New Principal Investigators 12

The discovery that networks of brain regions show correlated spontaneous activity at rest has generated a large amount of interest, both in characterizing these networks and in understanding their relationship to cognition and disease states. One application of resting-state fMRI connectivity data has been to use automated clustering of voxels, based on correlations with other brain regions, in order to identify functional networks in the brain, or functional modules within specific brain regions. However, the relationship between networks identified at rest or during task states remains unclear. Some studies suggest that as the brain moves between rest and task states, changes in functional connectivity occur principally by modulating connections within networks, while other studies suggest that specific 'hub' regions dynamically switch between, or link, networks under different task conditions. In order to investigate the stability of network topography during rest relative to task, the present study used automated clustering applied to fMRI data acquired during rest and a task requiring continuous visual attention, in the same 16 healthy young adult participants. While broadly similar networks were identified in these two conditions, some regions, including portions of precuneus and the inferior parietal lobule, switched between networks under different task conditions in a consistent manner across individuals. These findings suggest that the topography of functional networks is dynamic and that functional modules defined solely based on resting-state connectivity should be interpreted with caution.