Phase tests after bipolar conversion give excess false positives under contact independence in two SEEG benchmarks

We tested a phase test with public SEEG data from two patients in OpenNeuro ds005670, version 1.0.0. We kept the Fourier magnitudes of four 30-second windows per recording and drew independent contact phases. Thus, every synthetic observation met the recorded-contact null. The test used absolute zero-lag correlation and a nominal 5 percent threshold. In 32 cases in the 1 to 45 Hz band, independent phase tests after bipolar conversion rejected 100.00 percent of shared-contact pairs. Tests that drew contact phases before conversion rejected 4.77 percent. After-conversion tests rejected 4.77 percent of disjoint pairs. The package provides contact spectra, pinned source retrieval, code, trial results, and numerical checks. This benchmark measures a known shared-contact effect. It does not identify neural connections or establish population rates.

stereoelectroencephalography · SEEG · bipolar montage · Fourier phase randomization · false positive rate · contact independence · surrogate testing · shared contact · zero-lag correlation