NETWORKS | The Role of the Basal Ganglia Circuits in the Control of Epileptic Seizures

Abstract

The alternation of epileptic seizures with interictal periods, the latter lasting from a few hours to several months, suggests the existence of active mechanisms which control the occurrence of seizures and/or take part in their interruption. The study of these control mechanisms is essential to understand the modalities of the transition between normal and paroxysmal activities within the epileptic networks. Recently, several studies in animal models have presented evidence showing that the basal ganglia (BG) play an essential part in this control. The BG have connections with several structures involved in the generation of seizures. Further, the direct or indirect inhibition of the substantia nigra pars reticulata, the main output of BG, has antiepileptic effects in several animal models. Similarly, the modulation of dopaminergic neurotransmission in the striatum, the main BG input station, modulates the occurrence of seizures, and a disruption of this neurotransmission appears associated with epileptogenesis. More recently, unit recordings of neurons from the different structures of the BG suggest that these circuits participate in the interruption of seizures. These results have led to the consideration of therapeutic approaches involving deep brain stimulation, the precise conditions of which remain to be specified.