Peace and Quiet?

Over the years, both my parents and teachers have stressed the importance of getting a good night’s sleep before big exams. Being well rested certainly does influence focus and concentration. Furthermore, there is a notable link between sleep and the consolidation of memory. However, it turns out that there may be more to improved performance than getting the ideal 7-8 hours of sleep. More specifically, certain types of auditory stimulation during sleep have been found to influence memory.

Dr. Iliana Vargas’ presentation on targeted memory reactivation provided an example of how specific auditory stimulation during sleep can positively affect performance on memory tasks. She described an experiment where participants learned a set of object-location associations on a computer screen while hearing object sounds prior to a nap. During the nap, half of the object sounds were played. After the nap, individuals attempted to match the images with their proper spatial locations. An advantage was found for objects that were cued during sleep versus those that were not, which suggests that retrieval can be influenced by information that is presented while asleep. Vargas also demonstrated that this advantage holds true when a single sound is associated with two objects that have different locations, which further suggests that sleep promotes the flexible use of information by reorganizing memories.

These findings relate to a study carried out by Dr. Phyllis Zee of Northwestern University Feinberg School of Medicine, which found that gentle sound stimulation, synchronized to the rhythm of brain waves, improves memory in older adults. Pink noise, such as a rushing waterfall, increased the time individuals spent in deep sleep and significantly improved performance on memory tests. Deep sleep is crucial for memory consolidation, but as one ages, deep sleep is substantially reduced. This is thought to be associated with memory decline that is characteristic of the aging process. This study demonstrates that time spent in deep sleep, even at an older age, is important for memory.

Although the precise mechanism for memory consolidation during sleep is not entirely understood, it is clear that there are several components at play.  Specific auditory cues can strengthen individual memories, while gentle pink noise improves memory in a more general sense, by increasing the time spent in deep sleep. Auditory stimulation, in some shape or form, may be key to the quintessential “good night’s sleep.”

References

Paul, Marla. "Sound Waves Enhance Deep Sleep and Memory." Northwestern Now. Northwestern University, 24 Apr. 2017. Web. 24 Apr. 2017.

Rudoy, John D., Joel L. Voss, Carmen E. Westerberg, and Ken A. Paller. "Strengthening Individual Memories by Reactivating Them During Sleep." Science. American Association for the Advancement of Science, 20 Nov. 2009. Web. 24 Apr. 2017.