Oscillatory mechanisms of intrinsic brain networks

Neuroimaging studies of hemodynamic fluctuations have shown specific network-based organization of the brain at rest, yet the neurophysiological underpinning of these networks in human brain remain unclear. Here, we recorded resting-state activities of neuronal populations in the key regions of default mode network (DMN, posterior cingulate cortex and medial prefrontal cortex), frontoparietal network (FPN, dorsolateral prefrontal cortex and inferior parietal lobule), and salience network (SN, anterior insula and dorsal anterior cingulate cortex) from 42 human participants using intracranial electroencephalogram (iEEG). We observed stronger within-network connectivity of the DMN, FPN and SN in broadband iEEG power, stronger phase synchronization within the DMN across theta and alpha bands, and weaker phase synchronization within the FPN in delta, theta and alpha band. We also found positive power correlations in high frequency band (70-170Hz) and negative power correlations in alpha and beta band for FPN-DMN and FPN-SN. Robust negative correlations in DMN-SN were found in alpha, beta and gamma band. These findings provide intracranial electrophysiological evidence in support of the network model for intrinsic organization of human brain and shed light on the way how the brain networks communicate at rest.