Granger causality: cortico-thalamic interdependencies during absence seizures in WAG/Rij rats.
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.
Sitnikova
Evgenia
E
Department of Neuroontogenesis, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Butlerova Str. 5A, 117485 Moscow, Russia. jenia-s@mail.ru
Dikanev
Taras
T
Smirnov
Dmitry
D
Bezruchko
Boris
B
van Luijtelaar
Gilles
G
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*