In "On Intelligence" he postulates that he's not necessarily going for a "human-like" intelligence or even a "life-like" one.

Basically he just wants something that's very good at recognizing patterns over time, which I can imagine the neocortex would be great at.

Though, he also references the thalamus and hippocampus in the books a lot, as very important parts of the brain to his framework. [http://en.wikipedia.org/wiki/Memory-prediction_framework#Neu...]