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The source of afterdischarge activity in neocortical tonic-clonic epilepsy

Lookup NU author(s): Professor Andrew Trevelyan, Professor Miles Whittington

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Abstract

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.


Publication metadata

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

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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