Article Figures & Data
Figures
- Figure 1.
Experimental protocol and predictions. A, Timeline of an example nontarget trial. An auditory cue preceded each visual stimulus (face or scene), followed by a jittered intertrial interval. A reminder of the current target category (here: outdoor scenes) remained on screen throughout each block. B, Two versions of tone-picture associations were used, with each subject experiencing one version only. In version 1 (Ver. 1), a rising (falling) tone indicated a probability of 75% that the forthcoming nontarget stimulus was a male face (outdoor scene), respectively. In version 2 (Ver. 2), a rising (falling) tone indicated a probability of 75% that the forthcoming nontarget stimulus was an indoor scene (female face), respectively. C, Schematic illustration of model predictions: each disk represents the multivariate voxel pattern associated with a given experimental condition and the overlap between disks represents the degree of pattern similarity. If attention promotes error signals, then this should render the representations of unexpected stimuli more different from those of expected stimuli (left cluster), whereas the opposite would hold for attentional suppression of prediction errors (right cluster).
- Figure 2.
Category selectivity is enhanced by both attention and expectation. A, Searchlight MVPA (p < 0.05, corrected) identified regions in right fusiform gyrus (upper brain slice) and right parahippocampal gyrus (lower brain slice), where attention enhanced the discrimination between face and scene stimuli. B, For comparison, the upper and lower brain slices display single-subject activation peaks (one color per subject) in fusiform and parahippocampal gyri, respectively, as based on conventional functional definition of the FFA (univariate contrast of faces > scenes) and PPA (univariate contrast of scenes > faces). C, Searchlight MVPA (p < 0.05, corrected) identified regions in right fusiform gyrus (upper brain slice) and right parahippocampal gyrus (lower brain slice) where expectation enhanced the discrimination between face and scene stimuli. *p < 0.05; **p < 0.001; ***p < 0.0001.
- Figure 3.
Attention enhances the distinction between unexpected and expected stimuli. A, B, Searchlight MVPA (p < 0.05, corrected) identified regions in right fusiform gyrus (A) and right parahippocampal gyrus (B) where attention enhanced the discrimination between expected and unexpected faces and scenes, respectively. C, D, The (univariate) attentional modulation of expected versus unexpected stimuli for each individual FFA/PPA voxel (y-axis) is plotted against the voxels' SVM classifier weight in the attended condition. C, FFA voxel weights for classifying face stimuli (“FFA-face,” left) and scene stimuli (“FFA-scene,” right). D, PPA voxel weights for classifying face stimuli (“PPA-face,” left) and scene stimuli (“PPA-scene,” right). **p < 0.001.
- Figure 4.
Control analyses. A, Univariate fMRI effects of attention, expectation, and stimulus categories (preferred vs nonpreferred, collapsed across FFA and PPA). The bar graphs show group mean activation estimates in MVPA feature values (t-values of activation normalized across experimental conditions within each subject) plotted as a function of the attention, expectation, and stimulus category conditions. The FFA and PPA ROIs over which these data are collapsed were defined by the clusters reported in our analysis of attentional modulation on expectation (Fig. 3A,B). B, Voxelwise t-values for the univariate attention × expectation interaction group contrast in voxels of the FFA (top) and PPA (bottom) as defined by MVPA results in Figure 3, A and B. C, Schematic illustration of how MVPA results could in theory be driven by a single distinct multivariate pattern in the attended/expected stimulus condition. Each disk represents the multivariate voxel pattern associated with a given experimental condition and the overlap between disks represents the degree of pattern similarity. D, MVPA results for classifiers attempting to distinguish attended from unattended preferred stimuli, plotted as a function of expectation.
