Article Figures & Data
Figures
- Figure 1.
Experimental design: stimuli, procedure, and the operationalization of the in-phase group versus the out-of-phase group. A, Gabor gratings used as CSs. The 45° grating served as CS+ (paired with the US during acquisition). The other four served as CS– (never paired with the US). The luminance of each CS was sinusoidally modulated at 4 Hz. The US was a broadband white noise, amplitude modulated at 4 Hz and presented at a maximum of 96.5 dB(A). B, Fear-conditioning procedure with the learning phases habituation, fear acquisition, and extinction (day 1) and delayed recall (day 2). Each CS grating was presented 12 times in each learning phase. The US was only presented during fear acquisition (12 times coterminating with the CS+). At the end of day 2, the unimodal audio task comprised 75 presentations of the 4 Hz modulated white noise (4 s each) at a nonaversive volume (maximum = 70.4 dB(A)]. Vertical lines below the timeline indicate the rating time points. Extended Data Figure 1-1 shows the specific trial orders 1 and 2 that were used. C, Operationalization of the in-phase group versus the out-of-phase group. Fear conditioning for both groups was identical to the only exception that the in-phase group received the 12 CS+ US pairings during acquisition without a phase shift (0°) and the out-of-phase group received the CS+ US pairings with phase shifts of 90°, 180°, and 270° (four trials each). In C, the top row shows a simplified depiction of a CS changing luminance at 4 Hz for 750 ms. The bottom part of C shows the first 750 ms of an overlapping CS+ US presentation for the two groups. The light gray curve shows the luminance of the CS+ (each vertical line shows one step following the 85 Hz refresh rate of the monitor). The black (0° phase shift), dark gray (90°), yellow (180°), and blue (270°) graphs show a downsampled representation of the 4 Hz modulated, white noise US.
- Figure 2.
Processing steps and validation of in-phase versus out-of-phase stimulation. A, Processing example (one trial of one participant) of our audio (microphone in front of the participant’s speakers) and video signal (photodiode attached to the participants’ monitor). Data were segmented relative to the onset of a US (i.e., 12 segments per subject). Before analysis, video data were shifted 40 ms forward in time to account for the 40 ms time shift programmed into the stimulus presentation. Data were rectified, bandpass filtered between 3 and 5 Hz, and subjected to a Hilbert transform. Instantaneous phase information at 4 Hz was extracted from the imaginary part of the analytic signal. B, Visualization of in-phase (left column) and out-of-phase (right column) CS+–US stimulation for all CS+–US trials and all participants (12 × 20 trials per group). Each thin orange line shows the video signal of one participant and one trial. Each thin blue line shows the audio signal (one participant and trial). In B, the top rows show bandpass-filtered data; the middle row shows the extracted phase information; and at the bottom, polar histograms show the clustering of all phase differences per group.
- Figure 3.
ssVEP and the auditory steady-state response 4 Hz signal in the time domain and frequency domain, as well as the scalp distribution of the 4 Hz signal. A, B, The signal-to-noise ratio, averaged over all 40 participants (i.e., regardless of factor group) is presented for the visual (A) and auditory (B) 4 Hz stimulation. Orange lines show averaged data from participants of the in-phase group, blue lines show data from the out-of-phase group.
- Figure 4.
Contrast weights. A, Generalization weights to test the fit for a generalized fear response toward the CS+ and neighboring CS– orientations, independent of the factor group. B, Contrast weights (discrimination) to test the group × orientation interaction. The weights shown for a narrow (blue) and broad (orange) generalization pattern are just examples that if subtracted (narrow – broad) produce the exact discrimination weights we used for the group × orientation interaction contrast (numbers in black font, 0.142, −0.498, 0.694, −0.498, 0.142), resembling a Mexican Hat (black line). For better readability, contrast weights in the graphs A and B are inserted with 2 decimals.
- Figure 5.
US expectancy ratings separated for each measurement point: after acquisition, after extinction on day 1, and before delayed recall on day 2 in the in-phase and the out-of-phase groups. US expectancy was rated per CS on scale ranging from −5 (very certain, no US after this CS) over 0 (uncertain) to 5 (very certain, a US will follow this CS). Each data point presents the mean US expectancy rating for each CS orientation (averaged over participants per group and measurement point), error bars show 1 SEM. Extended Data Figure 5-1 shows discrimination indices (CS+ minus the weighted average of all CS–) and estimation statistics for US expectancy ratings. For transparency, Extended Data Figure 5-2 shows discrimination indices that result when subtracting the unweighted average of the CS– from the CS+.
