Scientists at the Cardiff University Brain Research Imaging Centre have produced the world’s most detailed scans of the brain’s internal wiring. These wires, or axons, carry electrical signals that encode information around the brain.

Axons labelled green travel back to front, red run left and right, and blue go up and down. To make these images, a team of researchers and engineers used a powerful type of MRI scanner, one of only three in the world. It measures the motion of water molecules along axons. Scientists then combined this data with advanced mathematical models to infer axon orientation and density. They visualised the results with a technique called cinematic rendering, which is used in animated blockbusters to create realistic hairs and grass.

They also scanned the brain of a woman with multiple sclerosis and spotted an area of unusually low axon density. This finding may give clues to what causes this and other brain conditions.