Researchers Develop New Tool to Study Autism Risk Factors

Courtney Roper, assistant professor of environmental toxicology, and Shayla Victoria, a 2025 graduate from the pharmaceutical sciences doctoral program, published their research on the impact of urban pollution on the behavior and development of zebrafish in Neurotoxicology and Teratology.

"The current status of scientific literature is that autism spectrum disorder in humans is caused by a variety of factors that may involve a connection between genetics and the environment," Roper said. "While we didn't see a clear connection between particulate matter in every assay, it's still a model that we can use to start to look at gene-environment interactions.

"It gives us a new tool to study autism spectrum disorder."

About 1 in 31 children in the U.S. is diagnosed with autism spectrum disorder, according to the Centers for Disease Control and Prevention. Scientists have documented a connection between exposure to air pollution with an increased risk of autism in children, but its exact causes remain complex.

"There have been some studies that have linked exposure (to air particulate matter) during development – specifically in utero – to children being born and later being diagnosed with autism spectrum disorder," she said. "But in humans, that's very challenging to study."

By creating a model that allows scientists to test multiple environmental influences across genetic combinations, the researchers are opening a new path to study autism risk factors.

"ASD in humans is very complex, and our study aims to establish a model for investigating a part of this complexity, which is how environmental exposures can influence ASD-like behaviors," Victoria said.

"Our goal was to establish this model so that readers are encouraged to ask further questions that will drive important research about the environmental influences of ASD, and hopefully eventually lead to prevention measures."

Using a zebrafish model, Roper and Victoria were able to control the genetics and exposure levels of particulate matter on developing fish embryos. Zebrafish are particularly well-suited for this type of study because they have defined behaviors at very early stages of development, Roper said.

"Because we are looking at autism spectrum disorder-like behaviors, we want to have a model where we can identify behaviors quickly and in large scale," she said. "With zebrafish, we can study a large number quickly and look for patterns and behavior."

Valproic acid, a medication that is widely prescribed for epilepsy and bipolar disorder, is a proven risk factor for autism spectrum disorder in children. The U.S. Food and Drug Administration has warned against its prescription for pregnant women.

By introducing valproic acid to the fish, the researchers established a benchmark for autism-like behaviors to compare against pollution exposure.

While the air particulate matter tested did alter the neurological development and behavior of the fish, those changes were not always in line with autism spectrum disorder-like behavior.

"This model would be fairly simple to implement for the study of how other environmental contaminants impact neurodevelopment, which is partially why zebrafish are such a powerful model system in general," Victoria said. "Just like we used air pollution particles in our study, others could conduct similar exposure to other environmental contaminants that are predicted to have neurodevelopmental impacts and measure those same behaviors.

"The results could prompt additional questions about those contaminants or even drive the research into a specific direction, based on which behaviors are impacted and how."

Future experiments can model different particulate matter and test longer periods of development.

"It's important to say that this is a model that helps us better understand the risk factors for autism spectrum disorder, not one that can immediately prove or disprove anything," Roper said.

"Now that we have this model, we can start expanding the types of behaviors we're looking at. We can look at long-term changes and see how this exposure might play out in adulthood. We can try other kinds of environmental exposures and combinations.

"It's a new tool we have that can help us understand autism."

Top: Research has previously found a connection between air pollution and autism spectrum disorder, but understanding that connection is difficult. A recent study from UM researchers offers a new tool to understanding how the two may be connected. Photo by Thomas Graning/Ole Miss Digital Imaging Services