title: Propagation of epileptiform activity on a submillimeter scale.
abstract: Microseizures are highly focal low-frequency epileptiform-appearing events recorded from the neocortex of epilepsy patients. Because of their tiny, often submillimeter distribution, they may be regarded as a high-resolution window into the epileptic process, providing an excellent opportunity to study the fine temporal structure of their origin and spread. A 16 mm² 96-microelectrode array with 400-μm interelectrode spacing was implanted in seven patients undergoing invasive EEG monitoring for medically refractory epilepsy. Seven microdischarge populations were tested for a substantial contribution by volume conduction to the observed waveform amplitudes. Single-unit activity was examined for specific evidence of neural activity at multiple sites within the microdischarge fields. We found that microdischarges appear to originate at a highly focal source location, likely within a single cortical macrocolumn, and spread to local and more distant sites via neural propagation.
authors.affiliation: Department of Neurology, Columbia University, New York, NY 10032, USA. cas2044@columbia.edu
authors.forename: C A
authors.initials: CA
authors.lastname: Schevon
authors.forename: R R
authors.initials: RR
authors.lastname: Goodman
authors.forename: G
authors.initials: G
authors.lastname: McKhann
authors.forename: R G
authors.initials: RG
authors.lastname: Emerson
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000704:Analysis of Variance; D004569:Electroencephalography; D004827:Epilepsy / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D008839:Microelectrodes; D019579:Neocortex / Q000473:pathology / Q000503:physiopathology*; D009474:Neurons / Q000502:physiology*; D058067:Wavelet Analysis