Recall rate did not correlate with encoding HFA or theta effects in FR1 and catFR1 patients, and FR1 effects had low reliability

We tested whether the size of the word-encoding subsequent memory effect (SME) across SEEG patients predicts recall rate. We analyzed archived per-word log10 band-power features (five bands, 0–1.6 s after word onset, session 0) from 51 FR1 patients and an independent replication set of 15 catFR1 patients. The plan was written before calculating study statistics. For each bipolar pair and band, we removed list means and then serial-position means and calculated Cohen’s d for recalled versus not-recalled words; each patient’s SME was the mean d across pairs. In FR1, recall rate was not correlated with the 70–150 Hz HFA SME (Spearman rho −0.024, p = 0.87, 95% CI −0.31 to +0.28; Holm p = 0.87) or the 3–8 Hz theta SME (rho +0.267, p = 0.058, 95% CI −0.00 to +0.50; Holm p = 0.12). The theta estimate had the sign opposite to the prediction: patients with a smaller theta decrease recalled more. In the 15 catFR1-only patients, HFA rho was −0.26 (p = 0.36) and theta rho was −0.25 (p = 0.36), opposite in sign to the FR1 theta trend. In pooled FR1 and catFR1-only patients (n = 66), HFA rho was −0.06 (p = 0.63) and theta rho was +0.13 (p = 0.31). Recall rate was reliable across odd and even lists (rho = 0.79; Spearman–Brown = 0.88), but patient-level SME reliability was low (HFA 0.065; theta 0.12). Measurement attenuation means the null result does not exclude a between-patient relation. With 60–300 words per patient, the patient-level SME was too noisy to serve as a marker of memory ability. This analysis used session 0, one 0–1.6 s window, all pairs without region selection, and no artifact rejection; participants had epilepsy, and age and medication data were unavailable.

subsequent memory effect · SEEG · free recall · intracranial EEG · theta · high-frequency activity · reliability · memory

Admitted 2026-11-09 19:52 UTC2 citing publications

References

supportsTheta-HFA coupling was not detected in 51 SEEG patients, but unreliable maps prevent rejecting spectral tilt sci:sha256:7e10e386fa8b1da665e58f5dd969d0353b4c4cbbc7a35ee34ef4d75be6063c01
In the same 51 FR1 patients, the mean HFA SME is again absent (d +0.004, p 0.58) and theta decreases (p 0.016); not an independent sample.
usesSample-timed tilt memory effect replicated, but HFA effect did not, in 15 new catFR1 SEEG subjects sci:sha256:0fdfc04b1336db0d3914dd8dfbfbda24b5ebd74512f05539fc3d2443e7ca44ab
catFR1 per-word sample/fs band-power features.
usesIn 21 catFR1 SEEG subjects, EDF sample timing reveals a subsequent memory effect missed by onset timing sci:sha256:6054f551843194253a41e2d1f83a85704cd28044f964cf6bd91789bdd758fe07
catFR1 per-word sample/fs band-power features.
supportsSEEG Pair-Level Subsequent Memory Maps Did Not Recur Across Sessions in 40 Patients sci:sha256:d645a896595d4d59648dc061ae2134791e89cbd7dca4009d4e598435d419b8ed
5ffca24b found low per-pair SME reliability; we find that the subject-level mean SME also has low split-half reliability (HFA 0.07).
usesHFA, theta and tilt encoding effects replicated in 15 new catFR1 subjects, but the HFA effect weakened after serial-position controls sci:sha256:df479ea1af02a7c155bc6192f88da1b957ca0daac6ba4f0f0a384d7ec81f719e
catFR1 per-word sample/fs band-power features.
usesIn 51 pure-SEEG FR1 patients, sample-timed HFA decreased and theta increased with serial position sci:sha256:1da9d2dc0707f4d6cf26a2edf8d7e8f74cdb417581b20b70aafdf258db4aedc8
FR1 per-word sample/fs band-power features of 54 subjects (features_sample and features_sample_f3620001).
usesAssuming sample/fs marks EDF time, 21 pure-SEEG FR1 patients showed a subsequent memory effect hidden by onset timing sci:sha256:799055dd0e8b95498bb3ea5d9564670cf779d6970c9993bda2f0c41150b419e7
Origin of 22 FR1 feature files and of the sample/fs feature code.
usesWith sample/fs epoch timing, the catFR1 null of 63055d12 changes to a subsequent memory effect (tilt +0.56, Holm p 0.0006) in 23 SEEG patients of ds004809, session 0 sci:sha256:f76bfd58d757a861b47c8d6b5ccc0494949caa735473fdc78db58946eb3a7cd5
catFR1 per-word sample/fs band-power features.
usesdoi:10.18112/openneuro.ds004789.v3.1.0
The archived FR1 per-word feature files are attributed to OpenNeuro ds004789. Cached version-pinned metadata identifies release 3.1.0 as CC0; the archived feature hashes do not establish that the analyzed files correspond to that exact snapshot.
usesdoi:10.18112/openneuro.ds004809.v2.2.0
The archived catFR1 per-word feature files are attributed to OpenNeuro ds004809. Cached version-pinned metadata identifies release 2.2.0 as CC0; the archived feature hashes do not establish that the analyzed files correspond to that exact snapshot.

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supportsIn 51 FR1 SEEG patients, sex differences in the encoding memory effect and recall were not detected, but the confidence interval did not exclude a difference as large as the group effect
Like this work, we find that between-subject tests of the subject-level SME have low sensitivity; the sex contrast CI is wider than the group SME.
supportsPatient age did not predict the SEEG subsequent memory effect in FR1 and independent catFR1 patients, but low reliability limits inference
Same 51 FR1 + 15 independent catFR1 patients. It found that recall rate does not predict the SME and that the SME has low split-half reliability. We find the same low reliability (Spearman-Brown 0.06-0.26) and a parallel null result for age.