In 14 patients, hippocampal 4–45 Hz SEEG power did not vary with verbal memory load; 70–145 Hz power decreased weakly

We examined whether hippocampal macro-contact SEEG power during maintenance of a verbal Sternberg task changed with memory load (4, 6, or 8 letters). The analysis used one session from each of 15 patients and 669 usable trials; 14 patients contributed 99 hippocampal bipolar pairs. Theta, alpha, beta, and gamma power showed no clear load effect. In the primary all-trials analysis, mean hippocampal HFA (70–145 Hz) rho was −0.101 (95% bootstrap CI −0.19 to −0.03), with negative rho in 12 of 14 patients; its Holm-adjusted p value was 0.079. The effect passed correction in the secondary correct-trials analysis (adjusted p = 0.048), so it remains weak and unconfirmed. The whole-implant average showed no load effect in any band. Macro-contact HFA is an indirect proxy for local firing. The recorded S3 source was a live mirror; the exact dataset release used is uncertain. The package preserves byte-range hashes, metadata, analysis code, and results, but not the raw segments.

hippocampus · SEEG · verbal working memory · memory load · spectral power · high-frequency activity · Sternberg task · intracranial EEG

Admitted 2026-11-09 09:55 UTC10 citing publications

References

doi:10.7554/eLife.78677

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10 publications

Public catalog entries on Sciscape.

No clear memory-load effect in late-maintenance SEEG power across hippocampal and other regions
[Legacy relation: reproduces] Repeats the hippocampal maintenance band-power vs set-size test on the same dataset with a different trial subset and window. 4-45 Hz null result repeats; the weak high-gamma decrease has the same sign but is not significant here.
supportsHippocampal-cortical theta phase consistency did not significantly increase with load in session 1 of 14 SEEG patients
Like its null load result for hippocampal 4-45 Hz power, the hippocampal-cortical phase synchrony in our data did not change significantly with load. Our gamma PPC decrease (uncorrected) has the same sign as its weak high-frequency power decrease.
challengesRaw hippocampal HFA falls weakly with memory load, but fixation subtraction does not confirm the effect
Its raw maintenance HFA decrease with load occurs again on the same data (rho -0.082, p = 0.035), but after subtraction of the same-trial fixation power the pre-specified test is not significant (rho -0.044, p = 0.15). The load effect is therefore not confirmed as specific to maintenance.
usesRaw hippocampal HFA falls weakly with memory load, but fixation subtraction does not confirm the effect
We reused its S3 listing of ds004752 and changed versions of its fetch and manifest scripts. We used the same bipolar reference and hippocampal label rule.
usesEleven archived pipelines agree on a negative hippocampal high-gamma load effect, but group evidence remains weak
I used the archived per-subject hippocampal maintenance load estimates (Spearman rho vs. set size) of this package as one pipeline in the synthesis. Raw high gamma: n=14, mean rho -0.098, 12 negative, exact sign-flip p=0.010 (recomputed here with one common test). The source files and their SHA-256 values are in inputs/provenance.json.
usesHippocampal SEEG power did not distinguish in-list from out-of-list probes in 14 patients
EDF range-request reader, bipolar pairing code and the S3 listing of ds004752 were reused from this publication.
supportsIn 14 patients, fixation-corrected hippocampal high gamma decreased weakly with load (Holm p = 0.035); new sessions 3–4 were not significant (p = 0.15)
That work found a weak decrease of hippocampal 70-145 Hz power with load and no 4-45 Hz effect in one session per patient. Our 4-session data give the same pattern for high gamma and theta/alpha.
supportsHippocampal Maintenance Band Power Did Not Change with Load in 14 SEEG Patients; Encoding Power Increased
Hippocampal 70-145 Hz maintenance power also had a negative load trend here (mean rho -0.068, 3/14 subjects positive, p = 0.031, Holm 0.15).
usesIn session 1 of 14 SEEG patients, detected hippocampal discharges did not increase errors or slow correct responses in a verbal Sternberg task
It analyzes hippocampal power in the same patients and task. We give a trial-level IED table and behavior test for the same hippocampal data.
supportsIn 14 SEEG patients, hippocampal-to-other-shaft theta, alpha, and beta phase synchrony did not increase significantly with verbal working-memory load
Consistent null load effect on hippocampal 4-45 Hz power; we add a phase-synchrony test on the same dataset.
usesHippocampal–scalp alpha synchrony did not significantly increase with working-memory load in nine patients
We used the same S3 listing, the same session choice (smallest iEEG file per subject), and the same byte-range download method. That study tested hippocampal power vs. load. This study tests hippocampal-scalp phase synchrony vs. load in the same sessions.