Abstract
Object identity and layout are two essential features of a scene representation. Yet, how these two features interact during scene representation and whether they can be represented independently of each other are not fully understood. Using the fMRI adaptation paradigm, here we examined how attention to object identity and layout would impact scene representation in three key brain regions involved in scene representation, namely, the parahippocampal place area (PPA), the retrosplenial complex (RSC), and the transverse occipital sulcus (TOS). We showed observers in each trial a sequential presentation of two scene images. Compared to the first image, the second image could either be identical, containing only object layout or identity changes, or containing both types of changes. Observers were asked to attend to object identities and ignore layout, or vice versa, and detect changes in the attended feature in the second image while ignoring changes in the unattended feature. In both PPA and TOS, we observed a significant release from adaptation when either or both features changed, regardless of which feature was attended. Responses in RSC followed a similar pattern although none of the effects reached significance. Additionally, responses in both PPA and TOS increased when the ignored feature changed but the attended feature did not, likely due to a prolonged processing required to inhibit a potentially erroneous response. Comparison between brain regions revealed that TOS showed greater modulation to layout changes than did PPA, consistent with an earlier finding we obtained. These results indicate that neural representations of object identity and layout may not be separable during scene processing, and that TOS likely plays a significant role in layout representation.
Meeting abstract presented at VSS 2013