Chronic postconcussive symptoms are common after mild traumatic brain injury (mTBI), and are difficult to predict or treat. Thalamic functional integrity is particularly vulnerable in mTBI, and may be related to long-term outcomes, but requires further investigation.
We compared structural magnetic resonance imaging (MRI) and resting state functional MRI in 108 patients with a Glasgow Coma Scale (GCS) of 13 to 15 and normal CT, and 76 controls. We examined whether acute changes in thalamic functional connectivity were early markers for persistent symptoms, and explored neurochemical associations of our findings using data from positron emission tomography.
Of the mTBI cohort, 47% showed incomplete recovery 6 months post-injury. Despite the absence of structural changes, we found acute thalamic hyperconnectivity in mTBI, with specific vulnerabilities of individual thalamic nuclei. Acute fMRI markers differentiated those with chronic postconcussive symptoms, with time- and outcome-dependent relationships in a sub-cohort followed longitudinally. Moreover, emotional and cognitive symptoms were associated with changes in thalamic functional connectivity to known dopaminergic and noradrenergic targets, respectively.
Our findings suggest that chronic symptoms can have a basis in early thalamic pathophysiology. This may aid identification of patients at risk of chronic postconcussive symptoms following mTBI, provide a basis for development of new therapies, and could facilitate precision medicine application of these therapies.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.