Resolving the projecjion of an occluded stimulus on the human cortical surface

The human visual system is capable of tracking multiple visual targets under a variety of task constraints and configurations. For nearly two decades, the psychophysical literature has shown that moving, occluded visual targets -- targets that are momentarily invisible as they pass behind an occluding bar -- are differentially represented by the visual system compared to their moving, non-occluded counterparts. Here, I sought to examine the neurophysiological basis of this behavioral difference in response to occluded versus non-occluded visual targets. I used brain imaging to conduct modern retinotopic mapping experiments in human participants. Once· their early visual cortices were mapped, I was able characterize the neural representations for both targets and distractors as well as during moments of occlusion and non-occlusion. The results show that, using our method, we can distinguish visual targets from distractors; furthermore, there appears to be a representation in retinotopically organized early visual cortex for visual targets that have momentarily disappeared from the visual field due to occlusion.