"Spilling-in" versus "Filling-in": Disentangling bottom-up drive from predictive completion in human V1 to V3

It is well established that responses in visual areas are a combination of bottom-up stimulus driven input and top-down input driven by expectation. However, it has been difficult to quantify the differential strength of these components, and how they vary across the visual hierarchy. Here, we introduce a method for dissociating bottom-up and top-down contributions in early retinotopic areas (V1-V3). Using a log-scaled bar stimulus, we measured BOLD responses under full-field vs. central scotoma conditions. Using the full-field stimulus, we estimated pRFs in human visual cortex 17 (V1-V3).