Medial Fiber Dissection of the Central Core. A, Some structures that border the central core can be seen at this medial view of the brain, although the central core is not directly present at the medial surface of the brain. The septal area and the fornix (both considered limbic structures), the third ventricle, and the head and body of the lateral ventricle are medially positioned in relation to the central core. The corpus callosum and the anterior commissure, both composed of commissural fibers that cross the midline and interconnect both cerebral hemispheres, are found around the central core, passing first over it and then later its anteroinferior border. B, The thalamus was removed, and some fiber pathways can be distinguished inside the central core. The habenular nuclei, found anterior and inferior to the pineal gland, receive afferents from limbic structures through the stria medullaris thalami and send efferent outputs to the interpeduncular nucleus through the fasciculus retroflexus. The mammillothalamic tract is found at the anterior aspect of the thalamus, the Forel field and thalamic fascicle are at its basal limit, and the internal capsule is at its lateral border. The subthalamic and red nuclei are inferior to the thalamus. (Images courtesy of E de Oliveira)