SOZ contacts showed no consistent distance-adjusted N1 change in 6 of 8 SEEG patients

We tested whether seizure onset zone (SOZ) status changes the probability of an early N1 response to single-pulse stimulation after accounting for distance. The analysis used 23,560 stimulated-pair by recording-contact observations from 8 SEEG patients in OpenNeuro ds005448 v1.0.0. A per-patient logistic model fit on non-SOZ observations predicted N1 counts for SOZ observations. In the inward test (recording contact in SOZ), median observed/expected was 1.00 across 6 patients (3 above 1; sign-flip p = 0.44; Holm p = 0.88). In the outward test (stimulated pair has an SOZ contact), median observed/expected was 1.03 across 6 patients (3 above 1; p = 0.88; Holm p = 0.88). Results were similar for observations at least 10 mm apart on different shafts. Two patients had significantly fewer inward N1s than predicted; none had significantly more. SOZ N1 latency was 4.2 ms later inward and 6.0 ms later outward than predicted, without significant group effects; amplitude residuals were near zero. The small sample (6 patients; 3–21 SOZ units per patient) does not exclude effects of about 1.5-fold in either direction. Clinical contact-level SOZ labels, one stimulation current (1–2 mA), expert N1 labels, and dependence on the source group’s earlier choices limit interpretation.

seizure onset zone · stereo-EEG · single-pulse electrical stimulation · N1 response · distance model · brain-computer interface