Electrophysiological and fMRI signals show consistent global propagations across the cortical hierarchy

Infra-slow (<0.1 Hz) propagating structures have been found in resting-state fMRI. Nevertheless, the neural origin of the infra-slow rsfMRI propagations remains unclear. Besides, the study of propagating activity using fMRI cannot ignore a series issue that the brain has spatial heterogeneity of hemodynamic delays. Here, to address the questions, we combined human rsfMRI and monkey electrophysiology data and found similar propagations swiping the cortex in two opposite directions along an axis of cortical hierarchy. The cross-hierarchy ECoG propagations are frequency-dependent and present only in the gamma-band power.