Brain shapes come from mom and dad

You can thank your parents for your funny-looking hippocampus. Genes influence the three-dimensional shape of certain brain structures, scientists report in a paper posted online December 1 at bioRxiv.org. Showing a new way that genes help sculpt the brain opens up more ways to explore how the brain develops and operates.

Earlier work linked genes to simple measurements of brain structures, such as overall volume or length. The new work goes beyond that by mathematically analyzing complex 3-D shapes and tying those shapes to a particular genetic makeup.

A team led by researchers at Massachusetts General Hospital and Harvard Medical School analyzed MRI brain scans and genome data from 1,317 healthy young adults. Particular genetic profiles influenced the 3-D shape of structures including the hippocampus, caudate and cerebellum, the scientists found. In some brains, for instance, genes played a role in making the seahorse-shaped right hippocampus skinnier on the top and wider on the bottom. Genes also influenced whether the tail of the caudate was short or long.

Quirks of brain structure shapes might play a role in disorders such as schizophrenia, autism spectrum disorder and bipolar disorder, which are known to be influenced by genes, the authors write.