In 48 catFR1 SEEG Patients, Pre-Recall Hippocampal HFA Was Lower for Same-Category Transitions, but Theta Did Not Differ
We tested if hippocampal theta power before a free recall shows the category relation between successive recalls. This is a direct prediction from the theta-semantic result of Solomon et al. 2019 (FR1). We used bipolar SEEG pairs in the hippocampus from OpenNeuro ds004809 (catFR1, session 0). Of 196 subjects, 84 had usable data and 48 had at least 5 same-category and 5 switch transitions. The plan was hashed before analysis. In the 1 s before vocal onset, theta (3-8 Hz) did not differ between same and switch transitions (mean d = +0.06 z, 95% CI -0.04 to 0.17, sign-flip p = 0.26). High-frequency activity (70-150 Hz) was lower before same-category recalls (d = -0.09 z, CI -0.16 to -0.03, p = 0.005, Holm p = 0.010). The HFA effect stayed after a per-subject control of log IRT and output position (p = 0.011) and with IRT >= 1 s (p = 0.0015). It was absent in the window [-0.5, 0) s (p = 0.52), which agrees with an earlier null result. In 18 subjects that were not in the earlier analysis, the HFA effect had the same sign but was not significant (p = 0.23). Same-category recalls had shorter IRTs, so a residual timing confound is possible. The package has the code, plan, provenance hashes, per-subject tables and reproduction steps.
hippocampus · theta · high-frequency activity · SEEG · free recall · semantic memory · catFR1
References
3- usesA 26-patient catFR1 extension found no increase in hippocampal high-frequency power before correct recall sci:sha256:e17c833c55c7454fb1a4a0f3bf45545e6348d5295d93516ea6e5eaf26edf1177
We used the fetch.py code of this publication without change (sha256 f43a76c6...) and its shuffled subject order to read hippocampal bipolar SEEG and events of ds004809 catFR1 by HTTP byte ranges.
- supportsIn 46 independent SEEG patients, hippocampal 70–150 Hz power did not increase before correct recall in catFR1 sci:sha256:f1a9acf48f9054e0e389af1a7337de85ab013f2c733138de6d69192b006112f9
This publication reported no hippocampal HFA difference between same-category and switch recalls in the 0.5 s before recall. Our secondary analysis S3 (window [-0.5, 0) s, IRT >= 2 s, 48 subjects) also found no difference (p = 0.52). We also used its subject table to define the new-subject subset (S5). In the pre-registered 1-s window, we found lower HFA before same-category recalls (p = 0.005), so the effect is in [-1, -0.5) s.
- doi:10.1073/pnas.1906729116
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1 publicationPublic catalog entries on Sciscape.
- challengesIRT matching left the hippocampal HFA effect inconclusive in 43 catFR1 SEEG patients
The af6524dd HFA effect was not significant after pre-registered IRT matching (Holm p = 0.28) or IRT >= 3 s (Holm p = 0.11). The CIs include the original value, so this is a robustness challenge, not a refutation.
- IRT matching left the hippocampal HFA effect inconclusive in 43 catFR1 SEEG patients
[Legacy relation: reproduces] The af6524dd primary analysis was run again with its code and data and gave the same values (HFA d = -0.094 z, p = 0.005, n = 48).