The surface of the cerebrum -- the cerebral cortex -- is composed of six thin layers of neurons, which sit on top of a large collection of white matter pathways. The cortex is heavily convoluted, so that if you were to spread it out, it would actually take up about 2 1/2 square feet (2500 sq cm).he cerebrum -- which is just Latin for brain -- is the newest (evolutionarily) and largest part of the brain as a whole. It is here that things like perception, imagination, thought, judgment, and decision occur.