Effective Connectivity Alterations of Directed Brain Network in Pediatric Patients With Spinal Cord Injury.

AIMS: To investigate the alterations in effective brain connectivity in pediatric patients with spinal cord injury (SCI), to reveal the mechanism of brain network reorganization and to identify potential key targets for therapeutic neuromodulation interventions. METHODS: This study enrolled 37 pediatric patients with SCI (24 with complete SCI, 13 with incomplete SCI) and 37 matched healthy controls. All participants underwent resting-state functional MRI. Independent component analysis was conducted to identify intrinsic brain networks and obtain key regions of interest. Dynamic causal modeling (DCM) was applied to further analyze the effective connectivity (EC). RESULTS: Patients with SCI showed significantly reduced connectivity between the default mode network (DMN) and the salience network (SAN). DCM revealed that the posterior cingulate cortex (PCC) was a key upstream regulator, exerting enhanced inhibitory influence on the medial prefrontal cortex, bilateral insula, and bilateral inferior parietal lobule. Subgroup analyses revealed that complete SCI was associated with increased excitatory drive from the DMN to the SAN, but enhanced inhibitory influence in the reverse pathway compared to incomplete SCI. CONCLUSION: The PCC is a pivotal node in post-SCI brain reorganization, suggesting it as a potential neuromodulation target. The bidirectional DMN-SAN regulatory imbalance is closely related to SCI severity.