Abstract
Due to its widespread connectivity with visual cortex, as well as with putative sources of attentional control in frontal and parietal cortex, the pulvinar is regarded as a likely hub for coordinating attentional modulation across visual areas. Despite the theoretical appeal of this idea, there is little direct evidence to support the role of the pulvinar in mediating spatial attention. Precisely representing object position would be critical to such a task, and we recently reported that the human pulvinar encodes position information with precision on the order of that found in early extrastriate areas. In the present study, we tested whether position coding in the pulvinar is modulated by the focus of spatial attention. In an fMRI experiment, we presented four Gabor patches situated in the four visual quadrants. While fixating, subjects attended to either the upper or lower pair of Gabors to detect slight changes in contrast, and ignored the remaining Gabors. We independently manipulated the positions of the attended and unattended stimuli so that we could test for position information about each separately in the BOLD response. Using a multivariate pattern analysis to track fine changes in the spatial pattern of the BOLD response, we found that activity in both the right and left pulvinar precisely reflected the positions of the attended stimuli, but contained no information about the positions of the ignored stimuli. Our results show that attention gates position coding in the pulvinar: when attended and ignored objects are present simultaneously, activity in the pulvinar selectively encodes the locations of the attended stimuli.