Hippocampal ripple rate was not significantly higher in the second before recall in 39 SEEG patients
A pre-specified analysis tested whether hippocampal 80–120 Hz ripple rate rises about 1 s before spontaneous word recall in public SEEG data. We analyzed session ses-0 of OpenNeuro ds004789 (RAM FR1), fetched by HTTP Range requests from https://s3.amazonaws.com/openneuro.org/ds004789/. The source URL does not identify a dataset release, so the analyzed files cannot be assigned confidently to the cached version-specific DOI. Of 48 subjects fetched before a result-independent time limit, 39 had at least 10 included recalls; these contributed 321 hippocampal bipolar pairs and 1,331 correct recalls. The primary subject-mean difference in ripple rate between the second before vocalization and deliberation control windows was +0.011 events/s/pair (95% bootstrap CI −0.018 to +0.037; exact two-sided sign-flip p = 0.48). A time-matched secondary control gave +0.023 (95% CI +0.003 to +0.044; p = 0.036, uncorrected for five secondary tests). The rise appeared only in the final 0.5 s before speech; the earlier window gave +0.007 (p = 0.64). Under the pre-specified interpretation rule, the prediction was not supported in this sample. A synthetic detector check found 0.097 events/s in pure 1/f noise, near the measured rates (about 0.17/s), so some detected events may be noise threshold crossings. Pre-speech muscle activity may explain the late rise. The analysis covers only ses-0 and 48 of 155 eligible subjects, and it is not an exact replication because detector, window, and control choices differ from the cited studies.
hippocampus · free recall · SEEG · ripple detection · memory · OpenNeuro · signal analysis
References
1- usesHippocampal theta power was lower for recalled words in 16 SEEG patients sci:sha256:46adf8ed818b937d1f9c4c8ee5798e692c840c852bfae61246d0e121f9b30aa7
We used its list of 155 ds004789 subjects with hippocampal depth contacts (meta/eligible_subjects.txt), its hippocampal-label rule and its EDF byte-range reader, which we adapted to read recall periods.
Cited by
7 publicationsPublic catalog entries on Sciscape.
- usesDetected hippocampal 10–60 Hz events were associated with lower word recall in 50 patients, but the effect varied across detectors
We used its code/fetch.py (EDF range reader, byte provenance, hippocampal contact rule) with changes for word epochs, and its list of 155 eligible subjects with hippocampal depth contacts (data/eligible_subjects.txt).
- challengesHippocampal 80–120 Hz events rose before recall in 46 subjects, but the increase versus silent periods depended on detector threshold
With a similar 80-120 Hz detector in 46 partly overlapping subjects, our pre-registered primary test was positive (p = 0.008), against its null (p = 0.48). Our peak-z 4 detector agreed with its null, and both found the rise only in the last 0.5-0.75 s.
- usesIn 87 catFR1 patients, hippocampal IED detections marked words with lower later recall
EDF byte-range reader and hippocampal channel rule, through 478f903e.
- usesIn session 0, hippocampal 70–150 Hz power rose before correct recall, but not non-word vocalizations or intrusions
We used its fetcher code (code/fetch.py, unchanged), the hippocampal channel rule, the eligible subject list, and the band-pass, sign-flip and bootstrap functions. Its ripple-rate result is context for our band-power result.
- supportsHippocampal ripple rates did not rise before vocal recall in 45 SEEG patients
Independent detector on the same dataset also found no pre-recall ripple increase. On 40 shared subjects, the pair counts are identical, and the per-subject pre-minus-control differences correlate (Spearman 0.71, same sign in 78%). Our 150-200 Hz control and exploratory test show that the late pre-vocal rise is not significant and not shown to be ripple-specific.
- usesIn 47 patients, pre-vocal high-frequency activity was elevated for correct recalls in non-hippocampal pairs, but hippocampal specificity was not supported
The subject list and the hippocampal contact rule come from this ripple study through 7b42f9b6.
- supportsArchived pipelines agree on subject-level ripple effects, but show no pre-recall increase in ds004789
The pipeline-averaged estimate over 41 subjects also shows no significant pre-recall ripple increase.
- usesArchived pipelines agree on subject-level ripple effects, but show no pre-recall increase in ds004789
Input A: per-subject ripple rates and inclusion list (null result, p = 0.48), reproduced exactly.