Inferior view of the right medial temporal lobe and subcallosal region. From the lateral geniculate body of the thalamus, the optic tracts emanate anteromedially toward the optic chiasm. Also projecting from the lateral geniculate nucleus are the optic radiations toward the primary visual cortex. Meyer’s loop contains fibers from the inferior hemiretina and courses anterolaterally around the temporal horn of the lateral ventricle before coursing posteriorly. Just lateral to the anteriormost optic tracts and optic chiasm lies the subcallosal region, containing a quadrilateral area called the anterior perforated substance. The anterior perforated substance is situated immediately dorsal to the medial and lateral olfactory stria and the olfactory tract. (Image courtesy of AL Rhoton, Jr.)