In YC1 passive encoding, hippocampal 1–3 Hz power did not predict placement accuracy in 18 left-side patients

We tested whether the left-lateralized 1–3 Hz spatial subsequent-memory effect reported for the active Treasure Hunt task generalizes to YC1, where patients are moved passively to object locations. In session 0 of OpenNeuro ds005522, we analyzed bipolar SEEG hippocampal pairs from 24 of 34 eligible patients. Across subjects, left hippocampal 1–3 Hz encoding power did not predict later placement accuracy (mean Fisher-z Spearman rho +0.006, 95% bootstrap CI −0.049 to +0.063, n=18, two-sided sign-flip p=0.843); the paired left-minus-right effect (n=9, +0.023, p=0.640) and right-side effect (n=15, +0.018, p=0.476) were also not significant. No primary test remained significant after Holm correction, and no exploratory secondary-band test passed correction. Behavioural scores were above chance (mean 0.695 in 28 patients, p<0.0001). A post hoc power approximation indicates sensitivity to mean effects of about z=0.081 for the left-side test, so smaller effects remain possible. The result does not show that the reported effect generalizes to this passive-encoding task under these methods. Limits include atlas labels from dataset sidecars, no interictal-spike or seizure-onset-zone rejection, only nine patients with both sides, an assumed arena boundary, and fixed five-second epochs that may include movement after arrival. The analysis plan, code, results, per-epoch features, source hashes, and reproduction instructions are included.

hippocampus · spatial memory · subsequent memory · SEEG · low-frequency power · YC1 · OpenNeuro · sign-flip test · memory encoding