Mean FA as a function of age group and interval along the tract. Error bars represent 1 SE. Panel A = genu and superior longitudinal fasciculus; Panel B = splenium-occipital and splenium-parietal. For genu and splenium, the tracts are oriented left-right, with 0 = axial midline. For the superior longitudinal fasciculus, the tracts are oriented anterior-posterior and 0 = central sulcus. Below the mean FA data, t-values are plotted for the age group comparison at each point along the tract. The dotted line represents the significant t value for p < .05, two-tailed. Figure modified from Madden et al. (2009). © Journal of Cognitive Neuroscience and MIT Press, 2009.