Development of top-down cortical propagations in youth

Hierarchical processing requires activity propagating between higher- and lower-order cortical areas. However, functional neuroimaging studies have chiefly quantified fluctuations within regions over time rather than propagations occurring over space. Here, we leverage advances in neuroimaging and computer vision to track cortical activity propagations in a large sample of youth (n = 388). We delineate cortical propagations that systematically ascend and descend a cortical hierarchy in all individuals in our developmental cohort, as well as in an independent dataset of densely sampled adults. Further, we demonstrate that top-down, descending hierarchical propagations become more prevalent with greater demands for cognitive control as well as with development in youth. These findings emphasize that hierarchical processing is reflected in the directionality of propagating cortical activity and suggest top-down propagations as a potential mechanism of neurocognitive maturation in youth. •Cortical activity systematically propagates up and down a cortical hierarchy•Bottom-up and top-down propagations are common in all participants across datasets•Top-down propagations are more common during cognitive demands•Top-down propagations become more prominent with development in youth Hierarchical processing requires activity propagating between higher and lower-order cortical areas. However, neuroimaging studies have chiefly quantified fluctuations within fixed regions over time rather than propagations over space. We used recent advances in neuroimaging and computer vision to demonstrate that top-down propagations become more prominent during task demands and over neurodevelopment.