Disrupted brain functional hub and causal connectivity in acute mild traumatic brain injury.

Fengfang Li,Peng Wang,Yu-Chen Chen,Hong Zhang,Xindao Yin,Huiyou Chen,Liyan Lu

doi:10.18632/aging.102484

Abstract

There have been an increasing number of functional magnetic resonance imaging (fMRI) reports on brain abnormalities in mild traumatic brain injury (mTBI) at different phases. However, the neural bases and cognitive impairment after acute mTBI are unclear. This study aimed to identify brain functional hubs and connectivity abnormalities in acute mTBI patients and their correlations with deficits in cognitive performance. Within seven days after brain injury, mTBI patients (n=55) and age-, sex-, and educational -matched healthy controls (HCs) (n=41) underwent resting-state fMRI scans and cognitive assessments. We derived functional connectivity (FC) strength of the whole-brain network using degree centrality (DC) and performed Granger causality analysis (GCA) to analyze causal connectivity patterns in acute mTBI. Compared with HCs, acute mTBI patients had significantly decreased network centrality in the left middle frontal gyrus (MFG). Additionally, acute mTBI showed decreased inflows from the left MFG to bilateral middle temporal gyrus (MTG), left medial superior frontal gyrus (mSFG), and left anterior cingulate cortex (ACC). Correlation analyses revealed that changes in network centrality and causal connectivity were associated with deficits in cognitive performance in mTBI. Our findings may help to provide a new perspective for understanding the neuropathophysiological mechanism of acute cognitive impairment after mTBI.

Highlights

Traumatic brain injury (TBI) is a traumatic brain structural injury or an injury in which other changes in brain function caused by external forces occur; TBI is a major reason for sustained disability and morbidity, both in military populations and civilians [1]
The degree centrality (DC) abnormalities in the left middle frontal gyrus (MFG) and the disrupted causal connectivity between left anterior cingulate cortex (ACC) and left MFG were significantly correlated with cognitive function performance in Mild TBI (mTBI) patients at the acute stage
Our findings showed significantly decreased DC in the left MFG region of mTBI patients than in that of healthy controls (HCs), suggesting that the left MFG is the main brain functional hub affected by acute mTBI, which is consistent with the hypothesis that the dysconnectivity pattern of the prefrontal cortex (PFC) is involved in acute mTBI

Summary

Introduction

Traumatic brain injury (TBI) is a traumatic brain structural injury or an injury in which other changes in brain function caused by external forces occur; TBI is a major reason for sustained disability and morbidity, both in military populations and civilians [1]. Mild TBI (mTBI) is the most common type of traumatic brain injury, representing 80%–90% of TBI cases [2]. Many mTBI patients may develop a wide range of cognitive deficits, such as deficits in executive function, attention, and working memory [3, 4]. Most mTBI patients recover quickly, approximately 10%-15% of patients have disabling problems that persist for a long time [5]. To date, no obvious structural damage has been identified in mTBI patients when using traditional brain imaging techniques (i.e., computed tomography (CT) and magnetic resonance imaging (MRI)) [6]. The cognitive problems of many mTBI patients may be underrated and have a substantial impact on the patients’ lives and social interactions. The pathophysiologic mechanisms of mTBI that cause the disorder to be persistent remain poorly understood

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