Article Figures & Data
Figures
- Figure 1.
Schema of experimental paradigm. A, Samples of stimuli used in this experiment: a face and a scene. B, Schema of experiment pipeline during encoding. We trained and tested the classifier for decoding image category (faces or scenes) based on MEG oscillatory activity (8–45 Hz) at different time bins when the images where shown alone (without the word). C, Schema of experimental pipeline during retrieval (when the word recognition Old/New response is “Old”). The replay of associated image after onset of the cue (the paired word) was decoded.
- Figure 2.
Face- and scene-specific representations during encoding and retrieval. A, Cross-validated accuracy of separate (for each time bin) pattern classifiers decoding faces and scenes during encoding (solid line). A rapidly (at 113 to 246 ms and peak at 180 ms) emergent pattern classifier decoded faces and scenes. Dotted lines show the cross-validated accuracy for decoding the signal from which the average category-specific ERF was subtracted (at 118 and 246 ms uncorrected p = 0.009 and cluster-level FWE-corrected p = 0.061). B, The performance of 180 ms classifier in decoding other stages of encoding (significant only at the immediately adjacent time bins). The 0 ms in A and B correspond to the onset of the images (face or scene) during encoding. C, The same 180 ms classifier from the encoding period showed significant replay of associated image information at 446 to 513 ms from onset of the cue, “Old” words, during correct word recognition. D, In trials in which the associated image is also correctly identified (recollected), replay is detected at 513 ms after onset of the cue. The 0 ms in C and D correspond to the word onset during retrieval. The time bins with significant classifications, multiple-comparisons corrected p < 0.05, are highlighted in gray (see Materials and Methods and Results sections for details). Error bars indicate SEM. In B and D, the classification accuracy only from time points depicted with black lines were considered in second-level analyses.
- Figure 3.
Classification accuracy correlates with source memory accuracy. Classification accuracy in decoding faces and scenes at 513 ms after onset of the memory cue (an “Old” word) correlated positively with behavioral accuracy in source memory (r = 0.73 and p = 0.017). In this analysis, all trials were considered in which the word was correctly recognized as “Old” (recognition hits). Each circle represents a participant.
- Figure 4.
Power differences between recognition hits (Hits) and CRs at 400–550 ms. A, Top: Topographic distribution of t-values of the Hits > CRs contrast at 3 Hz, where the difference peaked in the theta (3–8 Hz) band. Bottom: Time-frequency representation of log power differences between Hits and CRs (Hits − CRs) at a left temporal channel where the difference peaked (highlighted with the black circle). B, Top: t-value map for the difference in the beta (23–25 Hz) band, peaking at 23 Hz. Bottom: TF representation of the log power differences at a central channel (marked with black circle) where the difference peaked. In A and B, color bars illustrate the range of t-values in the top plots and the arrows show the FWE-corrected t-value threshold (set at p < 0.05). The color bars in other plots show the range of log power differences between Hits and CRs.
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