Coloured diffusion tensor imaging (DTI) magnetic resonance imaging (MRI) scan showing the white matter fibres of the inferior fronto-occipital fasciculus (IFOF) of the brain. The front of the brain is at right. The IFOF originates in the occipital and parietal lobes and terminates in the inferior frontal lobe. It plays a role in semantic language processing and goal-oriented behaviour. Diffusion tensor imaging measures the direction of water diffusion, which in the brain reveals the orientation of nerve fibres. Red fibres have a left to right orientation, green a front to back orientation and blue an up and down orientation.