From that model, family-wise error rate (FWER)-corrected P-values were inferred via permutation testing through PALM (Version: a103; iterations: 5000; one-sided P values) (Winkler et al. 2014). Clusters of vertices with significant age effects (P < 0.01) were identified by PALM’s threshold-free cluster enhancement approach (TFCE; Parameters: H=2, E=1, C=26). The chosen significance threshold (P < 0.01) was more conservative than for the remaining experiments (P < 0.05) to focus the discussion on only highly correlated age-related findings. Cross-sectional age differences were visualized by the vertex-wise βage values. Those computations were repeated with respect to the normalized myelin content scores averaged over the regions defined by the HCP multimodal parcellation atlas (MMP 1.0) (Glasser et al. 2016) consisting of 180 areas per hemisphere.
