Purchase this article with an account.
Elizabeth Louie, David Bressler, David Whitney; Precise discrimination of position in object-selective regions of human visual cortex. Journal of Vision 2007;7(9):1031. doi: 10.1167/7.9.1031.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Past studies have shown that the lateral occipital cortex (LOC) plays an important role in object recognition, and that a subdivision of LOC (LO) exhibits a coarse sensitivity to object position. Using fMRI, we studied the retinotopic precision of the LOC, the fusiform face area (FFA), and the parahippocampal place area (PPA) in six subjects. A region of interest (ROI) for the LOC was functionally defined for each subject as the area with the strongest activation while viewing images of intact objects versus scrambled objects. ROIs were similarly defined for FFA (faces minus houses) and PPA (houses minus faces). In separate runs, we presented flickering Gabors that were located in one of five different positions, ranging in eccentricity from ∼8 to 10 deg. Within the ROIs defined above, we cross-correlated spatial patterns of activity generated by the Gabors in these different positions. We found that when two Gabors were within close proximity of each other, there was a high correlation in the pattern of activity in LOC. However, the correlation significantly decreased as the Gabors were shifted further apart, indicating that LOC was sensitive to differences in Gabor position of 2 deg or less. The FFA was also able to discriminate changes in position, but less precisely than the LOC. The PPA did not show any significant discrimination of object position. Our findings suggest that object sensitive regions including the LOC and the FFA carry surprisingly precise information about object position.
This PDF is available to Subscribers Only