The paper presents data on the formation of spatial synchronization of brain potentials in 91 children aged 7-18 years living in European North of Russia. We estimated coherence values for 19 derivations (pair 171) in five EEG frequency bands (delta, theta, alpha-1, alpha-2 and beta). We described age-related changes, gender differences and topical specific features of the formation of coherence in the left and right hemispheres, and in inter- and intrahemispheric synchronization. We carried out computer assessment of the differences in EEG coherence between three age groups of children in order to determine criteria for identification of children with retarded formation of spatial organization of local EEG processes. Age-related changes in the structure of EEG patterns observed in the study reflect the processes of morphofunctional brain development in children and adolescents at different stages of postnatal ontogenesis under severe conditions of northern climate.