This is the most anterior neuropil of the brain and contains a variety of complex and as yet little understood neuropils . Amongst these, the mushroom bodies and central body complex stand out as architecturally distinctive constructions.
Developmental studies suggest that the protocerebrum is the first segmental neuropil.
The deutocerebrum is the second, the tritocerebrum the third. The segmental origin of the optic lobes is not yet fully resolved.