corpus callosum

n. The largest brain commissure in mammalians. It is a thick band of fibers composed of about 200-250 million axons (white matter) connecting the right and left hemispheres.

The corpus callosum allows integrated activity of both hemispheres. The corpus callosum is divided into three different portions: the genu (or knee) connects the frontal lobes, the body mainly connects the parietal lobes, and the splenium mainly connects the occipital lobes. In the so-called agenesis of the corpus callosum there is a complete or partial absence of the corpus callosum. It is an unusual congenital disorder due to an abnormality in the brain development. People with agenesis of the corpus callosum may have visual defects, poor motor coordination, speech and language development delay, and some mental retardation.

- AA

► See also COMMISSURE