Neurobiology of dissociation: unity and disunity in mind-body-brain.

This article reviews studies of the neural correlates of dissociative experiences as assessed by functional neuroimaging (positron emission tomography [PET] and functional magnetic resonance imaging [fMRI]). Current PET and fMRI studies are reviewed in reference to van der Kolk and colleagues’ [1] organizing psychologic constructs: primary, secondary, and tertiary dissociation. We believe the distinctive neural correlates of primary and secondary dissociative experiences, observed in response to reminders of previous psychologic trauma in individuals who have posttraumatic stress disorder (PTSD), support state-phase models of animal defensive reaction to external threat [2,3]. Furthermore, disconnection of neural pathways normally linking self-awareness with emotional body-state perception could occasion the development of dissociative identities in traumatized children.