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Abstract

A striking example of our sensitivity to dynamic information is our ability to infer motion from still images depicted in paintings, photographs or cartoons. What are the neural mechanisms that mediate this implied motion perception? In a recent paper, Krekelberg et al. demonstrate that form cues that imply motion are integrated with real motion information, and influence perception in both humans and monkeys and the neural processing in prototypical motion areas of the monkey brain.
Perception and successful interaction with moving objects entail that the visual system integrates information from form and motion cues into unified dynamic perceptual events. However, traditionally, shape and motion processing have been attributed to anatomically and functionally separable neural pathways in the primate brain [1]. An extrastriate visual area in the medial temporal monkey brain (MT/V5) and its human analogue in the ascending limb of the inferior temporal sulcus (hMT+/V5) have been identified as one of the main regions involved in the analysis of visual motion [2] and [3]. By contrast, regions in the occipitotemporal cortex (V4, IT) have been implicated in the analysis of shape properties and object recognition in the monkey and the human brain [4] and [5].
Although significant progress has been made in uncovering the neural mechanisms that mediate motion and form perception, surprisingly little is known about possible interactions of these mechanisms that may underlie the unified perception of moving objects in our dynamic visual environments. Krekelberg et al.[6] provide evidence for such interactions by showing similar responses in monkey MT and MST cells to real motion and static form patterns that have no coherent physical motion but imply motion. These physiological findings are consistent with the perception of their human and monkey subjects.