Complex phase synchronization in epileptic seizures: evidence for a devil's staircase.
We describe multifrequency phase synchronization in epileptic seizures. Using magnetoencephalographic recordings from three patients suffering generalized seizures, the evidence is presented that, in addition to the commonly studied 1:1 frequency locking, there exists complex multifrequency coordination that, in some cases, follows a classical "devil's staircase." Within the limitations of observing this phenomenon in a clinical experimental setting, these observations reveal that in pathological brain activity, complex frequency locking can be found similar to that identified in certain pathological cardiac re-entrant arrhythmias. This may suggest the existence of similar re-entrant mechanisms active in cerebral neocortex during epileptic seizures.
Perez Velazquez
J L
JL
Brain and Behaviour Programme, Department of Paediatrics, University of Toronto and Hospital for Sick Children, Toronto M5G1X8, Canada. jose-luis.perezvelazquez@sickkids.ca
Garcia Dominguez
L
L
Wennberg
R
R
D000818:Animals; D001703:Biophysics / Q000379:methods*; D001921:Brain / Q000473:pathology; D003344:Cortical Synchronization; D004827:Epilepsy / Q000473:pathology*; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods*; D008959:Models, Neurological; D015233:Models, Statistical; D008962:Models, Theoretical; D019579:Neocortex; D012815:Signal Processing, Computer-Assisted; D009435:Synaptic Transmission; D013997:Time Factors