- Figure 6.
A, B, Valence ratings (A) and arousal ratings (B) separated for each measurement point: after habituation, after acquisition, after extinction (day 1), and before delayed recall (day 2). Valence was rated with the Self-Assessment Manikin on a 9-point scale from 1 (unpleasant) to 9 (pleasant). For better comparability with arousal ratings, valence ratings were recoded, changing the scale from 1 (pleasant) to 9 (unpleasant). Arousal was also rated with the Self-Assessment Manikin, here ranging from 1 (calm) to 9 (arousing). Each data point presents valence or arousal ratings, respectively, for each CS orientation (averaged over participants per group and measurement point), error bars show 1 SEM. Note: for better visualization, the y-axis is scaled from 3 to 8 instead of showing the full range from 1 to 9. Extended Data Figure 6-1 shows discrimination indices (CS+ minus the weighted average of all CS–) and estimation statistics of valence and arousal data. Extended Data Figure 6-2 additionally shows the discrimination indices that use the unweighted average of all CS– values for subtraction.
- Figure 7.
A–C, Single-trial (A, B) and averaged (C) skin conductance responses. Single-trial SCRs are separated by the synchronization condition into the in-phase group (0° phase offset; A) and the out-of-phase group (90°, 180°, and 270° phase offset; B). Single-trial data are z-transformed SCRs, averaged over participants per group for each trial and CS orientation. Before averaging, data were smoothed over the 12 trials of a learning phase using a moving average (5 points long, symmetrical, shrinking at the end points). C depicts averaged data over 12 trials of habituation, acquisition, extinction, and delayed recall to visualize the response patterns within each learning phase. Here, each data point presents z-transformed SCRs of each CS orientation averaged over participants and trials per group. The z-transformation was calculated with the means and SDs over CS and US responses of all learning phases (habituation, acquisition, immediate extinction, delayed recall) per participant. Error bars show ±1 SEM. Extended Data Figure 7-1 shows single-trial SCR data without smoothing (i.e., no moving average). Extended Data Figure 7-2 shows discrimination indices (CS+ minus the weighted average of all CS–) for SCR and estimation statistics. Extended Data Figure 7-3 depicts discrimination indices without weighting the averaged CS– values.
- Figure 8.
A–C, Single-trial (A, B) and averaged (C) power of the 4 Hz ssVEPs for each learning phase (habituation, acquisition, extinction, and delayed recall). Single-trial data are separated by the synchronization condition into the in-phase group (0° phase offset; A) and the out-of-phase group (90°, 180°, and 270° phase offset; B). The ssVEP power is shown as the SNR at 4 Hz, corrected for habituation-level responding. Correction was performed by dividing individual SNR values by the average SNR from habituation (mean over all 60 trials of each participant, disregarding the different CS orientations). Therefore, values >1 describe an enhancement, and values <1 describe a decrease of ssVEP-SNR at 4 Hz relative to habituation. Single-trial data were smoothed over trials via a moving average along the 12 trials of each learning phase (5 point symmetrical shrinking at the end points). Each data point in A and B represents habituation corrected SNR for each trial and CS orientation, averaged over participants per group. C depicts data averaged over the 12 trials of habituation, acquisition, extinction, and delayed recall to visualize the response patterns within each phase. Error bars show ±1 SEM. Note: habituation data in C are nearly “flat” at ∼1 because of the habituation correction, as described above and in the Materials and Methods section. Extended Data Figure 8-1 shows single-trial data without the moving-average. Extended Data Figure 8-2 depicts discrimination indices with weighted CS- averages (CS+ minus weighted average of all CS-) and Extended Data Figure 8-3 shows discrimination indices without weighting the averaged CS- responses.
