Amyloid plaques by 17-18 months in the neocortex and hippocampus with detection of five to ten-fold more Aβ40 than Aβ42. Plaque burden significantly lower than in the double transgenic PS2APP. Lower levels of insoluble Aβ40 and Aβ42 than the PS2APP mouse at 16-18 months (Richards et al., 2003).