Anterior-posterior relationships of EEG in photosensitive subjects: coherence and cross-phase-spectral analysis.
Coherence and cross-phase-spectral analysis of EEG were applied to photo-sensitive subjects to investigate the mechanism of the generalization of photo-induced paroxysms. Coherence values were high between frontal (F) and central (C) in resting records and between F-C in EEGs revealing harmonic responses, where the coherence values of F-O (occipital) were also high, and the waves of F preceded those of O. In cases of occipital-localized 3/6 Hz (poly) spike-waves, discharges of O preceded those of F. During the stage of generalized paroxysms, discharges were highly cohered between all electrodes. Discharges of F preceded those of O, and appeared to play as a generator. Two conditions with clinical symptoms had higher frequencies (greater than or equal to 12 Hz) and shorter time lags (less than or equal to 5 msec) than conditions without symptoms.
Takasaka
Y
Y
Department of Psychiatry and Neurology, Hokkaido University School of Medicine, Sapporo, Japan.
Takamatsu
K
K
Nakagawara
M
M
D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography / Q000295:instrumentation; D004828:Epilepsies, Partial / Q000503:physiopathology*; D005074:Evoked Potentials, Visual / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009778:Occipital Lobe / Q000503:physiopathology*; D010775:Photic Stimulation; D012815:Signal Processing, Computer-Assisted