Sunday August 20 2017

Remembering Sleep

For the average university student, pulling the first all-nighter is like a rite of passage. When you spend all night studying for tomorrow’s exam or stay up Sunday night frantically typing out an essay due Monday morning, it’s a sign that you’ve really moved on to higher education-that you’ve hit the tough stuff. In our increasingly busy schedules, sleep is often the first thing we cut to make room for other commitments. After all, what good is sleep anyway?

Sleep is, in fact, important. We might not be sure about why we need sleep, but we do know that we cannot live without it. In serious cases of lack of sleep such as fatal familial insomnia, death can result in just a few months.1 While not usually deadly, insufficient sleep has had a large enough impact that it is considered a public health problem by the Centers for Disease Control and Prevention (CDC) in the United States.2 In both 2006 and 2008, the top two self-reported problems that result from lack of sleep among adults were difficulties concentrating and difficulties remembering things.2

Within the past two decades, scientists have made amazing discoveries on the importance of sleep, particularly in the formation and refinement of memories. While studying the function of sleep in Drosophila flies, Berry et al. found that sleep is important for preventing memory loss.3 There are dopaminergic neurons (DANs) in the brain that, when stimulated, promote forgetting.4 These DANs are normally active when we are awake and the brain needs them to systematically cut out information that we don’t need.4 Berry and colleagues suspected that sleep is involved in shutting down a pathway involving these DANs.4 When the team induced sleep in a fly and tracked the activity of one particular forgetting neuron, they found that activity of the DAN decreased as sleep increased. They also tested the fly on a learning task and found that the fly did significantly better on the memory task with sleep than without.3

So sleeping might actually help you do better on that exam by helping you remember more of what you studied!

Additionally, research has shown that REM sleep—a stage of sleep during which most dreams occur—does not only stabilize memory, it also improves it.1 Non-REM sleep can improve procedural memory, which is associated with the recollection of actions and execution of specific tasks. Sleep helps the brain select important or emotional information for retention. Getting enough sleep can also impact the type of memories that we form; when we don’t get enough sleep, we tend to remember depressing or negative things more vividly.1

Of course, none of these seems like the fundamental reason for why we need sleep, but we are likely to discover more functions as research continues. That’s something to consider the next time you think about skipping your nightly trip to the land of Nod.

By Joella Ho 



1.     Stickgold R. Sleep on it! Sci Am. 2015 Oct; 313(4):52-7.

2.     Insufficient Sleep is a Public Health Epidemic [Internet]. Atlanta (GA): Centers for Disease Control and Prevention; [date unknown] [updated 2015 Sep 3; cited 2015 Oct 13]. Available from: http://www.cdc.gov/Features/dsSleep/

3.    Berry JA, Cervantes-Sandoval I, Chakraborty M, Davis RL. Sleep Facilitates Memory by Blocking Dopamine Neuron-Mediated Forgetting. Cell [Internet]. 2015 Jun [cited 2015 Oct 14];161(7):1656–67. Available from: http://www.sciencedirect.com/science/article/pii/S0092867415005772

4.      Rihel J, Bendor D. Flies Sleep on It, or Fuhgeddaboudit! Cell [Internet]. 2015 Jun 18 [cited 2015 Oct 13];161(7):1498–500. Available from: http://www.sciencedirect.com/science/article/pii/S0092867415006947

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The Meducator is McMaster University’s undergraduate Health Sciences Journal. It publishes pieces that critically address current issues with a high degree of scientific rigor, but in a way that is accessible to a broad audience.


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