Figure 3. Estimated age-trajectories and critical ages.
The figure shows the estimated age-trajectories from the cross-sectional analyses for the 12 areas that deviated from linearity, based on the smoothing spline. Critical ages, identified by changes in the second derivative, are displayed. Pearson correlations between brain volume and age are shown for each age phase separated by the critical ages. All correlations were significant at p < .05, except for pallidum in middle age (.01), cerebellum WM in young age (−.02) and brain stem in young age (.01). Due to small age-variance, correlations are not presented for age-phases defined by critical ages of 80 years or higher. Critical ages are indicative of phases where estimated changes in brain volumes are in transitions.