Validating MEG estimated resting-state connectome with intracranial EEG

The ill-posed nature and low spatial resolution of EEG/magnetoencephalography (MEG) source imaging affects functional connectivity estimates, which become more complicated in the resting state due to the low signal-to-noise ratio. Several connectivity metrics have been proposed to address source leakage by removing zero-lag connectivity, although this can eliminate true neuronal zero-lag connections. Intracranial EEG (iEEG) is the gold standard for validating noninvasive measurements. In this study, we validated MEG-estimated connectivity for healthy subjects using the iEEG atlas of normal brain activity (Frauscher et al., 2018) as ground truth at a group level. We employed two amplitude-based metrics and two phase-based metrics. Our findings highlight how MEG connectivity compares with the iEEG atlas and provide valuable insights for resting-state EEG/MEG connectomic studies, particularly in the choice of connectivity metrics.