Temporal patterns in human epileptic activity are modulated by perceptual discriminations.
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.
Le Van Quyen
M
M
CNRS URA 654-University of Paris 6, Hôpital de la Salpétrière, France.
Adam
C
C
Lachaux
J P
JP
Martinerie
J
J
Baulac
M
M
Renault
B
B
Varela
F J
FJ
D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D004192:Discrimination, Psychological / Q000502:physiology*; D017029:Epilepsy, Complex Partial / Q000503:physiopathology*; D006801:Humans; D008297:Male; D013702:Temporal Lobe / Q000503:physiopathology*; D014796:Visual Perception / Q000502:physiology*