Abstract
Recent studies suggest that the parahippocampal place area (PPA) responds to a broad spectrum of objects and scenes: big objects (Konkle & Oliva, 2011; Troiani et al., 2012), line drawings (Walther et al., 2011), and texture patches (Komblith et al., 2013; Cant & Goodale, 2011; Cant & Xu, 2012). Here, we test two hypotheses about texture representation in the PPA within the scene context. One hypothesis is that the PPA represents the texture ensemble (e.g., the kind of texture) as is, irrespective of the scene context. Another hypothesis is that the PPA represents the texture because it provides an important cue about the placeness of a scene. In the latter case, the PPA would be sensitive to not only the texture ensemble but also the location of texture within a scene (e.g., ceiling or wall) that can change the placeness perception. In Experiment 1 (n=11), participants saw images of synthetic rooms varied by 2 different textures x 2 texture location x 2 spatial layout. Using multi-voxel pattern analysis (MVPA) and a regression with two hypothetical models, we found that the representation-similarity of the PPA activation patterns was explained by the change in texture ensemble but not by the change in placeness (p=0.015). In Experiment 2 (n=6) we asked the same question using the repetition suppression method. In contrast to MVPA results, two scenes with the same texture ensemble but different placeness did not show repetition suppression, suggesting PPA’s sensitivity to the change in placeness perception. These results add to growing evidence in the field showing contrasting results from MVPA and repetition suppression methods (Drucker & Aguirre, 2009; Epstein & Morgan, 2011). We’ll also discuss the results of other scene-selective areas (e.g., RSC and OPA) and the possibility of the PPA representing the texture in a scene in a hierarchical manner.
Meeting abstract presented at VSS 2015