The brain damage includes the enlargement of a part of the brain that is seen in humans who have autismand schizophrenia.

 

The study is published in the journal Environmental Health Perspectives.

 

As in autism and schizophrenia（精神分裂症）, the changes occurred predominately in males. The mice also performed poorly in tests of short-term memory, learning ability, and impulsivity¹.

 

The new findings are consistent with several recent studies that have shown a link between air pollution and autism in children.

 

Most notably², a 2013 study in JAMA Psychiatryreported that children who lived in areas with high levels of traffic-related air pollution during their first year of life were three times as likely to develop autism.

 

"Our findings add to the growing body of evidence that air pollution may play a role in autism, as well as in other neurodevelopmental disorders," said Deborah Cory-Slechta, Ph.D., professor of environmental medicine at the University of Rochester and lead author of the study.

 

In three sets of experiments, Cory-Slechta and her colleagues exposed mice to levels of air pollution typically found in mid-sized US cities during rush hour.

 

The exposures were conducted during the first two weeks after birth, a critical time in the brain's development. The mice were exposed to polluted air for four hours each day for two four-day periods.

 

In one group of mice, the brains were examined 24 hours after the final pollution exposure. In all of those mice, inflammation was rampant³ throughout the brain, and the lateral⁴ ventricles（侧脑室）  -- chambers⁵ on each side of the brain that contain cerebrospinal fluid -- were enlarged two to three times their normal size.

 

"When we looked closely at the ventricles, we could see that the white matter that normally surrounds them hadn't fully⁶ developed," said Cory-Slechta.

 

"It appears that inflammation had damaged those brain cells and prevented that region of the brain from developing, and the ventricles simply expanded to fill the space."

 

The problems were also observed in a second group of mice 40 days after exposure and in another group 270 days after exposure, indicating that the damage to the brain was permanent.

 

Brains of mice in all three groups also had elevated levels of glutamate（谷氨酸盐）, a neurotransmitter, which is also seen in humans with autism and schizophrenia.

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