When considered together, several patterns emerge. Compared with non-AU youth, some AU adolescents show significant smaller brain volumes and lower GM density within several important regions including the hippocampus (Nagel et al., 2005), and left frontal, temporal and parietal cortices (Fein et al., 2013), along with trend levels of the same pattern (e.g., AU youth showing smaller anterior ventral PFC volumes; Medina et al., 2008). This pattern was also observed in the one longitudinal study, whereby AU youth (those who commenced AU during the study) showed greater decreases in cortical thickness in a single cluster of the right middle frontal gyrus, and less WM development across the right precentral gyrus, lingual gyrus, middle temporal gyrus and anterior cingulate at the 2-year follow-up (Luciana et al., 2013). In addition, these studies reflect a significant inverse pattern between quantity of alcohol consumed and brain volume, whereby consuming more alcohol was related to less brain volume for these youth (Fein et al., 2013; Lisdahl et al., 2013b).
