BRAIN BIOELECTRIC ACTIVITY FORMING IN ADOLESCENTS LIVING IN DIFFERENT ENDEMIC GOITER AREA OF EUROPEAN NORTH

Northern European regions are goiter endemic and iodine-deficient areas, and also differ in the degree of extreme weather conditions in the Polar and Subpolar latitudes. The age formation of the nervous system in adolescents depends on these discomfort climatic factors. Aim. The study of functional brain activity depending on the thyroid profile in adolescents living in the European North. Patients and methods. 211 adolescents (male and female) aged 15–16 years living in the Subpolar (64°30' N) and Polar (67°40' N) Russian regions were observed. An electroencephalogram in a state of quiet wakefulness with eyes closed monopolar 16 standard leads was recorded. Electroencephalogram characteristic were performed by the values: of the wave amplitudes, index and absolute spectral power in each frequency band: 4–7 Hz, 8–12 Hz and 13–24 Hz. In serum samples by immune-enzyme assay thyrotropin, triiodothyronine and thyroxine levels were determined. All the described changes were statistically significant at p <0,05–0,001. Results. A higher activity of diencephalic subcortical brain structures, expressed in the form of increased θ-activity and photic driver reactions were determined in adolescents living in Polar region. Background thyroid status determines the age formation of brain activity. In adolescents living in the Polar region a high concentration of thyrotropin in the blood and the availability of significant relations with thyroid hormones levels with a brain θ-activity were detected. In adolescents living in Subpolar region is more intense age optimization of neural processes, as well as the greatest number of neuro-endocrine relationships.