Interictal oscillations and focal epileptic disorders

Area of Science:

• Neuroscience
• Epileptology
• Computational Neuroscience

Background:

• Neuronal network oscillations are fundamental to brain activity, observable in EEG signals during both healthy and pathological states like epilepsy.
• Interictal oscillations, occurring between seizures, are classified as interictal spikes and high-frequency oscillations (HFOs) based on their frequency and waveform.

Purpose of the Study:

• To review the cellular mechanisms generating interictal spikes and HFOs in animal models of epilepsy.
• To explore the role of these oscillations in ictogenesis (seizure generation) and epileptogenesis (chronic epilepsy development).

Main Methods:

• Analysis of existing literature on interictal spikes and HFOs in animal models of focal epilepsy.
• Review of in vitro and in vivo studies investigating neuronal network excitability changes associated with these oscillations.

Main Results:

• Interictal spikes are large-amplitude, short-duration events in wideband EEG.
• HFOs, including ripples (80-200 Hz) and fast ripples (250-500 Hz), are detected in filtered EEG signals.
• These oscillations reflect dynamic alterations in neuronal network excitability.

Conclusions:

• Interictal spikes and HFOs are critical biomarkers for localizing the seizure onset zone in focal epilepsy.
• Understanding the cellular basis of these oscillations provides insights into the mechanisms driving seizure generation and epilepsy progression.
• This knowledge is vital for developing targeted surgical and therapeutic interventions for drug-resistant epilepsy.