EEG Implantation

Slick‐H/Scn1b ^Fl/Fl, Slick‐H negative/Scn1b ^Fl/Fl , and Slick‐H/Scn1b ^E/E mice were implanted at P42 to 70 with 6 EEG electrodes. For surgery, each mouse was anesthetized with isoflurane or ketamine/xylazine and placed in a stereotaxic adapter. The electrodes were implanted over the left and right front lobes, the left and right parietal lobes, the cerebellum, and the sinus cavity using mounting screws. The electrodes were connected to a 6‐pin electrode pedestal and the headcap was secured using dental cement. After 7 days of recovery, simultaneous EEG recording and video monitoring were performed on Ceegraph Vision; Bio‐logic System Corporation and Natus recording systems. Following baseline recording for 2 days, mice were removed from recording for injection with TMX and recording was resumed at 7 days postinitial TMX injection. Signals were acquired at 256 Hz with simultaneous video monitoring. Data were filtered with a 1 Hz low pass filter, a 70 Hz high pass filter, and a notch filter at 60 Hz. Seizures were assessed manually.