A model using MT-like motion-opponent operators explains an illusory transformation in the optic flow field.

Previous studies have shown that a physiologically based model using motion-opponent operators to compute heading performs accurately for simulated observer translations. Here we show how this model can explain an illusory shift in the perceived focus of expansion of a radial flow field that occurs when a field of laterally moving dots is superimposed on a field of radially moving dots. Furthermore, we can use the model to predict the perceptual shift of the focus of expansion for novel visual stimuli. These results support the hypothesis that this illusion results from motion subtraction during the processing of optic flow fields.