(A and B) Most Aβ in the brains of plaque-bearing mice is extracted into the FA and SDS fractions. Consistent with amyloid burden (Figures 4 and Figure S3), SDS- and FA-extracted Aβ levels in untreated 9-mo-old mice were significantly higher than in untreated 6-mo-old mice (Tukey post-hoc test applied to significant effect of group ANOVA for SDS and FA fractions F 3,18 = 4.72–12.92, p < 0.02). In contrast, 3 or 6 mo of transgene suppression held Aβ at levels equivalent to those harbored when treatment was started (p > 0.2 compared to 6 mo untreated mice, Tukey post-hoc test). *, p < 0.05; **, p < 0.005; ***, p < 0.001 versus 9-mo-old untreated mice, Tukey post-hoc test. Significance for APP versus 9-mo-old untreated mice is based on Student's t-test.