A Experimental scheme for birthdating of adult-born neurons and recombination. For morphology analysis, CAG-RFP was stereotactically injected into the DG (C-F), for marker expression analysis, BrdU was injected i.p. every 24 hours for three days (B). Tamoxifen was applied i.p. every 12 hours for five days from day 10 to day 14. Mice were sacrificed 3 days post Tamoxifen (dpT) and 13dpT, which corresponds to 17dpi and 27dpi, respectively. 