Diffusion characteristics across typical adolescent development show a linear increase in FA and decrease in MD (Barnea-Goraly et al., 2005; Giorgio et al., 2008; Snook et al., 2005). These changes parallel the establishment of new cortical connections and growth of axons that continue at least through the second decade of life (Barnea-Goraly et al., 2005; Paus et al., 1999). Efficient organization of white matter fibers is linked to optimal cognitive performance. Anisotropic diffusion in the left parietal, right frontal, and corpus callosum regions correlate most with intellectual functioning in youth (Fryer et al., 2008; Schmithorst et al., 2005) and correspond to regional white matter maturation (Bonekamp et al., 2007).
