title: Granger causality: cortico-thalamic interdependencies during absence seizures in WAG/Rij rats.
abstract: Linear Granger causality was used to identify the coupling strength and directionality of information transport between frontal cortex and thalamus during spontaneous absence seizures in a genetic model, the WAG/Rij rats. Electroencephalograms were recorded at the cortical surface and from the specific thalamus. Granger coupling strength was measured before, during and after the occurrence of spike-wave discharges (SWD). Before the onset of SWD, coupling strength was low, but associations from thalamus-to-cortex were stronger than vice versa. The onset of SWD was associated with a rapid and significant increase of coupling strength in both directions. There were no changes in Granger causalities before the onset of SWD. The strength of thalamus-to-cortex coupling remained constantly high during the seizures. The strength of cortex-to-thalamus coupling gradually diminished shortly after the onset of SWD and returned to the pre-SWD level when SWD stopped. In contrast, the strength of thalamus-to-cortex coupling remained elevated even after cessation of SWD. The strong and sustained influence of thalamus-to-cortex may facilitate propagation and maintenance of seizure activity, while rapid reduction of cortex-to-thalamus coupling strength may prompt the cessation of SWD. However, the linear estimation of Granger coupling strength does not seem to be sufficient for predicting episodes with absence epilepsy.
authors.affiliation: Department of Neuroontogenesis, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Butlerova Str. 5A, 117485 Moscow, Russia. jenia-s@mail.ru
authors.forename: Evgenia
authors.initials: E
authors.lastname: Sitnikova
authors.forename: Taras
authors.initials: T
authors.lastname: Dikanev
authors.forename: Dmitry
authors.initials: D
authors.lastname: Smirnov
authors.forename: Boris
authors.initials: B
authors.lastname: Bezruchko
authors.forename: Gilles
authors.initials: G
authors.lastname: van Luijtelaar
mesh_terms: D000465:Algorithms; D000818:Animals; D002540:Cerebral Cortex / Q000503:physiopathology*; D004558:Electric Stimulation; D004569:Electroencephalography / Q000706:statistics & numerical data*; D004832:Epilepsy, Absence / Q000503:physiopathology*; D005246:Feedback / Q000502:physiology; D008297:Male; D009415:Nerve Net / Q000503:physiopathology; D010775:Photic Stimulation; D017397:Prefrontal Cortex / Q000502:physiology; D051381:Rats; D013788:Thalamus / Q000503:physiopathology*