Fig. 1.

Fibrillar Aβ burden in cognitively normal APOE ε4 noncarriers (NC), heterozygotes (HT), and homozygotes (HM) from our longitudinal study (white box), an HM with recent onset of MCI, and probable AD patients from a previous study (gray box). The data were generated from the ROIs shown in Fig. 3. The mean value in the HM group and statistical analyses in the text do not include data from the HM with MCI. P values correspond to the association between fibrillar Aβ burden and APOE ε4 gene dose (2-tailed linear trend) in the cognitively normal subjects.