Corpus callosum

The corpus callosum (Latin corpus " body " callus " callus " ) or bar (also known as brain bar or corpus callosum ) is a large, transverse connection ( commissure ) between the two cerebral hemispheres of the cerebrum of placental animals, a subclass of mammals. It belongs to the white matter and in humans consists of approximately 250 million nerve fibers.

Structure and functions

The corpus callosum consists of the parts rostrum ( beak ), genu (knee), trunk ( trunk) and splenium ( posterior end ) and extends to the base of the big brain longitudinal column and forms the roof of the lateral ventricles.

The bar serves the exchange of information and coordination between the two hemispheres, each part have different tasks in information processing for itself.

The partially double- fibers of the beam connecting mainly identical cortical areas of the respective hemispheres with each other, and occasionally different areas. Since it is shorter than the hemispheres, only his middle fibers are placed crosswise. The anterior fibers that radiate through the beam knee to the frontal poles and the posterior fibers that run through the splenium to the Occipitalpolen are bent into a U -shape. Because of these pliers shape the frontal U- fibers are summarized as forceps frontalis ( minor), the occipital than forceps occipitalis ( maior ).

The dorsal surface of the bar is covered by a thin gray covering ( indusium griseum ), which is attributable to cortical limbic areas.

Medical aspects

In some forms of epilepsy treatment, inter alia, is to cut through the bars surgically (this is in general but at least the splenium left intact ). This is to prevent a transfer of the excitation to the other side of the brain. Especially in the fall of epilepsy can be as the frequency and severity of serious injury often associated with falls are usually significantly reduced. On the other hand, these so-called split-brain surgery or callosotomy is associated with severe cognitive disorders, so that it is nowadays hardly performed. Also because of the division of the beam occurs, the then called split-brain syndrome. In his book The Man Who Mistook His Wife for a Hat Oliver Sacks reports of such patients and noted that work separated from each other in this particular case, both halves of the brain. He shows, for example, through experiments, that the speech center in the left hemisphere can no longer communicate with the visual center of the right hemisphere.

The beam engraving is an older treatment regimens for increased intracranial pressure.

The congenital absence of the beam is called the corpus callosum agenesis.

The Mild Encephalopathy with Reversible Lesion in the splenium ( MERS ) is a bounded on the rear end ( splenium ) of the beam encephalopathy, which usually occurs in the context of infection.