Decreases in white matter integrity of ventrolimbic pathway linked to posttraumatic stress disorder in mild traumatic brain injury.
Post-traumatic stress disorder (PTSD) is commonly observed in military service members with mild traumatic brain injury (mTBI); however, the relationship between mTBI and PTSD is complex and not well-understood. The present study aims to elucidate a link between the degree of alteration in limbic system-related white matter tracts and PTSD symptoms in an mTBI population. Diffusion tensor imaging with probabilistic tractography of the fronto-limbic pathways revealed decreased white matter integrity in the uncinate fasciculus in those with comorbid mTBI and PTSD (n=34), relative to those with only mTBI (n=35). Additionally, fractional anisotropy and radial diffusivity measures in the bilateral uncinate fasciculus correlated with PTSD checklist (PCL-C) scores, and primarily within the avoidance and re-experiencing domains. Findings from this study suggest the degree of traumatic injury within the limbic system could be directly related to post-traumatic stress and post-concussive symptoms, with disrupted white matter leading to significant PTSD outcomes.