Shaft-end bipolar pairs had higher 70–150 Hz power in 15 SEEG patients, with similar excess at both ends

This preregistered replication tested a post hoc finding in independent OpenNeuro ds004752 data from 15 patients performing a verbal working-memory task. Using the first 64 s of session 1 for each patient, we found that the highest-power 70–150 Hz bipolar pair was at a shaft end in 10/15 patients (4.30 expected; Holm-adjusted p = 0.0076). End pairs had higher power than interior pairs in all 15 patients (mean AUC = 0.754; Holm-adjusted p = 1.5 × 10⁻⁴). The outer and tip ends had similar power (mean difference +0.006 log₁₀; 6/15 positive; p = 0.48). Outer-end pairs had a flatter spectrum (mean difference +0.238; Holm-adjusted p = 0.0049), while their envelope correlation difference was not significant after Holm correction (p = 0.11). Thus, the shaft-end power excess recurred, but was not specific to the superficial end; the planned criteria for an EMG explanation were not met. This was a single-site, single-task study of 15 patients using 64 s per patient, without gray/white matter labels. The outer end was defined by distance from the contact centroid, not the skull. A possible tissue-related cause was not tested.

stereo-EEG · SEEG · high-frequency activity · bipolar pairs · electrode shaft · working memory · replication · power spectrum