Focal cortical seizures start as standing waves and propagate respecting homotopic connectivity

Focal epilepsy involves excessive cortical activity that propagates both locally and distally. Does this propagation follow the same routes as normal cortical activity? We pharmacologically induced focal seizures in primary visual cortex (V1) of awake mice, and compared their propagation to the reti...

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Bibliographic Details
Published in:Nature communications 2017-08, Vol.8 (1), p.217-11, Article 217
Main Authors: Rossi, L. Federico, Wykes, Robert C., Kullmann, Dimitri M., Carandini, Matteo
Format: Article
Language:English
Subjects:
631/378/116/2393
631/378/1689/178
631/378/2613/2614
Animals
Calcium
Calcium imaging
Calcium signalling
Convulsions & seizures
Cortex
Epilepsy
Humanities and Social Sciences
Hypotheses
Information processing
Mice, Transgenic
multidisciplinary
Picrotoxin
Propagation
Science
Science (multidisciplinary)
Seizing
Seizures
Seizures - etiology
Seizures - physiopathology
Sensory integration
Standing waves
Visual Cortex - physiopathology
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Summary:Focal epilepsy involves excessive cortical activity that propagates both locally and distally. Does this propagation follow the same routes as normal cortical activity? We pharmacologically induced focal seizures in primary visual cortex (V1) of awake mice, and compared their propagation to the retinotopic organization of V1 and higher visual areas. We used simultaneous local field potential recordings and widefield imaging of a genetically encoded calcium indicator to measure prolonged seizures (ictal events) and brief interictal events. Both types of event are orders of magnitude larger than normal visual responses, and both start as standing waves: synchronous elevated activity in the V1 focus and in homotopic locations in higher areas, i.e. locations with matching retinotopic preference. Following this common beginning, however, seizures persist and propagate both locally and into homotopic distal regions, and eventually invade all of visual cortex and beyond. We conclude that seizure initiation resembles the initiation of interictal events, and seizure propagation respects the connectivity underlying normal visual processing. Focal cortical seizures result from local and widespread propagation of excitatory activity. Here the authors employ widefield calcium imaging in mouse visual areas to demonstrate that these seizures start as local synchronous activation and then propagate along the connectivity that underlies normal sensory processing.
ISSN:2041-1723
2041-1723
DOI:10.1038/s41467-017-00159-6