Evolution may have given humans unique brain structures, say scientists

February 22, 2013

Evolution may have given humans unique brain structures, say scientists

Brain structures that are unique in humans are anatomically missing in Rhesus monkeys.

Has evolution given humans unique brain structures? For years, scientists have been asking themselves this question. Now, scientists from the University of Leuven have the first piece of evidence that could prove that humans have unique cortical brain networks. The study’s findings were published in The Journal of Neuroscience.

The scientists examined functional brain scans in humans and rhesus monkeys at rest and while watching a movie to compare both the location and the function of cortical brain networks. They report that even at rest, the brain is extremely active. Varying brain areas that are active simultaneously during rest create “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,” said Professor Wim Vanduffel, a member of the Faculty of Medicine’s Neurophysiology Research Group at the University of Leuven, in a statement.

Vanduffel said that the cortex processes an extraordinary amount of visual and auditory information when watching a movie. He also said that the two resting state networks unique to humans react to the visual and auditory stimulation in a completely different manner than any part of the monkey brain, which means that they have a different function than any of the resting state networks located in the monkey.

“In other words, brain structures that are unique in humans are anatomically absent in the monkey and there are 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,” Vanduffel posited.

The study used functional Magnetic Resonance Imaging (fMRI) to show which parts of the brain were involved in a particular mental process. fMRI works by detecting the changes in blood oxygenation and flow that occur in response to neural activity, according to PsychCentral.

“[Our findings] suggest that functions of structurally preserved networks can diverge over time and that novel, hence human-specific networks, have emerged during human evolution,” wrote the researchers in the study’s abstract.

 


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