In experiment 4, we investigated whether amnesia following damage that included PRC could be characterized

by a heightened susceptibility to perceptual interference. There were three conditions involving High Ambiguity stimuli (Low Interference 1, High Interference, Low Interference 2). The High Interference condition contained consecutive High Ambiguity Object trials, whereas every High Ambiguity Object trial in both Low Interference conditions was interspersed with two trials containing photographs of easily discriminable everyday objects (Figures 2E–2G). We predicted that the nature of the intervening stimuli would affect performance in individuals with PRC damage, with better performance under conditions of low interference. Analysis find more of eye movement patterns in healthy participants indicated that the High Ambiguity condition was associated with a greater degree of conjunctive processing than the other conditions. We performed a planned interaction comparison to determine if the High Ambiguity Object condition was associated with more conjunctive processing, relative to our size difficulty control: (High Ambiguity Objects – Low Ambiguity Objects) – (Difficult Size – Easy Size). This revealed that participants made more eye movement transitions within an individual object compared to transitions between the two objects in the High Ambiguity Enzalutamide solubility dmso condition relative

to the other conditions (t(15) = 4.08; p < 0.001) (Figure 3). Indeed, this ratio of within-item relative to between-item saccades was greater for High compared to Low Ambiguity discriminations (t(15) = 6.58, p < 0.001). We also performed an analysis of the temporal characteristics of these eye movements, which revealed a greater degree of temporal clustering in the High Ambiguity condition (see Supplemental Information, Figure S1C, available online). These results indicate that healthy participants analyzed the ambiguous objects as wholes, rather than by a serial comparison of single features. Experiments 2–4 investigated the neural substrates of this ability. In order to isolate brain regions associated with feature

ambiguity resolution, while controlling for general task difficulty, our planned comparison was the same interaction t contrast described above. Estimates of the mean BOLD Endonuclease signal for each of the four conditions were averaged across voxels within our two anatomically defined, bilateral regions of interest: the hippocampus and PRC. The planned comparison revealed feature ambiguity effects within the PRC (t(19) = 3.5, p < 0.001; Figure 4). This region showed reliably greater activity for High relative to Low Ambiguity discriminations (t(19) = 5.2, p < 0.001), but no difference in activity for Difficult relative to Easy Size discriminations (t(19) = 0.5, p = 0.3). By contrast, the comparison of High versus Low Ambiguity Objects was not significant in the hippocampus (t(19) = 1.4, p = 0.