Microseizures and the spatiotemporal scales of human partial epilepsy.
Focal seizures appear to start abruptly and unpredictably when recorded from volumes of brain probed by clinical intracranial electroencephalograms. To investigate the spatiotemporal scale of focal epilepsy, wide-bandwidth electrophysiological recordings were obtained using clinical macro- and research microelectrodes in patients with epilepsy and control subjects with intractable facial pain. Seizure-like events not detectable on clinical macroelectrodes were observed on isolated microelectrodes. These 'microseizures' were sparsely distributed, more frequent in brain regions that generated seizures, and sporadically evolved into large-scale clinical seizures. Rare microseizures observed in control patients suggest that this phenomenon is ubiquitous, but their density distinguishes normal from epileptic brain. Epileptogenesis may involve the creation of these topographically fractured microdomains and ictogenesis (seizure generation), the dynamics of their interaction and spread.
Stead
Matt
M
Department of Neurology, Mayo Systems Electrophysiology Laboratory, Mayo Clinic, 200 First Street SW, Rochester, MN 55901, USA. stead.squire@mayo.edu
Bower
Mark
M
Brinkmann
Benjamin H
BH
Lee
Kendall
K
Marsh
W Richard
WR
Meyer
Fredric B
FB
Litt
Brian
B
Van Gompel
Jamie
J
Worrell
Greg A
GA
D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D004569:Electroencephalography / Q000379:methods; D004828:Epilepsies, Partial / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D008839:Microelectrodes; D009415:Nerve Net / Q000503:physiopathology; D012640:Seizures / Q000473:pathology / Q000503:physiopathology*; D012815:Signal Processing, Computer-Assisted