Environment has extensively shaped human brain

New York: Human brains have evolved to be more responsive to environmental influences than chimpanzee brains, which may account for part of human evolution, says a new study.

The findings provide insight into why humans are capable of adapting to various environments and cultures.

The research team studied 218 human brains and 206 chimpanzee brains to compare two things: brain size and organisation as related to genetic similarity. 

The researchers found that human and chimpanzee brain size were both greatly influenced by genetics.

In contrast, the findings related to brain organisation revealed key differences between chimpanzees and humans. 

In chimpanzees, brain organisation is also highly inherited, but in humans this is not the case.

"We found that the anatomy of the chimpanzee brain is more strongly controlled by genes than that of human brains, suggesting the human brain is extensively shaped by its environment no matter its genetics," said lead author Aida Gomez-Robles, postdoctoral scientist at George Washington University.

These findings could also have important implications regarding human susceptibility to degenerative diseases.

"Though our findings suggest that the increased plasticity found in human brains has many benefits for adaptation, it is also possible that it makes our brain more vulnerable to many human-specific neuro-degenerative and neuro-development disorders," William Hopkins, professor at Georgia State University said.

In the study, the human brains were from twins or siblings, while the chimpanzee brains had a variety of kinship relationships. 

MRI scans were used to measure brain volume and reconstruct 3D models of the cortical surface. 

The study was published in the journal Proceedings of the National Academy of Sciences.