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Desire to Play

Scientists use video games to enhance hippocampus in humans

In the last decade a strong evidence has been accumulated that elucidates the positive correlation between playing some video games and the increase of the volume of the hippocampal grey matter and the improvement of the hippocampus-associated memory of young and elderly healthy human subjects.

The preferential application of the spatial learning strategy, the immersion in an enriched 3D environment, the allocentric spatial navigation in a 3D environment and the desire to play induced by the long term potentiation of dopaminergic neurons in the hippocampus and the prefrontal cortex were proposed as potential candidates for the explanation of the above mentioned phenomena by three separate groups of researchers. However, the underlying mechanism of hippocampal enhancement through playing of video games is yet poorly understood.

At the same time a growing amount of research underscores the significance of the dynamic integration of hippocampal and prefrontal circuitry in the cognitive development of adolescents. These findings demonstrate that hippocampal and prefrontal activation patterns in early adolescence are similar to activation observed during spatial memory retrieval in adults.

We hypothesize that the increase in hippocampal grey matter volume in adulthood may reflect the cognitive development that takes place in adults in response to the same environmental stimuli which induce the activation of hippocampal and prefrontal circuitry in adolescence when the initial integration of this circuit takes place.

Elevated ambiguity (unknown risk, unexpected uncertainty) tolerance in adolescence plays an important role in cognitive development induced by the hippocampal-prefrontal circuit integration. Although ambiguity aversion increases with age adults may successfully overcome it in virtual environments of video games by utilising the same dopaminergic pathway that is used in adolescent cognitive development.

The deficit of ambiguity (unknown risks, unexpected uncertainty) in real life of modern humans may impair cognitive development abilities of both adolescents and adults. Ambiguity enriched virtual environments of video games may successfully compensate for this deficit and thus stimulate cognitive development.

The long term potentiation of dopaminergic neurons in the process of hippocampal-prefrontal circuit activation manifests in the desire to play that should make ambiguity enriched games also very engaging.

In 2013 Véronique D. Bohbot from the McGill University published a research paper with a colleague in which they established correlation between the spontaneous choice of a navigation strategy by healthy older adults in a virtual 3D maze task and the volume of the grey matter in their hippocampuses. People who applied the spatial learning strategy i.e. learned the map of the entire maze using landmarks located at a significant distance (associations) had a larger volume of grey matter in their hippocampuses compared to people who favoured the response learning strategy i.e. used closely located cues (stimuli) to memorize each specific route in the maze.

The study was a replication of several previous studies conducted by the same team on mice in a 3D water maze and on healthy young adults in a virtual 3D maze which also demonstrated the positive correlation between the preference towards spatial learning strategy and the volume of grey matter in the hippocampus. It was a significant breakthrough because some earlier studies which didn’t take into account the learning strategy preference of the participants either demonstrated the same correlation or failed to do it. It became evident that research participants could apply either spatial or response learning strategy to the same task based on their preference rather than on the task’s structure.

Bohbot’s team also observed that more older adults than younger adults had a spontaneous preference towards the response learning strategy and a smaller grey matter volume in the hippocampus respectively. However their study didn’t establish the cause-effect relationship. It remained unclear if the strategy preference lead to shrinking of the hippocampus of the hippocampal atrophy caused the learning strategy preference. Researcher also pointed out “environmental factors such as repetition (which leads to habit) (Iaria et al., 2003), stress (Schwabe et al., 2008), or reward (Del Balso et al., 2010) could promote response strategies at the expense of spatial strategies associated with the hippocampus.”

The same year Bohbot’s team published another research paper that demonstrated a positive correlation between spontaneous choice of response learning strategy and sensation seeking behavior resulting in substance abuse. On the contrary, hippocampus related spatial learning preference had a negative correlation with substance abuse.

The research that demonstrated the correlation between the learning strategy preference and the hippocampal grey matter volume laid down the foundation for the explanation of Bohbot’s research in partnership with Greg L. West from the University of Montreal into the area of the impact of the learning strategy preference in playing video games on the volume of grey matter in the hippocampus.

In 2013 the first research paper demonstrating the correlation between playing video games and hippocampal grey matter volume was published by Simone Kuhn from the Max Planck Institute for Human Development in Berlin and Jurgen Gallinat from the University Medical Center in Hamburg. Bohbot and West referred to that paper in their later work.

Previously (in 2011) same authors conducted research among video game playing teenagers that demonstrated the positive correlation between frequency of playing and the striatal (caudate nucleus) grey matter volume.

In their paper in 2014 Gallinat and Kuhn established a positive correlation between playing Super Mario 64, an allocentric 3D platformer game, and the increase of the hippocampal grey matter volume in players compared to a non-player control group. They proposed the allocentric spatial navigation and the desire to play as two major factors which led to the hippocampal grey matter increase.

