The article discusses the mechanism concerning generation of gamma-oscillations. Latest researches demonstrate that gamma-oscillations participate in the realization of different psychological processes, including enhancing attention and changing functional states, perception and working memory, processes of recognition and identification, awareness and semantic operations. The author discusses two hypotheses on the origin of gamma-rhythm: pacemaker and binding. To analyse the problem, the author suggests a special method based on the narrow frequency filtering the so-called evoked gamma-rhythm, localization of their dipole sources over the structural MRI data. The obtained results are compatible with the pacemaker hypothesis.