APOE and Alzheimer disease: The Alzheimer's disease group demonstrated substantial decay in correlation strength with increasing anatomical distance (R = − 0.52, p ≪ 1.00e− 10), and a small but significant negative relationship was also found in the Young (R = − 0.07, p = 3.45e− 5), Old PIB- ApoE ε4- (R = − 0.09, p = 4.38e− 7), and Old PIB+ ApoE ε4- (R = − 0.11, p = 8.51e− 10) groups.