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Genetic factors influence human brain expansion

Results provide new insight into evolution and development of the human brain

Society for Neuroscience

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IMAGE: Interhemispheric correlations in areal expansion. Results of bivariate models examining correlations between vertex-level homologues in the contralateral cortex projected onto the left hemisphere. view more 

Credit: Schmitt et al., JNeurosci (2019)

An analysis published in JNeurosci of brain scans from more than 600 children and adolescents reveals genetically-mediated associations between the size of evolutionarily novel brain regions and intelligence test scores. Genetic influences on the brain follow the patterns of evolutionary expansion of the human brain relative to nonhuman primates.

Cerebral surface area has expanded dramatically over the course of human evolution. Brain regions that have undergone evolutionary expansion tend to follow a similar pattern during individual development. Despite these trends, brain structure can vary greatly between similar people. The relative contribution of genetic and environmental factors to individual differences in cerebral surface area in children has been unclear.

Eric Schmitt and colleagues found that more than 85 percent of individual differences in total cerebral surface area in their sample of twins and families could be attributed to genetic factors. The researchers also report that modest phenotypic correlations between surface area of the brain's language centers and scores on standard intelligence tests are largely genetically-mediated. These findings suggest that evolutionary expansion of the human brain - and the cognitive abilities it supports - is largely under genetic control.

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Article: A Comprehensive Quantitative Genetic Analysis of Cerebral Surface Area in Youth

DOI: https://www.jneurosci.org/lookup/doi/10.1523/JNEUROSCI.2248-18.2019

Corresponding author: J. Eric Schmitt (University of Pennsylvania, Philadelphia, USA), eric.schmitt@stanfordalumni.org

About JNeurosci

JNeurosci, the Society for Neuroscience's first journal, was launched in 1981 as a means to communicate the findings of the highest quality neuroscience research to the growing field. Today, the journal remains committed to publishing cutting-edge neuroscience that will have an immediate and lasting scientific impact, while responding to authors' changing publishing needs, representing breadth of the field and diversity in authorship.

About The Society for Neuroscience

The Society for Neuroscience is the world's largest organization of scientists and physicians devoted to understanding the brain and nervous system. The nonprofit organization, founded in 1969, now has nearly 37,000 members in more than 90 countries and over 130 chapters worldwide.

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