<p>Stable intrinsic timescale in young adults.</p>

Asterisk in the boxplot denotes significant difference in the means (two-tailed <i>t</i> test). <b>(b)</b> However, unlike the developmental cohorts, GAM results demonstrated that the whole-brain average timescale remains relatively stable in adulthood (partial <i>R</i>² = −0.004, <i>p</i>_anova = 0.04). <b>(c)</b> Region-wise GAMs identified heterogeneous age effects (i.e., partial <i>R</i>²) across the cortex; however, those age effects were not statistically significant for the majority of brain regions. <b>(d)</b> Unlike the developmental cohorts, age effects on the intrinsic timescale did not reflect the hierarchical organization along the S–A axis during adulthood.

Significance of the associations between cortical maps (i.e., scatter plots) was assessed using 10,000 spin tests. <i>r</i>_s denotes Spearman’s rank correlation coefficient. Linear regression lines are added for visualization purposes only. Data and code needed to regenerate this figure can be found at <a href="doi.org/10.5281/zenodo.22799416" target="_blank">doi.org/10.5281/zenodo.22799416</a>.</p>