The Neuroscience of Sleep

Writer/Researcher: Emily Hwang

Graphic Designer: Isra Chowdhury

Have you ever wondered what’s going on in your brain while you sleep? Well, your brain remains astoundingly active, working on energy conservation, self-repair, recovery, and brain maintenance as you rest (Cleveland Clinic [CC], 2023). Sleep affects nearly every body tissue and system, and poor quality sleep can increase the risk of various health problems (National Institute of Neurological Disorders and Stroke [NINDS], 2024). 

Sleep Stages: Your Brain’s Nightly Cycle 

Throughout a night, your brain cycles 4-5 times through rapid eye movement (REM) sleep and 3 stages of non-REM sleep. REM sleep, where most dreaming occurs, involves the rapid movement of your eyes under your eyelid. Brain wave activity is closer to that of wakefulness, but your muscles are temporarily paralyzed. Non-REM sleep progresses from light sleep to deep sleep, with the deepest stage critical for making you feel refreshed once you wake up. The deeper the sleep, the slower your brain activity, heartbeat, and breathing (NINDS, 2024). 

How Sleep Strengthens Memory and Learning

Sleep plays a vital role in forming and storing memories. Before learning, non-REM sleep helps your brain prepare to initially form memories. After learning, it helps solidify new information into your brain’s memory storage, making it easier to recall later. The hippocampus, a small seahorse-shaped structure in your brain, is crucial for memory formation but relies on sleep to properly function. REM sleep also plays a role in linking related memories, improving problem-solving skills and processing emotional memories (National Institutes of Health [NIH], 2013). 

Consequences of Sleep Deprivation 

Sleep deprivation is detrimental to your cognitive function and overall health. Without adequate sleep, your brain struggles to process and retain information, which makes learning and memory recall more difficult (John Hopkins Medicine [JHM], 2019). Short-term effects include slower reflexes, difficulty concentrating, mood disturbances, metabolism issues, headaches, and fatigue (CC, 2023). Long-term sleep deprivation can lead to hallucinations, microsleeps, and increased risks of depression, seizures, migraines, and high blood pressure (JHM, 2019). Unfortunately, sleep debt isn’t easily repaid, and “catching up” on lost sleep doesn’t fully restore cognitive function, making consistent rest essential (CC, 2023). 

How to Optimize Sleep for a Healthy Brain

Most adults need around 7-9 hours per night. Sticking to a regular sleep schedule, avoiding caffeine later in the day, and establishing a relaxing bedtime routine can all improve sleep quality (NINDS, 2024). Sleeping in a dark room is also important, as the sleep hormone melatonin is very sensitive to light. While short naps can strengthen memory, long or late naps may make falling asleep at night more difficult. Students, in particular, should prioritize sleep before and after studying, as sleep deprivation can reduce learning ability by up to 40% (NIH, 2013).  

Your brain is an incredibly powerful organ, but it needs sleep to function at its best. So next time you consider pulling an all-nighter, ask yourself: why do we need sleep at all? After all, we spend about a third of our lives doing it!   

References: 

Cleveland Clinic. (2023, June 19). Sleep. Cleveland Clinic. https://my.clevelandclinic.org/health/body/12148-sleep-basics

John Hopkins Medicine. (2019). The science of sleep: Understanding what happens when you sleep. Johns Hopkins Medicine Health Library. https://www.hopkinsmedicine.org/health/wellness-and-prevention/the-science-of-sleep-understanding-what-happens-when-you-sleep

National Institute of Neurological Disorders and Stroke. (2024, September 5). Brain basics: Understanding sleep. National Institute of Neurological Disorders and Stroke. https://www.ninds.nih.gov/health-information/public-education/brain-basics/brain-basics-understanding-sleep

National Institutes of Health. (2013, April). Sleep On It. NIH News in Health. https://newsinhealth.nih.gov/2013/04/sleep-it