Study shows developed brain shape in parallel with its function throughout course of evolution

A new study published in Nature Communications sheds light on how the shape of the brain has developed in parallel with its function over the last 70 million years of its evolution among the lineage that includes modern humans.

The study, which involves the University of Liverpool’s Professor Nathan Jeffery as a collaborator, has developed a novel method that can capture and distil this complexity, revealing remarkable trends over the course of evolution.

“Correlating external brain shape with function across many different extinct as well as living species has been a central ambition in neuroscience and evolutionary biology for many decades but has never really been realised because the variables involved are so fiendishly difficult to track,” explains Professor Jeffery, who is based in the Institute of Life Course and Medical Sciences.

For the study, 3D surface models of the brains of 90 species of Euarchontoglires (supraprimates) such as humans, macaques, marmosets, mice, rats, squirrels and hamsters were examined. A common representation of the brains of all species was created through computer-based modeling of common ancestors and shape analysis of brain structures. This enables, for the first time, the statistical analysis of the variability of their forms and their relationship to function, behavior and ecology, the relationship of living and extinct species with their environment. Researchers revealed that the adaptation of the brain to its environment begins with the expansion of visual areas and then leads to the expansion of association areas associated with higher cognitive functions such as language and episodic memory.

The findings could help to solve the difficulties in studying common and specific abilities of human and animal brain architecture and have some application in the translation of animal experiments to humans. “By framing these questions in terms of evolutionary relationships and the adaptive processes that lead to their current state, we hope to enable us and other researchers to gain a deeper understanding of specific neuroscientific questions,” explains lead study author Ernst Schwartz, Medical University of Vienna.

The study was carried out in collaboration with researchers from all over the world and provides new insights into the connections between brain structure and function in humans and animals. “This study would not have been possible without extraordinarily open, interdisciplinary, international cooperation. It connects neuroscience, anatomy, paleontology, and mathematics and more than a dozen laboratories around the world” explains study leader Professor Georg Langs, Massachusetts Institute of Technology.

“One of the triggers for this work was an interest in plasticity, the question of why some brain regions are better able to reorganize during illness. We hope that a better understanding of how the geometry of the brain came about will give us insights into these mechanisms.”