Previous neuroimaging evidence has shown an abnormal activation of the amygdala and prefrontal cortex in PTSD patients during fear conditioning and extinction. Nevertheless, the effects of a single-type adverse stressor on that circuit remain poorly explored. We tested the hypothesis that a single-type adverse episode is able to affect the prefrontal cortex and amygdala response to conditioned stimuli. To test this hypothesis, fMRI recordings were performed in PTSD patients and trauma-exposed controls during the observation of neutral and negative paired or non-paired pictures with an adverse stimulus by means of a single association. Results showed that left amygdala activation during negative reinforced stimuli was correlated with the score of PTSD clinical scale across all subjects. Furthermore, in the traumatized non-PTSD group, the activation of the dorso-medial prefrontal cortex and bilateral amygdala was lower during the observation of the reinforced (CS+) versus non-reinforced pictures (CS-) in response to emotionally negative stimuli. This was not the case in the PTSD patients. These results suggest that in PTSD patients, a single-episode conditioning unveils the failure of an inhibitory mechanism moderating the activity of the prefrontal cortex and amygdala in response to adverse and neutral stimuli.
|Number of pages||11|
|Journal||Brain Research Bulletin|
|Publication status||Published - May 1 2015|
- Functional magnetic resonance imaging (fMRI)
- Post-traumatic stress disorder (PTSD)
ASJC Scopus subject areas