tandem with astrocytic and microglia activation in brain tissue from human alcoholics. This is consistent with literature showing a general degradation of neurons as well as activation and proliferation of microglia after chronic alcohol exposure (Crews et al., 2011), which may contribute to addiction-related neuroplastic changes. Oligodendrocytes also show differential gene expression in multiple brain regions after chronic alcohol exposure. In the hippocampus, 83% of the differentially expressed transcripts enriched in oligodendrocytes were expressed at lower levels in alcoholics (McClintick et al., 2013). In the human frontal cortex, several myelin-related genes (MOBP, OPALIN, UGT8, and ERMN) were alcohol-responsive (Farris et al., 2015a). Abnormal white matter expression plays an essential role in brain morphology and behavioral responses to alcohol and other drugs of abuse (Pfefferbaum et al., 1997; Sokolov, 2007). The discrete alcohol-induced changes in cellular transcriptomes indicate that cell types may be important targets for future drug development.
