The role of coupling among brain regions between the default mode network and the “Mesocircuit” Model in arousal in disorders of consciousness

Introduction This study examined the association between inter-regional functional connectivity (FC) strength and arousal, and explored how interactions between the default mode network (DMN) and the brain regions of the “Mesocircuit” Model influence consciousness generation and recovery in patients with disorders of consciousness (DoC). Methods Thirty DoC patients [eight in coma, 10 in vegetative state (VS), 12 in minimally conscious state (MCS)] from the Department of Neurosurgery, Shaanxi Provincial People's Hospital underwent resting-state functional magnetic resonance imaging. Seed regions included DMN cores [posterior cingulate cortex (PCC), medial prefrontal cortex (mPFC) and the “Mesocircuit” Model core external globus pallidus (GPe)]; FC and correlation analyses were performed. Results Results showed that compared with VS/MCS groups, the coma group had weaker FC between PCC and left anterior cingulate gyrus/right middle temporal gyrus/GPe, and between mPFC and right superior frontal gyrus/left supramarginal gyrus/GPe, but stronger FC between mPFC/PCC and bilateral central lateral thalamus (CL). For GPe-seeded FC, the coma group had reduced FC with DMN nodes (PCC/mPFC) and left CL, but increased FC with right CL. Correlation analysis revealed positive associations of PCC-mPFC, PCC-GPe, mPFC-GPe, and GPe-CL_L FC with CRS-R/GCS scores, and negative associations of PCC-CL, mPFC-CL, and GPe-CL_R FC with these scores. Conclusion The functional integrity of the DMN and the “Mesocircuit” Model, as well as the FC between their brain regions, are closely related to the consciousness level of patients with DoC. PCC-GPe, PCC-mPFC, GPe-CL_L, and PCC-CL FC may serve as neurobiological markers for DoC diagnosis and prognosis, aiding precise management.