Brain regions associated with cognitive function and emotional control in young men changed after one week of playing video games, according to new research.

For years, critics have argued that playing violent video games can be harmful, but there has been little scientific evidence showing the games can negatively affect individuals. Researchers point to evidence of long-term effects.

The study by researchers at the Indiana University School of Medicine was presented at the annual meeting of the Radiological Society of North America (RSNA).

"We have found that a sample of randomly assigned young adults showed less activation in certain frontal brain regions following a week of playing violent video games at home," said Yang Wang, M.D., an assistant research professor at IU.

In the study, 22 healthy adult males ages 18-29 with little previous exposure to violent video games were randomly assigned into two groups. The first group played violent games for 10 hours at home, while other group did not play violent video games.

Each of the men were given a Functional magnetic resonance imaging (fMRI) The specialized type of MRI scans neural activity in the brain, before and after the study. Tests were given to measure emotional levels, words association and cognitive inhibition.

Results show that participants that played violent games after one week showed less activation in emotional tasks and counting tasks in the frontal lobe.

"These brain regions are important for controlling emotion and aggressive behavior," Wang said.

After the second week without game play, the changes to executive regions of the brain were diminished.

"These findings indicate that violent video games play has long-term effect on brain function," he said.