Tensor shapes are calculated inside the many voxels that make up brain scans by looking at the direction of water diffusion. Different scanning techniques allow for different levels of accuracy and detail.

DTI is a special form of magnetic resonance imaging (MRI) in which the directionality of water molecule diffusion is mapped. The water diffusion at every spatial point in the image volume is analyzed and used to determine the pathways that white matter fibers take throughout the brain, linking various areas of cortical grey matter.

The colors displayed in the image are used to represent the spatial orientation of the fiber pathways: red is left-to-right in the brain, green is anterior-to-posterior, and blue is inferior-to-superior.

Animation by Carlos Mena. Narration and Music by Ellen Armour. Script by Amanda Hammond. Scientific Consultation by Arthur W. Toga, Ph.D.

http://www.humanconnectomeproject.org/