Figure 6

Schematic model of the age-associated trajectories. The blue and red lines represent the age-associated decreases in ¹⁸F-FDG uptake in the ACC and PCC/PC, respectively. In the ACC (blue), ¹⁸F-FDG uptake decreased continuously over time. In the PCC/PC, ¹⁸F-FDG uptake was relatively stable before age 60–70 and then started to decease in an age-associated manner. ¹⁸F-FDG: fluorine-18-labeled fluorodeoxyglucose, ACC: anterior cingulate cortex, PCC/PC: posterior cingulate cortex/precuneus.