to the protocol: For HuC/D, sections were boiled for 30 min in 1 M TBST after rehydration. For BrdU, slides were pretreated with 50% formamide/50% 2X SSC at 65uC for 2h, followed by 2 M HCl at 37uC for 45 minutes and washed with boric buffer pH 8.5 and KPBS for 10 min, according to Zupanc et al. [42]. The following primary antibodies were used: goat anti-GFP (1:500000 for chromogenic staining and 1:5000 for fluorescent staining, Abcam); mouse anti-Hu C/D (1:100, Invitrogen), rat anti-BrdU (1:1000, Abcam), rabbit anti-GFAP (Abcam). The following secondary antibodies were used: donkey anti-Goat Alexa 568 (1:1000, Invitrogen), donkey Anti-Rat Alexa 488 (1:1000 Invitrogen), donkey anti-Rabbit (1:2000 Invitrogen), rabbit anti- goat biotin (1:1000, Vector), and rabbit anti-mouse Biotin (1:1000, Vector). Chromogenic visualization was done with the Standard ABC Elite Kit (Vector) with NiDAB as a substrate. 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