This review outlines how functional brain imaging, using an individual-differences approach in the processing of emotional stimuli, has begun to reveal the neural basis of extraversion (E) and neuroticism (N), two traits that are linked to both emotion and health. Studies using functional magnetic resonance imaging have shown that individual differences in participants' E and N scores are correlated with individual differences in brain activation in specific brain regions that are engaged during cognitive-affective tasks. Imaging studies using genotyped participants have begun to address the molecular mechanisms that may underlie these individual differences. The multidisciplinary integration of brain imaging and molecular genetic methods offers an exciting and novel approach for investigators who seek to uncover the biological mechanisms by which personality and health are interrelated.