File:Experimental design, BOLD signal during sham and hippocampal fields.webp

English: "a, The face–name task was composed of nine blocks of encoding and recall. Each block contained 16 unique face67–name pairs followed by a delay and a recall period, where participants tried to select the correct name for each face out of five options (that is, one target, two foil names that were present in the block but associated with a different face, and two distractor names that were not present during the task). After each name selection, participants were asked to rate their choice confidence (1 (not confident at all) to 4 (extremely confident)). b, Schematic of the Ant, Mid and Post ROIs along the hippocampal longitudinal axis. c, Participants’ envelope modulation amplitude in hippocampal ROIs during TI 1:1 and TI 1:3 stimulations, computed with individualized MRI-based anatomical models; n = 16 participants (Supplementary Fig. 3). Showing a steering of the envelope amplitude peak from Mid hippocampal ROI during TI 1:1 stimulation (LMM, F(2,30) = 26.05, P = 2.7 × 10−7; post hoc comparisons using the Tukey honestly significant difference (HSD) test, two-sided, Mid–Post/Ant, P < 0.0001, Post–Ant, P = 0.420) to Ant hippocampal ROI during TI 1:3 stimulation (LMM, F(2,30) = 359.62, P < 2.2 × 10−16; post hoc comparisons using the Tukey HSD test, two-sided, P < 0.0001 between all ROIs); amplitudes were normalized to total hippocampal exposure. For full statistics, see Supplementary Table 2. d, Participant’s performance across stimulation conditions, sham (gray), TI 1:1 (blue) and TI 1:3 (orange). Left: percentage mean response selection for each response category, showing a higher proportion of target selection compared to foils or distractors (probability of correct selection by chance was 0.2). Middle: median reaction time (RT) during recall, showing faster reaction times for target selection. Right: mean confidence rating for each response category, showing higher confidence ratings for correct associations compared to foils and distractors. There was no effect of stimulation for response type or reaction time. There was an effect of TI 1:3 stimulation for confidence rating. There was no interaction between stimulation and response category for any of the behavioral metrics. For full statistics, see Supplementary Table 4. e, Whole-brain group z-score change in BOLD signal during encode and recall. f, Group median change in BOLD signal in the left (L) and right (R) hippocampi in sham condition blocks. Showing significant BOLD signal increase during the encode (one-sample t-test, two-sided, left hippocampus t(19) = 3.70, P = 0.003; right hippocampus t(19) = 3.92, P = 0.003; FDR corrected), but not recall (left hippocampus t(19) = −1.28, P = 0.287; right hippocampus t(19) = −0.25, P = 0.805; FDR corrected); and significant effect of task stage (LMM, F(1,57) = 20.492, P = 3.09 × 10−5; for full statistics, see Supplementary Table 5. g, Group median change in BOLD signal in the anterior (Ant), middle (Mid) and posterior (Post) regions of the left hippocampus during the encoding stage in the sham condition. Showing a larger BOLD signal increase in the Ant hippocampal region in relation to the Mid and Post regions (LMM, F(2,38) = 8.72, P = 7.658 × 10−4; post hoc comparisons using the Tukey HSD test, Ant–Mid, P = 0.0008; Ant–Post, P = 0.0137; Mid–Post, P = 0.5518); for full statistics, see Supplementary Table 6. Asterisks identify significant differences, P < 0.05. Bar plots show mean and SE, black dots show individual participant data. Images in e were thresholded at Z > 3.1, with a cluster significance level of P < 0.05, and are displayed in x = −21 plane of the MNI template. n = 20 throughout except for c where n = 16."