Threat in Post-Traumatic Stress Disorder, Inhibitory Control, and Dissociation

Malara, Ruglass, Fertuck, and Hien (2018) investigated the association among exposure to trauma, post-traumatic stress disorder symptoms and inhibitory control in patients with PTSD, trauma-exposed individuals without PTSD, and healthy control subjects.

Participants performed on a temporal flanker paradigm in which they had to judje line orientations whilst ignoring lines that were not relevant to the task. Inhibitory control to threatening stimuli was also investigated during this task.

Event-related potentials were used during this task, focusing on the Rejection Positivity (RP). associations with the RP and dissociative symptoms were as well investigated.

As compared with trauma-exposed individuals without PTSD and healthy control subjects, patients with PTSD were less accurate on the task, reflected in more errors committed in making line decisions, which was particularly evident in the context of emotional stimuli that were threatening. In addition, the patients with PTSD showed also more distractor inhibition in blocks of threatening trials, as assessed by the RP. Furthermore, the strength of inhibitory control (RP) was related to more dissociative symptoms in patients with PTSD, especially concerning feelings of depersonalization.

Trauma-exposed individuals showed more inhibitory control (RP) that was related to less depersonalization (Melara et al., 2018).

Dipole source localization found the RP to be located in the posterior cingulate cortex in all three studied groups. In addition, another source was found to be in the ventromedial prefrontal cortex in trauma-exposed individuals (Melara et al., 2018).