To quantify ictal gamma dynamics in a large stereoelectroencephalography (SEEG) dataset and determine whether ictal gamma increase is preferentially associated with seizure onset zone (SOZ) contacts.
Key Findings:
SOZ contacts showed higher gamma log-ratio values than non-SOZ contacts (median 1.838 vs. 0.696, p = 9.46 × 10^-23).
Hierarchical mixed-effects modeling indicated SOZ status was significantly associated with higher contact-level gamma log-ratio values (β = 0.802, p < 2 × 10^-16).
Top-gamma contacts were enriched in SOZ contacts (28.8% vs. 6.7%, odds ratio 5.65, p = 2.92 × 10^-123).
The strongest SOZ versus non-SOZ separation was observed in mesial temporal contacts, with significant differences in other regions.
Interpretation:
Ictal gamma activity increases during seizures and is associated with seizure onset contacts.
Limitations:
The study relied on a single dataset, which may limit generalizability.
Variability in signal quality and metadata availability may affect the robustness of findings.
Conclusion:
Ictal gamma activity is localized to seizure onset contacts, with variability across different brain regions.
