fixed with 4% paraformaldehyde for 10 minutes at room temperature (RT). Cells were then incubated in 0.2% Triton X-100 (Sigma) in PBS for 5 minutes at RT. After washing twice with PBS, cells were blocked in a solution of PBS containing 4% BSA, 1% FBS for 30 minutes at RT. Primary and secondary antibodies were diluted in a solution of PBS containing 4% BSA and 1% FBS. Fields of cells for staining were outlined with a PAP pen (DAKO). Primary and secondary antibodies were typically applied for 1 hour and 30 minutes, respectively. Cells were washed three times with PBS between primary and secondary staining. For anti-BrdU staining, cells were treated with 2N HCl in PBS for 10 minutes and washed twice with PBS before permeablization with TritonX-100 (Sigma). The following antibodies were used for our analysis: goat anti-ChAT (Millipore, 1:100), rabbit anti-GABA (Sigma, 1:4000), rabbit-GFAP (DAKO,
