SCN1A and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy: Lastly, in an Scn1a+/− mouse model of Dravet syndrome, PV neurons are transiently hypoexcitable during development, whereas later they show an increased firing rate, both interictally and at seizure onset, and a decrease in synchrony in the transition to seizure (Favero et al., 2018; Tran et al., 2020).