Possible pathological mechanisms of absence seizures appearing in the reticular thalamic nucleus: A theoretical basis

Abstract

In this paper, we study the generation and inhibition mechanisms of absence epilepsy appearing in the reticular thalamic nucleus (TRN) of the thalamus in a basal ganglia-corticothalamic network, which has been proven to be effective for simulating epileptic seizures in the brain. We found that the spike-and-wave discharges (SWDs) activities (2–4 Hz) appeared in the TRN by adjusting the coupling weight in the excitatory pathway “SRN ⟶ EPN” and the delay in the inhibitory pathway “TRN ⊸ Thalamic relay nucleus (SRN)”. The SWDs can disappear by controlling the firing state of the substantia nigra pars reticulata (SNr), which sends strong inhibitory projections to both the SRN and TRN in the model. Suppression of seizure activities may be realized through both the isolated pathway “SNr ⊸ TRN” and the isolated pathway “SNr ⊸ SRN”, or through the competition mechanism between them. Unidirectional and bidirectional regulation phenomena were obtained in the simulations, and the mechanisms of these can be well explained in this model. The theoretical mechanism of epilepsy appearing in the TRN has received little attention to date, and we hope that the results shown in this paper can inspire new ideas for experimental study in the future.