Immediately dorsal to the body of the corpus callosum (i.e., that part between the splenium and genu) locate the crease that forms the callosal sulcus. The cortical outfolding just dorsal to the callosal sulcus is the cingulate gyrus, which, in turn, is bounded dorsally by a crease, the cingulate sulcus. Follow the cingulate gyrus caudally, and you will find that it courses ventrally and laterally, eventually becoming continuous with the hippocampal gyrus that we saw on the ventral surface of the rostral brain. Just inferior to the genu and rostrum of the corpus callosum is a region of medial face cortex called the septal area. As you will see in cross-sections, this region does not extend very deeply from the midline. At the caudal edge of the septal area, you should be able to locate the small, light-colored dot which is a cross-section of the anterior commissure. Just inferior to the attachment point of the pineal body, there is a much smaller (you won't be able to see it here, but it may appear in cross-section) bundle of decussating fibers called the posterior commissure. If the bisection of the brain was exactly on-center, there will be a membrane extending ventralwards from the body of the corpus callosum, the septum pellucidum, which separates the two lateral ventricles from each other. The fornix is a bundle of fibers that parallels the corpus callosum through much of its course. You can find the body of the fornix lying about midway between the massa intermedia and the body of the corpus callosum. You'll get a better look at the fornix in Plate 18.