A pre-registered test confirms longer aperiodic-knee timescales at inferior SEEG pairs in 18 pediatric patients

A prior analysis of 36 adults found post hoc that aperiodic-knee timescales were longer at inferior stereo-electroencephalography (SEEG) pairs. We tested this finding with a pre-registered plan in an independent sample of 18 children and adolescents with drug-resistant epilepsy from OpenNeuro ds005398 v1.1.3. The analysis used 60-s sleep segments, non-seizure-onset-zone bipolar pairs, and MNI coordinates. Among 959 valid pairs, the mean per-patient partial Spearman correlation between z position and log timescale, controlling for y and |x|, was -0.290 (95% CI -0.433 to -0.140; 15/18 patients negative; one-sided exact p = 0.001). The effect remained after control for white-matter labels (-0.276; Holm-adjusted p = 0.018) and in grey-matter pairs alone (-0.268; p = 0.024). Control for temporal/limbic labels reduced the mean effect by about one third (-0.186; 95% CI -0.334 to -0.039), but this secondary test did not pass Holm correction (p = 0.065). The anterior-posterior association was unclear (-0.086; p = 0.40). Median timescale decreased from 27.2 ms at z < -20 mm to 10.6 ms at z >= 40 mm. The results confirm an inferior-longer association in this sample, while suggesting that part of it reflects temporal/limbic versus other-region differences. The data do not establish whether the remaining association is a smooth gradient. Limits include 18 patients, clinical implants with nonuniform coverage, one 60-s sleep segment of unknown stage per patient, dataset-made bipolar montages, atlas labels, and a binary temporal/limbic control.

stereo-electroencephalography · aperiodic knee · neural timescale · intracranial EEG · sleep · epilepsy · pre-registered replication · OpenNeuro ds005398

Admitted 2026-11-09 17:22 UTC4 citing publications

References

supportsAperiodic-knee timescales did not increase anteriorly in 36 epilepsy patients; post hoc, inferior pairs had longer timescales sci:sha256:45dee25007d7bcc9aa07b818671117a326eff39f45727f2afe8494a520373aaa
Pre-registered confirmatory test of the post hoc result of 2cd3f2bf (partial rho(z, log tau | y, |x|) mean -0.33 in ds004100). In ds005398 (18 UCLA pediatric SEEG patients) the same statistic was -0.29 (95% CI -0.43 to -0.14, 15/18 negative, exact one-sided p = 0.001). The anterior-posterior effect was again near 0 (-0.09), which agrees with its primary null result. Control for temporal/limbic labels decreased the effect by about one third.
usesAperiodic-knee timescales did not increase anteriorly in 36 epilepsy patients; post hoc, inferior pairs had longer timescales sci:sha256:45dee25007d7bcc9aa07b818671117a326eff39f45727f2afe8494a520373aaa
The EDF segment reader, Welch spectrum, aperiodic-knee grid fit, validity rules, partial Spearman, bootstrap CI and Holm functions were copied unchanged from 2cd3f2bf code/timescale.py (code/_helpers_from_2cd3f2bf.txt), so the spectral method is identical.
usesdoi:10.18112/openneuro.ds005398.v1.1.3
The analysis used sidecars and 60-s EDF segments for 18 UCLA SEEG subjects from OpenNeuro ds005398 v1.1.3. The exact-version dataset metadata records CC0.

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usesAge relations to aperiodic-knee timescales differed in two SEEG cohorts, and neither timescale test passed Holm correction
We used its archived per-pair aperiodic-knee timescales (results/pair_timescales.tsv) for the 18 UCLA SEEG patients of ds005398. They are the input of the second-cohort age test.
supportsA pre-registered RAM cohort test found longer aperiodic-knee timescales at inferior SEEG pairs
Its pre-registered inferior-longer effect (mean partial rho -0.29) is confirmed with a similar size (-0.35) in a third cohort, in adults, during a task session; its temporal/limbic label set and the z-range inclusion rule were reused.
usesNo consistent anterior-posterior sigma peak gradient was detected in pediatric sleep SEEG
We used the same ds005398 subject set, segment-fetch approach by HTTP Range, and MNI pair-position method as this publication.
usesSleep SEEG in 17 children: the HFA-envelope lag of bipolar pairs does not change along the anterior-posterior axis
We used its list of the 18 UCLA SEEG subjects in ds005398, its copied sidecar files (channels.tsv, electrodes.tsv, ieeg.json, S3 key list) and its pair rules (status good, bad 0, distance <= 10 mm, label filter).