Neurophysiologic techniques have also been used to probe functional connectivity in the human brain. Compared with fMRI, EEG and magnetoencephalography (MEG) have poorer spatial resolution (millimeters for fMRI vs centimeters for EEG/MEG), but superior temporal resolution (milliseconds for EEG/MEG vs seconds for fMRI). Consequently, EEG and MEG permit study of temporal dynamics across a much broader bandwidth (on the order of order of 1–100Hz for EEG vs 0.001–0.5Hz for fMRI). Functional networks derived from fMRI data may thus in principle be more easily and directly related to precise anatomical structures, while EEG / MEG signals more directly reflect neuronal activity.
