Bioelectrical Activity in the Sleep–Waking Cycle in Rats after Pilocarpine-Induced Status Epilepticus

Chronic recording of electrograms of the somatosensory, auditory, and visual cortex, the hippocampus, and the caudate nucleus in Krushinskii–Molodkina and Wistar rats was used to study bioelectrical activity in the sleep–waking cycle during the month following pilocarpine-induced status epilepticus. The processes of normalization of behavior and the organization of sleep and waking were completed in animals over the three days following status epilepticus. From day 2 to day 4 after administration of pilocarpine, electrograms of the study structures in all rats at all stages of the sleep–waking cycle showed epileptiform activity in the form of sharp waves, multiple peaks, and peak-wave discharges. Interhemisphere asymmetry in the manifestations of paroxysmal activity was seen in some cases. Spontaneous epileptiform activity on the EEG, in the form of single or grouped peak-wave discharges, was recorded in rats only on the background of waking and slow-wave sleep. The simultaneous presence of different types of epileptiform activity on EEG patterns and the duration of paroxysms on the EEG during the post-status period indicated that exposure to pilocarpine can induce the formation of multiple foci of epileptogenesis in the rat brain, with production of stable paroxysmal syndrome, which has clear similarity with the clinical picture of nonconvulsive status epilepticus in humans. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.