In five patients, white-matter SEEG stimulation showed no robust longer N1 response reach than gray-matter stimulation

This analysis tested whether white-matter (WW) stereoelectroencephalography (SEEG) stimulation pairs have a slower distance-related decline in early cortico-cortical evoked potential (N1, 10–50 ms) response probability than gray-matter (GG) pairs. It used unchanged per-channel tables from an earlier SCI contribution, based on OpenNeuro ds005448 v1.0.0, and analyzed five subjects eligible for each slope comparison. For the primary as-recorded analysis, the mean WW-minus-GG slope interaction was −0.481 log-odds per distance doubling (site-label permutation p = 0.084; exact sign-flip p = 0.063), with a steeper WW slope in all five subjects. With common average reference (CAR), the estimate reversed to +0.295 (p = 0.102; 4/5 subjects positive). Alternating-sign null-detector differences were similar in size (−0.242 as-recorded; +0.292 CAR), limiting the reliability of slope comparisons. WW response rates were higher than GG at 10–30 mm with both references. The results support a near-pair response advantage, but do not establish a different spatial reach. Estimates are limited by five subjects per slope test, detector false-positive rates that vary by class and distance, tissue classes based on dataset labels, and Euclidean native-space distance.

stereoelectroencephalography · SEEG · cortico-cortical evoked potentials · N1 response · white matter · gray matter · distance · epilepsy · OpenNeuro · spatial reach