5. Using HCP-D, we found that most connections significantly strengthened from ages 8 to 22. Their developmental curves varied in curvature, from concave-down to concave-up. We quantified this shape using the average second derivative, revealing a continuous trajectory spectrum.
7. The non-monotonic trajectories led us to ask how this heterogeneity evolves across youth. Strikingly, alignment with the S-A connectional axis shifted from negative to positive, crossing zero at around age 15, indicating a transition from sensorimotor- to association-dominant strengthening.
8. These developmental findings generalized to two independent datasets and remained robust across multiple sensitivity analyses.
3. White matter connectivity is refined throughout youth, with different tracts maturing at different paces. Yet prior work has mainly focused on major bundles, leaving the spatiotemporal variability of connectome-wide structural connectivity development under-characterized.🤔
10. We now provide a concise framework for describing white-matter structural connectivity development across the human connectome. The beautiful trajectory and tractogram of each connection were provided on an interactive platform (connectcharts.cibr.ac.cn). Try to explore it!