INFLUENCE OF THE GEOMAGNETIC FIELD ON RECURRENCE QUANTIFICATION EEG INDEXES

Abstract

The effect of changes of the geomagnetic field on human electroencephalograms (EEG) has been studied. Based on the fact that the relationship between the characteristics of the geomagnetic field and the EEG was not linear, the method of recurrence quantification analysis (RQA) was used. EEGs were recorded in 16 sites of the left and right hemispheres in three background states. Subjects (10 people) participated in the multi-day studies. 9 recurrence indexes (RR, DET, L, DIV, ENTR, RATIO, LAM, TT, CLEAN) were calculated for each of the 16 EEG sites. The correlation coefficients were calculated for each index with the global and local coefficients of geomagnetic activity. Since each recurrence index showed significant individual dynamics in the course of the series, the data for all 9 indexes were averaged. All EEG recurrent indexes showed a reliable correlation with the geomagnetic activity, and the number of correlations in the left hemisphere was significantly bigger than in the right one. A significant excess in the number of correlations in the left temporal area (T3) compared to the right one (T4) has been found. It has been concluded that the geomagnetic field had the most pronounced effect on the temporal lobes.