Alteration of brain default network in subacute phase of injury in concussed individuals: Resting-state fMRI study

Abstract

There are a number of symptoms, both neurological and behavioral, associated with a single episode of r mild traumatic brain injury (mTBI). Neuropsychological testing and conventional neuroimaging techniques are not sufficiently sensitive to detect these changes, which adds to the complexity and difficulty in relating symptoms from mTBI to their underlying structural or functional deficits. With the inability of traditional brain imaging techniques to properly assess the severity of brain damage induced by mTBI, there is hope that more advanced neuroimaging applications will be more sensitive, as well as specific, in accurately assessing mTBI. In this study, we used resting state functional magnetic resonance imaging to evaluate the default mode network (DMN) in the subacute phase of mTBI. Fourteen concussed student-athletes who were asymptomatic based upon clinical symptoms resolution and clearance for aerobic exercise by medical professionals were scanned using resting state functional magnetic resonance imaging. Nine additional asymptomatic yet not medically cleared athletes were recruited to investigate the effect of a single episode of mTBI versus multiple mTBIs on the resting state DMN. In concussed individuals the resting state DMN showed a reduced number of connections and strength of connections in the posterior cingulate and lateral parietal cortices. An increased number of connections and strength of connections was seen in the medial prefrontal cortex. Connections between the left dorso-lateral prefrontal cortex and left lateral parietal cortex showed a significant reduction in magnitude as the number of concussions increased. Regression analysis also indicated an overall loss of connectivity as the number of mTBI episodes increased. Our findings indicate that alterations in the brain resting state default mode network in the subacute phase of injury may be of use clinically in assessing the severity of mTBI and offering some insight into the pathophysiology of the disorder.

Significant Improvements in Cognitive Performance Post-Transcranial, Red/Near-Infrared Light-Emitting Diode Treatments in Chronic, Mild Traumatic Brain Injury: Open-Protocol Study

“…Failure to properly modulate the DMN during cognitive tasks that require rapid shifting of attention and inhibition has also been observed in other studies with TBI cases. [58][59][60][61] For the five mTBI participants in the present study who entered with below-average Stroop inhibition switching scores, but who also improved by at least + 1 to + 4.5 SD post-LED, it is possible that nodes within the SN and/or the DMN were impacted post-LED, thus improving function and/or connections among these nodes. It is also possible that the red/NIR photons affected the DLPFC as well as the anterior cingulate cortex (ACC), both of which have been shown to be active during functional imaging studies of the Stroop effect.…”

Redirecting N-acetylaspartate metabolism in the central nervous system normalizes myelination and rescues Canavan disease

“…allows the detection of functional changes in the CNS after traumatic brain injury where conventional MRI is incapable of showing any pathology (17)(18)(19). In preclinical rodent models, fMRI is primarily used to study brain function in a neuroscience setting (20).…”

Sports-related brain injuries: connecting pathology to diagnosis

“…Another study examined the connectivity of the default mode network of 29 collegiate student athletes, 14 of whom had suffered a previous concussion. 63 Although each athlete was asymptomatic, fMRI and voxel-based correlation analysis revealed a significant decreased connectivity of the default mode network, which consists of the precuneus/posterior cingulate cortex; medial prefrontal cortex; and medial, lateral, and inferior parietal cortex. The magnitude of connectivity aberrations was also correlated with the number of concussions.…”