Distinct Sets of Internal, External, and Control Connector Hubs Integrate Human Brain Function

Control over behavior is enabled by the brain's control networks, which interact with lower-level processing networks to regulate their functions. Such interactions are facilitated by specialized "connector hub" regions that interconnect discrete networks. Previous work has treated hubs as a single category of brain regions, though their unitary nature is dubious when examined in individual brains. Here, we investigated the nature of hubs by using functional magnetic resonance imaging to characterize individual-specific hub regions in two independent datasets. We identified separable sets of Internal, External, and Control connector hubs that integrate information between specific brain networks. These three hub categories occupy different positions within the brain's network structure; they impact networks differently when artificially lesioned; and they are differentially engaged during cognitive and motor task performance. This work suggests a model of brain organization in which different connector hubs integrate control functions and enable top-down control of separate processing streams.