Activity in medial prefrontal cortex during cognitive evaluation of threatening stimuli as a function of personality style

Cognitive evaluation of emotional stimuli involves a network of brain regions including the medial prefrontal cortex (mPFC). However, threatening stimuli may be perceived with differential salience in different individuals. The goal of our study was to evaluate how different personality styles are associated with differential modulation of brain activity during explicit recognition of fearful and angry facial expressions. Twenty-eight healthy subjects underwent fMRI. Based on a cognitivist model, subjects were categorized according to how they attribute salience to emotional stimuli and how they regulate their emotional activation. We compared 14 phobic prone (PP) subjects, whose identity is more centered on the inner experience ("inward") and around control of environmental threat, and 14 eating disorders prone (EDP) subjects, whose identity is more centered on external referential contexts ("outward") and much less around control of threatening stimuli. During fMRI subjects either matched the identity of one of two angry and fearful faces to that of a simultaneously presented target face or identified the expression of a target face by choosing one of two simultaneously presented linguistic labels. The fMRI results indicated that PP subjects had greater mPFC activation when compared with EDP subjects during cognitive labeling of threatening stimuli. Activity in the mPFC also correlated with personality style scores. These results demonstrate that PP subjects recruit greater neuronal resources in mPFC whose activity is associated with cognitive aspects that are closely intertwined with emotional processing. These findings are consistent with the contention that cognitive evaluation and salience of emotional stimuli are associated with different personality styles.