Teenagers who play video games frequently have brains with larger pleasure centres, a new study finds.

Dr. Simone Kühn of Charité University Medicine in Berlin and a large team of European collaborators, report their results in the journal Translational Psychiatry this week. The researchers plan to train adults to use video games to see if a brain area gets larger. Ina Fassbender/Reuters

The team looked at 154 Berlin school children who were all aged 14 and also played video games. The children were split into two groups: infrequent video gamers, who played on average about 4 hours per week, and frequent gamers, who played about 21 hours a week on average.

"An important feature of our study is that none of the children were addicted to video games," says Kühn. The researchers were able to tell this by the childrens' answers to a questionnaire.

When the children underwent an MRI scan, the researchers found that a region of the brain called the 'ventral striatum' had more grey matter in the frequent video gamers. Grey matter consists of nerve cell bodies. The amount of white matter (connections between nerves) was similar across the two groups.

"The ventral striatum is usually associated with everything that brings pleasure," Kühn tells the Australian Broadcasting Corporation. "For instance food and monetary reward. It's also been associated with some addictions. If you show a smoker a cigarette for example, the ventral striatum is activated."

The neurotransmitter dopamine, which is important in motivation and reward, also plays a role in the ventral striatum. Other research has found that patients with Parkinson's disease, put on medication to increase their dopamine, sometimes become pathological gamblers and this has been linked to excess dopamine in the ventral striatum.

Frequent gamers' brains

In a second part of the study, the German schoolchildren were given a task which looked at their reaction to failing to get a monetary reward. The children played a computer game which promised them a reward if they were able to press the correct key very quickly when asked. They received feedback afterwards on whether they had succeeded or failed in getting the reward.

Brains scans of the frequent video gamers doing this task showed a very interesting response: their pleasure centres were active when they failed to get the reward.

"They perceive a reward as they lose," says Kühn.

She thinks this may be one reason why they persist with video games despite temporary setbacks. It also may have close links with 'loss chasing' in problem gambling, where people who lose respond by playing harder.

But does video gaming make the pleasure centre larger or do people with larger pleasure centres take up video games? Kühn cites another study that shows that enlargement of the nearby 'dorsal striatum' enables people to perform better in video games, taking quicker decisions. This favours the brain leading the behaviour. However her hunch is that playing the video games makes the pleasure centre grow bigger.

"We are doing another study now to look at that," she explains. "We are training adults who have never used video games to use them for two months, and then looking to see whether that brain area gets larger."

Professor Julio Licinio of the Australian National University, suspects, like Kühn, that experiments will show that the games cause the increase in pleasure centre size, and not the other way round.

He sees this paper as adding welcome information about the effects of video games on the brain. "It is an activity that a lot of adolescents are engaging in — some for many hours a day — yet it's really an area that has not been explored very well," he says.