This?

Triune brain - Wikipedia, the free encyclopedia

Reptilian complex

The reptilian complex, also known as the R-complex or "reptilian brain" was the name MacLean gave to the basal ganglia, structures derived from the floor of the forebrain during development. The term derives from the fact that comparative neuroanatomists once believed that the forebrains of reptiles and birds were dominated by these structures. MacLean proposed that the reptilian complex was responsible for species-typical instinctual behaviors involved in aggression, dominance, territoriality, and ritual displays.

http://science.howstuffworks.com/lif...ain/brain4.htm