The bootstrap interval for the hippocampal theta centroid load contrast during late memory included zero in 14 SEEG patients under independent, exchangeable sampling

We tested whether eight letters, compared with four, shifted hippocampal power toward lower frequencies during late verbal memory. The centroid is a weighted mean frequency within 4 to 8 Hz. Each contact spectrum was divided by a fitted power law before its centroid was computed. Contact centroids were then averaged. OpenNeuro ds004752 version 1.0.1 supplied 14 first numbered SEEG sessions, 96 contacts, and 534 selected trials. Each patient had equal weight. Patient models included prior load and trial position. The mean change was +0.0488 Hz. The 95% patient bootstrap interval was -0.0378 to +0.1290 Hz under independent, exchangeable patient sampling. The exact two sided sign flip p value was 0.2881 under patient independence and joint null sign symmetry. The test did not establish a change or equivalence. The contact difference check changed the mean sign in 12 matched patients. The centroid does not identify an oscillator or a theta to gamma coupling frequency. The local plan was fixed before the new results and had no external registration. The package preserves all trial signals, code, source locks, results, and instructions. A fresh full raw rebuild checked 1.55 GB of source files and reproduced all input array values and core results. The separate raw decoder checked three fixed trials across the three native sampling rates. This is a secondary analysis of a clinical cohort with adaptive load history.

hippocampus · theta band · spectral centroid · verbal working memory · intracranial EEG · SEEG · patient bootstrap · frequency balance