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Data-Driven Approach To Dynamic Resting State Functional Connectivity In Post-Traumatic Stress Disorder, Carissa Weis
Data-Driven Approach To Dynamic Resting State Functional Connectivity In Post-Traumatic Stress Disorder, Carissa Weis
Theses and Dissertations
Posttraumatic stress disorder (PTSD) is a heterogenous psychological disorder that may result from exposure to a traumatic event. Using functional magnetic resonance imaging (fMRI), symptoms of PTSD have been associated with aberrations in brain networks that emerge in the absence of a given cognitive demand or task, called resting state networks. Most previous research in resting state networks and PTSD has focused on aberrations in the static functional connectivity among specific regions of interest (ROI) in the brain and within canonical networks constrained by a priori hypotheses. However, dynamic fMRI, an approach that examines changes in brain network characteristics over …
Response To Uncertain Threat In Acute Trauma Survivors, Kenneth Bennett
Response To Uncertain Threat In Acute Trauma Survivors, Kenneth Bennett
Theses and Dissertations
Uncertainty is often associated with subjective distress and a potentiated anxiety response. The heightened response to uncertainty may be a central mechanism via which anxiety-, trauma-, and stressor-related disorders are developed and maintained. The current study compared the neural response to predictable and unpredictable threat in acute trauma survivors to clarify the role of the response to uncertain threat in fear circuitry and further inform the nature of the development of PTSD in the context of uncertain threat. The novel study showed that anticipating unpredictable (primarily negative images) relative to predictable images increased activation in a frontoparietal network and was …
Neural Substrates Of Active Avoidance And Its Impact On Fear Extinction, Elizabeth Parisi
Neural Substrates Of Active Avoidance And Its Impact On Fear Extinction, Elizabeth Parisi
Theses and Dissertations
Models of anxiety suggest that avoidance of a conditioned fear stimulus prevents new safety learning, thereby serving to maintain fear. However, there is little empirical data in humans on the impact of avoidance of conditioned fear stimuli on subsequent fear extinction. In the present study I investigated the effect of avoidance of threat on neural activity during avoidance/control and a subsequent extinction phase using ultra high-resolution (7T) fMRI. Results indicated that active avoidance was associated with increased activity in regions involved in reward prediction, but this did not differentiate active avoidance from an active control condition. Neural activation during the …