Thanks to a mouse watching clips from “The Matrix,” scientists have created the largest functional map of a brain to date – a diagram of the wiring connecting 84,000 neurons as they fire off messages.

In a massive scientific effort funded by the National Institutes of Health (NIH), hundreds of researchers have helped to map the connections between hundreds of thousands of neurons in the mouse brain and then overlayed their firing patterns in response to visual stimuli.

Information gathered in just one cubic millimeter of a rodent’s cerebral cortex will help unravel the complex neural networks behind cognition