April 30, 2012 -- Prenatal exposure to a pesticide used on many crops may be linked with abnormal changes in a child's developing brain, scientists report.

Compared to children with low prenatal exposure, those with high exposure to the pesticide chlorpyrifos had abnormalities in the cortex (the outer area of the brain), says Virginia Rauh, ScD, professor and deputy director of the Columbia Center for Children's Environmental Health at the Mailman School of Public Health at Columbia University.

The cortex helps govern intelligence, personality, muscle movement, and other tasks.

"In areas of the cortex, we detected both enlarged and reduced volumes that were significantly different from the normal brain," she tells WebMD. "This suggests the process of normal brain development has been disturbed in some way."

The study is published in Proceedings of the National Academy of Sciences' Early Edition.

In 2001, the U.S. EPA banned the residential use of chlorpyrifos. It still allows it on crops. It can also be sprayed in public places such as golf courses.

Some environmental advocates have petitioned the EPA to ban agricultural use.