How does our memory work, and how can we optimize its mechanisms on a daily basis? These questions are at the heart of many neuroscience research projects.
In a new study, researchers highlighted the lasting positive effect of a reward—monetary, in this case—on the ability of people to retain a variety of information.
Moreover, and much more surprisingly, they found that the average accumulation of reward should be neither too small nor too large.
By ensuring an effective neural dialog between the reward circuit and the memory circuit, this delicate balance allows the proper encoding of memories in our brain.
The research was conducted by scientists from the University of Geneva (UNIGE).
Empirically, it seems quite logical that obtaining a reward can improve the memories associated with it.
But what are the brain mechanisms at work, and how can we exploit them to optimize our memory capacity?
To answer these questions, the team developed an experiment using functional magnetic resonance imaging (fMRI), an imaging technique that allows real-time observation of the brain in action.
About 30 healthy people were asked to remember associations between objects and people; each correct answer was associated with points gained, and each incorrect answer with points lost (the points were then converted into money).
Twenty minutes later, the people were asked to retrieve these associations to earn additional points. Critically, the average number of points that could be gained varied over the course of the experiment.
The team found that contrary to what one might have thought, the best results were not associated with the highest accumulation of rewards, the point where people should have been the most motivated.
The most effective? Somewhere between the highest and lowest accumulated rewards.
The team says the brain needs rewards to motivate people, but also challenges.
If the task is too easy, motivation decreases as quickly as if it is too difficult, and that affects the ability to encode information.
In the brain, memory is primarily managed by the hippocampus, a region of the brain responsible for encoding and storing memories.
When a reward is involved, however, another region is activated, the ventral tegmental area, which is involved in the reward system and responsible for the release of dopamine-related to the satisfaction of obtaining a reward.
The team found it is the dialog between these two brain areas that help maintain motivation, improve learning, and consolidate memories, even over time.
This experiment shows the importance of motivation in memory and learning, but also the subtle, and probably individual-specific, a balance that should be instituted.
One author of the study is Sophie Schwartz, a full professor in the Department of Basic Neurosciences.
The study is published in Nature Communications.
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