White matter development in adolescence: a DTI study

Abstract

Adolescence is a unique period of physical and cognitive development that includes concurrent pubertal changes and sex-based vulnerabilities. While diffusion tensor imaging (DTI) studies show white matter maturation throughout the lifespan, the state of white matter integrity specific to adolescence is not well understood as are the contributions of puberty and sex. We performed whole-brain DTI studies of 114 children, adolescents, and adults to identify age-related changes in white matter integrity that characterize adolescence. A distinct set of regions across the brain were found to have decreasing radial diffusivity across age groups. Region of interest analyses revealed that maturation was attained by adolescence in broadly distributed association and projection fibers, including those supporting cortical and brain stem integration that may underlie known enhancements in reaction time during this period. Maturation after adolescence included association and projection tracts, including prefrontal-striatal connections, known to support top-down executive control of behavior and interhemispheric connectivity. Maturation proceeded in parallel with pubertal changes to the postpubertal stage, suggesting hormonal influences on white matter development. Females showed earlier maturation of white matter integrity compared with males. Together, these findings suggest that white matter connectivity supporting executive control of behavior is still immature in adolescence.

Figure 1.

Clusters showing significant effects of age maturing during adolescence are depicted on the MNI brain and on representative tracts to illustrate its approximate location. MNI coordinates for each ROI are detailed on Table 1. The clusters are depicted by yellow circles (dotted circles for closely neighboring ROIs). (A) SLF. (B) IFOF/ILF. (C) Corona Radiata. (D) CST.

Figure 2.

Clusters showing significant effects of age maturing after adolescence are depicted on the MNI brain and on representative tracts to illustrate its approximate location. MNI coordinates for each ROI are detailed on Table 1. The clusters are depicted by yellow circles (dotted circles for closely neighboring ROIs). (A) UF, (B) SLF, (C) Post CC = posterior corpus callosum, (D) ATR, and (E) corona radiata and IC.

Figure 3.

Graph demonstrating age × sex effects. Filled shapes depict the mean RD of the regions that showed RD values that were mature by adolescence. There were 4 regions that were mature in the male group and 18 regions in the female group by adolescence. The open shapes depict the mean RD of the regions that continued to show immature mean RD values in adolescence compared with adults. The one mature region showing late maturity in the females was the SLF. Specific mean RD values for each region are listed on Supplementary Table 1.