Mariko Frances Weber: Cognitive Control and Affective Processing Dysregulation in Veterans with Comorbid PTSD and mTBI: an fMRI Study (Under the direction of Aysenil Belger) Background: Deficits in cognitive control and affective processing are important aspects of comorbid PTSD and mTBI for which there are no effective treatments. Understanding the neural basis of symptoms and domain specific deficits is an important step in developing therapies for treating individuals with PTSD-mTBI. No studies have addressed this question, as most have examined PTSD or mTBI separately. We therefore utilize a large functional magnetic resonance imaging (fMRI) dataset to test the relationship between individual symptom severity, neurocognitive deficits and task-based functional activation. Methods: The relationship between the severity of clinical symptoms and neurocognitive deficits in patients with PTSD-mTBI and functional activation during an affective 1-back task, affective face matching task, and number Stroop task (n = 100) was assessed using correlation analysis. Results: Activity in cortico-limbic regions, and regions associated with striatal, default mode, and salience networks were found to be significantly associated with increased symptom severity and greater impairments in neurocognition. Discussion: Our findings suggest that researchers and clinicians should examine individuals neural and symptom profiles before making a treatment decision and that unique variable associations should be the focus rather than the average of the group as a whole. Furthermore, our results indicate a relationship between functional activity and clinical symptoms and neurocognitive deficits that suggest network level regional contribution to diagnoses, as well as greater resting baseline activity that is associated with increased symptom severity.