Previous neuroscience studies have shown that sleep plays an important role in memory consolidation . This new study goes a little further.
Researchers at the University of Geneva, in Switzerland, recently carried out a study aimed at investigating the ways in which the brain selects memories that will be reprocessed during sleep.
Their findings, presented in Nature Communications, suggest that the brain tends to prioritize the consolidation of memories or life experiences with high motivational relevance , that is, those associated with rewards.
Evolutionary advantages
The researchers carried out their experiments on 26 healthy participants. Participants were asked to play two games . The first, called the face game, was specifically designed to activate the brain network specialized in processing facial information. The second, called the maze game, is a game that activates the brain regions involved in space navigation.
In the face game, participants had to identify a specific face based on a series of cues that were provided to them. In the maze game, they were asked to find the way out of a maze, using some guide arrows.
Using brain decoding and functional magnetic resonance imaging techniques, specific patterns of brain activity observed in participants while awake were shown to spontaneously reappear during slow-wave sleep. Interestingly, these patterns were the ones known to be associated with receiving a reward for positive behavior :
From an evolutionary perspective, individuals must retain information that promotes survival, such as avoiding danger, finding food, or earning praise or money. Here, we test whether neural representations of rewarded events (compared to unrewarded ones) take precedence for reactivation during sleep.