ИСТИНА

Computation of equivalent current dipoles based on multichannel EEC data and their superposition onto slices of structural MRI for an individual human brain was used to identify localization of activated frequency-selective gamma (30-75 Hz), beta (14-29 Hz) and theta (4-7 Hz) generators in experiments with working memory.The subject has to memorize four pairs of two-digit numbers that are visually-presented and retain them during a delay interval for the subsequent comparison with target and no-target stimuli for performing motor reaction on target stimuli. Activity level in the frontal area during the perception stage was higher than during the retention interval.During the delay period the maximum activity of high-frequency generators was shifting from a frontal to an associative cortex and the cerebellum. The join activity of frequency-selective gamma and beta generators periodically appears in the frontal,visual and temporal cortex during the delay interval.Using the weighed centroid method for clusterization of neural dipole sources supported periodic fluctuations of join activity of gamma, beta, and theta generators. Our finding highlights the role of frequency-selective generators in the sub-function of visual working memory - the retention of memory traces in active form for future use in behavior.