Why your sleeping brain brings back new rewarding experiences
By Jim Davies | Published: 2024-12-30 18:00:00 | Source: Neuropsych – Big Think
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During these Olympics, I was cheering for Kelly Ryan, who is on the women’s chip team. She’s from Ottawa, where I live. Whenever she scored a point, she would let out a cry of victory, probably feeling a wave of pleasure. As I watched it on TV, I did too.
Getting better at something involves passion. When we do well, we have good feelings – pride, pleasure, excitement – and these feelings help reinforce the behaviors we have just engaged in. Likewise, the pain of failure makes recent behaviors less likely in the future. This is conditioning, and we have all experienced it when we are awake. But what about when we sleep?
Sleep enhances memories. We know this because after half an hour of sleep, people can remember things better than if they spent half an hour doing something else, like watching TV. Mice studies displays Their brains are trained to run through mazes while they sleep, in a process known as resleep. The function of memory is to store information that will be useful. For this reason, our brain prioritizes remembering some things over others. Studies have It is shownFor example, it is easier to remember things that are useful for survival. Could sleep similarly focus on things that are particularly good or bad for us, like food and dangerous animals, and ignore things that have nothing to do with our well-being, like the exact shape of a cloud?
Modern He studies Virginie Sterpenich and her colleagues from the University of Geneva tried to find out. They had participants play two computer games, which were designed to be engaging and use two very different areas of the brain. One game involved selecting a target face from a pool of 18 faces, while the other involved navigating through a 3D maze derived from Duke Nukem. Face game players use areas of the brain specialized in recognizing faces – the fusiform and occipital face areas. Maze game players use parahippocampal place areas, areas of gray matter that account for scene recognition and memory. Participants performed both tasks while Sterbinich and her team scanned their brains using an electroencephalogram (EEG), which measures electrical activity over time, and functional magnetic resonance imaging (fMRI), which provides information about which parts of the brain are active by measuring the amount of blood flow occurring throughout the brain.
What people didn’t know was that the games were rigged. The players only won one match, but they believed that their wins and losses were a result of their performance. If our brains are more likely to rehearse things for which they have been rewarded, then when we sleep, they should rehearse the game they won more than the game they lost. After the games ended, participants went to sleep in a brain scanner. The researchers used artificial intelligence trained on electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) data to recognize which game was played while awake, and to decode brain scans of sleeping players and see if they were thinking about one game or the other while asleep. (Once an AI learns how to identify a task in an awake person — when scientists know what task they’re doing — they can apply it to brain activity observed during sleep and see which task players’ brain scans are most similar to.)
It turns out that the participants’ brains revealed that they were doing a kind of “neural replay” of the game they had been manipulated to win. If you are one of the players who won the face game, you are more likely to replay the face game during sleep (compared to the maze game you lost). The reward you felt after “winning” the face game made the neural replay of it more likely to appear during your sleep. Not only did the detector identify this, but brain regions associated with rewarding games (face or space regions) were preferentially active.
This suggests that our brains rehearse things during sleep, and that they preferentially choose things that are useful to us over experiences that are not important to us. Does this have anything to do with the dream? Well, none of the participants entered rapid eye movement (REM) sleep, the time when most dreams occur, during their time in the sleep lab. (REM tends to occur later at night.) Neural remodeling occurs only during slow-wave sleep, when dreams tend to be infrequent, dull, and unmemorable. Participants may not have been aware of the exercise their brains were engaged in. Perhaps these exercises were not conscious!
Other evidence suggests Dreams during REM sleep tend to be more negative, with bad dreams more common than good dreams. This leads to the interesting idea that positive experiences are rehearsed during non-REM sleep, and negative experiences are rehearsed during REM sleep.
I can’t help but think Kelly’s cry of victory enhanced her happiness at scoring her points. It’s interesting to think that this made her more likely to practice fencing that night, when her adrenaline had subsided and she was ready for sleep. She was defeated in the quarter-finals by Larisa Korobenikova from Russia. She didn’t get a medal, but tonight her mind may be preparing for the next challenge.
this condition Originally appeared on Nautilusa scientific and cultural magazine for curious readers. Sign up for Nautilus Newsletter.
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