The 1st and 2nd derivatives of the time series of instantaneous phase-differences was calculated for all pair wise combinations of DMN voxels in the x, y, and z direction in order to detect instantaneous advancements and reductions of phase-differences. The same mathematical procedures published for measuring phase shift and phase lock duration of the scalp surface EEG were used for the computation of PR of the LORETA time series (Thatcher et al., 2008a, 2009a,b).
