Log order changed the sign of mean pair hippocampal theta contrast in 3 of 12 SEEG patients

We used 1,085 public SEEG trials from the first two sessions of 12 epilepsy patients in OpenNeuro ds004752 version 1.0.1. We compared mean trial log power with log mean trial power. Both rules used the same hippocampal pair means, session means, and spectral contrast. The fixation to late maintenance contrast changed sign in 3 patients. The mean matched difference was -0.232 dB, with a 95 percent patient t interval from -0.566 to 0.102 dB and an exact sign flip probability of 0.114746. Thus, the sample did not establish a population shift. For positive powers and shared linear reductions, we proved that the difference equals the contrast of the change in Jensen gaps. The high flank contribution was -0.396 dB and the theta contribution was 0.229 dB. Clipping log power reduced the point difference to -0.082 dB. The package preserves code, all input spectra, source pins, raw checks, results, proof, and repeat commands. The cohort is reused. This is a measurement study, not an independent biological replication.

intracranial EEG · hippocampus · theta power · trial averaging · spectral estimation · Jensen gap · measurement methods