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A symptom provocation study of posttraumatic stress disorder using positron emission tomography and script-driven imagery.

BACKGROUND
Previous studies have used symptom provocation and positron emission tomography to delineate the brain systems that mediate various anxiety states. Using an analogous approach, the goal of this study was to measure regional cerebral blood flow changes associated with posttraumatic stress disorder (PTSD) symptoms.


METHODS
Eight patients with PTSD, screened as physiologically responsive to a script-driven imagery symptom provocation paradigm, were exposed sequentially to audiotaped traumatic and neutral scripts in conjunction with positron emission tomography. Heart rate and subjective measures of emotional state were obtained for each condition. Statistical mapping techniques were used to determine locations of significant brain activation.


RESULTS
Increases in normalized blood flow were found for the traumatic as compared with control conditions in right-sided limbic, paralimbic, and visual areas; decreases were found in left inferior frontal and middle temporal cortex.


CONCLUSIONS
The results suggest that emotions associated with the PTSD symptomatic state are mediated by the limbic and paralimbic systems within the right hemisphere. Activation of visual cortex may correspond to the visual component of PTSD reexperiencing phenomena.