New research shows that the human brain is more unique than we think. In a recent study, scientists found that humans have at least two functional networks within their cerebral cortex that does not exist in rhesus monkeys*. Researchers theorize that these new networks were likely added to the human brain over the course of evolution.
This discovery was found through a study that analyzed, compared and contrasted the functional brain scans of humans and rhesus monkeys during different activities. As a result, the evidence leads scientists to believe that the ancestors of modern humans "evolutionarily split" from those of rhesus monkeys. About 25 million years ago, different areas of the brain were added, disappeared or changed in function. Now scientists are asking, "Has evolution given humans unique brain structures?" Though this question has been raised before, no conclusive evidence existed to support it ... until now?
One of the leading researchers who published the study, neurophysiologist Wim Vanduffel, explained the results of the study in detail:
"We did functional brain scans in humans and rhesus monkeys at rest and while watching a movie to compare both the place and the function of cortical brain networks. Even at rest, the brain is very active. Different brain areas that are active simultaneously during rest form so-called 'resting state' networks. For the most part, these resting state networks in humans and monkeys are surprisingly similar, but we found two networks unique to humans and one unique network in the monkey."
Professor Vanduffel continued, "When watching a movie, the cortex processes an enormous amount of visual and auditory information. The human-specific resting state networks react to this stimulation 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. In other words, brain structures that are unique in humans are anatomically absent in the monkey and there is no other brain structures in the monkey that have an analogous function. Our unique brain areas are primarily located high at the back and at the front of the cortex and are probably related to specific human cognitive abilities, such as human-specific intelligence."
The study used fMRI (functional Magnetic Resonance Imaging) scans to visualize brain activity which mapped functional activity in the brain by detecting changes in blood flow.
*[CORRECTION - 11:45 a.m. EST] Original sentence erroneously stated that rhesus monkeys were ancestral to humans and apes.