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Lookup NU author(s): Professor Andrew Trevelyan, Professor Miles Whittington
Tonic-clonic seizures represent a common pattern of epileptic discharges, yet the relationship between the various phases of the seizure remains obscure. Here we contrast propagation of the ictal wavefront with the propagation of individual discharges in the clonic phase of the event. In an in vitro model of tonic-clonic epilepsy, the afterdischarges (clonic phase) propagate with relative uniform speed and are independent of the speed of the ictal wavefront (tonic phase). For slowly propagating ictal wavefronts, the source of the afterdischarges, relative to a given recording electrode, switched as the wavefront passed by, indicating that afterdischarges are seeded from wavefront itself. In tissue that has experienced repeated ictal events, the wavefront generalizes rapidly, and the afterdischarges in this case show a different "flip-flop" pattern, with frequent switches in their direction of propagation. This same flip-flop pattern is also seen in subdural EEG recordings in patients suffering intractable focal seizures caused by cortical dysplasias. Thus, in both slowly and rapidly generalizing ictal events, there is not a single source of afterdischarge activity: rather, the source is continuously changing. Our data suggest a complex view of seizures in which the ictal event and its constituent discharges originate from distinct locations. Copyright © 2007 Society for Neuroscience.
Author(s): Trevelyan AJ, Baldeweg T, Van Drongelen W, Yuste R, Whittington M
Publication type: Article
Publication status: Published
Journal: Journal of Neuroscience
Year: 2007
Volume: 27
Issue: 49
Pages: 13513-13519
Date deposited: 04/08/2010
ISSN (print): 0270-6474
ISSN (electronic): 1529-2401
Publisher: Society for Neuroscience
URL: http://dx.doi.org/10.1523/JNEUROSCI.3005-07.2007
DOI: 10.1523/JNEUROSCI.3005-07.2007
PubMed id: 18057209
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