Evolution of interictal spiking during the latent period in a mouse model of mesial temporal lobe epilepsy

Abstract Interictal spikes and high-frequency oscillations (HFOs, ripples: 80-200 Hz, fast ripples: 250-500 Hz) occur in epileptic patients and in animal models of mesial temporal lobe epilepsy (MTLE). In this study, we explored how type 1 and type 2 interictal spikes as well as ripples and fast ripples evolve during the latent period in the hippocampus of pilocarpine-treated mice. Depth EEG recordings were obtained from the hippocampus CA3 subfield of adult male mice (n = 5, P60-P100) starting one day before pilocarpine-induced status epilepticus up to the first spontaneous seizure, the so-called latent period. We found that rates of type 1 (n = 1 655) and type 2 (n = 2 309) interictal spikes were significantly lower during the late phase of the latent period compared to its early and mid phase (p