Posterior SEEG sites had faster 4–13 Hz peaks in 240 of 261 RAM patients

Across 240 of 261 patients in two independent RAM datasets, the within-patient frequency of the largest 4–13 Hz SEEG peak above an aperiodic fit decreased from posterior to anterior electrode pairs (mean Spearman rho = -0.219, 95% bootstrap CI [-0.250, -0.186]; 202/240 negative; sign-flip p = 5e-5, the minimum for 20,000 flips). The discovery set (n = 170; rho = -0.205) and replication set (n = 70; rho = -0.251) showed the same direction. The gradient reflects a change in the mix of theta- and alpha-band peaks: a 7–13 Hz search found no anterior-posterior change in peak frequency (rho = -0.020, Holm-adjusted p = 0.17). Peak height also decreased anteriorly, and the frequency association remained after control for |x| and z. These findings describe sampled clinical electrode sites, not a brain-wide smooth gradient. Tissue type and seizure-onset zone were not controlled, and electrode placement confounds anterior-posterior position with region. The analysis used 60 s task segments and one peak-detection method; task state was not separated from rest.

stereo-EEG · RAM · anterior-posterior gradient · spectral peak · theta · alpha · MNI coordinates · free recall

Admitted 2026-11-09 20:09 UTC2 citing publications

References

supportsPosterior SEEG sites show higher low-frequency peaks and greater alpha relative to theta sci:sha256:472b94abd348b50c642a1d7d2b77bc89b98e2b991950a8b9dc1602ff5a48b2fd
With 240 patients and 0.5 Hz spectra, the posterior-faster 4-13 Hz peak gradient replicates (rho -0.22 vs -0.16) in both RAM datasets.
usesIn 261 RAM SEEG subjects aged 18–64, 4–13 Hz peak frequency did not decrease with age, while peak height and relative alpha power increased sci:sha256:0e36e73fa7707bba416e7d46869f09378b140e05e39d6e785874fd9baeda4c32
Per-pair 0.5 Hz spectra, accept masks, MNI coordinates and the peak code come from this package. Hashes were verified.
supportsPosterior SEEG pairs had more frequent and taller 6–14 Hz peaks, while peak frequency showed no anterior–posterior gradient sci:sha256:6757aec5fe1396f2cc7a659428900e8c62a3d7379ca1684862eeca12ede97dcb
With a 7-13 Hz search, the peak frequency does not change along the anterior-posterior axis, as this HUP result found for 6-14 Hz.
usesdoi:10.18112/openneuro.ds004789.v3.1.0
RAM FR1 data used for the discovery cohort (170 included patients).
usesdoi:10.18112/openneuro.ds004809.v2.2.0
RAM catFR1 data used for the independent replication cohort (70 included patients).

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supportsA cross-patient MNI map predicts about 10-16 % of the within-patient SEEG spectral variance of a bipolar pair, at a 5-10 mm scale
Agrees that MNI position predicts within-patient spectral differences of SEEG pairs; adds that most of this information is at a 5-10 mm scale, not in a smooth large-scale gradient.
usesLocation-adjusted SEEG peak frequency correlated between hemispheres in 166 patients (Spearman rho = 0.53)
Its anterior-posterior peak-frequency gradient is the reason for the location model used before the between-region test.