One way to spot The Invisible Man would be to send him out in the rain – patterns left by the water falling against his body would be a total giveaway. Researchers are using a similar principle to study human brains. Individual bundles of nerve fibres are invisible to many brain imaging techniques, yet here they are – traced out in rainbow colours in this human brain model. A technique called diffusion tensor imaging (DTI) watches water sloshing around the brain, recording how its motion changes when falling against, or running down, nerve bundles in different brain regions. Modelling these tiny changes in water current with a technique called tractography reveals nerves bundles linking the left and right sides of the brain (red), the front and back (green) and running bottom to top (blue) – otherwise invisible patterns that can be used to specifically compare healthy and injured brains.
Written by John Ankers
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