Open Access Dissertation
Date of Award
Moriah E. Thomason
Childhood trauma is one of the strongest risk factors for a range of common and debilitating neuropsychiatric disorders, including anxiety, depression, and posttraumatic stress disorder (PTSD). These emotion-related disorders have their roots in childhood and adolescence, underscoring a critical need to understand their biological bases in early life. In this dissertation, we evaluate how childhood trauma impacts emotion processing neurocircuitry in a sample of high-risk urban youth, ages 7-15. In four inter-related studies, we test neural function and functional connectivity of core emotion processing regions, including the amygdala, insula, and pregenual/subgenual anterior cingulate cortex (pgACC/sgACC). To examine the relevance of observed neurological changes, we evaluate behavioral performance on emotion processing neuropsychological tasks, as well as specific dimensions of subjective affective experience.
Results indicate that, relative to matched comparison youth, trauma-exposed youth have (1) increased neural response to salient emotional cues in amygdala and insula, (2) reduced functional connectivity between amygdala and pgACC/sgACC, a pathway critical for emotion regulation, and (3) altered within- and between-network connectivity of the salience network, involved in detecting and orienting attention to salient emotional stimuli. These neurological changes are accompanied by behavioral alterations: trauma-exposed youth have a lower ability to ignore distracting emotional information, and to automatically regulate emotion. Additionally, observed neurobehavioral changes relate to a specific dimension of affective experience – reward sensitivity (RS), rather than negative affect. Moreover, trauma-exposed youth with the greatest neurobehavioral impairment report lower RS, suggesting reduced positive environmental engagement.
These results suggest that RS may be a marker of stress susceptibility, a notion supported by emerging basic and clinical research. Based on our neurobehavioral findings, we discuss potential implications for intervention, and relay an emerging framework that dissociates neurological effects of different trauma types (i.e., threat/victimization vs. deprivation/neglect). In closing, we discuss future directions, including longitudinal research and evaluating the modulation of learned fear – a neurobehavioral mechanism that depends on emotion processing neurocircuitry, but has yet to be tested in trauma-exposed youth.
Marusak, Hilary A., "Childhood Trauma And Emotion Processing Neurocircuitry" (2016). Wayne State University Dissertations. 1462.