Friday, August 11, 2017

Impact of video games on plasticity of the hippocampus

West GL, Konishi K, Diarra M, Benady-Chorney J, Drisdelle BL, Dahmani L, Sodums DJ, Lepore F, Jolicoeur P, Bohbot VD. Impact of video games on plasticity of the hippocampus. Mol Psychiatry. 2017 Aug 8. doi: 10.1038/mp.2017.155. [Epub ahead of print]

The hippocampus is critical to healthy cognition, yet results in the current study show that action video game players have reduced grey matter within the hippocampus. A subsequent randomised longitudinal training experiment demonstrated that first-person shooting games reduce grey matter within the hippocampus in participants using non-spatial memory strategies. Conversely, participants who use hippocampus-dependent spatial strategies showed increased grey matter in the hippocampus after training. A control group that trained on 3D-platform games displayed growth in either the hippocampus or the functionally connected entorhinal cortex. A third study replicated the effect of action video game training on grey matter in the hippocampus. These results show that video games can be beneficial or detrimental to the hippocampal system depending on the navigation strategy that a person employs and the genre of the game.

In three neuroimaging studies, investigators are cautioning against blanket encouragement of children and young and older adults to play video games in order to improve cognitive skills.

New research suggests that certain types of games – and an individual's own navigation style – may lead to decreased brain plasticity.

There were almost 100 total participants in the three studies. In the first, there were significantly greater reductions in gray matter in the left hippocampus in a group of habitual action video-game players (VGPs) than in a group of nonplayers.

Also, 83% of the VGPs were considered to be response learners rather than spatial learners, vs 43% of the non-VPGs. Spatial learners favor their hippocampus and rely on various landmarks to orient and navigate themselves through a game. Response learners favor the reward system/caudate nucleus and memorize a sequence's left and right turns.

The second study randomly assigned 43 non-VGPs to play 90 hours of either first-person shooting (action) games or 3-D platform games. Among the response-learners in the shooting-game group, hippocampal gray matter was reduced, whereas in the spatial learners, it was increased.

Among those playing 3-D games, both the response and spatial learners showed increases in gray matter, although in different brain areas.

In the third study, all 21 non-VGPs were assigned to play role-playing (action) video games. Echoing the second study's action-game group, gray matter was decreased in the response learners, whereas it was increased in the spatial learners.

"We studied the impact of different genres of video games on the hippocampus structure important for healthy cognition and memory," lead author Greg L. West, PhD, associate professor of psychology at the University of Montreal, Quebec, Canada, told Medscape Medical News.

The most surprising finding "was that people's navigation strategy had such a big impact on the effect of the game on the hippocampus," said Dr West. "That tells me that there is something quite different about these two types of learners."…

Posttraining MRI scans were compared with pretraining scans for both groups. Findings from the action-game group showed the following:

Response learners (n = 11) were found to have significant reductions in levels of gray matter in the right hippocampus (P < .001);

Spatial learners (n = 10) were found to have significant increases in gray matter in the left hippocampus (P < .001); and

The difference in hippocampal changes was significant between the two strategy groups (P < .0001).

For the platform-game group:

Response learners (n = 11) were found to have a significant increase in gray matter within the right hippocampus (P < .005); and

Spatial learners (n=11) were found to have a significant increase in gray matter in the right entorhinal cortex (P < .005).

"The hippocampus and caudate nucleus memory systems each contributes to an individual's optimal function," write the investigators. They add that episodic memory and stress regulation are associated with the former, whereas the latter is part of the reward pathway and is associated with procedural memory.

Based on past research, "while engaging in behaviors that promote the caudate nucleus is important for developing habits as well as certain cognitive skills, such as implicit learning, the over reliance on this system may result in the underuse of the hippocampal memory system, leading to atrophy in this structure."…

"In other words, players are encouraged to follow a rigid path...rather than use the external landmarks to navigate," they add.

In the full group, posttraining scans showed significant gray matter reductions in both the left and right hippocampus (P < .001 for both locations).

When split into two subgroups on the basis of navigation strategy, the response learners were found to have a "bilateral decrease" in gray matter in the left (P < .001) and right hippocampus (P < .0001), whereas the spatial learners were found to have significantly increased gray matter in both areas (both, P < .001).

"We believe this is the first study to demonstrate the positive and negative impact of action video games on the brain, thereby offering reconciliation of opposing views in the literature," write the investigators.

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