Electrographic spikes are common in wildtype mice.

Area of Science:

• Neuroscience
• Epileptology
• Sleep Science

Background:

• High-voltage rhythmic electroencephalographic (EEG) spikes are observed in wildtype (WT) rats during specific sleep and wake states.
• The origin of these spikes in rats is debated, with theories suggesting either absence epilepsy or normal rodent sleep EEG features.
• Limited information exists regarding epileptiform spikes in WT mice.

Purpose of the Study:

• To characterize and quantify epileptiform discharges in WT mice for the first time.
• To establish a baseline understanding of normal EEG activity in WT mice.
• To aid in differentiating pathological from normal EEG activity in mouse epilepsy models.

Main Methods:

• Utilized 24-h wireless telemetry video-EEG recordings in 36 male WT C57 mice.
• Manually scored EEG data by blinded reviewers to identify individual spikes and spike trains.
• Analyzed spike frequency in relation to circadian rhythms and locomotor activity.

Main Results:

• Epileptiform spikes were detected in 100% of WT mice.
• Spike trains (≥3 spikes) were observed in 90% of WT mice.
• Spikes were more frequent during the day and inversely correlated with locomotor activity, though present during active periods.

Conclusions:

• The widespread presence of these discharges in WT mice suggests they may represent a baseline tendency toward seizures or benign variants of normal EEG.
• Further research is needed to elucidate the exact nature of these spikes.
• Establishing baseline WT EEG activity is essential for accurate interpretation of findings in mouse epilepsy models.