The study explores how distinct control networks in the brain develop through segregation and integration during childhood and adolescence. Using resting-state functional connectivity MRI (rs-fcMRI), the researchers compared the brain networks of children, adolescents, and adults. They found that as children grow, their brain networks undergo changes, with some regions becoming more segregated and others more integrated. In adults, two distinct control networks—frontoparietal and cinguloopercular—are identified. The frontoparietal network is involved in adaptive, trial-by-trial control, while the cinguloopercular network supports stable task sets. The study shows that in children, these networks are more interconnected, with regions like the dorsal anterior cingulate/medial superior frontal cortex (dACC/msFC) and the anterior insula/frontal operculum (aI/fO) connecting both networks. As children age, the dACC/msFC becomes more integrated into the cinguloopercular network, while the frontoparietal network strengthens its connections. This suggests that the brain's control networks develop through a process of segregation and integration, with long-range connections increasing and short-range connections decreasing with age. The findings indicate that the development of these networks is crucial for cognitive control functions such as attention, working memory, and task switching. Disruptions in this developmental process may contribute to disorders of control, such as autism, attention deficit hyperactivity disorder, and Tourette's syndrome. The study also highlights the importance of spontaneous neural activity and experience-dependent evoked activity in shaping these networks. The results suggest that the brain's ability to maintain task goals, selectively attend to relevant information, and avoid distraction is supported by these dynamic networks, which evolve through segregation and integration during development.The study explores how distinct control networks in the brain develop through segregation and integration during childhood and adolescence. Using resting-state functional connectivity MRI (rs-fcMRI), the researchers compared the brain networks of children, adolescents, and adults. They found that as children grow, their brain networks undergo changes, with some regions becoming more segregated and others more integrated. In adults, two distinct control networks—frontoparietal and cinguloopercular—are identified. The frontoparietal network is involved in adaptive, trial-by-trial control, while the cinguloopercular network supports stable task sets. The study shows that in children, these networks are more interconnected, with regions like the dorsal anterior cingulate/medial superior frontal cortex (dACC/msFC) and the anterior insula/frontal operculum (aI/fO) connecting both networks. As children age, the dACC/msFC becomes more integrated into the cinguloopercular network, while the frontoparietal network strengthens its connections. This suggests that the brain's control networks develop through a process of segregation and integration, with long-range connections increasing and short-range connections decreasing with age. The findings indicate that the development of these networks is crucial for cognitive control functions such as attention, working memory, and task switching. Disruptions in this developmental process may contribute to disorders of control, such as autism, attention deficit hyperactivity disorder, and Tourette's syndrome. The study also highlights the importance of spontaneous neural activity and experience-dependent evoked activity in shaping these networks. The results suggest that the brain's ability to maintain task goals, selectively attend to relevant information, and avoid distraction is supported by these dynamic networks, which evolve through segregation and integration during development.