Neuroscientists have produced the largest wiring diagram and functional map of a mammalian brain to date using tissue from a part of a mouse's cerebral cortex involved in vision, an achievement that could offer insight into how the human brain works.

From a tiny sample of tissue no larger than a grain of sand, scientists have come within reach of a goal once thought unattainable: building a complete functional wiring diagram of a portion of the brain.

Thanks to a mouse watching clips from “The Matrix,” scientists have created the largest functional map of a brain to date