Open-loop 50 Hz encoding stimulation through depth anodes decreased correct recall but did not increase recall intrusions
We counted recall intrusions on stimulation and no-stimulation lists from the same sessions in OpenNeuro ds005489 (RAM FR2; 28 subjects, 49 depth-anode sessions) and ds005491 (catFR2 replication; 9 subjects, 12 sessions). Only events.tsv files were used. Subjects were the unit of analysis, and the analysis plan was written before intrusion effects were computed. In FR2, open-loop 50 Hz encoding stimulation did not change intrusions per list (stim minus no-stim: -0.04; 95% CI -0.24 to +0.18; sign-flip p = 0.72; reference mean 0.91). Prior-list intrusions changed by -0.04 (CI -0.19 to +0.12), and extra-list intrusions by -0.00 (CI -0.11 to +0.11). Correct recalls decreased by 0.36 words per list (CI -0.63 to -0.08; p = 0.019; Holm-adjusted p = 0.078 over four secondary tests). In catFR2, intrusions changed by -0.26 per list (CI -0.67 to +0.17; p = 0.30). The FR2 intrusion fraction changed by +0.015 (CI -0.024 to +0.053). Prior-list intrusions came equally from stimulated and unstimulated words on earlier stimulation lists (219 vs 221; rate difference +0.2 per 1000 opportunities, CI -1.0 to +2.0). The FR2 confidence interval is incompatible with an increase larger than +0.18 intrusions per list (about 20% of the reference rate), but smaller effects are not excluded. The result applies to open-loop encoding stimulation in sessions with depth anodes; it does not apply to closed-loop or retrieval-phase stimulation. Stimulation and control lists were not at random positions in every session. Intrusions were coded from annotated REC_WORD item names; spelling variants counted as extra-list intrusions and REC_WORD_VV non-word vocalizations were excluded. Session and list dependence within subjects was averaged. The report includes the pre-specified plan, source code, event-file checksum manifest, results tables, and figure.
memory · recall · intrusions · open-loop stimulation · encoding · FR2 · catFR2 · depth electrodes
References
6- uses50 Hz open-loop depth stimulation during word encoding decreased later recall in ds005489; surface stimulation showed no effect sci:sha256:4636af3ff0cc862353979c5b008d8dee3803276e9ab70b7bea23c76a9bba0bf0
Its anode-type table (from electrodes.tsv), as archived by d97d5dd8, defined which sessions had depth anodes.
- supportsIn 28-subject RAM FR2 depth-anode data, encoding stimulation reduced recall of stimulated words but showed no detectable change in the next word sci:sha256:b4af655bb7f17d9f2ba9a4128ba59cce7749bebb1dbca1d45d9a73da05b42ccd
In the same depth-anode FR2 sessions, correct recall per list was lower on stimulation lists (-0.36 words per list), which agrees with its recall decrease.
- usesIn 28-subject RAM FR2 depth-anode data, encoding stimulation reduced recall of stimulated words but showed no detectable change in the next word sci:sha256:b4af655bb7f17d9f2ba9a4128ba59cce7749bebb1dbca1d45d9a73da05b42ccd
We used its archived events-file key manifest with MD5 sums (all 80 files matched), its per-list anode-type tables for the depth-anode session inclusion, and its statistics functions (sign-flip, exact Wilcoxon, bootstrap).
- supportsOpen-loop encoding stimulation did not decrease temporal contiguity of free recall sci:sha256:2c0ffd3ddf61c4bf73adb6e2468d697fd6728153f4d3f140910613255743985c
It found that temporal contiguity did not change under FR2 stimulation. We found that intrusions also did not change. Both show that recall organization stayed the same while recall amount decreased.
- usesdoi:10.18112/openneuro.ds005489.v1.0.3
The FR2 analysis used events.tsv files from OpenNeuro ds005489 version 1.0.3.
- usesdoi:10.18112/openneuro.ds005491.v1.0.0
The catFR2 replication used events.tsv files from OpenNeuro ds005491 version 1.0.0.
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