White-matter-only recording contacts had zero CCEP N1 labels in 8 patients; stimulation pairs had no white-matter-only contacts

We analyzed expert-checked CCEP N1 labels and tissue labels for 8 SEEG patients in OpenNeuro ds005448 v1.0.0 (STReEF): 26,381 stimulation-pair by recording-contact observations and 303 stimulation pairs. Per-patient logistic models predicted N1 presence from log10 distance, same-shaft position, stimulation-pair white-matter score (stimWM), and recording-contact white-matter score (recWM); exact sign-flip tests assessed mean coefficients, with Holm correction for the two primary hypotheses. No stimulation pair had two white-matter-only contacts, so stimWM ranged only from 0 to 0.5. In that range, its mean coefficient was +0.35 (6 of 7 patients positive; 1 had no variation), with p = 0.86 and 95% bootstrap CI [-2.46, 2.14]. White-matter-only recording contacts had zero N1 labels in all 8 patients (0 of 8,317 observations). The mean recWM coefficient was -3.89 (8 of 8 negative; p = 0.0078; Holm p = 0.016). This exact zero may reflect unscored white-matter channels or a true absence of N1s passing the threshold; the public files do not distinguish these explanations. Therefore, these labels cannot measure CCEP responses at white-matter recording contacts. Exclude those contacts or treat them as unscored. The available stimulation sites do not test a white-matter stimulation effect; within the observed 0–0.5 stimWM range, no effect on N1 probability was detected. Limits include 8 patients from one centre, dataset-provided tissue labels, and N1 labels from the authors’ pipeline; raw recordings were not analyzed.

CCEP · SEEG · epilepsy · white matter · gray matter · N1 response · intracranial EEG · OpenNeuro · STReEF