If mice commuted, their brains might find it progressively harder to navigate the maze of Los Angeles freeways. A new study reveals that after short-term exposure to vehicle pollution, mice showed significant brain damage -- including signs associated with memory loss and Alzheimer's disease.

The mind-numbing toxin is not an exhaust gas, but a mix of tiny particles from burning of fossil fuel and weathering of car parts and pavement, according to the study to be published April 7 in the journal Environmental Health Perspectives.

Many studies have drawn a link between vehicle pollution and health problems. This is the first to explore the physical effect of freeway pollution on brain cells.