“…Overall, the findings in those models were inconsistent. For example, in transgenic/knock-in mice expressing mutant PS1, mutant APP, or both, neurogenesis in the brain was impaired , Wen, et al, 2004, Chevallier, et al, 2005, Donovan, et al, 2006, Zhang, et al, 2007 or enhanced (Jin, et al, 2004b, Greenberg andJin, 2007). The reasons that led to this discrepancy among those different transgenic or knock-in mouse strains or between those studies and ours are not clear.…”