How do we "know" from the movements of speeding car in our field of view if it's coming straight toward us or more likely to move to the right or left? In a detailed study of the neurons linking the eyes and brains of mice, biologists discovered that the ability of our brains and those of other mammals to figure out and process in our brains directional movements is a result of the activation in the cortex of signals that originate from the direction-sensing cells in the retina of our eyes.