There has been a growing body of research studying the possible link between prenatal pesticide exposure and cognitive and behavioral problems of children and teenagers. Now a first of its kind study has used advanced brain imaging technology to reveal how exposure to these chemicals in the womb changes brain functioning and activity of adolescents.
Organophosphates are among the most commonly used classes of pesticides in the United States, despite numerous studies linking the pesticides to brain harm. Prenatal exposure to the organophosphate pesticides has been linked to poorer cognition and behavior problems in children.
A new study is one of the first to use advanced brain imaging to reveal how exposure can actually change brain activity. Scientists used functional near-infrared imaging (fNIRS) to monitor blood flow in the brains of 95 teenagers (ages 15 to 17), born and raised in a region where agricultural spraying of pesticides is common. The fNIRS technique uses infrared light to monitor blood flow in the outer regions, or cortex, of the brain. The fNIRS measured brain activation while the teens engaged in a variety of tasks requiring executive function, attention, social cognition and language comprehension.
The researchers then used data from the California Pesticide Use Reporting program, which documents when and where agricultural pesticides are sprayed, to estimate their residential proximity to organophosphate application during their mothers’ pregnancy.
The study revealed that teenagers estimated to have higher levels of prenatal exposure to organophosphates showed altered brain activity compared to their peers while performing tasks that require executive control.
More specifically, the scientists found that teens with higher prenatal organophosphate exposure had less blood flow to the frontal cortex when engaged in tasks that test cognitive flexibility and visual working memory, and that they had more blood flow to the parietal and temporal lobes during tests of linguistic working memory.
Similar patterns have been observed in other conditions affecting the brain, including Type 1 diabetes, Parkinson’s and Alzheimer’s.
Journal Reference: Sharon K. Sagiv, Jennifer L. Bruno, Joseph M. Baker, Vanessa Palzes, Katherine Kogut, Stephen Rauch, Robert Gunier, Ana M. Mora, Allan L. Reiss, Brenda Eskenazi. Prenatal exposure to organophosphate pesticides and functional neuroimaging in adolescents living in proximity to pesticide application. Proceedings of the National Academy of Sciences, 2019; 201903940. Overview/ Study DOI: 10.1073/pnas.1903940116