Areas with the most prominent FA change during adolescence are the superior longitudinal fasciculus, superior corona radiata, thalamic radiations, and posterior limb of the internal capsule (see Fig. 1) (Bava et al. 2010b). Other projection and association pathways including the corticospinal tract, arcuate fasciculus, cingulum, corpus callosum, superior and mid-temporal white matter, and inferior parietal white matter show anisotropic increases as well (Ashtari et al. 2007; Bonekamp et al. 2007; Giorgio et al. 2010; Giorgio et al. 2008; Tamnes et al. 2009). Changes in subcortical and deep grey matter fibers are more pronounced, with less change in compact white matter tracts comprising highly parallel fibers such as the internal capsule and corpus callosum (Bava et al. 2010b; Lebel et al. 2008). Fiber tracts constituting the fronto-temporal pathways appear to mature relatively later (Schneiderman et al. 2007; Tamnes et al. 2009), though comparison of growth rates among tracts comes largely from cross-sectional data that present developmental trends.
