Coloured diffusion tensor imaging (DTI) magnetic resonance imaging (MRI) scan showing the white matter fibres of the inferior cerebellar peduncle (ICP) in the brainstem. The ICP plays a role in the coordination of movement and proprioception. 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.