The new method of microstructure analysis of oscillatory brain activity was pro­posed for studying the structure and dynamics of working memory. Mapping local network activity according to dipole localization of frequency-selective gamma and beta generators supports the leading role of frontal areas in processes of working memory. The retention of information during the delay interval is presented by joint activity of frequency-selective gamma and beta generators which provide the integration of frontal areas, associative, visual cortex and cerebellum. The joint activity of the gamma- and beta-generators has a wave-like character and is modulated by low-frequency wave activity.