A retinotopic reference frame for space throughout human visual cortex

We perceive the world as stable despite our rapid eye movements. To explain our sense of visual stability, it has been suggested that the brain encodes the location of attended visual stimuli in an external, or spatiotopic, reference frame. However, such spatiotopy is seemingly at odds with the fundamental retinotopic organization of visual inputs. Here, we probe the spatial reference frame of vision using ultra-high-field (7T) fMRI and voxel-level receptive field modeling, while manipulating both gaze direction and spatial attention. To manipulate spatial attention, participants performed an equally demanding visual task on either a bar stimulus that traversed the visual field, or a small stimulus at fixation. To dissociate retinal stimulus position from its real-world position the entire stimulus array was placed at one of three distinct horizontal screen positions in each run. We found that population receptive fields in all cortical visual field maps are pinioned to the retina, irrespective of how spatial attention is deployed. This pattern of results is strong evidence for a fully retinotopic reference frame for visual-spatial processing. Reasoning that a spatiotopic reference frame could independently be computed at the population level of entire visual areas rather than in individual voxels, we additionally used Bayesian decoding of stimulus location from the BOLD response patterns in visual areas. We found that decoded stimulus locations also adhere to the retinotopic frame of reference. Again, this result holds for all visual areas and irrespective of the deployment of spatial attention. Our findings reorient the search for visual stability mechanisms toward transient sensorimotor interactions rather than static spatiotopic maps.