Transgene Suppression Attenuates Hyperactivity in tTA/APP Mice (A) A 48-h measure of ambulation records extreme hyperactivity in untreated double transgenic mice compared to single transgenic and nontransgenic controls (line 107). This phenotype is completely eliminated by rearing the double transgenic mice on dox. (B) The same data shown in (A) are replotted to magnify data from untreated control and dox-treated groups. (C and D) Activity levels in the combined control groups of (A) and (B) are here separated by genotype. None of the single transgenic or nontransgenic control groups display the hyperactivity present in untreated tTA/APP animals. Again, note the y-axes have been enlarged for detail compared to (A).