Bipolar SEEG reduced nearby LFP correlation in two resting patients, while monopolar and CAR signals remained correlated

We measured correlations between resting stereoelectroencephalography (SEEG) channels as a function of distance in two patients, using the first 120 s of OpenNeuro ds005670 version 1.0.0. We compared monopolar, common-average reference (CAR), and adjacent-contact bipolar montages for 1–40 Hz local field potential (LFP) and 70–150 Hz log high-gamma envelope features. For channel pairs less than 8 mm apart, median LFP correlation was 0.910 and 0.942 in monopolar signals, 0.784 and 0.867 in CAR signals, and −0.058 and 0.078 in bipolar signals for sub-01 and sub-02, respectively. Bipolar high-gamma envelope correlations were 0.160 and 0.147; corresponding medians for pairs more than 40 mm apart were 0.129 and 0.116. Monopolar LFP correlations remained 0.561 and 0.610 beyond 40 mm. These results show low correlation among nearby bipolar LFP channels in these recordings, while high-gamma envelope correlations retain a small distance-independent component. They may inform feature selection for brain-computer interfaces, but no task or decoding performance was measured. The analysis included two patients and 120 s of rest per patient, did not estimate across-subject statistics, and used only 67 of 238 sub-01 contacts because many EDF labels did not match coordinate labels.

stereoelectroencephalography · SEEG · electrode distance · channel correlation · bipolar montage · common-average reference · local field potential · high-gamma envelope · brain-computer interface