A substantial amount of research demonstrates that an early-life trauma can profoundly compromise the way in which emotional information is processed, and can predict neuropsychiatric illness, in adulthood.
In a recent fMRI study published in the Journal of Neuropsychopharmacology, Marusak et al (2015) hypothesized that children who experienced trauma would have a more difficult time ignoring emotional cues that contradicted emotional expressions in photographs. In addition, they postulated that such children would display a decreased ability to regulate emotional conflict when presented with mood incongruent stimuli.
To test this hypothesis Marusak et al (2015) utilized the Emotional Conflict Task, a test that uses emotional distractors that directly contradict emotional information within a task. All participants in the study, those who had experienced trauma and those who had not, viewed a series of photographs that paired an emotional word with a facial expression. For example, a photograph of an angry face might be displayed with the word ‘HAPPY’ written over top of it. The participants were timed on their ability to indicate the emotion displayed by the person in the photograph.
In their fMRI analysis, Marusak et al (2015) focused chiefly on the amygdala-pregenual cingulate cortex (pgACC) network because the amygdala plays a critical role in the processing of emotional information, and the pgACC has previously been identified as a pathway involved in ‘emotional conflict regulation’ via the suppression of amygdalar activity.
There were three significant findings. First, children and adolescents who experienced trauma displayed increased amygdalar reactivity when presented with incongruent emotional stimuli—what the researchers defined as ‘emotional conflict.’ Second, children and adolescents exposed to trauma had difficulty regulating emotional conflict, meaning it took them longer to identify the depicted facial expressions and they did so with less accuracy. Related to this finding, Marusak et al (2015) also observed an inability of traumatized participants to regulate the dorsolateral prefrontal cortex (DLPFC), an area known for it’s involvement in effortful attentional control. Third, activation of the amygdala in response to emotional conflict was linked to dampened reward sensitivity in children and adolescents with trauma exposure.
According to Marusak et al (2015), trauma-exposed youth, who show exaggerated amygdala reactivity when presented with emotional conflict, likely have altered neural networks responsible for attending to salient emotional cues—meaning that their heightened amygdalar activity results in a hypervigilance for emotional cues.
Adults with depression and anxiety disorders have also been shown to have similar deficits in the amygdala-pgACC pathway as well as elevated DLFPC activity. While such alterations could be the result of illness, researchers suggest that they may also indicate lasting changes in circuitry in response to early trauma.
Marusak, H. A., Martin, K. R., Etkin, A., & Thomason, M. E. (2015; 2014). Childhood trauma exposure disrupts the automatic regulation of emotional processing. Neuropsychopharmacology : Official Publication of the American College of Neuropsychopharmacology, 40(5), 1250. doi:10.1038/npp.2014.311