QUALITATIVE AND QUANTITATIVE CHARACTERIST ICS OF GEOMAGNETIC-FIELD VARIATIONS WITH REFERENCE TO FUNCTIONAL-STATE OF HUMAN BRAIN

The comparison of functional dynamics of human brain with reference to qualitative and quantitative characteristics of local geomagnetic fie ld (GMF) variations was conducted. It was showed that just local GMF v ariations can be a principal reason of modulation the human brain's fu nctional state. The steady and unsteady states of human brain can be d etermined: by geomagnetic disturbances before the observation period; by structure and doses of GMF variations; by different combinations of qualitative and quantitative characteristics of GMF variations. The o ptimal level of GMF activity, manifested in periodic oscillations in c ertain amplitude-frequency range is demanded for steady brain's functi onal state. The decrease of optimal GMF activity level and the appeara nce of aperiodic disturbances of GMF mn be a reason of unsteady brain' s state.