Explaining slow seizure propagation with white matter tractography

Area of Science:

• Neuroscience
• Epileptology
• Neuroimaging

Background:

• Epileptic seizure propagation patterns are not fully understood.
• Stereo-electroencephalography (stereo-EEG) records seizure activity, but its relationship with brain structure is unclear.

Purpose of the Study:

• To investigate the relationship between seizure propagation and white matter architecture.
• To elucidate seizure propagation mechanisms by combining stereo-EEG and tractography.

Main Methods:

• Combined patient-specific stereo-EEG seizure propagation maps with diffusion imaging tractography.
• Analyzed tract connectivity between seizure onset zones, spread regions, and non-involved regions.
• Compared connectivity in seizure-free versus non-seizure-free patients.

Main Results:

• Seizure onset zones showed higher tract connectivity to seizure spread regions than non-involved regions.
• In seizure-free patients, spread regions were more connected to the onset zone than to other spread regions.
• Onset zone connectivity to early spread regions was higher in seizure-free patients.

Conclusions:

• White matter tracts mediate seizure propagation.
• The seizure onset zone is a primary driver of seizure spread.
• Understanding structure-propagation links may improve epilepsy surgery target selection.