Tractography is the algorithmic procedure that estimates white matter pathways using directional information from diffusion-weighted magnetic resonance imaging. Tractography produces a sequence of tri-dimensional spatial points called a streamline. A streamline represents an estimate of the link between two anatomically connected brain regions. The image "Integrated Circuit" shows thousands of these streamlines. They are colored by the local average length of streamlines (low: light blue, medium: green, high: brown). Transparency is applied following the local average length, making longer streamlines appear through shorter streamlines. In the end, the image shows the estimated connectivity of the brain with emphasis on the length aspect of the streamlines distribution.