Neural correlates of implied motion
B. Krekelberg, S. Dannenberg, K.-P. Hoffmann, F. Bremmer & J. Ross
Nature, 427: 674-466, 2003
- Current views of the visual system assume that the primate brain analyses form and motion along largely independent
pathways; they provide no insight into why form is sometimes interpreted as motion. In a series of psychophysical
and electrophysiological experiments in humans and macaques, here we show that some form information is processed
in the prototypical motion areas of the superior temporal sulcus (STS). First, we show that STS cells respond to
dynamic Glass patterns, which contain no coherent motion but suggest a path of motion. Second, we show that when
motion signals conflict with form signals suggesting a different path of motion, both humans and monkeys perceive
motion in a compromised direction. This compromise also has a correlate in the responses of STS cells, which alter
their direction preferences in the presence of conflicting implied motion information. We conclude that cells in
the prototypical motion areas in the dorsal visual cortex process form that implies motion. Estimating motion by
combining motion cues with form cues may be a strategy to deal with the complexities of motion perception in our
natural environment.
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