FIGURE 1.

Recent studies on dissociation have investigated the neurophysiology of trauma responses. A. Classical or nondissociative patients with posttraumatic stress disorder (PTSD) demonstrate activity associated with hyperarousal; the corresponding brain activity is lessened ventromedial prefrontal cortex (vmPFC) inhibition of limbic activity. B. The dissociative subtype of posttraumatic stress disorder (PTSD+DS) demonstrates the opposite pattern of activity, involving overmodulation of limbic activity via vmPFC hyperactivation.