Corpus Callosum

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Corpus callosum (Wiki)   
    "The corpus callosum (from Latin: "tough body"), also known as the colossal commissure, is a wide, flat bundle of neural fibers beneath the cortex in the eutherian brain at the longitudinal fissure. It connects the left and right cerebral hemispheres and facilitates interhemispheric communication. It is the largest white matter structure in the brain, consisting of 200–250 million contralateral axonal projections."

Median sagittal section of brain (person faces to the left). Corpus callosum visible at center, in light gray. 

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