Neural, Hormonal and Experiential Control of Sex-Typical Expression of Social Behavior

Expression of social behaviors is regulated by various neuroendocrine and neurochemical factors. Among them, estradiol is known to have a profound influence on female sexual behavior as well as various types of social interactive behaviors, through its binding to two types of estrogen receptors, ER or ER . Since male gonadal hormone, testosterone, is aromatized to estradiol in neuronal cells in the brain, ERs are also essential for the regulation of male-type social behavior and the development of their neural network. In this article, we discuss how each type of ER plays a role in the expression of sex-typical social behavior in males and females by focusing on both organizational and activational action of estradiol. For this purpose we overview behavioral and neuroanatomical studies reported in knockout as well as brain site-specific knockdown models of ER genes. We also discuss how early life experiences may affect subsequent expression of social and socio-emotional behavior.