Attention is automatically drawn to biologically-relevant environmental cues, but this tendency can be regulated if the cue is not relevant to higher-order goals. Assault victims and patients with PTSD have an impaired ability to ignore such cues and show altered patterns of brain activity during implicit emotion regulation. However, current methods for characterizing these behavioral phenomena do not match existing theoretical models of implicit emotion regulation. Here, we utilized Hidden Markov Modeling to implement theoretical models of emotion regulation in order to test more specifically for behavioral and neural abnormalities related to assault exposure and psychopathology. First, we focused analyses on a control group of nonassaulted adolescent girls (N=24) and found the theoretical model most concordant with behavior and tested whether neural activity corresponded to the modeled emotion regulation subprocesses. Next, we tested whether a group of adolescent assault victims (N=18) differed behaviorally or neurally from the nonassaulted controls. Finally, we assessed whether clinical symptomatology among the assault victims was related to changes in these processes. In the control group, we found that a version of the model posited by Mathews et al. (1998) best explained the data and that the anterior insula and dorsal anterior cingulate cortex (dACC) were active during the detection of irrelevant threatening stimuli and were suppressed during regulatory control. The assault victims responded more slowly to dual threat/threat cues and the anterior insula and dACC responded more strongly when detecting relevant threats and were less suppressed during regulation. Additionally, there was evidence that the assault victims exerted greater executive control to detect the irrelevant threatening stimuli. Focusing on symptomatology, greater symptoms were associated with altered neural responses to the stimuli themselves, rather than the model-based subprocesses. Specifically, threatening relevant stimuli produced a smaller response in the inferior frontal gyrus (IFG) among the assault victims with PTSD, and emotion regulation symptoms were associated with exaggerated visual processing of the threatening distractor stimuli. These findings suggest that assault is associated with exaggerated emotional responses to model-based detection of threatening cues, especially relevant cues, and that more severely symptomatic assault victims have altered processing of the stimuli themselves.
|Commitee:||Bush, Keith, James, Andrew, Kilts, Clint, Stowe, Zachary|
|School:||University of Arkansas for Medical Sciences|
|Department:||Interdisciplinary Biomedical Sciences|
|School Location:||United States -- Arkansas|
|Source:||DAI-B 76/01(E), Dissertation Abstracts International|
|Subjects:||Neurosciences, Womens studies, Clinical psychology|
|Keywords:||Adolescence, Assault, Emotion regulation, Fmri, Hidden markov modeling, Ptsd|
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