Multiple resting state network functional connectivity abnormalities in mild traumatic brain injury

Abstract

Several reports show that traumatic brain injury (TBI) results in abnormalities in the coordinated activation among brain regions. Because most previous studies examined moderate/severe TBI, the extensiveness of functional connectivity abnormalities and their relationship to postconcussive complaints or white matter microstructural damage are unclear in mild TBI. This study characterized widespread injury effects on multiple integrated neural networks typically observed during a task-unconstrained "resting state" in mild TBI patients. Whole brain functional connectivity for twelve separate networks was identified using independent component analysis (ICA) of fMRI data collected from thirty mild TBI patients mostly free of macroscopic intracerebral injury and thirty demographically-matched healthy control participants. Voxelwise group comparisons found abnormal mild TBI functional connectivity in every brain network identified by ICA, including visual processing, motor, limbic, and numerous circuits believed to underlie executive cognition. Abnormalities not only included functional connectivity deficits, but also enhancements possibly reflecting compensatory neural processes. Postconcussive symptom severity was linked to abnormal regional connectivity within nearly every brain network identified, particularly anterior cingulate. A recently developed multivariate technique that identifies links between whole brain profiles of functional and anatomical connectivity identified several novel mild TBI abnormalities, and represents a potentially important new tool in the study of the complex neurobiological sequelae of TBI.

Multi-Modal Approach for Investigating Brain and Behavior Changes in an Animal Model of Traumatic Brain Injury

“…Recently added 6,22,23 to the conventional MRI techniques used in clinical TBI studies, [24][25][26][27] FC has just begun to investigate potential damage to specific interregional neural connections generated by mild to moderate TBI. 6,28,29 rsFC imaging, in the present study, detected discrete differences in connectivity strength between selective brain areas of the rats with TBI from the time of initial injury to the study end-point. Consistent with our cognitive behavioral measurement, disrupted connectivity was observed immediately after injury.…”

Altered cross-frequency coupling in resting-state MEG after mild traumatic brain injury

“…This linkage supports the assumption that ICN function is vulnerable to the effects of mTBI, considering that diffuse axonal injury (DAI) usually damages long-distance white-matter tracts that connect key brain areas (known as hubs) in these networks (Smith et al, 2003;Gentleman et al, 1995). ICN abnormalities after TBI have been widely observed in resting-state fMRI, demonstrating both increase and decrease of connectivity in a number of networks, including the default mode network (DMN) and salience network (SN) (Sharp et al, 2011;Stevens et al, 2012). Several studies have also reported that these abnormalities correlate with cognitive impairment or post-concussive symptoms (Messe et al, 2013;Caeyenberghs et al, 2014).…”

Functional brain network modularity predicts response to cognitive training after brain injury

“…30 Modular network organization may be of particular importance for patients with acquired brain injuries. Theoretical work suggests that modularity constrains the flow of information across the brain 2 and enhances the ability of networks to rapidly reconfigure in response to environmental influences and tasks.…”