An improved index of phase-synchronization for electrophysiological data in the presence of volume-conduction, noise and sample-size bias

►New measure of phase‐synchronization, the Weighted Phase-Lag-Index. ►Reduced sensitivity to addition of uncorrelated sources. ►Increased sensitivity to detect differences in phase‐synchronization. ►New, unbiased estimator procedure for Phase-Lag‐Index. ►Debiased estimator for Weighted Phase‐Lag‐Index.