Cytochrome oxidase activity was measured from the orbitofrontal, prefrontal, and entorhinal cortices, the dorsal and ventral portions of the hippocampus, and the habenula as described for Figure 4. A) The correlation matrices are organized from top to bottom and left to right as follows: OFC = DLO, LO, VO, MO; PFC = Cg, Prl, IL, Dp; dHPC = dDG, dCA3, dCA1, dS; Hb = MHb, LHb; vHPC = vDG, vCA3, vCA1, vS; EC. Normal adolescent to adult maturation involves specialization of brain regions, which can be seen as “islands” of high correlations within brain regions, surrounded by low correlations between brain regions in the adult brain (lower, left matrix). Adult GD17- MAM rats have altered functional connectivity to the ventral hippocampus (lower, right matrix) that is evident already in adolescence (upper, right matrix). Values are Pearson Product Correlations. See Table 1 for details. Correlations significantly different (p < 0.05) from corresponding age group. B) Networks were generated from the significant correlations (p < 0.05). Gray lines are correlations that did not reach significance after false discovery rate correction. Network properties of the dorsal hippocampus undergo maturation in both control and GD17-MAM rats from adolescence to adulthood. However, while the control dorsal hippocampus loses edges from adolescence to adulthood, the GD17-MAM dorsal hippocampus gains edges. Subregions are as follows: OFC = orbitofrontal cortex, PFC = prefrontal cortex, dHPC and vHPC = dorsal and ventral hippocampus, respectively, Hb = habenula, EC = entorhinal cortex. DO, LO, VO, and MO = dorsolateral, lateral, ventrolateral, and medial orbitofrontal cortex, respectively. Cg, PrL, IL = cingulate, prelimbic, and infralimbic cortex, respectively. Dp = dorsal peduncular nucleus. dDG and vDG = dorsal and ventral dentate gyrus, respectively. dCA3 and vCA3 = dorsal and ventral Cornu Ammonis 3, respectively. dCA1 and vCA1 = dorsal and ventral Cornu Ammonis 1, respectively. dS and vS = dorsal and ventral subiculum, respectively. mHb and LHb = medial and lateral habenula, respectively.