Ultra-Rapid serial visual presentation reveals dynamics of feedforward and feedback processes in the ventral visual pathway
- Massachusetts Institute of Technology, United States
- Freie Universität Berlin, Germany
Figures
Figure 1
Rapid serial visual presentation (RSVP) task.
(a) Experimental procedure. The stimulus set comprised 12 face targets, 12 object targets, and 45 masks of various objects. Participants viewed a RSVP sequence of 11 images, with the middle image …
Figure 2
Decoding of target images from MEG signals.
(a) Multivariate pattern analysis of MEG signals. A support vector machine (SVM) classifier learned to discriminate pairs of target images using MEG data at time point t. The decoding accuracies …
Figure 3 with 1 supplement
Categorical information encoded in MEG signals.
(a) Time course of categorical division depending on presentation rate. For each condition, the MEG decoding matrix was divided into 3 segments for pairs of within-face, within-object, and …
Figure 3—Figure supplement 1
Linear decoding of faces vs. objects category.
For each condition and at each time point a SVM classifier was trained to decode object versus face trials with a leave-one-out procedure. The shape and peaks of the time series largely match the …
Figure 4
Temporal generalization of target image decoding for the 500, 34, and 17 ms per picture conditions.
The SVM classifier was trained with MEG data from a given time point t (training time) and tested on all other time points (testing time). The temporal generalization decoding matrix was averaged …
Figure 5
Representational similarity of MEG to fMRI signals at EVC and IT.
(a) For every time point t, the EVC-specific MEG RDM was compared (Spearman’s rho) with the EVC-specific fMRI RDM, yielding a time series of MEG-fMRI representational similarity at EVC. (b) Same as …
Author response image 1
Decoding seen versus unseen faces in the 17ms per picture condition.
https://doi.org/10.7554/eLife.36329.014Tables
Table 1
Peak and onset latency of the time series for single image decoding (Figure 2) and categorical division decoding (Figure 3), with 95% confidence intervals in brackets.
https://doi.org/10.7554/eLife.36329.005| Presentation rate | Peak latency (ms) | Onset latency (ms) | |
|---|---|---|---|
| Grand total | 500 ms per picture | 121 (102–126) | 28 (9–53) |
| 34 ms per picture | 100 (96–107) | 64 (58–69) | |
| 17 ms per picture | 96 (93–99) | 70 (63–76) | |
| Within-faces | 500 ms per picture | 113 (104–119) | 59 (30–73) |
| 34 ms per picture | 104 (96–109) | 74 (62–81) | |
| 17 ms per picture | 98 (96–104) | 86 (78–117) | |
| Within-objects | 500 ms per picture | 102 (93–102) | 48 (10–55) |
| 34 ms per picture | 97 (90–97) | 60 (27–67) | |
| 17 ms per picture | 94 (87–95) | 70 (64–74) | |
| Between minus within | 500 ms per picture | 136 (130–139) | 46 (15–51) |
| 34 ms per picture | 169 (165–177) | 73 (67–78) | |
| 17 ms per picture | 197 (175–218) | 139 (67–155) |
Table 2
Peak and onset latency of the time series for MEG-fMRI fusion at EVC and IT, with 95% confidence intervals in brackets.
https://doi.org/10.7554/eLife.36329.009| Peak latency (ms) | Onset latency (ms) | ||
|---|---|---|---|
| 500 ms per picture | IT | 131 (127–135) | 63 (50–75) |
| EVC | 104 (93–120) | 53 (50–57) | |
| 34 ms per picture | IT | 166 (162–173) | 70 (50–88) |
| EVC | 87 (83–97) and 169 (164-176)* | 71 (61–81) | |
| 17 ms per picture | IT | 195 (170–203) | 162 (55–183) |
| EVC | 80 (75–100) and 202 (190-219)* | 71 (50–76) |
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*Time series had two early peaks.
Additional files
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Source data 1
Figures 2, 3 and 5 source data and code.
Decoding target images; resolving categorical information; and computing MEG-fMRI representational similarities.
- https://doi.org/10.7554/eLife.36329.011
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Transparent reporting form
- https://doi.org/10.7554/eLife.36329.012
