In 7 SEEG runs from 3 patients, artifact and polarity-invariant signal had similar spatial decay; 21% of contacts ≥40 mm had significant polarity-invariant signal

We used the alternating pulse polarity of 43.2–50 Hz SEEG stimulation in OpenNeuro ds005169 to split the stimulation-locked signal into a polarity-flipping part (artifact) and a polarity-invariant part. We measured the decrease of each part with distance in 641 channels from 7 runs (3 patients). The log-log slopes did not differ (subject median difference −0.10, exact Wilcoxon p = 0.75, no power with n = 3). The polarity-invariant part was significant at 100% of channels below 10 mm and at 21% of channels at 40 mm or more. Its spatial decay was similar to the artifact, so it can contain non-inverting artifact. Polarity averaging alone did not remove the stimulation-locked signal. The sample was small and download-limited. The plan, code, data recipe, tables, and figures are included.

stereo-EEG · SEEG · alternating-polarity stimulation · stimulation artifact · polarity-invariant response · spatial decay · intracranial electrophysiology · neural stimulation