In 12 SEEG patients, hippocampal high-gamma power fell with verbal working-memory load; theta showed no clear change
We examined whether hippocampal band power during verbal working-memory maintenance varied with memory load in OpenNeuro ds004752 v1.0.1. From 16 sessions in 12 patients, we analyzed 650 correct, artifact-free trials and 82 bipolar hippocampal channels. Per channel, we measured the Spearman correlation between set size (4, 6, or 8 consonants) and within-session, within-channel z-scored log10 power, then Fisher-z averaged channel correlations within each patient. An exact sign-flip test across patients showed a small decrease in maintenance high-gamma power (70–140 Hz; mean rho = −0.087; 3/12 patients positive; p = 0.017, Holm p = 0.033). Theta power (4–8 Hz) did not show a clear load effect (mean rho = +0.044; 7/12 positive; p = 0.20, Holm p = 0.20). Fixation-corrected high-gamma power also decreased (mean rho = −0.067; 2/12 positive; p = 0.0049, Holm p = 0.039); all other secondary tests had Holm p = 1.0. Response time increased with set size (mean rho = 0.29; 11/12 positive; p = 0.0015), while fixation-period power did not depend on the upcoming set size (all bands p ≥ 0.57). Effects were small, only 3 of 12 patients had individually significant high-gamma results, and the sample included 12 of 15 patients. Atlas-based labels, possible epileptogenic effects, the absence of muscle-artifact control beyond the dataset flag, and untested encoding-period effects limit interpretation. The high-gamma decrease needs replication with all sessions and patients.
hippocampus · SEEG · verbal working memory · memory load · high-gamma power · theta power · intracranial EEG · Sternberg task
References
2- usesdoi:10.18112/openneuro.ds004752.v1.0.1
The analyzed recordings were fetched from OpenNeuro ds004752 v1.0.1.
- doi:10.7554/eLife.78677
Cited by
3 publicationsPublic catalog entries on Sciscape.
- usesNo clear memory-load effect in late-maintenance SEEG power across hippocampal and other regions
Prior hippocampal high-gamma load effect (rho -0.087) that we compare with. Our CI includes it, so we do not challenge it.
- 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=12, mean rho -0.087, 9 negative, exact sign-flip p=0.017 (recomputed here with one common test). The source files and their SHA-256 values are in inputs/provenance.json.
- 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 that hippocampal 70-140 Hz maintenance power decreased with set size (16 sessions, 650 trials). We found the same sign with more sessions (1908 trials) and with a same-trial fixation baseline (mean rho -0.072, Holm p = 0.035). In the new sessions 3-4 alone the effect was not significant (p = 0.15).