Early PFAS Exposure Linked to Altered Brain Genes and Impulsivity in Rats

Study finds lasting neurological effects from common 'forever chemicals' in pregnant rats and their offspring

Apr. 19, 2026 at 2:24am

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A highly detailed, translucent X-ray-style image of a rat's brain, showing the complex neural structures in ghostly, glowing lines against a dark background, conceptually representing the study's findings on how early PFAS exposure can alter brain development and function.An X-ray-like image reveals the intricate neural networks in a rat's brain, highlighting the molecular changes linked to early PFAS exposure.Riverside Today

A new study published in Environmental Health Perspectives found that early exposure to per- and polyfluoroalkyl substances (PFAS), commonly known as 'forever chemicals,' is linked to changes in brain gene expression and increased impulsive behavior in rats. Pregnant rats given drinking water containing PFOA and PFOS, two prevalent PFAS compounds, had offspring that showed altered activity in genes related to neurodevelopment and neurotransmitter signaling, as well as measurable increases in impulsivity-like behaviors in adulthood.

Why it matters

The study adds to growing evidence of the potential impact of PFAS on brain health, as previous research has associated exposure with altered thyroid function, reduced vaccine response, and increased cancer risk. While rodent studies provide valuable mechanistic insights, the consistency of findings across animal models strengthens the case for treating PFAS as a potential neurodevelopmental hazard for humans.

The details

To evaluate impulsivity, researchers used a delay discounting task, a behavioral test that measures an individual's tendency to choose a smaller, immediate reward over a larger, delayed one. Rats exposed to PFAS consistently chose the smaller, sooner reward more often than control animals, indicating heightened impulsive tendencies. Gene expression analysis of the prefrontal cortex revealed significant alterations in pathways related to synaptic plasticity, dopamine signaling, and thyroid hormone regulation.

  • Pregnant rats were given drinking water containing PFOA and PFOS during gestation and early life.
  • The offspring continued to receive the same exposure through maternal milk and direct consumption until weaning.
  • Researchers then assessed the animals' behavior and brain tissue when they reached young adulthood, approximately 60 days after birth.

The players

Dr. Margarita Curras-Collazo

Lead author of the study and a professor of neuroscience at the University of California, Riverside.

Dr. Linda Birnbaum

Former director of the National Institute of Environmental Health Sciences (NIEHS), who was not involved in the study.

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What they’re saying

“We're seeing that early-life PFAS exposure doesn't just cause transient effects—it appears to reprogram brain development in ways that endure into adulthood.”

— Dr. Margarita Curras-Collazo, Lead author of the study and professor of neuroscience at UC Riverside

“Rat models allow us to control exposure and examine brain tissue in ways impossible in human studies, but we must be cautious about assuming identical outcomes.”

— Dr. Linda Birnbaum, Former director of the National Institute of Environmental Health Sciences (NIEHS)

What’s next

Future work will need to explore sex differences—this study observed effects primarily in males—and examine whether similar patterns appear in other brain regions or across generations.

The takeaway

The findings reinforce calls for stricter regulation of PFAS, as research continues to uncover the long-term consequences of early-life chemical exposure. Reducing preventable risks, especially for vulnerable populations like pregnant women and children, is crucial for lifelong health.