Changes of inter-hemispheric functional connectivity between motor cortices after brachial plexuses injury: A resting-state fMRI study

• Inter-hemispheric FC of the motor areas was compared between patients with BPAI and healthy controls.
• BPAI decreases resting-state inter-hemispheric FC between the two M1 areas.
• Decreased inter-hemispheric FC implies declined efficiency of information transfer and collaboration.

ObjectThe aim of this study is to explore the changes of inter-hemispheric functional connectivity in patients with unilateral brachial plexus injury.MethodsNine patients with five roots of unilateral brachial plexus avulsion injury and 11 healthy controls were recruited in this study. Resting-state functional connectivity magnetic resonance image was used to study the differences of inter-hemispheric functional connectivity between patients and healthy controls. Four areas were defined as regions of interest (ROI): the two primary motor areas (M1 areas) and two supplementary motor areas (SMAs) in the two hemispheres activated when the healthy controls performed unilateral hand grasping movement of the two hands, respectively. Functional connectivity maps were generated by correlating the regional time course of each ROI with that of every voxel in the whole brain. Then, functional connectivity was calculated by correlating the functional magnetic resonance image signal time courses of every two ROIs.ResultsResting-state inter-hemispheric functional connectivity of the primary motor areas was reduced following brachial plexus avulsion injury. The correlation coefficients of the SMAs showed no difference between the brachial plexus patients and healthy volunteers.ConclusionsOur results indicate that brachial plexus injury decreases resting-state inter-hemispheric functional connectivity of the two primary motor areas. These results provide new insight into functional reorganization of the cerebral cortex after brachial plexus injury.