SCN1A and Cognitive impairment: Experimental paradigm: in vivo chronic video EEG recordings.Findings: spontaneous epileptiform discharges observed during reduced γ oscillatory activity (generated by inhibitory PV cells) in hAPP-J20 mice. Decreased levels of the interneuron-specific and PV cell-predominant voltage-gated sodium channel subunit Nav1.1. Restoring Nav1.1 level in hAPP-J20 mice increased inhibitory synaptic activity and γ oscillations and reduced hyperexcitability and cognitive deficits.