Evolution Gave Humans Unique Brain Structure: Other Primates Out of Luck

Evolution may have given humans a unique brain structure that gave them a leg up over other primates--are we really surprised? New research shows that humans have at least two functional networks in their cerebral cortex that may have been added in the course of evolution from primate ancestors to humans.

According to researchers, our ancestors evolutionarily split from rhesus monkeys about 25 million years ago. Since then, brains areas have been added, disappeared or have changed in function over the course of our evolution. Yet scientists have long wondered whether evolution gave humans any unique brain structures that separate them from other primates. Now, they've found evidence that could prove that humans do indeed have networks that differ.

The researchers conducted functional brain scans in humans and rhesus monkeys with fMRI scans. The scientists conducted these scans while the subjects were at rest and while they were watching a movie. This allowed them to compare both the place and the function of the cortical brain networks. Although the resting states in humans and monkeys were found to be surprisingly similar, the researchers also found networks that were unique to humans, and one network that was unique to the rhesus monkeys.

In fact, the scientists noted while watching the movie, human brains reacted to the stimulation in a totally different way than any part of the monkey brain. The cortex processes an enormous amount of visual and auditory information, and the difference means that they also have a different function than any of the resting state networks found in the monkey. These unique brain areas in humans are located high at the back and the front of the cortex, and are probably related to specific human cognitive abilities, such as human-specific intelligence.

Although more research needs to be conducted, the findings show that humans process things differently due to an actual difference in brain structure. Further studies could allow researchers to see how the human brain has evolved over the thousands of years it took to develop it.