Our data show decreased myelination (Table 1D) in the hippocampus. Decreased hippocampal volume (Agartz et al., 1999; Laakso et al., 2000; Tyan et al., 2012) and decreases in hippocampal neurogenesis have been observed in alcoholism (Crews & Nixon, 2009; Morris et al., 2010; Richardson et al., 2009). Pathways (WNT/β catenin, reelin signaling in neurons, and ERBB4) and genes (APP, PSEN1, ADAM10, ERBB2, and reelin) that play a role in neurogenesis (Lazarov & Marr, 2010) have decreased activity or expression in the hippocampi of the alcoholics. Both inflammation (Monje et al., 2003) and stress with increased cortisol production (Schoenfeld & Gould, 2012) can inhibit neurogenesis. Chronic cortisol decreases neurogenesis and treatment with the glucocorticoid antagonist mifepristone reverses this reduction (Mayer et al., 2006).
