New studies suggest human-computer interactions— including action video games— may have a negative impact on the brain.

Scientists have long held the belief that action video game players have better visual attention, motor control abilities and short-term memory but the games may be having an impact on another area of the brain.

“Thanks to navigation tests and brain scans, our studies show that response learners, those players using their brain's autopilot and reward system to navigate, experienced grey matter loss in their hippocampus after playing action video games for 90 hours,” first author Greg West, Ph.D., a researcher and associate professor at the Université de Montréal, said in a statement. “The hippocampus is the key structure involved in spatial memory [orientation] and episodic memory [autobiographical events] within the brain.

“On the contrary, spatial learners, those using their hippocampus to navigate, increased their grey matter after playing for the same amount of time,” he added. “The same amount of screen time with 3D-platform games caused only increases within this system across all participants.”

According to Véronique Bohbot, Ph.D., a researcher at the Douglas Mental Health University Institute and associate professor at McGill University, action video game players are nearly twice more prone to be categorized as response learners compared to non-video game players.

“This matters a lot when you know how important the hippocampus is for a healthy cognition,” Bohbot said in a statement.

People with lower amounts of grey matter in the hippocampus see an increased risk of developing neuropsychiatric illnesses including depression, schizophrenia, post-traumatic stress disorder and Alzheimer’s disease.

During the study, the researchers examined 64 people between ages 18 and 30 who were recruited to play 90 hours of different types of video games.

The games—which none of the participants had previously played—included first-person shooters like Call of Duty, Killzone, Medal of Honor and Borderlands 2 or 3D-platform games including Super Mario 64.

The results show that video games are either detrimental or beneficial to the brain’s spatial memory system, depending not only on the navigation strategy players use but also on the video game genre being played.

The researchers found that playing 3D-platform games for 90 hours increases grey matter in the hippocampal memory systems for both types of players.

“Remember that the same amount of screen time with first-person shooter video games leads to atrophy within the hippocampus,” West said. “This suggests that 3D-platform games are safer for consumption and can be beneficial to the brains of all players.”  

The researchers said a causal link between human-computer interactions including action games and actual illness is not currently known and requires future long-term studies.

The study was published in Molecular Psychiatry.