PT  - JOURNAL ARTICLE
AU  - Mark A. Kramer
AU  - Uri T. Eden
AU  - Eric D. Kolaczyk
AU  - Rodrigo Zepeda
AU  - Emad N. Eskandar
AU  - Sydney S. Cash
TI  - Coalescence and Fragmentation of Cortical Networks during Focal Seizures
AID  - 10.1523/JNEUROSCI.6309-09.2010
DP  - 2010 Jul 28
TA  - The Journal of Neuroscience
PG  - 10076--10085
VI  - 30
IP  - 30
4099  - http://www.jneurosci.org/content/30/30/10076.short
4100  - http://www.jneurosci.org/content/30/30/10076.full
SO  - J. Neurosci.2010 Jul 28; 30
AB  - Epileptic seizures reflect a pathological brain state characterized by specific clinical and electrical manifestations. The proposed mechanisms are heterogeneous but united by the supposition that epileptic activity is hypersynchronous across multiple scales, yet principled and quantitative analyses of seizure dynamics across space and throughout the entire ictal period are rare. To more completely explore spatiotemporal interactions during seizures, we examined electrocorticogram data from a population of male and female human patients with epilepsy and from these data constructed dynamic network representations using statistically robust measures. We found that these networks evolved through a distinct topological progression during the seizure. Surprisingly, the overall synchronization changed only weakly, whereas the topology changed dramatically in organization. A large subnetwork dominated the network architecture at seizure onset and preceding termination but, between, fractured into smaller groups. Common network characteristics appeared consistently for a population of subjects, and, for each subject, similar networks appeared from seizure to seizure. These results suggest that, at the macroscopic spatial scale, epilepsy is not so much a manifestation of hypersynchrony but instead of network reorganization.