Concurrent EEG- and fMRI-derived functional connectomes exhibit linked dynamics

Connectivity across distributed brain regions commonly measured with functional Magnetic Resonance Imaging (fMRI) exhibits infraslow (<0.1Hz) spatial reconfigurations of potentially critical importance to cognition. Cognitively relevant neural communication, however, employs synchrony at fast speeds. It is unclear how fast oscillation-coupling across the whole-brain connectome relates to connectivity changes in fMRI, an indirect measure of neural activity. In two datasets, electroencephalography (EEG) revealed that synchronization in all canonical oscillation-bands reconfigures at infraslow speeds, coinciding with connectivity changes in concurrently recorded fMRI in corresponding region-pairs. The cross-modal tie of connectivity dynamics was widely distributed across the connectome irrespective of EEG frequency-band. However, the cross-modal tie was strongest in visual to somatomotor connections for slower EEG-bands, and in connections involving the Default Mode Network for faster EEG-bands. The findings provide evidence that functionally relevant neural synchrony in all oscillation-bands slowly reconfigures across the whole-brain connectome, and that fMRI can reliably measure such dynamics.