Beyond seizure control: identifying deficits in cognitive networks in absence seizure.

Abstract

Absence epilepsy is frequently associated with cognitive impairments, yet the direct or indirect involvement of cognitive circuits remains poorly understood, as spike-and-wave discharges are rarely reported in these regions. Here, we investigate the role of a thalamic-prefrontal pathway in a mouse model of absence epilepsy (Scn8a+/-). We find that Scn8a+/- mice exhibit deficits in reversal learning, along with impaired recruitment of medial prefrontal cortex (mPFC) neurons by the Reuniens nucleus of the thalamus. This deficit is accompanied by an altered excitation-inhibition balance and reduced excitability of layer I interneurons in the mPFC, which constitutes the main recipient zone of reuniens inputs to the mPFC. Remarkably, stimulation of Reuniens at 20 Hz significantly reduces seizure incidence and improves performance in reversal learning. Our findings reveal previously unrecognized cognitive circuit dysfunctions in absence epilepsy and highlight the thalamo-prefrontal axis as a promising target for both cognitive and seizure-related interventions.