Macro and micro scale of high frequency epileptiform activity within human brain

Over the last 50 years, the success rate of surgical interventions in drug-resistant epilepsy has not significantly improved, remaining at around 50-60%. During presurgical evaluation, the identification of the “epileptogenic zone” (EZ) is crucial for its subsequent removal. In the past, high frequency oscillations (HFOs, 80-500 Hz) were shown to be a promising interictal (seizure independent) marker of the EZ. Recently, our group showed that very high frequency oscillations (VHFOs, 500-2000 Hz) are frequent in epileptic patients and appear to be more specific for the EZ than traditional HFOs. In this project, we aim to describe electrophysiological properties of the epileptic and healthy brain beyond the limit of 500 Hz in a large multi-centric dataset. To study the origin and propagation of these fast oscillatory events we will utilize macro electrodes in vivo, micro electrodes in vivo, and micro-electrode arrays (MEA) ex vivo. The results of this project will bring new knowledge about pathophysiology, the VHFOs exact role and their contribution to the successful epilepsy surgery.