et al., 2008) and cingulum (Kubicki et al., 2003). A recent meta-analysis by Ellison-Wright et al., (2009) of fifteen voxel-based DTI studies also reported evidence for abnormalities in frontally-projecting fasciculi in patients with schizophrenia. In contrast, however, while Kanaan et al. (2005) identified DTI abnormalities of some sort in 16 of the 19 studies analyzed, they did not identify a consistent pattern of abnormality, suggesting that while there is some evidence that the frontally-projecting fibers are preferentially affected in patients with schizophrenia, this point remains open to debate. Nevertheless, it is notable that in contrast to the primary sensorimotor fasciculi, which generally mature in utero or in early childhood, these frontally-projecting fasciculi are among the latest to structurally mature, with myelination typically continuing through adolescence and into early adulthood (Lebel et al., 2008; Schneiderman et al., 2009; Tamnes et al., 2010; Yakovlev et al., 1967). In light of the fact that adolescence/early adulthood is the most common age-of-onset for SZ, it has been proposed that abnormalities in these developmental processes of periadolescent myelination could represent a root cause of the disorder (Bartzokis, 2002).
