Background: Previous MRI studies of healthy children have reported age-related white matter (WM) changes in language and motor areas of the brain. The authors investigated WM development in healthy adolescent males through age-associated changes in fractional anisotropy (FA), radial (λ⊥) and axial (λ||) diffusivity. Methods: Twenty-four healthy adolescent males (mean age = 16.6, SD = 2.5 years) were divided into two groups with an age split of 16.9 years and underwent a whole-brain voxelwise analysis. Results: At a threshold of p < 0.001 and extent threshold of 100 contiguous voxels, several clusters with increased FA and axial diffusivity and no differences in radial diffusivity were observed in older adolescents compared to the younger adolescents in the left arcuate fasciculus, bilateral posterior internal capsule/thalamic radiation, bilateral prefrontal gyrus, right superior temporal gyrus, and posterior corpus callosum. Increased FA and λ|| of several clusters along the arcuate fasciculus significantly correlated with a test of language and semantic memory. Conclusions: These results suggest ongoing maturational changes especially in the arcuate fasiculus during late adolescence. Increased FA and λ|| with no changes in radial diffusivity may reflect a developmental pattern of reduced tortuousity toward more straightened fibers and/or increased axonal fiber organization during late adolescence.
Bibliographical noteFunding Information:
This study was supported by NIMH grants MH-60221 to Dr. Kumra; MH-070612 to Dr. Ashtari; and support was provided by the General Clinical Research Center of the North Shore-LIJ Health System's Feinstein Institute for Medical Research, Grant #M01 RR018535. Presented in part at the 14th International Society for Magnetic Resonance in Medicine, Seattle Washington, 2006 and the 43rd American College of Neuropsychopharmacology Annual Meeting, San Juan, Puerto Rico, 2004.
Copyright 2008 Elsevier B.V., All rights reserved.
- Arcuate fasiculus
- Axial diffusivity
- Diffusion tensor imaging
- Fiber pathways
- Fractional anisotropy
- Magnetic resonance imaging