Rodent and human seizures demonstrate a dynamic interplay with spreading depolarizations

Area of Science:

• Neuroscience
• Epilepsy Research
• Clinical Neurophysiology

Background:

• Spreading depolarizations (SDs) are implicated in seizure termination in experimental epilepsy models.
• The precise mechanisms and occurrence of SDs during human seizures remain debated.
• Understanding SDs' role is crucial for developing novel seizure control strategies.

Purpose of the Study:

• To investigate the co-occurrence and characteristics of SDs during human and rodent seizures.
• To elucidate the mechanisms underlying SD induction during ictal events.
• To explore the potential of SDs for premature seizure termination.

Main Methods:

• Analysis of human clinical electroencephalography (EEG) recordings during seizures.
• Electrophysiological recordings in a rodent model of ictogenesis.
• Correlation analysis of SD occurrence with seizure duration, low gamma activity, and extracellular potassium ([K+]o) levels.

Main Results:

• SDs were prominent features following ictal events in both human and rodent data.
• SDs were associated with shorter seizure-like events (SLEs) and delayed subsequent SLEs in rodents.
• Increased low gamma activity during SLEs predicted SD induction more strongly than [K+]o levels.

Conclusions:

• SDs are a hallmark of ictal activity and are strongly associated with seizure termination.
• Neuronal dynamics, particularly increased low gamma activity, play a key role in SD induction during seizures.
• These findings support further investigation of SDs as a therapeutic target for premature seizure termination.