The target volume is reached at the age of 6–9 years. It reaches its final shape in midgestation (week 20) but is still small and grows, initially by addition of fibers and later by myelination. From this time on the corpus callosum grows mainly in the anterior direction, pushing the splenium posteriorly. Callosal development is a very quick process and takes place in 13th week of gestational life. Īccording to the newest theory the corpus callosum in its embryological development is fused of two separate parts: the anterior one, consisting of the rostrum, genu, and body and the posterior one-splenium. The fibers in the rostrum connect fronto-basal cortex, in the genu-prefrontal cortex and anterior cingulate area, in the body-precentral (motor) cortex, insula, and cingulate gyri, in the isthmus-precentral and postcentral gyri (motor, somatosensory) and primary auditory areas, and in the splenium-posterior parietal, medial occipital, and medial temporal cortexes. In the anterior-posterior direction the corpus callosum is divided into rostrum, genu, body, isthmus, and splenium. ![]() Transection of the anterior part of the callosal body during neurosurgical procedures aiming at the removal of tumors of the third or lateral ventricles leads to the deficits of memory, the dysexecutive cognitive and behavioral syndrome, disturbances in interhemispheric transfer of learning from one hand to the other, and an increase in reaction times. The patients that underwent callosotomy present a “disconnection syndrome” as well as subtle social and emotional deficits. Another example is the role of the corpus callosum in the interhemispheric spread of epileptic activity and the efficacy of corpus callosotomy in cases of medically intractable epilepsy. The callosal type of AHS can best be explained by the loss of interhemispheric connection, revealed during activities that require control of the dominant hemisphere. A good example of this role is an alien hand syndrome (AHS): anterior callosal injury (in case of stroke, trauma, and tumor) leads to intermanual conflict with involuntary movements of nondominant hand. Its role is interhemispheric connection and coordination. IntroductionĬorpus callosum is one of the three interhemispheric commissures (anterior commissure, hippocampal commissure and corpus callosum) and the greatest of them-it consists of approximately 190 000 000 axons. Cases include fetuses, children, and adults with rich iconography from the authors’ own archive. ![]() The purpose of this review is to illustrate the wide spectrum of lesions in the corpus callosum, both congenital and acquired: developmental abnormalities, phakomatoses, neurometabolic disorders, demyelinating diseases, infection and inflammation, vascular lesions, neoplasms, traumatic and iatrogenic injury, and others.
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