Figure 8—figure supplement 1. | Testing sensory evidence against mnemonic templates

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Testing sensory evidence against mnemonic templates

Figure 8—figure supplement 1.

Affiliation details

University of Oxford, United Kingdom; Ernst Strüngmann Institute for Neuroscience, Germany; Ecole Normale Supérieure, France
Figure 8—figure supplement 1.
Download figureOpen in new tabFigure 8—figure supplement 1. Multidimensional Scaling and Pairwise Mahalanobis distances between Angular Distances.

(A) Dissimilarity structure of angular distances. We used MDS, which maps the multidimensional (32× 32) Mahalanobis distance matrix between target-relative angles into two dimensions. During relatively early stimulus processing (250–400 ms after stimulus onset), geometry is elliptical—that is, in addition to conditions separating along the target-relative axis (horizontal), conditions separate along a task-irrelevant axis (vertical). During later processing stages (B: 450–900 ms), the task-related axis accounts for most of the condition differences. Since MDS is rotation-invariant, the solution in B happens to have flipped axis 2, without affecting the geometrical relationship between points. (C) Mahalanobis distances (shuffle-corrected) between trials with equal target proximity, but different direction (i.e., clockwise vs. counter-clockwise deviations of the stimulus angle, with respect to the template angle). The figure shows the mean z-score (with respect to 250 random permutations of the trial labels) of pairwise distances between equal target proximities, averaged over the pairs ± 11.25º, ± 22.5º, and ± 33.75º. Shading indicates standard error of the mean. The black bar denotes significant time points (p<0.05, cluster-corrected). MDS, multi-dimensional scaling