Imaging study reveals how brain’s structure shaped our evolution

Imaging study reveals how brain’s structure shaped our evolution

 

Monday, 20 November, 2017

Using data from an existing bank of brain scans held in the USA, researchers have found that chimpanzee brains may be more different from those of humans than was previously thought.

A team of researchers, led by Professor Neil Roberts at the Edinburgh Imaging Facility - QMRI, studied images from an existing bank of chimpanzee brain scans held in the USA. Working in collaboration with researchers at the University of Oxford, as well as in China, they compared the brains of humans and chimpanzees who were scanned using similar equipment – magnetic resonance imaging (MRI) – and identical experimental procedures.

They found that chimpanzee brains may be more different from those of humans than was previously thought.  In fact, the pattern of asymmetry in human brains could be a unique feature of our species and may hold the key to explaining how we first developed language ability. The study explores the phenomenon of brain torque, in which the human brain shows slight twisting. Until now, this was also thought to be true of other primates. 

Chimpanzee brains were shown to be made up of equal halves, or hemispheres, whereas in human brains a subtle twist was present. Asymmetry was seen in humans – but not chimpanzees – with the left hemisphere longer than the right. Language ability has been linked to areas within the left hemisphere of the brain and has also been associated with asymmetry. The research sheds light on how humans developed skills for language. A new study of particular brain areas related to language using the same image bank could aid understanding of this.

The study was published in the journal Neuroimage.

Professor Neil Roberts (Medical Physics and Imaging Science, University of Edinburgh) said: “Our findings highlight a special, subtle feature of the human brain that distinguishes us from our closest primate cousins and may have evolved rapidly. Better understanding of how this came about in our evolution could help explain how humans developed language.”