Preferential inactivation of Scn1a in parvalbumin interneurons increases seizure susceptibility

► Nav1.1 is expressed in most PV interneurons in the neocortex and hippocampus. ► Nav1.1 is expressed in 5-13% of excitatory cells in neocortex and hippocampus. ► Preferential inactivation of one Scn1a allele in PV interneurons reduces seizure thresholds. ► Inactivation of one Scn1a allele in excitatory cells does not alter seizure thresholds. ► Preferential inactivation of one Scn1a allele in PV interneurons results in spontaneous seizures.