Tables
Data structure Type of test Effects Statistic p Value Effect size US expectancy Acquisition a Normal ANOVA ME: o F(3,109) = 12.491 6.764E-7 η2p = 0.247 b Normal ANOVA GEN F(1,38) = 28.360 0.000005 η2p = 0.427 c Normal ANOVA ME: g F(1,38) = 7.310 0.010 η2p = 0.161 d Normal ANOVA o × g INT F(3,109) = 1.133 0.338 η2p = 0.029 e Normal ANOVA MEX F(1,38) = 4.796 0.035 η2p = 0.112 Extinction f Normal ANOVA ME: g F(1,38) = 0.621 0.436 η2p = 0.016 g Normal ANOVA o × g INT F(3,113) = 1.363 0.258 η2p = 0.035 h Normal ANOVA MEX F(1,38) = 6.660 0.014 η2p = 0.149 Delayed recall (day 2) i Normal ANOVA ME: g F(1,36) = 0.688 0.412 η2p = 0.019 j Normal ANOVA o × g INT F(3,100) = 1.172 0.323 η2p = 0.032 k Normal ANOVA MEX F(1.36) = 3.090 0.087 η2p = 0.079 Valence and arousal Acquisition i Normal ANOVAVal ME: o F(3,96) = 7.756 0.000272 η2p = 0.170 m Normal ANOVAAro ME: o F(3,100) = 10.928 0.000008 η2p = 0.223 n Normal ANOVAVal GEN F(1,38) = 12.352 0.001 η2p = 0.245 o Normal ANOVAAro GEN F(1,38) = 19.587 0.000078 η2p = 0.340 p Normal ANOVAVal ME: g F(1,38) = 1.221 0.276 η2p = 0.031 q Normal ANOVAVal o × g INT F(3,96) = 1.502 0.224 η2p = 0.038 r Normal ANOVAAro ME: g F(1,38) = 1.248 0.271 η2p = 0.032 s Normal ANOVAAro o × g INT F(3,100) = 1.658 0.187 η2p = 0.042 t Normal ANOVAVal MEX F(1,38) = 9.228 0.004 η2p = 0.195 u Normal ANOVAAro MEX F(1,38) = 7.325 0.010 η2p = 0.162 Extinction v Normal ANOVAVal ME: g F(1,38) = 1.810 0.186 η2p = 0.045 w Normal ANOVAVal o × g INT F(3,117) = 0.647 0.590 η2p = 0.017 x Normal ANOVAAro ME: g F(1,38) = 0.355 0.555 η2p = 0.009 y Normal ANOVAAro o × g INT F(3,112) = 0.437 0.724 η2p = 0.011 Delayed recall (day 2) z Normal ANOVAVal ME: g F(1,36) = 0.074 0.788 η2p = 0.002 aa Normal ANOVAVal o × g INT F(3,96) = 0.216 0.864 η2p = 0.006 bb Normal ANOVAAro ME: g F(1,36) = 0.239 0.628 η2p = 0.007 cc Normal ANOVAAro o × g INT F(3,100) = 0.121 0.938 η2p = 0.003 SCRs Acquisition dd Normal ANOVA ME: o F(3,96) = 14.856 3.1057E-7 η2p = 0.281 ee Normal ANOVA GEN F(1,38) = 31.987 0.000002 η2p = 0.457 ff Normal ANOVA ME: g F(1,38) = 0.931 0.341 η2p = 0.024 gg Normal ANOVA o × g INT F(3,96) = 0.833 0.461 η2p = 0.021 Extinction hh Normal ANOVA ME: g F(1,38) = 1.170 0.286 η2p = 0.030 ii Normal ANOVA o × g INT F(3,117)= 0.921 0.435 η2p = 0.024 Delayed recall (day 2) jj Normal ANOVA ME: g F(1,38) = 0.002 0.965 η2p = 0.00005 kk Normal ANOVA o × g INT F(3,116)= 1.483 0.222 η2p = 0.038 ssVEPs Acquisition ll Normal ANOVA ME: o F(4,137) = 5.696 0.000479 η2p = 0.130 mm Normal ANOVA GEN F(1,38) = 8.447 0.006 η2p = 0.182 nn Normal ANOVA o × g INT F(4,137) = 1.042 0.384 η2p = 0.027 Extinction oo Normal ANOVA ME: g F(1,38) = 2.957 0.094 η2p = 0.072 pp Normal ANOVA o × g INT F(4,147) = 0.418 0.790 η2p = 0.011 Delayed recall (day 2) qq Normal ANOVA ME: g F(1,38) = 5.354 0.026 η2p = 0.123 rr Normal ANOVA o × g INT F(3,122) = 0.556 0.657 η2p = 0.014 Table shows statistical analyses including p value and effect size for each memory outcome measure, separated by learning phase. For each outcome measure, we calculated repeated-measures ANOVAs with the CS orientation as the within-subject factor and the group (in-phase group vs out-of-phase group) as the between-subject factor. Successful conditioning (i.e., increased response toward the CS+ respective of group) was validated by the main effects of orientations (noted in the column effects as ME: o). To account for the specific symmetric generalization pattern (CS+ in the middle), additional generalization contrast fits were used (noted as GEN). The main effects of group (ME: g) and group × orientation interactions (o × g INT) addressed differences between in-phase and out-of-phase conditioning. Better grating discrimination versus stronger generalization across orientations are described by a Mexican Hat contrast fit for the group × orientation interactions (MEX). ANOVA, Mixed repeated-measures ANOVA; ME, main effect; o, orientation; η2p, partial η2; g, group; MEX, Mexican Hat contrast fit of orientation × group interaction; INT, interaction; GEN, generalization fit; Val, valence; Aro, arousal.
