Information flows into and out of the cerebral cortex via the subcortical white matter. The myelinated fibres forming the white matter are grouped into:
1. Association fibre bundles that connect gyri within one hemisphere
2. Commissural fibres that connect the two hemispheres (the largest of these is the corpus callosum)
3. The internal capsule which contains axons projecting to downstream nuclei (corticofugal fibres) and to the cerebral cortex (corticopetal fibres)
References:
1. Haines DE, Mihailoff GA. The telencephalon. In: Haines DE, Mihailoff GA, Willis MA. Fundamental Neuroscience for Basic and Clinical Applications. 6th edition, 2025. Philadelphia: Elsevier.
2. Henley C. External brain anatomy. In: Foundations of Neuroscience. Available at: https://openbooks.lib.msu.edu/neuroscience/. Accessed December 2025.