Sleep and Memory

 

    It is not uncommon to hear students talking about the "all-nighters" they have done to study for an exam. Although it may be tempting to do so, many studies have shown that memory consolidation heavily relies on sleep. So pulling that "all-nighter" may not be the best idea after all. Interestingly, many studies in the field of neuroscience have looked into this process of memory consolidation during sleep and how it could possibly be enhanced. Targeted Memory Reactivation, or TMR, has been an area of interest over recent years due to its potential to non-invasively enhance someone's memory while they're sleeping. 

    In an article by Laura K. Shanahan and her colleagues, they review multiple past studies that have broadened our knowledge on TMR. She describes TMR as the "practice of sensory cues to influence memory consolidation." The article reports a study done by Rasch and his colleagues, where they found that odors have can help with declarative memory consolidation during slow-wave sleep. A follow-up study showed that the hippocampus was receptive to olfactory stimuli during slow-wave sleep. Rasch’s study paved the way for many future studies, including one from Ritter and his colleagues, where they found that TMR had a positive effect on creativity levels.

In one of the most recent studies, Whitmore and colleagues tested the efficacy of TMR. However, rather than testing the effects of olfactory stimuli, researchers used auditory cues to test whether TMR during sleep could improve participants' face memory. They did so by testing participants in either a Japanese-history class or a Latin-American-history class. Here, participants learned the names of multiple people. Participants viewed 80 face-name pairs while they also listened to the spoken names. Before sleeping, their face recognition and name recall abilities were tested. After the participants were sleeping for around 7.3 minutes, TMR was initiated by playing the same background music from class along with half of the names previously learned by the participants. Results found a positive correlation between increased memory and duration of stage N3 sleep (slow-wave sleep). In other words, they did find they did find a significant improvement in memory because of TMR, but the extent of this improvement depends on how much uninterrupted N3 sleep a person gets. 

    Overall, memory is an important component of our everyday lives. Whether this involves studying for a test, remembering the names of people you just met, or remembering how to read the words in this article. The continued research behind TMR has shown many promising results that could possibly be integrated into our everyday lives. 

References 

Shanahan, L. K., & Gottfried, J. A. (2017). Scents and Reminiscence: Olfactory Influences on Memory Consolidation in the Sleeping Human Brain. Cognitive Neuroscience of Memory Consolidation, 335–346. https://doi.org/10.1007/978-3-319-45066-7_20

 

Whitmore, N., Bassard, A. M., & Paller, K. A. (2021). Targeted Memory Reactivation of Face-Name Learning Depends on Ample and Undisturbed Slow-Wave Sleep. BioRxiv. Published. https://doi.org/10.1101/2021.02.16.431530