Information from studies using FAD transgenic animal models seems to be more complex (Table 1). This complexity may result from the numerous FAD-linked variables that affect neurogenesis, as revealed above. In an attempt to better understand the effect of FAD aspects on neurogenesis as they are reflected in the animal models we categorized studies by type of transgene(s) and number of mutation(s) expressed, and then analyzed the experimental settings used in individual studies (Table 1). Most studies which examined hippocampal or SVZ neurogenesis in transgenic mice expressing one or two APP mutation show impaired proliferation of progenitor cells and/or impaired neuronal differentiation in these mice. Thus, for example, using PDAPP mice expressing human V717F mutant APP under control of the PDGF promoter, Donovan and colleagues report a decrease in number of BrdU+ newly-formed cells and in the number of surviving cells in the SGL of the hippocampus. These impairments were evident at one year of age, post-onset of deposition, but not at 2 months of age. Examination of newly-formed BrdU+DCX+ neuroblasts revealed their decrease in the SGL concomitantly with an
