As with SUDs, numerous myelin-related genes are downregulated in the depressed brain (Aston et al. 2005; Honer et al. 1999). Quaking homolog, KH domain RNA-binding, an oligodendrocyte-specific RNA-binding protein critical for oligodendrocyte progenitor differentiation, is also reduced in the neocortex, hippocampus, and amygdala of depressed suicide victims (Klempan et al. 2009). Oligodendrocytes are transiently activated by electroconvulsive therapy (Ongur et al. 2004) and rodent electroconvulsive seizures (Jansson et al. 2009). As further molecular evidence of electroconvulsive seizure response, neuronglial antigen 2-expressing oligodendrocyte progenitor cells proliferated and selectively differentiated into mature oligodendrocytes in the rat amygdala (Wennstrom et al. 2004). Thus, overlapping white matter dysfunction and oligodendrocyte cytopathology occurs in both SUDs and depression.
