Scientists have suggested that memory retention could be improved through sleep spindles.
Sleep spindles are half-second to two-second bursts of oscillatory brain activity—occurring during non-rapid eye movement sleep stages two and three—and measured in the 10 to 16 Hertz range on an electroencephalogram (EEG). Previous studies have shown that number of spindles during the night could predict a person’s memory the next day.
University of Birmingham post-doctoral student Bernhard Staresina said that while previous studie shave shown that targeted memory reactivation can boost memory consolidation during sleep, they have now shown through their latest study that sleep spindles might represent the key underlying mechanism.
“Thus, direct induction of sleep spindles—for example, via transcranial electrical stimulation—perhaps combined with targeted memory reactivation, may enable us to further improve memory performance while we sleep.” For the study, published in the journal Current Biology, the researchers devised an experiment in which people learned to associate particular adjectives with particular objects and scenes.
Some study participants then took a 90-minute nap after their study session, whereas others stayed awake. While people napped, the researchers cued those associative memories and unfamiliar adjectives.
The results showed that the memory cues led to an increase in sleep spindles.
Interestingly, the EEG patterns during spindles enabled the researchers to discern what types of memories — objects or scenes — were being processed.
“Our data suggest that spindles facilitate processing of relevant memory features during sleep and that this process boosts memory consolidation,” he said.
Also, the new understanding of the way the brain normally processes and strengthens memories during sleep may help to explain how that process may go wrong in people with learning difficulties, the researchers added.