title: Sferics provoke changes in EEG power.
abstract: The present study investigated electrocortical and psychological influences of Very Low Frequency (VLF) sferics. Eighty female subjects, who were divided into two groups participated in the study. After a 10-minute baseline period the experimental group (n=40) underwent a 10-minute exposure to a previously recorded 10 kHz-sferics impulse, which was presented with a pulse repetition frequency statistically varying between 1 and 3 Hz. After the sferics stimulation, an additional 20 minutes without treatment were recorded in order to examine possible prolonged sferics effects. The control group (n=40) received no treatment. As the physiological dependent measure, the background electroencephalogram (EEG) was registered throughout the course of the experiment. Absolute power values for different EEG frequency bands were determined by means of a Fast Fourier Transform (FFT) and compared between the two groups at four electrode sites (P3/P4; O1/O2). Also, the emotional and somatic state of the subjects and their ability consciously to perceive sferics were investigated. It could be shown that the two groups were characterized by different courses of EEG alpha and beta power. Whereas the sferics group displayed power increases in both frequency bands, which reached their maximum 20 minutes after the end of exposure, the control group showed a slight power reduction. Sferics had no effect on the subjective state and could not be perceived consciously.
authors.affiliation: Department of Clinical and Physiological Psychology, Justus-Liebig-University, Otto-Behagel-Strasse 10, 35394 Giessen, Germany. anne.schienle@psychol.uni-giessen.de
authors.forename: A
authors.initials: A
authors.lastname: Schienle
authors.forename: R
authors.initials: R
authors.lastname: Stark
authors.forename: D
authors.initials: D
authors.lastname: Vaitl
mesh_terms: D000293:Adolescent; D000328:Adult; D000513:Alpha Rhythm; D001611:Beta Rhythm; D001921:Brain / Q000503:physiopathology*; D003198:Computer Simulation; D003866:Depressive Disorder / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D004311:Double-Blind Method; D004569:Electroencephalography / Q000706:statistics & numerical data*; D004574:Electromagnetic Fields; D005260:Female; D006801:Humans; D011897:Random Allocation; D011795:Surveys and Questionnaires; D014887:Weather