Changes in intrinsic functional brain networks following blast-induced mild traumatic brain injury

Abstract

Objective: Blast-induced mild traumatic brain injuries (mTBI) commonly go undetected by computed tomography and conventional magnetic resonance imaging (MRI). This study was used to investigate functional brain network abnormalities in a group of blast-induced mTBI subjects using independent component analysis (ICA) of resting state functional MRI (fMRI) data.

Methods: Twenty-eight resting state networks of 13 veterans who sustained blast-induced mTBI were compared with healthy controls across three fMRI domains: blood oxygenation level-dependent spatial maps, time course spectra and functional connectivity.

Results: The mTBI group exhibited hyperactivity in the temporo-parietal junctions and hypoactivity in the left inferior temporal gyrus. Abnormal frequencies in default-mode (DMN), sensorimotor, attentional and frontal networks were detected. In addition, functional connectivity was disrupted in six network pairs: DMN–basal ganglia, attention–sensorimotor, frontal–DMN, attention–sensorimotor, attention–frontal and sensorimotor–sensorimotor.

Conclusions: The results suggest white matter disruption across certain attentional networks. Additionally, given their elevated activity relative to controls', the temporo-parietal junctions of blast mTBI subjects may be compensating for diffuse axonal injury in other cortical regions.

• Blast
• cognition
• functional magnetic resonance imaging (fMRI)
• independent component analysis (ICA)
• mild traumatic brain injury (mTBI)
• resting state networks (RSN)

Acknowledgements

The authors would like to thank Dr Larry E. Davis for his help in subject recruitment from the Veterans Affairs Hospital, as well as the National Library of Medicine for the use of its Visible Human data.