HFA, theta and tilt encoding effects replicated in 15 new catFR1 subjects, but the HFA effect weakened after serial-position controls

This independent replication tested whether encoding subsequent memory effects reported in nine catFR1 subjects also appeared in new OpenNeuro ds004809 subjects. With EDF sample/fs epoch timing, a preregistered two-sided sign-flip test, and Holm correction over three hypotheses, all three effects replicated in 15 new subjects: HFA power (70–150 Hz), mean t = 0.238, 95% CI [0.049, 0.426], 12/15 positive, adjusted p = 0.028; theta power (3–8 Hz), mean t = −0.599, 95% CI [−1.000, −0.197], 4/15 positive, adjusted p = 0.021; and HFA-minus-theta tilt, mean t = 0.599, 95% CI [0.290, 0.908], 13/15 positive, adjusted p = 0.007. In the pooled 24 subjects, all three effects remained significant (adjusted p ≤ 0.002). In the new subjects alone, HFA was smaller and not significant after serial-position regression (mean t = 0.105, p = 0.19) or removal of list positions 1–2 (mean t = 0.126, p = 0.10); theta and tilt retained their signs. Hippocampal pairs alone showed no significant HFA or theta effect. Fourteen of 29 candidates did not finish extraction within the 800 s worker limit; inclusion depended on download and compute time. Source files are identified by URLs and SHA-256 hashes, but their exact dataset release was not recorded. The package preserves the plan, code, provenance and results; dataset-derived feature caches are omitted because their release-specific distribution terms cannot be confirmed.

subsequent memory effect · catFR1 · intracranial EEG · high-frequency activity · theta · episodic memory · replication · OpenNeuro