Is desire for social relationships mediated by the serotonergic system in the prefrontal cortex? An [18F]setoperone PET study

Social behavior and desire for social relationships have been independently linked to the serotonergic system, the prefrontal cortex, especially the orbitofrontal cortex (OFC), and the anterior cingulate cortex (ACC). The goal of this study was to explore the role of serotonin 5HT2A receptors in these brain regions in forming and maintaining close interpersonal relationships. Twenty-four healthy subjects completed the Temperament and Character Inventory (TCI) prior to undergoing [18F]setoperone brain positron emission tomography (PET) to measure serotonin 5HT2A receptor availability within the OFC (BA 11 and 47) and ACC (BA 32). We explored the relationship between desire for social relationships, as measured by the TCI reward dependence (RD) scale, and 5HT2A receptor non-displaceable binding potential (BPnd) in these regions. Scores of RD were negatively correlated with 5HT2A BPnd in the ACC (BA 32, r = -.528, p = .012) and OFC (BA 11, r = -.489, p = .021; BA 47, r = -.501, p = .017). These correlations were corroborated by a voxel-wise analysis. These results suggest that the serotonergic system may have a regulatory effect on the OFC and ACC for establishing and maintaining social relationships.