Which of the following is a major commissural tract other than the corpus callosum?

Which of the following is a major commissural tract other than the corpus callosum?

• A. Fornix
• B. Internal capsule
• C. Posterior commissure
• D. Anterior commissure

Answer: (D)

Interhemispheric communication happens through commissural tracts that cross the midline. While the corpus callosum is the largest example, there are other major cross-hemisphere pathways. The anterior commissure is one of these key bundles, linking the two temporal lobes and olfactory areas so that signals can cross between the hemispheres. This makes it a true major commissural tract besides the corpus callosum. The other options don’t fit as well. The fornix is a limbic pathway that connects the hippocampus to the mammillary bodies and other limbic structures, but it doesn’t cross between the two hemispheres as a commissure. The internal capsule contains projection fibers carrying information between cortex and subcortical structures and does not serve interhemispheric communication. The posterior commissure is another commissural bundle, but it is relatively small and not considered a major cross-hemisphere tract like the anterior commissure.

Interhemispheric communication happens through commissural tracts that cross the midline. While the corpus callosum is the largest example, there are other major cross-hemisphere pathways. The anterior commissure is one of these key bundles, linking the two temporal lobes and olfactory areas so that signals can cross between the hemispheres. This makes it a true major commissural tract besides the corpus callosum.

The other options don’t fit as well. The fornix is a limbic pathway that connects the hippocampus to the mammillary bodies and other limbic structures, but it doesn’t cross between the two hemispheres as a commissure. The internal capsule contains projection fibers carrying information between cortex and subcortical structures and does not serve interhemispheric communication. The posterior commissure is another commissural bundle, but it is relatively small and not considered a major cross-hemisphere tract like the anterior commissure.