Background: Investigation of the neural substrates of post-traumatic stress disorder (PTSD) in military personnel using whole-brain approaches remains scarce, hindering the development of circuit-based neuromodulatory interventions.
Objectives: This study aimed to identify potential associations between clinical symptoms and whole-brain resting-state functional connectivity with magnetic resonance imaging in military personnel with adulthood-onset war-related PTSD.
Methods: Thirty-seven soldiers from the Canadian Armed Forces with moderate to severe treatment-resistant PTSD participated in this study. We assessed PTSD, anxiety and depressive symptoms, quality of life, and time since trauma. We characterized the whole-brain functional connectome using independent component analysis and regions of interest (ROI)-to-ROI connectivity, as well as its topology using graph theory.
Results: Greater severity of PTSD and anxiety symptoms was associated with lower connectivity (r < 0) between the default mode network (DMN) and frontoparietal network. Greater severity of PTSD symptoms was also associated with a higher nodal clustering coefficient of the inferior parietal lobule from the DMN. Greater severity of anxiety symptoms and longer time since trauma was the only clinical variables that correlated with higher connectivity patterns, all involving the visual networks (the frontoparietal-visual, the visual-DMN, and within-visual networks).
Conclusions: This work contributes to identifying brain targets for the development of personalized neuromodulatory interventions. In particular, the DMN may be a promising target to alleviate PTSD symptoms, and the visual network may be a target to treat comorbid anxiety symptoms.
Keywords: anxiety; fMRI; post-traumatic stress disorder.