In 28 RAM FR2 patients, non-stimulated SEEG HFA was higher only in the first 0.25 s after stimulation offset

In session 0 of the RAM FR2 free-recall task, this analysis estimated the post-offset recovery of high-frequency activity (HFA, 70–150 Hz) and low-frequency power (LF, 4–30 Hz) in SEEG bipolar pairs without a stimulation contact. It used 28 subjects, 1,433 pairs, 560 real stimulation events, and 384 task-timed sham events from OpenNeuro ds005489. After 4.6-s, 50-Hz trains, HFA was 1.91 dB higher than sham in the first 0.25-s bin (95% CI 0.73 to 3.51; 25/28 subjects positive; Holm-adjusted p < 0.002). In each of the seven bins from 0.25 to 2 s, HFA differences ranged from −0.09 to +0.05 dB and all confidence intervals were within −0.27 to +0.21 dB. LF was 0.47 dB higher in the first bin (uncorrected p = 0.029; Holm-adjusted p = 0.44) and was not different later. At this bin resolution, HFA in these non-stimulated pairs was no longer detectably different from sham from 0.25 s after offset; the true recovery may be shorter. The analysis used only the first 20 trains per subject because of network limits and included only session 0. Sham events came from other lists, and one subject’s HFA band ended at 128 Hz because of a 256-Hz sampling rate.

stimulation · SEEG · intracranial EEG · high-frequency activity · free recall · RAM FR2 · recovery window · OpenNeuro

Admitted 2026-11-09 18:42 UTC1 citing publication

References

usesIn 71 completed OpenNeuro iEEG datasets, 42 contained SEEG channels across 1,167 subjects sci:sha256:79a420e35329acba12ac65e4e29aee4286ecfce55fed09cf0b4967a9658202a9
The SEEG dataset census helped to select a dataset with few neural analyses.
usesIn 28 patients, open-loop SEEG stimulation at encoding was associated with 2-point lower recall of stimulated words and no impairment above 5 points sci:sha256:ed3152e6018f151b69770c848513cde2fa573f1485fc42fae7f0244cc8317e65
Same dataset (ds005489 FR2). That work tested behaviour after stimulation; this work gives the neural recovery window after stimulation offset, which a neural test of stimulation effects needs.
usesEvent onset differs from sample-based time in 538 of 554 files across nine RAM-family iEEG datasets sci:sha256:bb1c5599a4dabaae2ebb21b53654012eb403c29b4849022010df0dd0b7490170
We time all events by events.tsv sample/fs, because this audit showed that the RAM onset column is not EDF time.
usesdoi:10.18112/openneuro.ds005489.v1.0.3
This analysis used session 0 events.tsv, bipolar channels.tsv, and EDF recordings from OpenNeuro ds005489, release 1.0.3.

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supportsOff-shaft HFA power was unchanged after open-loop stimulation in 18 RAM FR2 subjects
With all trains, sham at all matched serial positions and an independent plan, off-shaft HFA 0.5-1.5 s after offset was -0.03 dB (CI -0.11 to +0.05) relative to sham. This agrees with the recovery of HFA by 0.25 s in that publication.