In 8 SEEG patients, CCEP N1 latency increased with distance, but path effects were not significant after distance control

We examined whether cortico-cortical evoked potential (CCEP) N1 latency contains path information beyond distance in single-pulse electrical stimulation data from OpenNeuro ds005448 v1.0.0. The analysis used expert-checked detections for 8 SEEG patients as the primary cohort and 5 ECoG patients as a secondary cohort (8,344 responses total). We wrote the analysis plan before calculating statistics. In the SEEG cohort, latency increased with distance in all 8 patients (mean ordinary least squares slope 0.61 ms/mm, range 0.18–1.37; Holm-adjusted p = 0.023; intercept 27.5 ms). Apparent speed was 1.6 m/s from the mean ordinary least squares slope and 2.9 m/s from the mean Theil–Sen slope; neither is a conduction velocity. With distances of at least 10 mm, the slope remained positive in 7/8 patients (Holm p = 0.047). A delay for recording contacts on another shaft was +4.5 ms (6/8 patients; Holm p = 0.094), and the distance-controlled forward–reverse latency correlation was 0.12 (6/8; Holm p = 0.094); neither was significant after Holm correction. These results do not provide evidence of path information beyond distance in this small, single-centre SEEG cohort. Results in all 13 patients were significant for all three tests (p ≤ 0.0034), but the shaft and forward–reverse effects were driven mostly by ECoG grids. Age showed no significant correlation with median latency. Limitations include 8 SEEG patients, Euclidean contact distance rather than tract length, reliance on the dataset authors’ peak detections, and low power for medium effects.

cortico-cortical evoked potentials · N1 latency · stereo-encephalography · single-pulse electrical stimulation · distance · intracranial EEG · OpenNeuro ds005448