Injection of brain extracts from MCI and NDAN individuals induce Aβ aggregation in the cortex of AD-transgenic mice. Serial brain slices of animals inoculated with brain homogenates from different sources (n = 5-8) were analyzed by histological staining using an anti-Aβ (4G8) antibody. (a) Representative pictures of the Aβ deposits in different experimental groups and untreated 6 month old animals in cortical area are shown. (b) Magnification of the regions labeled in rectangles in panel (a) of AD-, MCI-, and NDAN-inoculated animals are shown. The scale bar corresponds to 250 μm in (a) and 100 μm in (b). The burden of amyloid deposits was compared among all different control and experimental groups. The 4G8-immunoreative area was measured and divided by the total brain area analyzed (Aβ burden) in the cortex (c) of each group.