Uniform decrease of alpha-global field power induced by intermittent photic stimulation of healthy subjects

  • Nineteen-channel EEGs were recorded from the scalp surface of 30 healthy subjects (16 males and 14 females, mean age: 34 years, SD: 11.7 years) at rest and under trains of intermittent photic stimulation (IPS) at rates of 5, 10 and 20 Hz. Digitalized data were submitted to spectral analysis with fast fourier transformation providing the basis for the computation of global field power (GFP). For quantification, GFP values in the frequency ranges of 5, 10 and 20 Hz at rest were divided by the corresponding data obtained under IPS. All subjects showed a photic driving effect at each rate of stimulation. GFP data were normally distributed, whereas ratios from photic driving effect data showed no uniform behavior due to high interindividual variability. Suppression of alpha-power after IPS with 10 Hz was observed in about 70% of the volunteers. In contrast, ratios of alpha-power were unequivocal in all subjects: IPS at 20 Hz always led to a suppression of alpha-power. Dividing alpha-GFP with 20-Hz IPS by alpha-GFP at rest (R = a-GFPIPS/a-GFPrest) thus resulted in ratios lower than 1. We conclude that ratios from GFP data with 20-Hz IPS may provide a suitable paradigm for further investigations. Key words: EEG, Brain mapping, Intermittent photic stimulation, IPS, Global field power ratios

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Author:Rüdiger Rau, Christoph Raschka, Horst Josef Koch
Parent Title (German):Brazilian journal of medical and biological research
Document Type:Article
Date of Publication (online):2010/10/19
Year of first Publication:2002
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2010/10/19
Tag:EEG; IPS; brain mapping; global field power ratios; intermittent photic stimulation
First Page:605
Last Page:611
http://www.scielo.br/scielo.php?pid=S0100-879X2002000500014&script=sci_arttext ; licensed under a Creative Commons Attribution License
Source:Brazilian journal of medical and biological research (2002), vol. 35, no. 5, pp. 605-611. ISSN 1678-4510
Institutes:Psychologie und Sportwissenschaften / Sportwissenschaften
Dewey Decimal Classification:6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit
Licence (German):License LogoDeutsches Urheberrecht