Playing violent video games for even a week can alter the brain and make players more aggressive, researchers say. This is because key areas in the brain suffer reduced activity and are left physically altered, a new study has shown. Scientists at the Indiana University School of Medicine in Indianapolis took a group of 22 men aged 18-29 and performed MRI scans on them. They then divided the group in half, and one group was asked to play violent video games for at least 10 hours a week while the second group played none. According to the Sunday Times, the researchers found that the effects on the brain were discovered in the left inferior frontal lobe and the anterior cingulate cortex. The results are important as they show that the games cause the brain to alter to accommodate demands put on it. "This investigation provides the first longitudial, experimental investigation of video game play on brain activity," the Daily Mail quoted an abstract of the research report as saying. However they found that when gamers stopped playing, their brains returned to normal. The results will be published at the annual meeting of the Radiological Society of North America.