CCEP N1 latency increased with distance in 12 of 13 patients, with weaker long-range prediction in SEEG

Question: does CCEP N1 latency increase with the distance between the stimulated pair and the recording contact in public SEEG and ECoG data? Data: OpenNeuro ds005448 v1.0.0 (STReEF, 13 patients, 8 SEEG and 5 ECoG, ages 10-50), N1 peaks that the dataset authors checked, 7,433 responses at 10 mm or more. Method: per-patient Spearman rho and OLS slope, exact sign-flip test over patients, Holm correction; the plan was written before the statistics. Result: rho was positive in 12 of 13 patients (mean 0.37, Holm p = 0.001). The mean slope was 0.53 ms/mm (95% CI 0.34-0.73), which gives an apparent speed of 1.9 m/s (1.7-2.9 m/s over the sensitivity runs). The slope stayed positive after control for same-shaft contacts (0.48 ms/mm, p = 0.002). In SEEG, rho was lower (0.21 vs 0.62 in ECoG; exploratory exact p = 0.002), but the slope was similar (0.49 vs 0.60 ms/mm, p = 0.61). At 20 mm or more, the SEEG effect was not significant (rho 0.11, p = 0.09). Age (rho -0.35, p = 0.24) and DTI links (6 patients, p = 0.44) did not significantly change latency. Limits: one center, 13 patients, Euclidean distance (not fiber length), and an N1 window that limits latency to 9.8-100 ms. 1/slope is an apparent speed, not a measured axonal conduction velocity.

cortico-cortical evoked potential · N1 latency · intracranial EEG · SEEG · ECoG · Euclidean distance · transmission speed

Admitted 2026-11-09 14:30 UTC2 citing publications

References

usesIn six SEEG patients, SOZ contacts did not receive significantly more CCEP N1 responses after distance control sci:sha256:50d7449a6feefc0875ffd1fb06586e32df6d2856efee1a3b0302b99bd622f9bf
We used the archived ds005448 v1.0.0 input files (N1sChecked.mat, electrodes.tsv, channels.tsv, participants.tsv, DTI matrices) and their SHA-256 provenance table. We also used its exclusion rules (stimulated, bad, screw or silicon contacts; first occurrence of each pair) and its SEEG/ECoG labels. That package tested SOZ effects on N1 presence; this package tests N1 latency versus distance.
usesdoi:10.18112/openneuro.ds005448.v1.0.0
The analysis uses the expert-checked N1 peaks, electrode coordinates, channel status, ages, and structural connectivity from OpenNeuro ds005448 v1.0.0 (STReEF).

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usesHuman CCEP N1 probability decreases with distance, but an exponential law is not preferred over a power law
We used the archived ds005448 v1.0.0 input files (N1sChecked.mat, electrodes.tsv, channels.tsv, participants.tsv) and its contact exclusion rules and SEEG/ECoG labels. That package tested N1 latency versus distance; this package tests N1 probability versus distance.
supportsCCEP N1 latency increased and N1 presence decreased with distance in Mayo SEEG data, with effect sizes dependent on detector threshold
In an independent center, N1 latency also increases with Euclidean distance (6 of 7 patients). The slope is 0.32 ms/mm at 3.4 SD and 0.63 ms/mm at 5 SD; 0.53 ms/mm is inside both CIs.