SEASONAL VARIATIONS IN CEREBRAL ENERGY EXCHANGE IN URBAN ARCTIC RESIDENTS

Background: Daylight is an important ecological factor influencing human physiology particularly in high latitudes. Aims: To seasonal variations in cerebral energy exchange among young healthy adults living in an urban Arctic setting. Methods: A cohort of 49 healthy volunteers aged 30-34 years permanently living in Arkhangelsk was followed over a year. All measurements were taken in autumn (October), winter (December), spring (March), and summer (June). Cerebral energy exchange was studied using the 5-channel diagnostic complex "Neuro-KM". The analysis of DC potential indicators was carried out by mapping monopolar values of constant potential and calculating their gradients. No gender differences were found; therefore all calculations were performed in the full sample. Differences in the average values of the measurements across the seasons were analyzed using Mann-Whitney tests with Bonferroni correction to control Type I error. Results: The most optimal distribution of DC potentials in in the studied individuals was observed in October. Significant decrease in the intensity of cerebral energy exchange in the cerebral cortex was registered in March and June. At the same time, we registered an increase in DP potentials in the frontal and occipital structures of the cerebral cortex, but a decrease in DC potential in the temporal areas in the period in the same period. Conclusions: We observed significant seasonal variations in neuroenergy metabolism among young healthy volunteers in Arkhangelsk which is highly likely linked to changes in the number daylight hours. The least favorable changes in DC potential were registered in spring and summer months. For better understandings seasonal variations and their mechanisms larger studied including other age-groups are warranted in different Arctic settings.

Arctic, photoperiodism, brain, DC-potentials, energy exchange processes