Brain State Dynamics in Ketamine-Induced Dissociation Resemble Those in Posttraumatic Stress Disorder

Area of Science:

• Neuroscience
• Psychiatry
• Computational Biology

Background:

• Dissociation, a detachment from self and environment, is a key feature of posttraumatic stress disorder (PTSD).
• The neurocognitive underpinnings of dissociation are not well understood, hindering PTSD diagnosis and treatment.
• Understanding these mechanisms is crucial for improving therapeutic outcomes in PTSD.

Purpose of the Study:

• To investigate the neural dynamics of dissociative states using network control theory.
• To compare brain activity during ketamine-induced dissociation in healthy volunteers with that in patients with PTSD.
• To examine the effects of an intervention for dissociative symptoms in PTSD patients.

Main Methods:

• Applied network control theory to resting-state functional magnetic resonance imaging (fMRI) data.
• Studied 30 healthy volunteers receiving ketamine and 78 PTSD patients undergoing treatment.
• Analyzed changes in default mode network (DMN) and somatomotor network (SOM) meta-states and brain entropy.

Main Results:

• Ketamine-induced dissociation mirrored brain dynamics in treatment-naïve PTSD patients, showing increased DMN and decreased SOM meta-state dominance.
• Reduced DMN dominance post-treatment in PTSD patients correlated with decreased dissociative symptoms.
• Post-treatment, PTSD patients displayed more organized, less entropic brain states, though ketamine did not significantly alter entropy.

Conclusions:

• Dissociative states, whether pharmacologically induced or clinically present, share common neural characteristics.
• These states are marked by a heightened dominance of the DMN meta-state and a reduced dominance of the SOM meta-state.
• Interventions targeting dissociative symptoms in PTSD may restore more organized neural dynamics.