Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden. [email protected]
Research on the biological underpinnings of personality can provide leads to the pathophysiology of psychiatric disorders. In particular, interpersonal aspects of behavior are a common problem during the course of psychiatric illness. Animal research has demonstrated a role for the dopamine system in social behaviour, and recent molecular imaging studies have shown a negative correlation between dopamine D2-receptor binding in the striatum and social desirability. The emotional and cognitive aspects of social behavior suggest involvement of brain regions outside of the striatum, such as limbic structures. The aim of the present study was to explore associations between the personality trait social desirability and dopamine D2-receptor binding in both striatal and extrastriatal brain regions. We examined 16 control subjects with Positron Emission Tomography and the radioligands [(11)C]raclopride and [(11)C]FLB 457, in relation to social desirability in the inventory Swedish universities Scales of Personality. [(11)C]raclopride D2-receptor binding in the striatum showed negative correlations to social desirability scores, corroborating previous findings. Furthermore, a correlation of a higher statistical significance was demonstrated for [(11)C]FLB 457 binding in the hippocampal-amygdala complex. A separate analysis of social desirability items in relation to a model of interpersonal behaviour revealed that the associations were driven by items reflecting high submissiveness and high affiliation. Taken together with previous evidence on D2-receptor binding and social behaviour, a role for dopaminergic neurotransmission in regulating displays of dominance vs. submissive behaviour is proposed.