Prior studies of adult post-traumatic stress disorder (PTSD) suggest abnormal functioning of prefrontal and limbic regions. Cumulative childhood and adult trauma exposures are major risk factors for developing adult PTSD, yet their contribution to neural dysfunction in PTSD remains poorly understood. This study aimed to examine the neural correlates of childhood and adult trauma exposure and post-traumatic stress symptoms (PTSS) within a single model.

Medication-free male combat veterans (n = 28, average age 26.6 years) with a wide range of PTSS were recruited from the community between 2010 and 2011. Subjects completed an emotional face-morphing task while undergoing functional magnetic resonance imaging (fMRI). Clinical ratings included the Clinician-Administered PTSD Scale (CAPS), Childhood Trauma Questionnaire (CTQ) and Combat Exposure Scale (CES). A priori regions were examined through multivariate voxelwise regression in SPM8, using depressive symptoms and IQ as covariates.

In the angry condition, CAPS scores correlated positively with activation in the medial prefrontal cortex [mPFC; Brodmann area (BA) 10, z = 3.51], hippocampus (z = 3.47), insula (z = 3.62) and, in earlier blocks, the amygdala. CES and CTQ correlated positively with activation in adjacent areas of the dorsal anterior cingulate cortex (dACC; BA 32, z = 3.70 and BA 24, z = 3.88 respectively). In the happy condition, CAPS, CTQ and CES were not correlated significantly with activation patterns.

dACC activation observed in prior studies of PTSD may be attributable to the cumulative effects of childhood and adult trauma exposure. By contrast, insula, hippocampus and amygdala activation may be specific to PTSS. The specificity of these results to threat stimuli, but not to positive stimuli, is consistent with abnormalities in threat processing associated with PTSS.

Patients with major depressive disorder (MDD) present with highly heterogeneous symptom profiles. We aimed to examine whether individual differences in amygdala activity to emotionally salient stimuli were related to heterogeneity in lifetime levels of depressive and subthreshold manic symptoms among adults with MDD.

We compared age- and gender-matched adults with MDD (n = 26) with healthy controls (HC, n = 28). While undergoing functional magnetic resonance imaging, participants performed an implicit emotional faces task: they labeled a color flash superimposed upon initially neutral faces that dynamically morphed into one of four emotions (angry, fearful, sad, happy). Region of interest analyses examined group differences in amygdala activity. For conditions in which adults with MDD displayed abnormal amygdala activity versus HC, within-group analyses examined amygdala activity as a function of scores on a continuous measure of lifetime depression-related and mania-related pathology.

Adults with MDD showed significantly greater right-sided amygdala activity to angry and happy conditions than HC (p < 0.05, corrected). Multiple regression analyses revealed that greater right-amygdala activity to the happy condition in adults with MDD was associated with higher levels of subthreshold manic symptoms experienced across the lifespan (p = 0.002).

Among depressed adults with MDD, lifetime features of subthreshold mania were associated with abnormally elevated amygdala activity to emerging happy faces. These findings are a first step toward identifying biomarkers that reflect individual differences in neural mechanisms in MDD, and challenge conventional mood disorder diagnostic boundaries by suggesting that some adults with MDD are characterized by pathophysiological processes that overlap with bipolar disorder.

Individuals with bipolar disorder demonstrate abnormal social function. Neuroimaging studies in bipolar disorder have shown functional abnormalities in neural circuitry supporting face emotion processing, but have not examined face identity processing, a key component of social function. We aimed to elucidate functional abnormalities in neural circuitry supporting face emotion and face identity processing in bipolar disorder.

Twenty-seven individuals with bipolar disorder I currently euthymic and 27 healthy controls participated in an implicit face processing, block-design paradigm. Participants labeled color flashes that were superimposed on dynamically changing background faces comprising morphs either from neutral to prototypical emotion (happy, sad, angry and fearful) or from one identity to another identity depicting a neutral face. Whole-brain and amygdala region-of-interest (ROI) activities were compared between groups.

There was no significant between-group difference looking across both emerging face emotion and identity. During processing of all emerging emotions, euthymic individuals with bipolar disorder showed significantly greater amygdala activity. During facial identity and also happy face processing, euthymic individuals with bipolar disorder showed significantly greater amygdala and medial prefrontal cortical activity compared with controls.

This is the first study to examine neural circuitry supporting face identity and face emotion processing in bipolar disorder. Our findings of abnormally elevated activity in amygdala and medial prefrontal cortex (mPFC) during face identity and happy face emotion processing suggest functional abnormalities in key regions previously implicated in social processing. This may be of future importance toward examining the abnormal self-related processing, grandiosity and social dysfunction seen in bipolar disorder.