It’s common knowledge that our surroundings affect our health — decades of research have linked things like air, water and soil quality to various measures of physical well-being. But much less is known about how the environment changes our brain. Now, a research team at the Keck School of Medicine of USC is pooling thousands of brain scans to better understand how aspects of our physical space — including air pollution, noise and green space — alter brain structure, influence our behavior and impact our risk for various developmental, neurodegenerative and psychiatric problems.

“We know that things like air pollution and tobacco smoke exposure affect the brain and can increase the risk of dementia and vascular problems decades after exposure,” said Lauren Salminen, PhD, instructor of research neurology at the USC Mark and Mary Stevens Neuroimaging and Informatics Institute (USC Stevens INI) and a co-founder of the new effort, the ENIGMA-Environment Working Group (ENIGMA-ENV). “But we still have so much to learn about disease risk and the processes that underlie those changes.”

ENIGMA-ENV is working to pool brain scans from more than 19,000 people. About half of those participants are healthy, while others have conditions such as HIV, major depressive disorder or Parkinson’s disease. The group’s first project will use a geospatial approach to map each participant’s home location and track pollution exposure using publicly available data.

“We’ll also look at how migration patterns influence the brain,” Salminen said. “If people move from an area that’s highly polluted to an area that’s less polluted — or vice versa — what effect does that have on the brain?”

Salminen is working with Megan Herting, PhD, who studies neurodevelopment, and JC Chen, MD, ScD, who studies environmental influences on neurological diseases, both members of the Keck School’s Department of Preventive Medicine. The team seeks to answer numerous questions about pollution and brain health, including how pollution affects development, aging and disease risk; whether the way pollution impacts the brain may differ by sex, race/ethnicity and socioeconomic status; and how lifestyle changes like improving nutrition and exercise may offset some of the damage caused by exposure to pollution.

“We want to learn more about risk mitigation — for example, are there dietary changes that people can make on a personal level to optimize their brain health?” Salminen said.

ENIGMA-ENV builds on the success of the Enhancing Neuro Imaging Genetics through Meta-Analysis (ENIGMA) consortium, which unites neuroimaging researchers in 45 countries to study a variety brain diseases and processes, led by the USC Stevens INI’s associate director, Paul M. Thompson, PhD.

“The ENIGMA Environment Working Group is a truly global quest to identify environmental factors that help or harm our brains. The sheer ability to coordinate a project on this scale is impressive,” Thompson said. “Comparing data worldwide should reveal what factors help our brains develop and age, and what protects us against mental illness, which may ultimately guide public health policy.”

The project’s long-term goals include influencing environmental policy and informing decisions about research. At this stage, Salminen and her team are seeking collaborators to join their effort. Any researchers who have collected neuroimaging data and participants’ residential address information can contribute — no experience in environmental neuroscience is required.

The research described in this article is supported by a pilot grant from the USC Southern California Environmental Health Sciences Center and by the National Institutes of Health (P30ES007048).

— Zara Greenbaum