Focal Scn1a knockdown induces cognitive impairment without seizures

► Nav1.1 (SCN1A) deficits are linked to Dravet syndrome and other cognitive disorders. ► RNA interference was used to knockdown Nav1.1 expression in the basal forebrain region. ► Nav1.1 knockdown impaired spatial cognition in the absence of seizures. ► Impaired spatial performance was associated with a dysregulation of theta frequency. ► Nav1.1 deficits may impair network oscillations and cognition in human disorders.