In addition, using social isolation in rodents, another animal model of depression, it was observed a marked reduction in Egr1 mRNA levels in the hypothalamus, the hippocampus, and the medial prefrontal cortex (Matsumoto et al., 2012; Hodges et al., 2014; Okada et al., 2014). Here, EGR1 is linked to major depressive disorder.