A new imaging method that offers an unprece­dented view of ­complex neural structures could help explain the workings of the brain and shed light on neurological diseases.

Interactive Tools

The three tools below and on the next two pages show data gathered in different ways from a living human volunteer. In each image, the brain is viewed from the back at a three-quarter profile, with the volunteer’s eyes pointed back and toward the right.

In this interactive tool, only the fibers that intersect a given vertical plane are shown in each still image. Visualizing only a subset of the brain’s densely packed neural fibers allows individual networks to be studied in greater detail. Users can either click on the arrow in the center of the image to view a movie that moves the plane through the brain from left to right, or they can move manually through the brain using the cursor below. Neurosurgeons sometimes use this type of visualization when searching for signs of a tumor.

Just as most roads in the United States are local streets rather than interstate highways, most connections in the brain are short range. In this interactive tool, fibers are removed based on their length. As the cursor moves right, progressively longer fibers are subtracted from the visualization.

The red and orange fibers in the lower left quadrant of the image, which begin to disappear when the cursor is at its midpoint, are part of the brain’s sensory association pathways, integrating visual auditory information, for example. The last fibers to remain–the blue C-shaped fibers running horizontally across the middle of the image–are part of the cingulum bundle, which runs from the prefrontal cortex, which is involved in planning and higher cognitive function, to the parietal cortex, which is mainly involved in synthesizing sensory information.

This visualization begins with a view of the brain’s right hemisphere, then rotates clockwise. A head-on view is shown about one-fifth of the way through. This image shows only a subset of fibers that intersect a vertical plane in the left hemisphere of the brain. Because most connections in the brain are short range, the left hemisphere appears more densely packed than the right; few fibers travel from their origins in the left hemisphere to the right.