Scientists Can Now Read Our Memories While We Sleep
Scientific study has already shown that memories are better remembered after sleep than wakefulness. Recently acquired information is thought to be ‘reactivated’ and strengthened in the sleeping brain.
The researchers, in collaboration with scientists at the University of Birmingham, have now demonstrated that there is a particular pattern of brain activity that supports this reactivation process.
Sleep spindles, the short bursts of activity in the brain during sleep, are enhanced when memories are reactivated. This new study has also shown that the content of reactivated memories can be decoded at the time that spindles occur.
Dr Scott Cairney, from the University of York’s Department of Psychology, said: “We are quite certain that memories are reactivated in the brain during sleep, but we don’t know the neural processes that underpin this phenomenon.
“Sleep spindles have been linked to the benefits of sleep for memory in previous research, so we wanted to investigate whether these brain waves mediate reactivation. If they support memory reactivation, we further reasoned that it could be possible to decipher memory signals at the time that these spindles took place.”
The research findings could be important for enhancing understanding of how the brain learns and retains information. Improving knowledge of the mechanisms that are active during sleep could also have implications for further study into memory conditions that arise as a result of these mechanisms failing.
Reactivating memories during sleep occurs spontaneously, but to understand the impacts of this mechanism, the researchers devised a simple test that would allow them to see the reactivation in a controlled manner.
Dr Cairney said: “We asked participants in our study to learn associations between words and pictures of objects or scenes before a nap. Half of the words were then replayed during the nap to trigger the reactivation of the newly learned picture memories.
“When the participants woke after a good period of sleep, we presented them again with the words and asked them to recall the object and scene pictures. We found that their memory was better for the pictures that were connected to the words that were presented in sleep, compared to those words that weren’t.”
The team monitored brain activity during sleep using an electroencephalogram (EEG) machine and this showed them that sleep spindles occurred when memories were reactivated by the presentation of the associated words.
Dr Bernhard Staresina, of the University of Birmingham’s School of Psychology, said: “Direct induction of sleep spindles - for example, by stimulating the brain with electrodes - perhaps combined with targeted memory reactivation, may enable us to further improve memory performance while we sleep.
“Our data suggest that spindles facilitate processing of relevant memory features during sleep and that this process boosts memory consolidation.”
Importantly, the researchers were able to differentiate the brain signals associated with reactivated objects and scenes. This demonstrates that spindles produces a specific code for the content of reactivated memories; a process that may underpin our ability to remember more after sleep.
Dr Cairney said: “When you are awake you learn new things, but when you are asleep you refine them, making it easier to retrieve them and apply them correctly when you need them the most. This is important for how we learn but also for how we might help retain healthy brain functions.”
This article has been republished from materials provided by The University of York. Note: material may have been edited for length and content. For further information, please contact the cited source.
Cairney, S. A., Guttesen, A., Marj, N. E., & Staresina, B. P. (2018). Memory consolidation is linked to spindle-mediated information processing during sleep. Current Biology. doi:10.1016/j.cub.2018.01.087
NeuroTrauma Sciences and Henry Ford Health System Announce Agreements for Neurological Injury ResearchNews
Research indicates exosomes have therapeutic potential for improving recovery after stroke, traumatic brain injury.READ MORE
Processed Meats Associated with Manic EpisodesNews
Analysis of over 1,000 people with and without psychiatric disorders has shown that nitrates—chemicals used to cure meats such as beef jerky, salami, hot dogs and other processed meat snacks—may contribute to mania, an abnormal mood state.READ MORE
Orexin Neurons are Promising Target for Medications to Treat Binge EatingNews
The researchers studied female rats fed a control diet or a sugary, high-fat diet that causes weight gain and binge eating patterns.READ MORE