<p>Replication in an independent dataset.</p>

<p>Developmental patterns of intrinsic timescale were replicated in an independent dataset (i.e., HBN). <b>(a)</b> Consistent with the finding in the HCPD dataset, GAM results demonstrated that the average timescale increases during development in youth in the HBN dataset (partial <i>R</i>² = 0.037, <i>p</i>_anova = 1.13 × 10⁻⁷). <b>(b)</b> Region-wise GAMs identified heterogeneous age effects (i.e., partial <i>R</i>²) across the cortex. <b>(c)</b> Age effects on intrinsic timescale were hierarchically organized along the S–A axis.

Significance of the association between age effects and S–A axis rank was assessed using 10,000 spin tests. <i>r</i>_s denotes Spearman’s rank correlation coefficient. Linear regression line is added for visualization purposes only. <b>(d)</b> Regional trajectories of developmental patterns in intrinsic timescale were obtained from region-wise GAM results (as shown in panel <b>b</b>). Each line corresponds to the model fit of each cortical region and is colored based on the region’s rank along the S–A axis.