A team of American and Italian scientists have found the biology of the human brain to be distinct from that of rhesus monkeys, which are thought to be our closest evolutionary ancestors. Using fMRI scans, researchers measured differences in how human brains respond to a watching a film compared with a monkey. They specifically noticed that the so-called “resting-state” networks in humans reacted in a totally different way than any part of the monkey brain. “This means that they also have a different function than any of the resting state networks found in the monkey.”
What’s the Big Idea?
Scientists have long been hesitant to say that evolution selected for humans’ more powerful brains because conclusive evidence was lacking. This new evidence, however, of at least two functional networks in the cerebral cortex which are not found in rhesus monkeys seems to confirm the existence of biologically distinct areas. “In other words, brain structures that are unique in humans are anatomically absent in the monkey and there no other brain structures in the monkey that have an analogous function.” This means that new brain networks were likely added in the course of evolution from primate ancestor to human.