The Importance of Sleep's Role in the Formation and Maintenance of Long Term Memories

Sleep is absolutely vital in living organisms for various important bodily functions, especially in learning and the consolidation periods of this memory. How much sleep one is getting as well as the quality of the sleep in which they are getting alongside the inner neural mechanisms occurring during this sleep can severely impact cognitive function in relation to one’s memory.

Two neuroscientific research projects conducted in 2022 offer some clarity on this exact relationship between learning and memory capabilities and sleep. The first, published by Poe Et al. in February 2022, focuses on Drosophila while the second, published by Rebecca Sohn, focuses on the impact on humans. The study by Poe et al. was presented to my class by one of the researchers on the project, Dan Cavanaugh, providing us with insight into the sleep rhythms found in the formations of long term memory in fruit flies. Dan and the other researchers worked and found that, as Drosophila begin the pupal stage, they develop a circadian rhythm while sleeping. It is within the development of this rhythm that the ability to form long-term memories is gained. From there, they worked with sleep disruptions to see the impact on long term memory, finding that sleep disruptions did in fact disrupt the formation of long-term memories in this vulnerable state. With this, it was also found that manipulating the rhythms did enhance memory and improve cognitive capabilities in terms of long term memory maintenance. 

The secondary project, relating to the work Cavanaugh completed, published by Rebecca Sohn in the Scientific American journal in September 2022, worked with sleep spindles in the human brain and how they correlate to cognitive and memory functionality. These sleep spindles are defined as brief bursts of brain activity during non-REM sleep by which the brain consolidates memories, coordinating activity between different regions of the brain as the brain strengthens connections between neurons during memory formation. This work was conducted at the University of Chicago and used EEG to measure brain activity. It was found that these sleep spindles were directly associated with enhancing cognitive performance in visual memory tasks, suggesting that the strength of these spindles are strong predictors of memory performance, ultimately aiding in the encoding of memories and protecting them from interference. These bursts of energy can be increased in number and in strength with healthy habits, such as frequent exercise, healthy diets. calming activities such as meditation, etc., but their presence is ultimately mainly due to genetic reasons.

Together, these two studies are able to exhibit the importance of sleep in the cognitive processes of long term memories, both in terms of the development of circadian rhythms for formation and in the event of sleep spindles for consolidation and protection. By understanding the importance of the relationship between sleeping and memory, whether in fruit flies or in humans, can provide humans with insight in how to enhance learning down at the neurological level. 

References: 

Poe, A. R., Zhu, L., McClanahan, P. D., Szuperak, M., Anafi, R. C., Thum, A. S., Cavanaugh, D. J., & Kayser, M. S. (2022). Developmental emergence of sleep rhythms enables long-term memory capabilities in Drosophila. Neuroscience. https://doi.org/10.1101/2022.02.03.479025

Sohn, R. (2022, September 1). Spiky ‘sleep spindles’ linked to acts of learning. Scientific American. https://www.scientificamerican.com/article/spiky-lsquo-sleep-spindles-rsquo-linked-to-acts-of-learning/