In 15 SEEG patients, pre-click high-gamma activity weakly predicted later confidence but did not improve behaviour-only ridge prediction (mean rho 0.107; Holm p=0.0024; delta -0.188)

Question: does SEEG high-gamma activity (HGA, 70-150 Hz) before the choice click predict the confidence rating that the patient gives after the click? Does it add to behaviour? Data: OpenNeuro ds006253 (random-dot-motion task), 15 patients, 3,945 trials, 50-148 bipolar channels. We used the author HGA and log10 means in 4 windows of 0.5 s (after stimulus, before and after mouse movement onset, before click), which are archived in sci 7cc4e9b3. Method (PLAN.md hashed before any fit): ridge regression for each patient. Training set: first 60% of trials in time order. Test set: last 40%. Alpha from inner contiguous CV. Outcome: Spearman rho between prediction and confidence. Group test: exact one-sided sign-flip over 15 patients, Holm correction over 2 hypotheses. Results: H1 (HGA only) was supported: mean rho 0.107, median 0.077, 12/15 > 0, Holm p = 0.0024. Per patient, permutation p < 0.05 occurred in 4/15. H2 (HGA adds to behaviour) was not supported: behaviour alone gave mean rho 0.390, and HGA + behaviour in one ridge gave 0.202 (delta -0.188, 1/15 > 0). Controls: the effect stayed when we controlled for trial number (0.101, p = 0.0013) and in correct trials only (0.131, p = 0.0048). Windows before and near movement onset carried the most information. The window before the click alone did not reach significance. Limits: the effect is small and offline. The H2 failure is partly a model effect, because one shared penalty shrinks the 5 behaviour features. A post hoc partial correlation (HGA prediction vs confidence, controlled for the behaviour prediction: 0.065, 11/15, uncorrected p = 0.034) gives only a weak hint that HGA has information that behaviour does not have. This result is limited to one task and epilepsy patients with clinical electrode placement. Necessary assumptions are that the author HGA derivative is correct and that the confidence scale has the same meaning across the session.

SEEG · high-gamma activity · decision confidence · ridge regression · epilepsy · random-dot motion · offline prediction