Unlocking the Secrets of Sleep: How Brain Activity During Slumber Optimizes Learning and Memory

September 1, 2024

by Cathe Friedrich

Who isn’t intrigued by the mysteries of sleep? We spend a third of our life immersed in slumber, so it must be important. But what happens when we drift off into dreamland? Your body rests, although it’s also a time of cellular repair. But there’s one part of your body that’s active when you’re asleep. It’s your brain. Scientists are discovering more about why we sleep. What they’re finding is that sleep plays a key role in learning and remembering what you learn.

The Science of Sleep and Memory Consolidation

While you need sleep for many reasons, one of the main purposes of getting a good night’s sleep is the role it plays in consolidating memories. Whatever information you learned during the day; your brain replays it when you are asleep. This includes experiences you had during the day and what you learned at work or school. After replaying the information, it transfers information from its temporary storage location in the hippocampus of your brain to other parts of your brain that will store it longer-term.

How does it do this? New research shows your brain reactivates the same nerve pathways that it turned on when you learned the material. This phenomenon called neural replay is critical for retaining information – and sleep is when neural replay occurs. Using brain-computer interfaces, scientists have documented neural replay happening in the motor cortex of the brain. This is a part of your brain that helps plan and execute your plans. It also helps consolidate memory.

This activity occurs mostly during slow-wave sleep, the most restorative stage of sleep. This is a stage where you’re in the deepest slumber. It’s also a time when you repair muscle tissue after a workout and release hormones, like growth hormone. It’s also a stage of sleep that causes you to feel groggy and foggy if you wake up.

Other research shows sleep boosts learning and memory through a “pruning” process. Your brain removes old memories and connections that are no longer useful to you. This makes it easier for your brain to make new connections.

Sleep Affects How You Learn and Remember

It’s not a surprise that when you don’t sleep well or enough your brain feels foggy and you won’t remember what you learned yesterday as well. Being deprived of quality sleep has a negative impact on your memory, motivation, attention, and even your decision making. Plus, other research shows portions of your brain involved in learning lose some of their connectivity in response to poor or too little sleep.

One study found that not getting enough sleep cripples the ability of your neurons (nerve cells) to encode information. It also makes it harder to turn what you see into conscious thoughts. So, it’s not surprising that it’s hard to remember what you learned the previous day and use it to make decisions when you’re skimping on sleep. Lack of sleep can even affect your moods and emotions. These emotional changes can affect how well you remember too.

Practical Aspects

Now that we’ve explored the crucial role of sleep in memory consolidation, let’s look at how you can apply this information to your daily life and remember more of the “important stuff” in your life.

Research shows that getting a good night’s sleep after you learn new information helps. It can also help you better remember and access that information. The reason? When you enter slow-wave sleep, your brain consolidates what you learned into longer-term memory. Studies also show that reviewing information before falling asleep increases the odds you’ll remember it.

For example, if you have an important test, don’t cram so much that you jeopardize your sleep time. Instead, review what’re you’re trying to remember before bedtime and then get a good night’s sleep. Research also shows that naps lasting less than 90 minutes can help you remember better.

What Science Says

One study involving forty-four people shows how a nap may help. Both groups studied material at noon and repeated their study session at 6:00 PM. One group napped between their two study sessions and the other didn’t. The group that napped were better able to learn in the 6:00 PM session than those who didn’t.

So, you can leverage the power of sleep and napping to ace your exams or a presentation at work. On the other hand, skimping on sleep cripples the ability of your neurons to encode information and commit it to longer-term storage.

Optimizing Sleep for Lifelong Learning and Memory

So, what does this tell you about sleep? It’s critical for your health but you also need it for remembering what you learn during the day. According to The National Sleep Foundation, adults need 7-9 hours of sleep each night. The best way to get that is to make sleep a priority rather than an afterthought.

So how can you ensure you’re getting a good night’s sleep? Practice good sleep hygiene habits. Get back to basics. Sleep in a dark, comfortable room, and don’t take your smartphone with you to bed. The blue light from devices reduces melatonin production, making it harder to sleep. Optimize melatonin production by exposing your eyes to natural light in the morning.

If you are practicing good sleep hygiene habits but still struggle to fall asleep or stay asleep, see your healthcare provider.

Conclusion

So now you know why you’ll remember more of what you study or learn during the day if you get a good night’s sleep. You need neuronal activity to maximize your memory retention. Sleep helps consolidate all your memories and weed out extra information that you don’t need. So, make sleep a priority for your health, cognitive well-being, and for lifelong learning.

References

Krause AJ, Simon EB, Mander BA, Greer SM, Saletin JM, Goldstein-Piekarski AN, Walker MP. The sleep-deprived human brain. Nat Rev Neurosci. 2017 Jul;18(7):404-418. doi: 10.1038/nrn.2017.55. Epub 2017 May 18. PMID: 28515433; PMCID: PMC6143346.
“Sleep-learning impairs subsequent awake-learning.” 01 Jan. 2022, https://www.sciencedirect.com/science/article/pii/S107474272100191X.
Rasch B, Born J. About sleep’s role in memory. Physiol Rev. 2013 Apr;93(2):681-766. doi: 10.1152/physrev.00032.2012. PMID: 23589831; PMCID: PMC3768102.
Takashima, A., et al. (2019). Sleep-dependent reactivation of neural activity in the human brain. Neuron, 103(3), 531-543.
Klinzing, Jens G, Niels Niethard, and Jan Born. 2019. “Mechanisms of Systems Memory Consolidation during Sleep.” Nature Neuroscience 22 (10): 1598–1610. https://doi.org/10.1038/s41593-019-0467-3.
Guskjolen, A., et al. (2023). Engram neurons: Encoding, consolidation, retrieval, and forgetting of memory. Molecular Psychiatry, 28, 3207-3219.
Wagner, U., et al. (2004). Sleep inspires insight. Nature, 427(6972), 352-355.
Rasch, B., et al. (2007). Odor cues during slow-wave sleep prompt declarative memory consolidation. Science, 315(5817), 1426-1429.
Harrison, Y., et al. (2000). Sleep deprivation and the effects of sleep on cognitive performance. Sleep and Biological Rhythms, 8(2), 125-136.
“Sleep’s Crucial Role in Preserving Memory.” 10 May. 2022, https://medicine.yale.edu/news-article/sleeps-crucial-role-in-preserving-memory/.