The authors suggested that the desire to play reflected the long term potentiation of dopaminergic neurons that induced the increase of grey matter volume in both the hippocampus and the prefrontal cortex.

Bohbot and West in their paper in 2015 for the first time showed that playing first person view shooter video games (egocentric) engages response learning strategy in players and induces the increase of their striatal (caudate nucleus) grey matter volume.

In the meantime Gregory Clemenson & Craig Stark from the University of California, Irvine, shared their findings that two weeks of playing Super Mario 3D World improved hippocampal-associated memory of players whilst playing Angry Birds (2D) didn’t induce any improvement.

Authors hypothesized on the basis of their findings that “the exploration of vast and visually stimulating environments within modern-day video games can act as a human correlate of environmental enrichment”. They proposed that their results suggested “that modern day video games may provide meaningful stimulation to the human hippocampus”.

Bohbot and West conducted further research on the matter of action shooters versus 3D platformers impact on the hippocampus. Their results showed in 2017 “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,” as Greg West, put it in a comment.

Later during the same year the team of Bohbot and West reproduced their previous results obtained from younger adults with elderly people.

In 2018 Bohbot and West reproduced their results for the third time. Their “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.”

Clemson and Stark also in 2018 published a comprehensive overview of research in the area of environmental enrichment and neuronal plasticity including adult hippocampal neurogenesis in humans.

Further on they published in 2019 a paper reporting on their research in which they “used the video game Minecraft and show that the spatial exploration of a virtual environment can improve hippocampus-associated memory.”

In 2019 Clemson and Stark also shared in a preprint paper the results of them reproducing the results of their research for the third time, this time with older adults.

“Previously, we showed that playing immersive 3D video games can improve hippocampal-based memory in young healthy adults, suggesting that the exploration of the large open worlds of modern-day video games may act as proxy for environmental enrichment in humans. Here, we replicated our previous video game study in older adults,” they wrote.

Based on the above we can conclude that the impact of playing commercial video games on hippocampal grey matter volume and hippocampal-based memory is well documented and supported by the research that was replicated several times. However, its underlying mechanism is yet poorly understood.

A team of researchers from the University of Pittsburgh in 2016 proposed that the development of hippocampal and prefrontal circuit was mediated by increases in dopaminergic neuromodulation present in adolescence, which might underlie memory processing, plasticity, and circuit integration. Similar dopaminergic neuromodulation process was observed in adult players of video games in the experiment cited earlier in this post.

“Dopamine, particularly the enhanced dopamine signaling in adolescence, results in increased novelty-seeking and exploratory behaviors (Ikemoto & Panksepp, 1999), specifically behaviors that reflect hippocampal-mediated, active acquisition of information from novel environments, rather than simple orientation to novel stimuli.”

In 2018 a group of researchers from the Harvard Medical School and the McLean Hospital reported their findings from the application of virtual Morris water task to probe function of the adolescent hippocampus.These findings demonstrate that hippocampal and prefrontal activation patterns in early adolescence are similar to activation observed during spatial memory retrieval in adults.

Several studies recently suggested that the elevated exploration behavior in adolescence is associated with the integration of the hippocampal and prefrontal circuit.

A team of Neeltje Blankenstein from the University of Leiden proposed to separate the impact of adolescents’ attitudes to risk (known probabilities) and attitudes to ambiguity (unknown probabilities).

The research suggesting that adolescents are more risk averse and less ambiguity averse than adults allows us to interpret the elevated sensation seeking behavior in adolescence as, predominantly, the exploration of ambiguity.

“Sensation seeking is primarily motivated by exploration of the environment under ambiguous risk contexts, while impulsive action, which is likely to be maladaptive, is more characteristic of a subset of youth with weak control over limbic motivation,” as the team of researchers from Cornell University and the University of Pennsylvania suggests.

A discussion paper published by Mihail Semenov from Boston University in 2019 proposes that the adult hippocampal neurogenesis is a manifestation of the continuous cognitive development of the human brain throughout the entire lifespan. Semenov hypothesizes that “only a continuously developing brain may properly adapt to the continuously changing world.”

If so, than the mechanism supporting cognitive development throughout the entire lifespan may also be the same.

“Cognitive neurogenesis is a development process and therefore, its most immediate and plausible therapeutic use can be expected in the field of intellectual developmental disorders. The use for the treatment of cognitive disorders and cognitive aspects of mental disorders could also be perspective. Cognitive enhancement and treatment of cognitive decline in the elderly might also be viewed as a perspective direction,” Semenov concludes. Video games enriched with ambiguity which people desire to play may offer a viable platform for such a therapeutic use.

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