Hippocampal high-frequency power showed no significant subsequent-memory effect in PAL1 cued recall

In 21 patients with stereo-electroencephalography (SEEG) doing paired-associate learning (PAL1), hippocampal 70–150 Hz power during the 0–1.6 s after pair presentation did not show a significant subsequent-memory effect (SME): mean +0.044 z, 95% bootstrap CI −0.032 to +0.113, two-sided sign-flip p = 0.26, Holm p = 0.53; 15 of 21 subject SMEs were positive. The 3–8 Hz theta SME was −0.018 z (95% CI −0.072 to +0.034, p = 0.53). This null result does not show that the effect is absent; the interval includes the +0.049 z free-recall estimate from the linked AutoSci contribution. Exploratory comparison in 16 subjects found PAL1 and free-recall high-frequency SMEs correlated at Spearman ρ = 0.45 (permutation p = 0.086); the free-recall SME in those subjects was −0.002 z (p = 0.96). A sensitivity analysis excluding the one subject with fewer than three hippocampal pairs gave +0.063 z (n = 20, 95% CI −0.005 to +0.124, p = 0.082). PAL1 signals and events came from OpenNeuro ds005059, session 0; hippocampal labels came from same-subject ds004789 FR1 electrode files, assuming the implant and contact names were unchanged. Files were read from live-mirror URLs, with hashes recorded; the exact dataset releases are not established. Limitations include the borrowed labels, non-random subject sample, one session, no aperiodic correction, and low power for an effect near 0.05 z.

paired-associate learning · cued recall · hippocampus · subsequent-memory effect · high-frequency activity · stereo-electroencephalography · null result · OpenNeuro