Visual disappearance illusions, such as motion-induced blindness, are commonly used to study the neural correlates of visual perception. In such illusions a salient visual target becomes perceptually invisible. Previous studies are inconsistent regarding the role of early visual areas in these illusions. Here we provide physiological and psychophysical evidence suggesting a role for early visua...

We optically imaged a visual masking illusion in primary visual cortex (area V-1) of rhesus monkeys to ask whether activity in the early visual system more closely reflects the physical stimulus or the generated percept. Visual illusions can be a powerful way to address this question because they have the benefit of dissociating the stimulus from perception. We used an illusion in which a flick...

Computing motion on the basis of the time-varying image intensity is a difficult problem for both artificial and biological vision systems. We show how gradient models, a well known class of motion algorithms, can be implemented within the magnocellular pathway of the primate’s visual system. Our cooperative algorithm computes optical flow in two steps. In the first stage, assumed to be located...

Impossible objects are a type of optical illusion involving ambiguous visual descriptions of figures that cannot physically exist. It is shown by way of example that such objects can be further developed using standard fractal techniques to create new, more complex designs that retain the perceptual illusion, sometimes allowing additional illusions to emerge from the process. The balanced Pytha...