Sex steroids impact on cortical function through both direct and indirect pathways. Dopaminergic neurons in the midbrain and elsewhere have been shown to be sensitive to sex steroid activity(Creutz & Kritzer, 2004; Kritzer & Creutz, 2008; Stewart & Rajabi, 1994). Serotonergic neurons in areas such as the dorsal raphe nucleus have also been identified as containing sex steroid receptors.(Bethea, Lu, Gundlah, & Streicher, 2002; Vanderhorst, Gustafsson, & Ulfhake, 2005). Both dopaminergic and serotonergic nuclei project diffusely to wide areas of the cortex. In addition to effects mediated through these systems, sex steroid receptors have within many cortical regions, (Montague et al., 2008), adding the potential for direct effects of sex steroids on cortical development. Among the cortical areas with high densities of steroid receptors are areas of the frontal cortex, motor and somatosensory cortex, posterior parietal cortex, agranular insular cortex and parahippocampal regions (Goldstein et al., 2001).
