Fig. 4: Variability in the magnitude and timing of thalamocortical structural connectivity development.
a, A spectrum of FA developmental trajectories manifests across thalamocortical connections in PNC (top) and HCPD (bottom). Developmental trajectories are GAM smooth estimates that are independently zero-centered along the y axis for each connection. Trajectories are colored by the connection’s age effect (partial R2) and represent the partial effect of age on FA conditional on model covariates. b, Thalamocortical connections from the tractography atlas are colored by their age effect, revealing the brain-wide distribution of developmental heterogeneity. c, A correlation plot confirming close correspondence between connection-specific age effects derived across datasets is shown; the linear fit (with 95% confidence interval) is plotted. The result of Spearman’s correlation with a spin test is indicated. d, Developmental trajectories for thalamic connections to primary motor, lateral parietal and superior prefrontal cortical regions are shown, overlaid on participants’ data, in PNC (top) and HCPD (bottom). Trajectories represent GAM-predicted FA values with a 95% credible interval. Corresponding color bars chart the rate of increase in FA during windows of significant developmental change. e, Connection-wise age effects and ages of maturation were correlated (PNC data and linear fit shown with a 95% confidence interval). The result of Spearman’s correlation with a spin test is indicated and confirms that the age of maturation metric provides insight into both the magnitude and timing of development. f, A brain map localizing cortical regions with the earliest-maturing thalamic connections (age of maturation first quartile; yellow) and latest-maturing thalamic connections (fourth quartile; blue) is shown. White and gray regions matured in middle age quantiles and were not included in the atlas, respectively. g, Results of a Neurosynth analysis used to functionally decode differences in thalamocortical connectivity maturational timing. Psychological terms linked to cortical regions with early-maturing thalamic connections are shown in yellow. Terms associated with cortical regions with the late-maturing thalamic connections are shown in blue. PNC data are presented; 11 terms that were also present in the HCPD Neurosynth analysis are written in bold font. L, lateral; M, medial; A, anterior; P, posterior.
