Inferior view of the right medial temporal lobe. The midbrain has been sectioned at the level of the crus and substantia nigra. The optic tracts sweep around the crus cerebri to terminate in the lateral geniculate nucleus.  Projecting from the lateral geniculate nucleus are the optic radiations. Meyer’s loop contains fibers from the inferior hemiretina and courses anterolaterally around the temporal horn of the lateral ventricle before coursing posteriorly to the primary visual cortex of the occipital lobe. Just lateral to the optic chiasm lies the subcallosal region, containing a quadrilateral area called the anterior perforated substance which is situated immediately caudal to the medial and lateral olfactory stria and the olfactory tract. (Image courtesy of AL Rhoton, Jr.)