APOE genotype affects Aβ plaque morphology in EFAD subiculum and deep layers of cortex. Morphologically distinct Aβ plaques were visualized in the subiculum and deep layers of the cortex of 6-month-old EFAD mice using immunofluorescence staining with Aβ antibody MOAB2. (A) Heterogeneous plaque types were evident in EFAD brains and grouped into three categories: diffuse, dense core and compact. Scale bar: 12 μm. (B) Subiculum. Left: E4FAD mice exhibited larger plaques on average than E3FAD mice. Center: Fluorescence intensity of plaques did not differ by APOE genotype. Right: E2FAD mice exhibited a greater percentage of diffuse plaques than E3FAD or E4FAD mice, and a lower percentage of dense core plaques than E3FAD mice. Interestingly, E4FAD mice exhibited an increased percentage of compact plaques in the subiculum. (C) Deep layers of the cortex. Left: Plaque size did not differ by APOE genotype. Center: Fluorescence intensity of deep cortical plaques was highest in E4FAD mice. Right: E2FAD mice had a greater percentage of diffuse plaques in this region than E4FAD mice. No differences were detected between APOE genotype for dense core or compact plaques. One-way ANOVA, * P < 0.05. Two-way ANOVA, * P < 0.05, ** P < 0.01.