Dendritic spine density is reduced in the hippocampus and frontal cortex from 15 months on.

(A, B) High-resolution images of dendrites and dendritic spines in the vicinity of (d<50 µm) and distant to (d>50 µm) amyloid plaques in the hippocampus. Scale bars: 10 µm (overviews); 2 µm (close ups) (C, D) In the hippocampus (C) and frontal cortex (D) of 15 and 20 month-old 3xTg-AD mice, the dendritic spine density was significantly reduced in areas close to (grey columns) and distant from (black columns) amyloid plaques compared to non-AD transgenic control mice (white) (* P<0.05, ** P<0.01, *** P<0.001, Student's t-test, n = 50 dendrites in n = 5 mice per group). The dendritic spine density was unchanged at 6 and 10 months of age. Error bars indicate +S.E.M.