Circadian alterations of dentate gyrus excitability may contribute to the afternoon peak of seizures in experimental mesial temporal lobe epilepsy

In human mesial temporal lobe epilepsy (mTLE), seizure occurrence peaks in the late afternoon and early evening. This temporal binding of seizures is also manifest in animal models of mTLE developing as a consequence of electrically-induced status epilepticus. In this study, we hypothesized that circadian alterations in excitatory and inhibitory functions of the dentate gyrus (DG), which is believed to regulate the generation of limbic seizures, form the pathophysiological basis for the predominant occurrence of seizures in the late afternoon/early evening. We performed electrophysiological single and paired pul…