CHICAGO - Just one week of playing a violent video game produced measurable differences in blood flow to select areas of the brain on functional MRI (fMRI), which may explain why game playing has been linked to behavioral changes in some people.
"We found that gamers showed reduced activity in areas of the brain involved in attention, inhibition, and decision-making," said Dr. Vincent Mathews, professor of radiology at Indiana University, in a press briefing at this week's RSNA 2011 conference.
"What we have observed in our study provides an explanation for what other researchers have observed in behavioral studies that indicate that when people are exposed to violent video games, they may show more aggression," Mathews said.
He and colleagues enrolled 28 young men (ages 18 to 29) in the study, in which 14 of the men spent about two hours a day playing a violent video shooting game for one week. They then took a week off. The other 14 young men did not play the game at all during the two weeks. The researchers evaluated the participants using standard functional MRI tests and discovered differences in various areas of the brain.
None of the men involved in the study were hard-core video game players, Mathews said.
All had an fMRI at baseline, and again after the first and second weeks. During the scans, the subjects completed an emotional interference task and a cognitive inhibition counting task to assess activity in regions important for controlling emotion and aggressive behavior, Mathews explained.
The scans conducted after game exposure revealed diminished activity in the left inferior frontal lobe during the emotional task, as well as less activation in the anterior cingulate cortex during the counting task -- compared to both their own baseline results and activity in the control group.
Those regions are important for controlling emotional and aggressive behavior, Mathews noted.
By the end of the second week, after the men had been off violent video games for seven days, the researchers found that they regained more prefrontal activation -- a sign that quitting video game playing could modify the changed brain activity.
Still, Mathews warned that the findings only extend over a week: "We don't know the effects of years and years of gaming," he said.
"The data presented here are certainly thought provoking and interesting," said Dr. Candice Johnstone, assistant professor of radiation oncology at the Medical College of Wisconsin, who moderated press briefing.
"To make recommendations based on functional studies would be going beyond the data," she said. "The key here is to note decreases in areas of the brain that are thought to be critical in certain areas, and that diminished activity is worrisome. This study answers the question that was asked, but it doesn't answer all the questions that we have."
Some of those questions include what happens if the participants play for longer periods of time, and what happens in the brain if they play nonviolent games, such as racing games, for example.
