Abnormal Resting-State Functional Connectivity in Individuals with Spinal Cord Injury: A Systematic Review

Spinal cord injury (SCI) leads to sensorimotor deficits and secondary health complications, such as pain and cognitive impairment. At the brain level, functional reorganization phenomena occur, affecting resting-state (rs) networks devoted to higher-order information processing. However, most studies have focused on changes of the sensorimotor cortex, and current results are partially conflicting. This systematic review aims to synthesize studies on rs networks implicated in SCI and to investigate whether functional connectivity (FC) is affected beyond the somatomotor network, which may be linked to secondary health conditions. Original seed-based whole-brain rs FC (rsFC) studies comparing individuals with SCI and controls were retrieved from Medline, Embase, and Web of Science (last searched on 02.09.2024). Each seed was assigned to a standard rs network, and studies were grouped based on seed network and direction of changed rsFC. Risk of bias was assessed using the quality assessment tool by the National Heart, Lung, and Blood Institute. The study was registered in Prospero (CRD42024574397). Nine included studies provided 11 datasets (151 SCI individuals, 208 controls). RsFC changes were found between the somatomotor and ventral attentional network, between the ventral attention network and the frontal pole, and between the cerebellum and regions of the attentional and default-mode networks in SCI compared with controls. We propose a model of SCI with widespread network changes that extend beyond the somatomotor network. Our findings call for deeper examination of functional brain changes following SCI in clinical settings and thorough investigations of higher-order cognitive functions.