Posted on Mar 12, 2018, 9 p.m.
Sleep has been established to be an important part of formation and retention of new memories. Sleep spindles can be measured and visualized on an electroencephalogram, which are sudden burst of oscillatory activity in the brain that memory consolidation is associated with and has now been shown to play a role in strengthening new memories when newly learned information is played back to an individual during sleep, as published in Current Biology.
Targeting memory reactivation can boost memory consolidation during sleep, sleep spindles may represent the underlying mechanism. Direct induction of sleep spindles combined with targeted memory reactivation may enable further improvement of memory performance while we sleep according to the researchers.
Sleep spindles are measure in the 10-26 Hertz range on an EEG in half to two second bursts of brain activity, occurring during non-rapid eye movement sleep stages 2 and 3. The number of spindles during the night has been shown in previous studies to possibly be an way to predict a person’s memory the next day. Sleep spindles have been linked to the process in which the brain makes new connections.
It was suspected that experimental reactivation of memories may lead to a surge of sleep spindles in an individual’s sleeping brain. An experiment was designed in which participants learned to associate certain adjectives with certain scenes and objects, with some participants taking a 90 minutes nap after study session and some staying awake. While participants napped researchers cued the associative memories and unfamiliar adjectives. Researchers observed that memory cues as expected led to increased sleep spindles. EEG patterns occurring during sleep spindles enabled the researchers to discern which types of memories were being processed whether it be objects or scenes.
These findings add to a growing body of evidence for an important information processing role of sleep spindles in the service of consolidation, with data suggesting that sleep spindles facilitate processing of relevant memory during sleeping and that this process may boost memory consolidation according to the researchers.
New understandings of the way the brain would normally strengthen and process memories during sleep may help to explain how the process may go wrong in individuals with learning difficulties, and may lead to future development of effective interventions that are designed to boost memory for important information.
Materials provided by Cell Press.
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Scott A. Cairney, Anna á Váli Guttesen, Nicole El Marj, Bernhard P. Staresina. Memory Consolidation Is Linked to Spindle-Mediated Information Processing during Sleep. Current Biology, 2018; DOI: 10.1016/j.cub.2018.01.087