<Tr> <Td_colspan="2"> Anatomical terms of neuroanatomy (edit on Wikidata) </Td> </Tr> <P> The commissural fibers or transverse fibers are axons that connect the two hemispheres of the brain . In contrast to commissural fibers, association fibers connect regions within the same hemisphere of the brain, and projection fibers connect each region to other parts of the brain or to the spinal cord . </P> <P> The commissural fibers make up tracts that include the corpus callosum, the anterior commissure, and the posterior commissure . </P> <P> The corpus callosum is the largest commissural tract in the human brain . It consists of about 200 - 300 million axons that connect the two cerebral hemispheres . The corpus callosum is essential to the communication between the two hemispheres . </P>

The great majority of which tracts pass through the corpus callosum