Scientists have discovered how stress physically reshapes the brain and causes long-lasting harm to humans and animals.
“Stress causes neurons (brain cells) to shrink or grow,” said Bruce McEwen, a neuroscientist at Rockefeller University. “The wear and tear on the body from lots of stress changes the nervous system.”
Stress in early life, even in the womb, can later lead to undesirable changes in behavior and the ability to learn and remember. Other consequences may be substance abuse and psychiatric disorders, researchers said at a conference of neuroscientists in Washington this week.
Even short-term stress can be harmful, said Tallie Baram, a neurologist at the University of California, Irvine. Laboratory mice were immobilized for five hours and subjected to loud rock music. The ordeal reduced the number of delicate fibers that carry signals between neurons, an MRI brain scan of the mice showed. The experiment offered “insights into why some people are forgetful or have difficulty retaining information during stressful situations,” Baram said.
Lauren Jones of the University of Washington in Seattle found that rats subjected to 60 minutes of restraint and electric tail shocks lost their ability to decide which path in a maze to take to receive a reward.