UDC

612.825-053.6(470)(045)

Authors

Demin Denis Borisovich, The Institute of Environmental Physiology,Ural Branch of the Russian Academy of Sciences (Arkhangelsk, Russia)

Abstract

Russian polar and circumpolar territories differ in the degree of extremeness of their climate and, thus, serve a natural ground to study physiological adaptation to harsh habitat conditions in various ethnic groups. The nervous system formation in adolescents is largely affected by adverse climatic conditions of the north. This paper studies brain bioelectrical activity in 140 healthy adolescents of both sexes aged 16–17 years belonging to various ethnic groups and living in the Nenets Autonomous Area (lat. 67°40' N) and Arkhangelsk Region (lat. 64°30' N). Electroencephalogram (EEG) was recorded monopolarly, with eyes closed, in 16 standard leads. EEG was described using the index and amplitude values in each frequency range (4–7 Hz, 8–12 Hz, 13–25 Hz). No statistically significant difference in the studied EEG parameters between the Nenets and Russians from the Nenets Autonomous Area was identified: regardless of their nationality, these adolescents had higher activity of subcortical diencephalic brain structures than the adolescents from the Arkhangelsk Region. This activity was manifested in raised levels of theta-activity, presence of photic driving response and increased incidence of high-amplitude hypersynchronous EEG variants. Russian adolescents from the Arkhangelsk Region showed a rather developed age-specific pattern of EEG. Thus, the ethnic factor makes the smallest contribution to the identified changes in the EEG structure, while the combined effect of adverse conditions of the polar region has major impact.

Keywords

electroencephalography, adolescents, ethnic group, north.

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