Which structure is the largest white matter tract that connects the cerebral hemispheres?

• A. Fornix
• B. Thalamus
• C. Corpus Callosum
• D. Anterior Commissure

Answer: (C)

The corpus callosum is the main highway for interhemispheric communication, making it the largest white matter tract in the brain. It consists of a vast bundle of axons that connect homologous cortical regions across the two hemispheres, enabling quick, coordinated activity between sides. It’s organized into sections (rostrum, genu, body, and splenium) that span from the frontal lobes to the occipital lobes, reflecting its broad role in integrating information.

The other structures are not the main interhemispheric connector. The fornix is a limbic pathway linking the hippocampus to diencephalic targets, not a dominant cross-hemisphere tract. The thalamus is gray matter made of nuclei, not a white matter tract. The anterior commissure is a much smaller midline bridge connecting the temporal lobes and olfactory regions. Thus, the corpus callosum stands out as the largest tract linking the two cerebral hemispheres.