Figure 1-1
Table of trial lists 1 and 2 for CS presentation order within each learning phase. The table shows the sequential order of CS presentation across the 60 trials of each learning phase. CS were Gabor gratings differing only in orientation (orientation degrees are shown in the second to last columns). The first column (Trial) shows the sequential number (e.g., trial 2 was the second CS seen by a participant in the specified learning phase). Each participant within the in-phase and out-of-phase groups was randomly assigned to receive stimuli according to list 1 or 2. Assignment to list 1 and 2 was balanced across groups. Download Figure 1-1, TIF file.
Figure 5-1
Weighted discrimination indices for US expectancy ratings. US expectancy ratings were first z-transformed within each participant using the mean and SD of all US expectancy ratings of a participant. With the z-transformed data we computed a weighted discrimination index per learning phase as the difference between the rating of the reinforced 45° (CS+) grating and the weighted average of the four CS– gratings. Weights for the CS– correspond to the angular difference in orientation between the four CS– orientations (25°, 35°, 55°, 65°) and the CS+ orientation (45°). The two more similar CS– orientations (±10° to the CS+) were weighted with 0.33[…], while the more dissimilar orientations (±20° to the CS+) were weighted with 0.166[…]. Data and effect sizes are shown as a Cumming estimation plot (http://www.estimationstats.com). Top row, Swarm plots show the raw discrimination indices per learning phase (each dot is the discrimination index of one participant). Group statistics are indicated to the right of each swarm as gapped lines (gap = mean, line length = 1 SD). Bottom row, Effect size estimates (Hedges’ g, black dots) for the three relevant comparisons (in-phase vs out-of-phase for each learning phase) and their 95% confidence interval (CI; vertical error bars). The unpaired Hedge’s g: for acquisition: –0.364 [95% CI, –0.981, 0.315], p = 0.2578; for extinction: –0.463 [95% CI, –1.089, 0.205], p = 0.1532; for delayed recall: –0.249 [95% CI, –0.907, 0.370], p = 0.4206. The 5000 bootstrap samples were taken for CI estimation; the CI is bias corrected and accelerated. The two-sided p values are the likelihoods of observing the effect sizes, if the null hypothesis of zero difference is true. For each permutation p value, 5000 reshuffles of the group labels were performed. Download Figure 5-1, TIF file.
Figure 5-2
Unweighted discrimination indices for US expectancy ratings. US expectancy ratings were z-transformed within each participant using the mean and SD of all US expectancy ratings of a participant. The unweighted discrimination index shown is the difference between ratings of the CS+ and the unweighted average of the four CS– orientations. Data and effect sizes are shown as a Cumming estimation plot (http://www.estimationstats.com). See the legend of Extended Data Figure 5-1 for a detailed description of a Cumming estimation plot. The unpaired Hedge’s g: for acquisition:–0.306 [95% CI, –0.928, 0.375], p = 0.3356; for extinction: –0.372 [95% CI, –1.021, 0.289], p = 0.2346; for delayed recall: –0.198 [95% CI, –0.842, 0.433], p = 0.5166. The 5000 bootstrap samples were taken for CI estimation; the CI is bias corrected and accelerated. The two-sided p values are the likelihoods of observing the effect sizes, if the null hypothesis of zero difference is true. For each permutation p value, 5000 reshuffles of the group labels were performed. Download Figure 5-2, TIF file.
