Corticolimbic blood flow during nontraumatic emotional processing in Posttraumatic stress disorder
ABSTRACT Recent brain imaging studies implicate dysfunction of limbic and paralimbic circuitry, including the amygdala and medial prefrontal cortex (MPFC), in the pathogenesis of posttraumatic stress disorder (PTSD) during traumatic recollection and imagery. However, the relationship between activity in these regions and general emotional processing unrelated to traumatic experience has not been fully examined.
To investigate activity in the limbic and paralimbic brain regions in PTSD in response to a challenge with emotionally salient generic visual images.
Cross-sectional, case-control study.
Academic medical center.
Sixteen Vietnam veterans with combat-related PTSD (PTSD group), 15 combat-exposed Vietnam veterans without PTSD (combat control group), and 15 age- and sex-matched healthy controls (normal control group).
We used positron emission tomography to study regional cerebral blood flow while participants viewed complex visual pictures with negatively valenced/aversive, nonaversive ("neutral"), and blank pictures. Psychophysiologic and emotional self-report data were also recorded.
All 3 groups activated the dorsal MPFC to general salient content. Controls without PTSD activated the left amygdala in response to aversive stimuli. Normal controls activated the ventral MPFC and combat-exposed non-PTSD and PTSD participants exhibited either no response or deactivation in these regions, respectively, during negative emotional experience.
Consistent with current functional neuroanatomic models, patients with PTSD exhibited altered neural responses in the amygdala and ventral MPFC during the processing of emotionally salient but trauma-unrelated stimuli, potentially reflecting disorder-specific changes. Activation of the amygdala and lack of ventral MPFC deactivation to negatively valenced images in combat controls may reflect compensatory changes after trauma exposure that are not associated with PTSD.
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ABSTRACT: Although recent research has begun to describe the neural and genetic processes underlying variability in responses to trauma, less is known about how these processes interact. We addressed this issue by using functional magnetic resonance imaging (fMRI) to examine the relationship between post-traumatic stress symptomatology (PTSS), a common genetic polymorphism of the serotonin transporter (5-HTT) gene, and neural activity in response to viewing images associated with the 9/11 terrorist attack among a rare sample of high-exposure 9/11 survivors (n=17). Participants varied in whether they carried a copy of the short allele in the promoter region of the 5-HTT gene. During scanning, participants viewed images of the 9/11 attack, non-9/11 negative, and neutral images. Three key findings are reported. First, carriers of the short allele displayed higher levels of PTSS. Second, both PTSS and the presence of the short allele correlated negatively with activity in a network of cortical midline regions (e.g. the retrosplenal and more posterior cingulate corticies [PCC]) implicated in episodic memories and self-reflection when viewing 9/11 versus non-9/11 negative control images. Finally, exploratory analyses indicated that PCC activity mediated the relationship between genotype and PTSS. These results highlight the role of PCC in distress following trauma.Social Cognitive and Affective Neuroscience 10/2014; DOI:10.1093/scan/nsu125 · 5.88 Impact Factor
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ABSTRACT: The great Sichuan earthquake in China on May 12th, 2008 was a traumatic event to many who live near the earthquake area. However, at present, there are few studies that explore the long-term impact of the adolescent trauma exposure on adult's brain function. In the present study, we used functional magnetic resonance imaging (fMRI) to investigate the brain activation evoked by masked trauma-related stimuli (earthquake versus neutral images) in 14 adults who lived near the epicenter of the great Sichuan earthquake when they were adolescents (trauma-exposed group) and 14 adults who lived farther from the epicenter of the earthquake when they were adolescents (control group). Compared with the control group, the trauma-exposed group showed significant elevation of activation in the right anterior cingulate cortex (ACC) and the medial prefrontal cortex (MPFC) in response to masked earthquake-related images. In the trauma-exposed group, the right ACC activation was negatively correlated with the frequency of symptoms of post-traumatic stress disorder (PTSD). These findings differ markedly from the long-term effects of trauma exposure in adults. This suggests that trauma exposure during adolescence may have a unique long-term impact on ACC/MPFC function, top-down modulation of trauma-related information, and subsequent symptoms of PTSD. Copyright © 2014. Published by Elsevier B.V.International journal of psychophysiology: official journal of the International Organization of Psychophysiology 12/2014; DOI:10.1016/j.ijpsycho.2014.12.001 · 3.05 Impact Factor