Techniques of evaluation were studied of the EEG synchronization between different EEG derivations in humans. It was shown that the pattern of cortical cooperativity constructed on the basis of classical EEG crosscorrelation and coherence could be substantially supplemented with estimations of coincidences of the moments of sharp changes (MSC) in multichannel EEG recording (the so called "operational synchronization"). The multichannel EEG was recorded in humans during memory task performance. A non-parametric technique was developed on the basis of the family of Kolmogorov-Smirnov's statistics for revealing the MSC in separate EEG realizations and subsequent spatial-temporal mapping of the MSC coincidences in different derivations of the multichannel EEG. It was shown that such maps markedly change depending on the current cognitive activity of the subjects. An attempt was made to interpret the estimations of the frequency and operational synchronization of multichannel human EEG.