Description of the image from https://en.m.wikipedia.org/wiki/Diffusion-weighted_magnetic_resonance_imaging

Visualization of DTI data, depicting a detail of an axial slice of a human brain. The visualization uses standard diffusion ellipsoids, colored with the XYZ-RGB principal eigenvector color mapping. Elongated ellipsoids indicate the presence and direction of homogeneous fiber tracts (white matter) within the voxel. Small spherical ellipsoids indicate gray matter, large spherical ellipsoids indicate that some part of the voxel is filled with cerebrospinal fluid (in the black area at the bottom, very large ellipsoids have been masked to avoid occlusions). Date 22 September 2006 Source Own work Author Thomas Schultz Permission (Reusing this file) Rendering is own work, using a modified version of the BioTensor application developed at the University of Utah. The dataset is courtesy of Gordon Kindlmann at the Scientific Computing and Imaging Institute, University of Utah, and Andrew Alexander, W.M. Keck Laboratory for Functional Brain Imaging and Behaviour, University of Wisconsin, Madison. It is publicly available from [1]

[1] https://www.sci.utah.edu/~gk/DTI-data/