Brain Activity in Epilepsy

Prospective interventional study with implantation of micro-electrodes to study the brain networks in epilepsy at high spatiotemporal resolution.

The goal of this trial is to study brain activity in epilepsy at high spatiotemporal resolution. Apart from the epileptogenic network (dysfunctional areas), the investigators will study human brain function. The use of micro-electrode arrays allows to study the human brain a high spatiotemporal resolution, even at the single neuron level. Scientific objectives of the current project: To record neural signals from macro-electrodes and delineate the epileptogenic network and study brain function during specific tasks. To record neural signals from micro-electrodes and delineate the epileptogenic network and study brain function during specific tasks. Identifying pivotal regions for BMI applications and developing online decoding algorithms. Comparing neural recordings to fMRI activity

intracranial macro/micro-electrode placement at the cerebral cortex or in deeper brain areas with te use of macro/micro electrode recording. Macro/micro electrodes are placed at the cerebral cortex or in deeper brain areas in order to precisely identify the epileptogenic focus

The investigators will investigate the epileptogenic network by recording neural activity at different spatiotemporal scales and using different modalities. The investigators will be looking at * Electrophysiological recordings: - single neuron recordings (outcome measure: spike rate)

The investigators will investigate the epileptogenic network by recording neural activity at different spatiotemporal scales and using different modalities. The investigators will be looking at * Electrophysiological recordings: - local field potentials (LFP) (outcome measure: mainly power in the beta and gamma band, but also alfa and theta band)

* fMRI recordings (outcome measure: Blood Oxygen Level Dependent (BOLD) signal increases/decreases) By performing electrophysiological recordings and fMRI recordings in the same subjects, we will be able to compare both modalities with each other.

Since electrodes are placed for clinical purposes, the investigators will also use these electrodes to investigate normal neural functions of the human brain: vision, perception and motor. * Macro-electrodes record local field potentials (LFP). The main outcome measure for visual research is the power in the gamma band. The main outcome measure for motor research is power increase in the beta and gamma band.

* Micro-electrodes and multi-electrode arrays (Utah-array) record local field potentials (LFP) and spike-activity. The outcome measure for spike activity is spike rate. For the local field potentials, the main outcome measure for visual research is the power in the gamma band. The main outcome measure for motor research is power increase in the beta and gamma band.

The outcome measure is blood oxygen level dependent (BOLD) signal changed in response to visual and/ or motor experiments.

Inclusion Criteria: Age ≥18 yo Epilepsy patients undergoing intracranial electrode placement. Able to understand the procedure involved and to consent. Exclusion Criteria: Age < 18 yo Pregnancy