Evidence for disrupted gray matter structural connectivity in posttraumatic stress disorder

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Posttraumatic stress disorder (PTSD) is linked to structural changes in the brain's prefrontal-limbic network.
• Understanding how these structural changes affect brain connectivity is crucial for PTSD research.

Purpose of the Study:

• To investigate the association between atrophy in the prefrontal-limbic network and impaired structural connectivity in PTSD.
• To determine how this network's integration with the whole brain is affected by atrophy in PTSD.

Main Methods:

• Volumetric MRI scans were performed on 85 male veterans (45 PTSD negative, 40 PTSD positive).
• Manual labeling and FreeSurfer were used for subfield volumes, cortical thickness, and subcortical volumes.
• Graph analysis using the Graph Analytical Toolbox (GAT) assessed structural connectivity.

Main Results:

• PTSD positive individuals showed thinner rostral anterior cingulate and insular cortex, but no hippocampal volume loss.
• Graph analysis revealed altered nodal properties (degree, clustering coefficient, betweenness) in the prefrontal-limbic network and reduced small-worldness in whole-brain analysis.
• Atrophy in PTSD led to increased structural connectivity within the prefrontal-limbic network, negatively impacting its integration with the broader brain network.

Conclusions:

• Structural atrophy in PTSD is associated with altered connectivity within the prefrontal-limbic network.
• These alterations within the network paradoxically increase local connectivity, hindering its functional integration with the rest of the brain.
• Findings highlight the complex impact of PTSD-related brain changes on neural network dynamics.