A, The opercular lips of the sylvian fissure have been removed to expose the insula. The superior longitudinal fasciculus courses in the deep white matter around the outer edges of the insula and lentiform nucleus. B, The insular gray matter has been removed to expose the extreme capsule that separates the insular cortex from the claustrum. The superior longitudinal fasciculus arches around the outer margin of the insula and lentiform nucleus to interconnect the frontal, parietal, occipital, and temporal lobes. C, The extreme capsule has been removed. A small patch of the lower part of the claustrum remains. The external capsule, which separates the claustrum and lentiform nucleus, is exposed deep to the claustrum. Some of the fibers of the external capsule have been removed to expose the lateral surface of the putamen. The superior longitudinal fasciculus has also been removed. The uncinate fasciculus is located deep to the limen insula and interconnects the frontal and temporal lobes. D, The external capsule has been removed to expose the putamen. The anterior commissure, interconnecting the temporal and septal areas, is exposed below the putamen. The corona radiatus spreads out around the putamen. E, The posterior part of the putamen has been removed to expose the lateral medullary lamina that separates the putamen and globus pallidus. The white matter prominence (red arrows) around the putamen is created by the intersection of the fibers of the corpus callosum and the corona radiata. The optic radiations pass through the retrolenticular and sublenticular parts of the internal capsule to reach the visual cortex. Fibers of the anterior commissure spread laterally into the temporal lobe. F, All of the putamen has been removed to expose the lateral surface of the globus pallidus. The anterior commissure passes below the anterior part of the globus pallidus. Transcapsular bridges of gray matter extending between the lentiform and caudate nuclei cross the anterior part of the internal capsule to give it a dark appearance. (Images courtesy of AL Rhoton, Jr.)