fMRI Study of Psychophysiological and Brain Responses to Script-Driven Imagery in Identical Twins Discordant for Trauma Exposure and PTSD
Laifer, Lauren M.
2015
- Background: Neuroimaging studies have demonstrated increased psychophysiologic responses as well as medial prefrontal cortex (mPFC) hyporesponsivity to both trauma-related and -unrelated emotional stimuli in posttraumatic stress disorder (PTSD). However, the origin of these biological abnormalities has not yet been identified. Objective: To determine whether psychophysiological and functional brain ... read moreabnormalities in the mPFC, specifically the rostral anterior cingulate cortex (rACC), seen in individuals with PTSD during script-driven imagery (SDI) are familial vulnerability factors, due to trauma exposure, or acquired characteristics of the disorder. Method: Participants were male trauma-exposed individuals with PTSD (ExP+, n=11) and their trauma-unexposed identical co-twins (UxP+, n=11) as well as trauma-exposed individuals without PTSD (ExP-, n=13) and their trauma-unexposed co-twins (UxP-, n=13). We used functional magnetic resonance imaging (fMRI) and SDI to study blood-oxygen-level-dependent (BOLD) signal changes during the recollection and imagery of stressful versus neutral autobiographical scripts. Results: No significant differences were found between groups for skin conductance response to stressful imagery versus neutral imagery. Voxelwise analyses of the fMRI data, however, revealed significant differences between the PTSD and Control twin pairs in the rACC for the stressful imagery versus neutral imagery contrast. Specifically, this main effect of Diagnosis represented greater BOLD decreases in the PTSD group during stressful imagery relative to neutral imagery and appeared to be largely driven by deactivation in ExP+ participants to stressful imagery relative to baseline. Conclusions: Diminished rACC activation observed in individuals with PTSD appears to represent neither a familial vulnerability factor for PTSD nor a characteristic of trauma exposure, but instead is likely to be an acquired trait of the disorder itself.read less
- ID:
- q524k093r
- Component ID:
- tufts:sd.0000218
- To Cite:
- TARC Citation Guide EndNote
