A : Olfactory bulb. This rests over the cribriform plate of the ethmoid bone. Through the perforations of the plate, olfactory nerves reach the nasal cavity.

B : Olfactory tract, the long slender bundle. Often damaged in specimens that have been handled!

C : The tract bifurcates into medial and lateral olfactory striae.

The cross shows the optic chiasm.

The encircled area includes the cortex of the insula, exposed by cutting off a part of the temporal lobe. The insula will be seen later from the lateral side.

The next picture is a magnified part of the base of the brain.

The quadrangular area is the interpeduncular fossa, bounded anteriorly by the optic chiasm and posteriorly by the cerebral peduncles. The peduncles are difficult to see in this picture - so they will be in a real brain unless you gently depress the brainstem and pull the temporal lobes apart.

The mamillary bodies are seen as two rounded structures near the caudal limit of the fossa. Beyond them the pituitary stalk is seen as a midline projection.

The anterior perforated substance is shown in the oval. It is "perforated" because central branches enter the brain here.