Topographic mapping of rapid transitions in EEG multiple frequencies: EEG frequency domain of operational synchrony

This paper describes for the first time the phenomenon of spatio-temporal mapping of interchannel temporal coincidences of rapid transition processes (RTPs) in multiple EEG frequencies. It is suggested that RTPs in multiple EEG frequencies found in different EEG channels could reflect the process of switching between brain operations performed by different neuronal assemblies. Systematic non-random temporal coincidences among RTPs found in those EEG channels could reflect functional (operational) synchrony. However, until now there have been no studies examining the existence of systematic RTPs synchronization among different EEG channels in a frequency domain. Therefore functional synchrony based on precise (point to point) temporal coincidence of RTPs found in different EEG channels and comparison with surrogate data were estimated. Findings of the present study demonstrated for the first time that non-random temporal coincidence of RTPs in EEG multiple frequencies exist for both closed and open eyes conditions. Each of the states had its own distinguished peculiarities. Similarity of the main peculiarities of operational synchrony found in EEG frequency domain (the present study) with EEG amplitude and phase domains (previous studies) permitted us to conclude that operational synchrony is a universal phenomenon in brain activity. Therefore, patterns of interaction between the cortical areas, which are usually calculated with classical cross-correlation and coherence analysis, may be complemented with operational synchrony.