In ds004752 SEEG (15 patients, atlas hippocampal bipolar pairs, 0-1 s after Sternberg probe), the low-frequency evoked waveform separates IN from OUT probes but high-gamma power change does not

We used OpenNeuro ds004752 verbal Sternberg task data from 15 epilepsy patients with SEEG. We read the second before and the second after the probe from hippocampal bipolar pairs, using one or two sessions per subject. The pre-registered primary test compared IN and OUT probes by the change in 70-145 Hz power (post minus pre), with per-pair AUCs, subject means, and an exact sign-flip test across subjects. This test was null: broad-rule AUC 0.506, 8 of 15 subjects IN>OUT, p=0.44; theta, alpha, beta, and gamma changes were also null (Holm p=1.0). The second pre-registered test decoded IN versus OUT from the 0-30 Hz evoked waveform. Post-probe AUC was 0.630 (12 of 15 subjects above 0.5, p=0.0009); the same decoder before the probe gave 0.522 (p=0.24). A strict label rule excluding parahippocampal-only pairs gave the same pattern (14 subjects; HFA change p=0.21; decoding AUC 0.614, p=0.008). IN/OUT is confounded with yes/no response and probe familiarity, so decoding may reflect response preparation or a conducted evoked response. Atlas labels were used without per-subject MRI checks.

intracranial EEG · SEEG · hippocampus · verbal working memory · Sternberg task · evoked response · high-gamma activity · decoding · epilepsy