Figure 6-1
A, B, Weighted discrimination indices for valence ratings (A) and arousal ratings (B). Valence and arousal ratings were first z-transformed within each participant using the mean and SD of all ratings of valence and arousal of a participant, respectively. With the z-transformed data, we computed a weighted discrimination index per learning phase as the difference between the reinforced 45° (CS+) grating and the weighted average of the four CS– gratings. Weights for the CS– correspond to the angular difference in orientation between the four CS– orientations (25°, 35°, 55°, 65°) and the CS+ orientation (45°): the two more similar CS– orientations (±10° to the CS+) were weighted with 0.33[…], while the more dissimilar orientations (±20° to the CS+) were weighted with 0.166. Data and effect sizes are shown as a Cumming estimation plot (http://www.estimationstats.com). See the legend of Extended Data Figure 5-1 for a detailed description of a Cumming estimation plot. For valence data (A), the unpaired Hedge’s g: for habituation: –0.039 [95.0% CI, –0.680, 0.568], p = 0.896; for acquisition: –0.660 [95% CI, –1.219, 0.048], p = 0.0372; for extinction: –0.291 [95% CI, –0.925, 0.354], p = 0.3522; and delayed recall: –0.218 [95% CI, –0.832, 0.423], p = 0.4848. For arousal data (B), the unpaired Hedge’s g: for habituation: –0.296 [95% CI, –0.914, 0.386], p = 0.3372; for acquisition: –0.877 [95% CI, –1.459, 0.302], p = 0.0074; for extinction: –0.382 [95% CI, –1.020, 0.273], p = .2216, and for delayed recall, –0.142 [95% CI, –0.778, 0.510], p = 0.6472. The 5000 bootstrap samples were taken for CI estimation; the CI is bias corrected and accelerated. The two-sided p values are the likelihoods of observing the effect sizes, if the null hypothesis of zero difference is true. For each permutation p value, the 5000 reshuffles of the group labels were performed. Download Figure 6-1, TIF file.
Figure 6-2
A, B, Unweighted discrimination indices for valence (A) and arousal (B) ratings. Ratings were z-transformed within each participant using the mean and SD of all valence and arousal ratings of a participant, respectively. The unweighted discrimination index shown is the difference between ratings of the CS+ orientation and the unweighted average of the four CS– orientations. Data and effect sizes are shown as a Cumming estimation plot (http://www.estimationstats.com). See the legend of Extended Data Figure 5-1 for a detailed description of a Cumming estimation plot. For valence data (A), the unpaired Hedge’s g: for habituation: 0.011 [95% CI, –0.622, 0.618], p = 0.9678; for acquisition, –0.578 [95% CI, –1.153, 0.047], p = 0.07; for extinction: –0.220 [95% CI, –0.864, 0.423], p = 0.488; for delayed recall: –0.218 [95% CI, –0.826, 0.422], p = 0.485. For arousal data (B), the unpaired Hedge’s g: for habituation: –0.255 [95% CI, –0.866, 0.439], p = 0.407; for acquisition: –0.820 [95% CI, –1.424, –0.225], p = 0.0128; for extinction: –0.361 [95% CI, –1.001, 0.295], p = 0.2466; for delayed recall: –0.141 [95% CI, –0.774, 0.503], p = 0.6512. The 5000 bootstrap samples were taken for CI estimation; the CI is bias corrected and accelerated. The two-sided p values are the likelihoods of observing the effect sizes, if the null hypothesis of zero difference is true. For each permutation p value, 5000 reshuffles of the group labels were performed. Download Figure 6-2, TIF file.
Figure 7-1
Single-trial data of SCRs without smoothing over trials. Same data as in Figure 7, A and B, plotted without the moving average over trials. SCRs are separated by learning phase (habituation, acquisition, extinction on day 1, and delayed recall on day 2) and by the synchronization condition into the in-phase group (i.e., 0° phase offset; A) and the out-of-phase group (i.e., 90°, 180°, and 270° phase offset; B). Error bars show ± 1 SEM. Download Figure 7-1, TIF file.
Figure 7-2
Weighted discrimination indices for averaged for averaged SCRs. SCRs were first z-transformed within each participant using the means and SDs over CS and US responses of all learning phases (habituation, acquisition, extinction, delayed recall). With the z-transformed data, we computed a weighted discrimination index per learning phase as the difference between the reinforced 45° (CS+) grating and the weighted average of the four CS– gratings. Weights for the CS– orientations correspond to the angular difference in orientation between the four CS– orientations (25°, 35°, 55°, 65°) and the CS+ orientation (45°): the two more similar CS– orientations (±10° to the CS+) were weighted with 0.33[…], while the more dissimilar orientations (±20° to the CS+) were weighted with 0.166[…]. Data and effect sizes are shown as a Cumming estimation plot (http://www.estimationstats.com). See Extended Data Figure 5-1 legend for a detailed plot description. The unpaired Hedge’s g: for habituation: –0.249 [95% CI, –0.827, 0.371], p = 0.451; for acquisition: –0.405 [95% CI, –0.938, 0.211], p = 0.2044; for extinction: 0.847 [95% CI, 0.277, 1.361], p = 0.0096; for delayed recall: 0.535 [95% CI, –0.091, 1.056], p = 0.0916. Download Figure 7-2, TIF file.
