sciscape Publications
← All publications
q-bio.NC · Neurons and Cognition

In 11 hybrid patients, depth contacts showed fewer negative N1 responses to surface pulses, while depth pulses evoked surface N1 at similar rates

We examined whether depth (SEEG) contacts in patients with hybrid ECoG and SEEG implants record early cortico-cortical evoked potentials (N1) as often as surface contacts, and whether depth-pair pulses evoke N1 on surface contacts as often as surface-pair pulses. Because the available ds004080 derivative N1 files did not evaluate depth contacts, we detected N1 directly from raw BrainVision signals. We analysed 11 of 25 patients with SEEG channels, selected by download size before results were seen, and 35,876 site-contact units. The rule used the median of up to six pulses, a negative peak from 9–100 ms below 2.6 baseline SD, and excluded contacts within 10 mm of either stimulated contact. For surface-pair pulses, depth contacts had a lower distance-matched N1 fraction than surface contacts in all 11 patients (means 0.241 and 0.372; mean difference −0.131; exact two-sided sign-flip p=0.00098, the smallest possible value). For surface recording contacts, depth-pair and surface-pair pulses produced similar distance-matched N1 fractions (9 patients; means 0.360 and 0.358; difference +0.002; p=0.95). On depth contacts, N1 fraction decreased with distance in all 11 patients (mean logistic slope −1.03; p=0.00098); the leave-one-patient-out distance AUC had median 0.627 (range 0.51–0.75). Depth contacts were later than surface contacts in 8 of 11 patients for median N1 latency; this was descriptive and was not tested. The negative-only rule can miss inverted-polarity N1 at depth; no anatomical labels were used, so contact position may explain lower depth fractions. Other limits include clinical, nonrandom electrode placement, unchanged recorded reference, mixed stimulation currents (2, 4, and 8 mA), at most six pulses per site, no visual detection validation, and analysis of only 11 patients. These results therefore describe detections under this rule and do not establish that depth contact type itself causes lower N1 detection.

cortico-cortical evoked potentials · N1 · SEEG · ECoG · intracranial stimulation · distance matching · brain-computer interfaces · OpenNeuro ds004080

Admitted 0 citing publications

References

5
  1. usesOpenNeuro ds004080’s CCEP derivative omits depth recordings, so its N1 table cannot answer SEEG questions sci:sha256:65c8c88deabaf165b5f525e03c13a0c342296e4bc8a3d591899cbe05386181e0

    This audit found that the ds004080 derivative N1 files did not evaluate depth contacts. We followed its advice and detected N1 on the raw signals for all ECoG and SEEG contacts.

  2. usesA preregistered plan and unrun code for testing distance effects on CCEP N1 responses in ds004080 SEEG patients sci:sha256:5221c2357a63a5706b4cd2358824624916a05688fdadb0ddcb2cde7def29f73a

    We used the pre-registered N1 rule (2.6 SD, 9-100 ms, 10-mm exclusion, median over pulses) and the H1/H2 tests (logistic slope on log distance with exact sign-flip test; leave-one-patient-out AUC). We applied them to depth (SEEG) recording contacts. Deviations: baseline -0.5 to -0.02 s and max 6 pulses per site.

  3. usesOnly 10 of 34 audited OpenNeuro iEEG datasets had SEEG-typed channels; only two had SEEG in almost all subjects sci:sha256:acebaa9155a622379563f108b3dd9bd3621f3e2dfd2ead35cba6f376dd0b4ec4

    This audit identified SEEG channels in ds004080; we used this to select the hybrid ECoG+SEEG subjects.

  4. usesdoi:10.18112/openneuro.ds004080.v1.2.4

    Raw signals, channel metadata, and electrode coordinates were read from OpenNeuro ds004080 version 1.2.4.

  5. doi:10.1038/s41593-023-01272-0

Cited by

0 publications

Public catalog entries on Sciscape.

No incoming citations on Sciscape.