Spatiotemporal brain dynamics in 8-to-9-year-old children: A comparative study between preterm and term...

Preterm birth disrupts critical phases of brain maturation, placing individuals at increased risk for long-term cognitive and functional impairments. This study investigated how very preterm birth affects the spatial and temporal organization of functional brain networks in school-aged children born very preterm using a spatiotemporal connectome framework. Multimodal MRI, including diffusion-weighted imaging and resting-state fMRI, was acquired from 25 children born before 30 gestational weeks and 25 age- and sex-matched full-term controls (8-9 years). We characterized the structure-function coupling of dynamic brain activity through Connected Components (CCs) defined as structurally constrained sets of functionally co-active regions identified on a multilayer graph. Three different metrics were computed: CC number (count of distinct co-activation patterns), CC height (peak number of regions within a CC, representing the spatial extent) and CC width (temporal span across consecutive time repetitions (TRs)). In addition, we quantified System Diversity (SD) and Spatiotemporal Diversity (STD), indices reflecting integrative richness and temporal variability of functional network dynamics. CC number decreased with age across groups, reflecting typical developmental patterns, while CC height was significantly greater in preterm children and positively associated with processing speed, suggesting altered or compensatory network co-activation. No significant group differences were observed for SD metrics. However, network-level analyses revealed significantly lower STD values in all functional networks in the preterm group, indicating possible heightened temporal stability and reduced functional flexibility. These findings suggest that very preterm birth selectively alters the dynamic engagement of functional systems, with potential implications for cognitive vulnerabilities. (243 mots; 250 max).