Cerebral Blood Flow and Personality: A Positron Emission Tomography Study

TLDR

The study aimed to identify brain regions linked to introversion and extraversion. Cerebral blood flow was measured in 18 healthy participants using [15O]H2O PET, and regional CBF was correlated with introversion/extraversion to produce a 3‑D correlation map. Introversion correlated with higher frontal lobe and anterior thalamic blood flow, while extraversion correlated with activity in the anterior cingulate, temporal lobes, and posterior thalamus, supporting a fronto‑striato‑thalamic circuit underlying personality differences.

Abstract

OBJECTIVE: This study sought to describe brain regions associated with the personality dimension of introversion/extraversion. METHOD: Measures of cerebral blood flow (CBF) were obtained from 18 healthy subjects by means of [15O]H2O positron emission tomography. Correlations of regional CBF with introversion/extraversion were calculated, and a three-dimensional map of those correlations was generated. RESULTS: Overall, introversion was associated with increased blood flow in the frontal lobes and in the anterior thalamus. Regions in the anterior cingulate gyrus, the temporal lobes, and the posterior 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.