title: Frequency interactions in human epileptic brain.
abstract: We have used two algorithms, wavelet phase coherence (WPC) and modulation index (MI) analysis to study frequency interactions in the human epileptic brain. Quantitative analyses were performed on intracranial electroencephalographic (iEEG) segments from three patients with neocortical epilepsy. Interelectrode coherence was measured using WPC and intraelectrode frequency interactions were analyzed using MI. WPC was performed on electrode pairings and the temporal evolution of phase couplings in the following frequency ranges: 1-4 Hz, 4-8 Hz, 8-13 Hz, 13-30 Hz and 30-100 Hz was studied. WPC was strongest in the 1-4 Hz frequency range during both seizure and non-seizure activities; however, WPC values varied minimally between electrode pairings. The 13-30 Hz band showed the lowest WPC values during seizure activity. MI analysis yielded two prominent patterns of frequency-specific activity, during seizure and non-seizure activities, which were present across all patients.
authors.affiliation: Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada. marija.cotic@utoronto.ca
authors.forename: Marija
authors.initials: M
authors.lastname: Cotic
authors.forename: Osbert
authors.initials: O
authors.lastname: Zalay
authors.forename: Taufik
authors.initials: T
authors.lastname: Valiante
authors.forename: Peter L
authors.initials: PL
authors.lastname: Carlen
authors.forename: Berj L
authors.initials: BL
authors.lastname: Bardakjian
mesh_terms: D001683:Biological Clocks; D001921:Brain / Q000503:physiopathology*; D004569:Electroencephalography / Q000379:methods*; D004827:Epilepsy / Q000503:physiopathology*; D006801:Humans; D008959:Models, Neurological; D058067:Wavelet Analysis