Figure 7-3
Unweighted discrimination indices for averaged SCRs. SCRs were z-transformed within each participant using the means and SD over CS and US responses of all learning phases (habituation, acquisition, extinction, delayed recall). The unweighted discrimination index shown is the difference between SCR to the CS+ and the unweighted average of the four CS– orientations. Data and effect sizes are shown as a Cumming estimation plot (http://www.estimationstats.com). See Extended Data Figure 5-1 legend for a detailed plot description. The unpaired Hedge’s g: for habituation: –0.146 [95% CI, –0.754, 0.461], p = 0.6618; for acquisition: –0.385 [95% CI, –0.920, 0.230], p = 0.2296; for extinction: 0.754 [95% CI, 0.197, 1.259], p = 0.0212; for delayed recall: 0.549 [95% CI, –0.071, 1.059], p = 0.0848. The 5000 bootstrap samples were taken for CI estimation; the CI is bias corrected and accelerated. The two-sided p values are the likelihoods of observing the effect sizes if the null hypothesis of zero difference is true. For each permutation p value, 5000 reshuffles of the group labels were performed. Download Figure 7-3, TIF file.
Figure 8-1
Single-trial power of the 4 Hz ssVEPs without smoothing over trials. Same data as in Figure 8, A and B, plotted without the moving average over trials. Single trials are separated by learning phase (habituation, acquisition, extinction on day 1, and delayed recall on day 2) and by the synchronization condition into the in-phase group (i.e., 0° phase offset; A) and the out-of-phase group (i.e., 90°, 180°, 270° phase offset; B). Error bars show ±1 SEM. Download Figure 8-1, TIF file.
Figure 8-2
Weighted discrimination indices for ssVEPs. Within each learning phase, using the habituation corrected SNR at 4 Hz (Fig. 8C), we computed a weighted discrimination index per learning phase as the difference between the reinforced 45° (CS+) grating and the weighted average of the four CS– gratings. Weights for the CS– correspond to the angular difference in orientation among the four CS– orientations (25°, 35°, 55°, 65°) and the CS+ orientation (45°): the two more similar CS– orientation (±10° to the CS+) were weighted with 0.33[…], while the more dissimilar orientations (±20° to the CS+) were weighted with 0.166[…]. Data and effect sizes are shown as a Cumming estimation plot (http://www.estimationstats.com). See Extended Data Figure 5-1 legend for a detailed plot description. The unpaired Hedge’s g: for habituation: 0.008 [95% CI, –0.652, 0.633], p = 0.979; for acquisition: –0.114 [95% CI, –0.731, 0.511], p = 0.7084; for extinction: 0.130 [95% CI, –0.519, 0.741], p = 0.683; for delayed recall: 0.054 [95% CI, –0.564, 0.702], p = 0.08622. The 5000 bootstrap samples were taken for CI estimation; the CI is bias corrected and accelerated. The two-sided p values are the likelihoods of observing the effect sizes if the null hypothesis of zero difference is true. For each permutation p value, 5000 reshuffles of the group labels were performed. Download Figure 8-2, TIF file.
Figure 8-3
Unweighted discrimination indices for ssVEPs. Here, the discrimination index was computed as the difference between the reinforced 45° orientation (CS+) grating and the unweighted average of the four CS– orientations. Data and effect sizes are shown as a Cumming estimation plot (http://www.estimationstats.com). See Extended Data Figure 5-1 legend for a detailed plot description. The unpaired Hedge’s g: for habituation: –0.074 [95% CI, –0.708, 0.569], p = 0.8106; for acquisition: –0.161 [95% CI, –0.774, 0.464], p = 0.6074; for extinction: 0.080 [95% CI, –0.561, 0.706], p = 0.7948; for delayed recall: 0.044 [95% CI, –0.579, 0.687], p = 0.891. The 5000 bootstrap samples were taken for CI estimation; the CI is bias corrected and accelerated. The two-sided p values are the likelihoods of observing the effect sizes, if the null hypothesis of zero difference is true. For each permutation p value, 5000 reshuffles of the group labels were performed. Download Figure 8-3, TIF file.
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