The corpus callosum is an example of which type of white matter fiber tract?

• A. Commissural Fibers
• B. Projection Fibers
• C. Association Fibers
• D. Short Fibers

Answer: (A)

The main concept here is how white matter tracts are categorized by their connections. The corpus callosum is composed of commissural fibers, which cross from one cerebral hemisphere to the other to connect homologous areas and enable coordinated function between the left and right sides of the brain. It’s the largest and most well-known example of a commissural tract, bridging the two hemispheres.

Projection fibers, by contrast, run between the cortex and distant targets like the brainstem or spinal cord, carrying signals up and down the neuraxis. Association fibers stay within one hemisphere, linking different regions there, such as pathways connecting various cortical areas. Short (U-fiber) bundles connect neighboring gyri within the same hemisphere.

So the corpus callosum specifically exemplifies commissural fibers because its primary role is interhemispheric communication.