Figure 2.

Electrophysiological recordings during spontaneous fatal seizures in homozygous Cacna1a^S218L mice. (A) Example of cortical MUA and ECoG (DC and AC) recordings during a fatal seizure (behavioural onset indicated by the vertical dashed line). MUA (histogram) decreased during seizure behaviour (clonic behaviour in grey, tonic behaviour in black). MUA and AC ECoG were attenuated in the minute preceding the terminal depolarization (TD; indicated by an arrow). Note that the pre-ictal transition of AC ECoG amplitude parallels vigilance state (non-REM sleep followed by wakefulness). (B) ECG recordings during a fatal seizure in another mouse showing cardiac electrical activity following TD. Electrocardiographic arrest (not shown) occurred 7 min after the terminal depolarization. The onset of seizure-related behaviour preceded the plotted time series. AC = alternating current; bps = beats per second; DC = direct current; IHR = instantaneous heart rate.