Temporal patterns in human epileptic activity are modulated by perceptual discriminations

• Published in: Neuroreport Vol. 8; no. 7; p. 1703
• Main Authors: Le Van Quyen, M, Adam, C, Lachaux, J P, Martinerie, J, Baulac, M, Renault, B, Varela, F J
• Format: Journal Article
• Language: English
• Published: England 06.05.1997
• Subjects: Adult; Auditory Perception - physiology; Discrimination (Psychology) - physiology; Epilepsy, Complex Partial - physiopathology; Humans; Male; Temporal Lobe - physiopathology; Visual Perception - physiology
• ISSN: 0959-4965
• DOI: 10.1097/00001756-199705060-00028

We studied subdural recordings from a patient with an unusually focal and stable occipito-temporal epileptic discharge under four experimental conditions. The series of time intervals between successive spike discharges displayed a few (3-5) clusters of periodic values representing statistically significant short-term periodicities when tested against surrogate data. This short-term predictability was modulated during the different experimental conditions by periodicity shifts of the order of 15-30 ms. Correspondingly, there was an increased gamma-band (30-70 Hz) coherence between the epileptic focus and surrounding recording sites. We conclude that the focal epileptic activity is part of an extended network of neural activities which exert a fast modulation reflected in changes of transiently periodic activities.