The fragmentation of self and others: The role of the Default Mode Network in post-traumatic stress disorder

In Post-Traumatic Stress Disorder (PTSD), social and emotional dysfunction has been interpreted as a secondary consequence of the broad impact of amygdala and fear circuitry dysregulation. However, research in social neuroscience has uncovered a number of neural systems involved in attachment and emotional regulation that may be impacted by trauma. One example is the Default Mode Network (DMN), which is implicated in human beings’ sense of self and ability to connect with others. This qualitative study explored the impact of physical and emotional traumata on the structures and functions of the DMN. The goal was to determine if dysregulation of the DMN could account for aspects of the psychological and social dysfunction found in PTSD. This study explored the following two questions: 1. What does the research literature tell us about the role of the DMN? 2. How does trauma impact DMN functioning? The DMN has been associated primarily with autobiographical recall, self-referential processing, social cognition, prospection, and moral sensitivity. The DMN appears to support internal reflective capacity, further maintaining and connecting self-functions and social cognition. Trauma results in internetwork rigidity, as well as overall reductions in DMN activity, volume, and connectivity. These objective changes result in a Traumatized Resting State (TRS), characterized by increased Salience Network connectivity and reductions in Central Executive functioning. Studies suggest that a TRS develops in reaction to acute trauma, even before the development of PTSD, and may continue despite the stabilization of other networks. Overall, DMN incoherence significantly disrupts core psychosocial processes