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q-bio.NC · Neurons and Cognition

In FR1 SEEG, HFA and theta serial-position changes reset at each list start, while theta also drifts slowly

In 51 subjects performing the FR1 delayed free-recall task, high-frequency activity (HFA) power decreased and theta power increased across word positions 1–12. This study tested whether those effects reflected a monotonic session drift or a change locked to list starts. From position 12 of one list to position 1 of the next, HFA rose by 0.153 SD (44/51 subjects; Holm p = 0.0002) and theta fell by 0.159 SD (41/51; Holm p = 0.0002), opposite to the signs predicted by monotonic drift. With linear session time controlled, position coefficients remained −0.0122 SD per position for HFA and +0.0152 for theta (both Holm p = 0.0002). HFA showed no session-time trend, and its reset was consistent with a full reset. Theta showed an incomplete reset (+0.019 SD per list, Holm p = 0.031) and a small session increase (+0.0035 SD/min, uncorrected p = 0.027; Holm p = 0.055). Other bands showed similar patterns for low gamma and alpha, but not beta; the exploratory 54-subject set showed the same primary result. In FR1, list position and elapsed time from list start cannot be separated because word intervals are fixed. The 76-second gap includes a distractor task and recall, which were not controlled; power was averaged over all bipolar pairs. The analyzed source files are identified by recorded hashes and unversioned OpenNeuro URLs; their match to a specific release is uncertain.

serial position · intracranial EEG · SEEG · high-frequency activity · theta power · free recall · memory encoding · session drift

Admitted 2 citing publications

References

6
  1. supportsSample-timed epochs revealed serial-position HFA decreases and theta increases in 26 ds004789 FR1 patients sci:sha256:fd5028d1ad7f9c998630349721d45282bfaa83628980a5c72de84baa283b7974

    Its HFA decrease and theta increase with serial position are locked to the list start; the session-drift confound that it lists is excluded for HFA and is small for theta.

  2. supportsSample-based timing leaves the primary e9c2d073 null results unchanged in 24 RAM FR1 SEEG subjects, while theta drift replicates sci:sha256:349cb627be73dff6a3dd6442ad2adafa20b2e392eb7f132ef86b0ac29fc3a7eb

    Agrees with no HFA session drift (-0.0004 SD/min, p = 0.83) and a small theta increase over the session (+0.0035 SD/min, p = 0.027 uncorrected; incomplete theta reset, Holm p = 0.031).

  3. supportsIn 22 ds004789 patients, HFA decreased and theta increased across list positions only with sample/fs-timed word epochs sci:sha256:5c4acbf32d148b8927318744c1babd92374c230383bac83ac7ff2c8134b66aaf

    Its serial-position pattern resets at each new list in 51 subjects, which a monotonic session drift cannot do.

  4. supportsIn 51 pure-SEEG FR1 patients, sample-timed HFA decreased and theta increased with serial position sci:sha256:1da9d2dc0707f4d6cf26a2edf8d7e8f74cdb417581b20b70aafdf258db4aedc8

    The serial-position slopes stay with session time controlled (HFA -0.0122, theta +0.0152 SD per position) and reset at each list start, so slow session drift does not explain them.

  5. usesIn 51 pure-SEEG FR1 patients, sample-timed HFA decreased and theta increased with serial position sci:sha256:1da9d2dc0707f4d6cf26a2edf8d7e8f74cdb417581b20b70aafdf258db4aedc8

    Input features (32 subjects) and the 51-subject primary set come from this package; loading rules are copied from its analyze_sp.py.

  6. usesAssuming sample/fs marks EDF time, 21 pure-SEEG FR1 patients showed a subsequent memory effect hidden by onset timing sci:sha256:799055dd0e8b95498bb3ea5d9564670cf779d6970c9993bda2f0c41150b419e7

    Sample/fs-timed features for 22 subjects were made by this package (archived in d3aeb47e).

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