We share 98.8% of DNA with our closest living relatives, chimpanzees. However, despite this almost identical genetic blueprint, chimpanzees have not built civilizations, fought wars, or mastered the art of Tiktok dance routines.
But what exactly makes us stand out? Now, neuroscientists may finally have the answer.
New research published in the journal jneurosci looks at new data from the brains of humans, chimpanzees, and macaques.
“We were interested in finding things that ticked different brains.” Professor Logier Mars, the study co-author said to BBC Science Focus. “And the human brain is something we were particularly interested in, for obvious reasons.”
According to Mars, most studies comparing human brains with other animal brains tend to focus on factors such as overall size, the size of a particular region, or the number of neurons. “But our philosophy is that if we really want to understand what is going on, we need to look into how our brains are organized,” he said.
With that approach in mind, Mars and his team set out to investigate. Similar to the scans used in hospitals, published MRI data were used to create a “connectivity blueprint” for three different species of brains. These blueprints essentially map out whether different regions of the brain communicate with each other.
One area the team expected to find a difference was in the prefrontal cortex. This region is related to complex thinking, planning, and decision making.
This area, often referred to as the “personality center” of the brain, plays an important role in regulating emotions and teaching behaviors. At first glance, it seems to be an obvious place to search for the essence of what makes us human. In fact, this study revealed that this region exhibited more connectivity than in other species.
But was that the whole story?
“The prefrontal cortex is where researchers tend to see when they look for something unique about humans,” Mars said. “But we have found a difference in many places in the cortex of time just above your ears.
Temporal cortex plays an important role in the processing of sensory information – especially visual, sound, and language. Given our highly social and cooperative nature, it is probably not surprising that these areas are connected more intricately in the human brain.
“We are a very social and cooperative species,” explained Mars. “So these properties are likely the driving force behind the changes we observe.”
All of these suggest that there is no single definition switch that makes humans human. Some believe that highly evolutionary events have led us to dominance, but reality can be more complicated.
Like relatives not too far in the trees, we are the result of the progressive, widespread evolutionary changes that have shaped us over time.
Or, as Mars said, “There’s nothing big that makes us different.”
About our experts
Rosier Mars is a professor of neuroscience at Oxford University. His work focuses on the differences between primate brains, especially humans. Mars’s research is published in the following journals: Natural Communication, Frontiers of human neuroscience, and Science.
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Source: www.sciencefocus.com
