Altered topological organization of the brain functional networks in children with intellectual disability.

Intellectual disability (ID) is one of the most serious developmental disorders of children, characterized by significant limitations in intellectual function and adaptive behaviors. However, topological alterations of functional brain networks in children with ID remain unclear. This study combined resting-state functional MRI (rs-fMRI) data and graph theory analysis to quantify the topological properties of functional brain networks in children with ID. Thirty-four children diagnosed with ID and twenty-eight sex-, age-, and education-matched healthy controls (HC) were included. Global, modular and nodal characteristics were calculated to investigate ID-related alterations in functional brain networks. Compared with HCs, decreased clustering coefficient and local efficiency were revealed in children with ID, indicating reduced functional segregation. At the nodal level, children with ID exhibited nodal alterations concentrated in the ventral attention network (VAN), particularly in the left middle cingulate gyrus and bilateral insula, together with nodes in the dorsal attention network (DAN) and the subcortical network (SubN). At an uncorrected threshold, modular connectivity analysis revealed exploratory decreases of subcortical-cortical connectivity between SubN and the somato-motor network (SMN), between the SubN and VAN, between the SubN and frontoparietal network (FPN), and between the SMN and VAN, as well as altered connector and provincial hub indices across the default mode, limbic, frontoparietal, visual and subcortical networks in the ID group. Together, our findings provided preliminary multi-level evidence of functional network reorganization spanning subcortical, sensory, attention, and control systems in children with ID, providing new insights into the topological organization of the cognitive dysfunction in ID.