Seven-patient analysis did not show greater adaptation of the polarity-invariant response than the polarity-flipping component

This analysis tested whether the polarity-invariant component (S) of pulse-locked SEEG responses to alternating-polarity 43.2 Hz trains adapts differently from the polarity-flipping component (D), interpreted in the original proposal as artifact. From OpenNeuro ds006519 v1.0.0, 12 candidate trains in 7 patients were identified; 3 trains failed train quality control, leaving 9 trains. In the main analysis, 59% of 430 non-excluded channels met a mid-train S threshold above twice the pre-train noise floor. S decreased from first to last second (mean log ratio -0.155; exact sign-flip p = 0.094), D also decreased (-0.060; p = 0.17), and their primary contrast was -0.096 (5/7 patients negative; p = 0.20). The result is undetermined: the data show neither that S adapts differently from D nor that they scale together. Selecting channels on first-second S produced an apparent adaptation effect consistent with regression to the mean (contrast -0.20, p = 0.047), so this biased analysis is not interpreted. The main inclusion rule and train quality control were selected after the first results. The sample included 7 patients and 9 trains, and sensitivity analyses were not corrected for multiple comparisons. The 50 Hz non-alternating trains were excluded; ds005169 was not analyzed.

stereo-EEG · intracranial EEG · alternating-polarity stimulation · response adaptation · artifact · regression to the mean · sign-flip test