MAPT and Alzheimer disease: Dendritic spine density did not change over time (Fig. 2D1, 2D2, 2E1, 2E2) in 4–6 and 8–10 months-old 3xTg-AD mice, when only soluble Aβ, but neither hyperphosphorylated tau nor amyloid plaques are present in the somatosensory cortex (Fig. S1).