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Corticolimbic Blood Flow During Nontraumatic Emotional Processing in Posttraumatic Stress Disorder
K. Luan Phan, MD;
Jennifer C. Britton, MS;
Stephan F. Taylor, MD;
Lorraine M. Fig, MD;
Israel Liberzon, MD
Arch Gen Psychiatry. 2006;63:184-192.
Context 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.
Objective To investigate activity in the limbic and paralimbic brain regions in PTSD in response to a challenge with emotionally salient generic visual images.
Design Cross-sectional, case-control study.
Setting Academic medical center.
Participants 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).
Main Outcome Measures 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.
Results 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.
Conclusions 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.
Author Affiliations: Department of Psychiatry, Pritzker School of Medicine, The University of Chicago, Chicago, Ill (Dr Phan); Neuroscience Program, University of Michigan (Dr Liberzon and Ms Britton), Department of Psychiatry, University of Michigan Medical School (Drs Taylor and Liberzon), and Nuclear Medicine Service (Dr Fig) and Psychiatry Service (Dr Liberzon), Veterans Administration Medical Center, Ann Arbor.
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