Cerebral blood flow and personality: A positron emission tomography study

Objective: This study sought to describe brain regions associated with the personality dimension of introversion/extraversion. Method: Measures of cer ebral blood flow (CBF) were obtained from 18 healthy subjects by means of [ O-15]H2O positron emission tomography. Correlations of regional CBF with in troversion/extraversion were calculated, and a three-dimensional map of tho se correlations was generated. Results: Overall, introversion was associate d with increased blood flow in the frontal lobes and in the anterior thalam us. Regions in the anterior cingulate gyrus, the temporal robes, and the po sterior thalamus were found to be correlated with extraversion. Conclusions : The findings of the study lend support to the notion that introversion is associated with increased activity in frontal lobe regions. Moreover, the study suggests that individual differences in introversion and extraversion are related to differences in a fronto-striato-thalamic circuit.