White matter of the cerebral hemisphere. The lateral hemisphere has been dissected to reveal the deep white matter tracts of the cerebrum.  Arcuate fibers, seen here within the subcortical frontal lobe, are U-shaped bundles of corticocortical axons that connect adjacent gyri with one another.  These fibers (which should not to be confused with the arcuate fasciculus) are also referred to as short associational fibers.  The superior longitudinal fasciculus, located lateral to the corona radiata, is a massive fiber tract that interconnects the occipital, parietal and temporal lobes with the frontal lobe. The external capsule contains numerous corticocortical association fibers including the inferior fronto-occipital fasciculus and the uncinate fasciculus.  The claustrum, only partly visible in this dissection, is a thin sheet of gray matter that lies lateral to the external capsule and deep to the insula.  It has extensive and reciprocal interconnections with widespread areas of the ipsilateral cerebral cortex; however, it function is enigmatic.  The optic radiations project from the lateral geniculate nucleus of the thalamus and travel through the temporal and parietal lobes to the primary visual cortex on the medial surface of the occipital pole. (Image courtesy of PA Rubino)