Your ability to notice what matters visually comes from an ancient brain system over 500 million years old. The brain can make sense of the visual world even without relying on its most advanced outer layer, the cortex. A new study published in PLOS Biology shows that a far older brain structure, known as the superior colliculus, has the neural machinery needed to carry out essential visual computations. These processes allow the brain to separate objects from their background and determine which visual signals matter most in a given space.

The research also shows that these ancient circuits, which exist in all vertebrate brains, can independently produce center surround interactions. This basic visual principle helps the brain detect contrast, edges, and visually important features in the environment.