Seeing and Extrapolating motion trajectories share common informative activation patterns in primary visual cortex

Abstract

The natural environment is dynamic and moving objects become constantly occluded, engaging the brain in a challenging completion process to estimate where and when the object might reappear. Although motion extrapolation is critical in daily life – imagine crossing the street while an approaching car is occluded by a larger standing vehicle – its neural underpinnings are still not well understood. While the engagement of low-level visual cortex during dynamic occlusion has been postulated, most of the previous group-level fMRI-studies failed to find evidence for an involvement of low-level visual areas during occlusion. In this fMRI-study, we therefore used individually-defined retinotopic maps and multivariate pattern analysis to characterize the neural basis of visible and occluded motion in humans. To this end, participants learned velocity-direction pairings (slow motion-upwards; fast motion-downwards or vice versa) during a training phase without occlusion and judged the stimulus direction, based on its velocity, during a following test phase with occlusion. We find that occluded motion direction can be predicted from the activity patterns during visible motion within low-level visual areas, supporting the notion of a mental representation of motion trajectory in these regions during occlusion.Highlights* Dynamically occluded information is processed in low-level visual cortex* Specific regions inside low-level visual areas encode visible and dynamically occluded information* Overlap of visible and occluded informative activity patterns in the visual field suggest shared computational circuits in primary visual cortex