| A large literature has implicated stress, especially social stress, in the etiology and maintenance of depression. A new literature is emerging examining the relationship between brain activation in stress-related regions and cognitive and biological features associated with (e.g. cognitive, emotional) stress-related disorders like depression. In an experimental design in study 1, exclusion was related to negative, self-evaluative bias and diminished positive affect. Negative affective bias, indexed by corrugator activity, and sex predicted more negative, self-evaluative bias in males. Further, cortisol and sex moderated the effects of exclusion on positive affect. In study 2, we sought to examine neural circuitry associated with HPA regulation. A region of medial prefrontal cortex (mPFC), Area 24/25) consistently predicted individual differences in plasma cortisol concentrations. Using the brain regions identified in study 2, study 3 examined the relationship between activation in mPFC, BA 24, and emotional ratings of ambiguous self-referential words in healthy controls and depressed participants. In depressed females, cortisol affected self-referent ratings, and individual differences in cortisol-related brain activation in mPFC were related to self-evaluation and affect in depressed females. Taken together findings from these studies demonstrate 1) exclusion leads to negatively biased self-evaluation and diminished positive affect; 2) individual differences in affective physiology, sex, and cortisol influence this relationship; 3) individuals prone to elevated mPFC activity who also show consistently heightened cortisol may be at risk for stress-related HPA dysregulation; and 4) cortisol elevations are related to mPFC activity and self-evaluation in depression. |
