An illusion is when we see and perceive an object that doesn't match the sensory input that reaches our eyes. In the case of the image below, the sensory input is four Pac Man–like black figures.

Illusion circuits in the visual cortex were uncovered with two-photon holography, advancing perception and neurophysiology studies.

Have you ever stared at a simple drawing and seen something that isn’t actually there? Well, that’s your brain creating an ...