Fig. 4: Predicting age from structural similarity and DWI tractography human brain networks.

a, Pairwise correlation between the edges of age-specific MIND networks, computed by averaging over subjects grouped by age in years. All age-specific group-level networks were highly correlated (r > 0.94) but nonetheless demonstrated a clear age-dependent progression—that is, age-specific group networks became less similar when compared across larger age gaps. b, Comparison of the performance of models trained to predict age using nodal weighted degree or edge weights of either MIND networks or MSNs in the HCP-D cohort (ages 8–21 years). The dataset was split into 10 training and test sets (90:10 ratio, all test sets non-overlapping); each point indicates the performance on one test set. The y axis indicates the partial Spearman correlation between predicted and true age, corrected for sex, Euler index (a proxy for scan quality) and a global connectivity coefficient (the sum over all matrix elements) to mitigate confound effects. Further training and evaluation details are provided in Methods. Significantly differential performance between MSNs and MIND networks (**P < 0.01, FDR corrected from paired two-sided t-tests) was observed for both edge-based (P = 0.004) and degree-based (P = 0.004) models. c, An analogous plot to b, comparing the performance of models trained on MIND networks, MSNs or DWI tractography connectomes in the HCP-YA cohort (ages 21–35 years). Networks in b used the DK-318 parcellation, whereas networks in c were based on the HCP 360-region parcellation to match the publicly available DWI tractography connectomes (**P < 0.01 and *P < 0.05, FDR corrected from paired two-sided t-tests). Exact P values for edge-based models were as follows: MSN versus DTI (P = 0.11), MSN versus MIND (P = 0.12) and DTI versus MIND (P = 0.01). Exact P values for degree-based models were as follows: MSN versus DTI (P = 0.25), MSN versus MIND (P = 0.008) and DTI versus MIND (P = 0.002). For b and c, box plots indicate data quartiles, and whiskers indicate the full data range, excluding outliers. NS, not significant.