Source tracing with spatial phase gradients in epileptiform activity localizes seizure onset zone

Area of Science:

• Neuroscience
• Epilepsy Research
• Computational Neuroscience

Background:

• Epileptic traveling waves are crucial for localizing the seizure onset zone (SOZ) in epilepsy patients.
• Current source-tracing methods are limited by epileptiform activity instability and lack of tailored approaches.
• Reliable SOZ localization is essential for effective preoperative assessment and treatment planning.

Purpose of the Study:

• To analyze epileptic expanding traveling wave (ETW) propagation patterns during seizures.
• To develop a novel framework for tracing the sources of ETWs.
• To assess the framework's reliability for SOZ localization, especially with sparse data.

Main Methods:

• Recorded 101 seizure events from 4-Aminopyridine-induced rat epilepsy models.
• Classified epileptiform activities into multiband and non-multiband categories using time-frequency analysis.
• Applied spatial-phase-based analysis to extract ETWs and traced sources via spatial-phase-gradient intersection.

Main Results:

• Multiband activities showed a higher ETW proportion (62.7%) compared to non-multiband (53.8%).
• Single-band signals exhibited more stable ETW propagation, leading to concentrated source tracing.
• Source tracing remained stable and clustered around the SOZ center, even when the center was out of coverage.

Conclusions:

• The developed framework effectively extracts ETWs and traces their sources, even with incomplete data.
• This method offers improved SOZ localization accuracy compared to traditional techniques.
• The framework holds significant clinical potential for epilepsy surgery planning, particularly with sparse intracranial recordings.