Gamers have long heralded the brain-boosting attributes of their favorite hobby. Research has shown the benefits of video games include enhanced memory and improved cognitive performance, but a new study indicates that action-oriented varieties could actually harm the brain.

In a small study conducted at the University of Montreal in Canada, researchers determined that people who regularly play games like Call of Duty, for example, had less grey matter in the hippocampus. This area of the brain is associated with spatial learning and regulates emotions, and assists with memory and our autonomic nervous system. Healthier brains have more grey matter, and researchers believe that people without a healthy hippocampus could be at an increased risk for diseases including depression, schizophrenia, and Alzheimer’s.

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While this study indicates that video games could be bad for the hippocampus, it also showed that they could be good for a different part of the brain.

"Video games have been shown to benefit certain cognitive systems in the brain, mainly related to visual attention and short-term memory," said study co-author Greg West, in a statement. "But there is also behavioral evidence that there might be a cost to that, in terms of the impact on the hippocampus."

The region benefiting from gaming is called the caudate nucleus and is associated with response learning and a reward system. We can thank this area for helping us act on autopilot, like when we drive the same route from work to home without thinking. As gaming actually stimulates this area of the brain most, the more neglected hippocampus begins to atrophy for habitual players.

Researchers first determined whether the 100 participants were spatial or response learners. Then, everyone played 90 hours of action video games and 90 hours of 3D-based games. They found that response learners lost grey matter in the hippocampus when playing the action games. However, everyone who played the 3D games had increased levels of grey matter in the hippocampus.

But that doesn’t mean lovers of action games have to give them up completely. The study authors note that manufacturers can change the design of their offerings to encourage spatial learning. For now, though, the team cautions using action video games to treat with Alzheimer’s, depression or Post Traumatic Stress Syndrome.

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In recent years, numerous studies have shown that video games may be a viable alternative to medicine for certain issues. A study published in March found that Tetris actually could help prevent flashbacks in patients with PTSD. Another study found that games specifically developed to treat people with depression actually helped people feel more in control of their condition. However, many of these results are preliminary and researchers said it’s unlikely that games will be the main prescription any time soon.

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