You probably take your depth perception for granted. It allows you to easily judge distances. Each eye sends a different signal to the brain, and the brain compares the two pictures. But even using just one eye, the world doesn't suddenly appear flat. So how can just one eye provide depth perception? A team at the University of Rochester recently published a possible answer to that question on-line in the journal Nature. It has to do with a small part of our brain called the middle temporal area. This region processes information both from visual cues and from the motion of our eyes. Researchers examined macaque monkeys watching virtual reality. Basically, the eye moves when something crosses the path of vision. This middle temporal area picks up the speed of the objects relative to these eye movements. Neurons in that brain region showed activity that signaled depth perception even in the absence of other cues. This new information may be useful for creating better virtual reality. And scientists also hope that it leads to better tools to assist children born with misalignder.