Comparison of coherence and phase synchronization of the human sleep electroencephalogram

► Coherence and phase synchronization analyses yield practically the same statistical differences between stages of human sleep EEG. ► Coupling between EEG signals is dominated by phase synchronization which turns into complete synchronization in the most strongly coupled EEG signals. ► In gamma band the type of synchronization depends on sleep state, while in other spectral bands it is determined by topographic positions of considered electrodes.