Spatial attention in early vision for the perception of border ownership

Spatial attention alters contrast gain in early visual areas, which might affect the determination of border ownership (BO)that indicates the direction of figure with respect to the border. We investigated the role of spatial attention applied to earlyvision in the determination of BO with a computational model that consists of V1, V2, and posterior parietal (PP) modules.Attention alters contrast gain in the V1 module so that it enhances local contrast. The V2 module determines BO based onthe surrounding contrast extracted by the V1 module. The simulation results showed that the attention significantlymodulates BO; BO is even flipped in figures with ambiguous BO while BO is stable for unambiguous figures such as asimple square. To evaluate the model quantitatively, we carried out psychophysical experiments to measure the effects ofattention in the perception of BO and compared the results with those from corresponding simulations. The model showedgood agreement with human perception including the determination of BO for ambiguous random-block stimuli. Theseresults indicate that the activity of BO-selective neurons could be modulated significantly by spatial attention that alters localcontrast gain in V1, which may account in part for automatic, bi-stable perception in ambiguous figures.Keywords: attention, border ownership, early vision, computational model, surrounding modulationCitation: Wagatsuma, N., Shimizu, R., & Sakai, K. (2008). Spatial attention in early vision for the perception of borderownership. Journal of Vision, 8(7):22, 1–19, http://journalofvision.org/8/7/22/, doi:10.1167/8.7.22.