Although the contribution of 5-HT in the OFC to the emotional behavior such as anxiety- and depression-like behavior is less understood in rodents, it is reported that microinjection of 5-HT1A or 5-HT1B receptors agonist into the OFC suppressed aggressive behavior in mice (De Almeida et al., 2006; Centenaro et al., 2008; Stein et al., 2013). This evidence concerns the gene HTR1A and major depressive disorder.