Dynamics and Distant Effects of Frontal/Temporal Epileptogenic Focus Using Functional Connectivity Maps

Area of Science:

• Neuroscience
• Epileptology
• Computational Neuroscience

Background:

• Interictal epileptiform discharges (IEDs) offer subtle clues to the three-dimensional (3D) seizure onset zone.
• Understanding these patterns is crucial for localizing seizure sources in focal epilepsy.

Purpose of the Study:

• To investigate connectivity patterns of IEDs in electroencephalogram (EEG) signals.
• To assess the impact of 3D seizure onset on functional brain maps in focal epilepsy patients.

Main Methods:

• Functional connectivity maps were derived using phase synchrony among EEG electrodes.
• A data-driven recurrence-based method with novel parameter selection was employed.
• Connectivity matrices were analyzed to evaluate regional effects of the epileptic source.

Main Results:

• High synchronization was observed in temporal and frontal areas of the affected hemisphere.
• Strong connections were found between the epileptic focus and the contralateral frontal and temporal lobes.
• Epileptic activity in temporal or frontal lobes affected homologous areas in both hemispheres.

Conclusions:

• IED connectivity patterns provide insights into the dynamics of focal epilepsy.
• The study highlights how epileptic activity affects both the epileptogenic zone and distant brain regions.