A Rather Unhealthy Snack: Your Brain

Picture this: It’s late at night. You’re fighting yawns, cramming for an exam, finishing that big assignment, or trying to solve an impossible math problem when your stomach suddenly growls. You reach for a snack, but what if, instead, your brain became the snack?

Building on Sydney's previous blog post, I wanted to explore the impact of inadequate sleep on your brain, leading to eating itself as the worst case scenario, and consequently, neurological problems. The brain-eating itself started off as a morbid or scary rumor, but there is actually some basis of fact with this "rumor". As we have come to learn and will continue to learn over the next years of our education, sleep is vital for focus, but survival as well. Now the question is how?

Our brain is made up of dynamic tissues that behave differently when we’re awake versus asleep. During sleep, it clears out toxins and byproducts from daytime neural activity. Two glial cell types, astrocytes and microglia, handle this cleanup. Glial cells act as the “glue” of the nervous system (Crew, 2018). Normally, this process happens during deep sleep, but with chronic sleep deprivation, the brain’s cleanup crew starts working overtime, even while we’re awake.

Microglial cells know which cells to eat due to cells having "eat me" and "don't eat me" receptors along their cell surface. A common "don't eat me" signal is CD47, and when we lose this, microglial cells enable phagocytosis (Allendorf et al., 2019). Chronic sleep deprivation causes both cognitive dysfunction and increased microglial activation. All of that to say, chronic sleep loss increases both stress and microglial activity, leading to excessive pruning of synapses and neurons. Over time, this self-cannibalization contributes to cognitive decline and diseases such as Alzheimer’s. 

Studies show that reducing this excessive autophagy can improve synaptic plasticity and memory retention (Puigdellívol & Brown, 2024; Tavernarakis, 2020). To strengthen our synapses to also improve plasticity, enhance memory and learning, long-term potentiation is absolutely necessary, but sleep deprivation, in addition to the above, disrupts our hippocampus and disrupts neural signaling (Chen et al., 2023). If our brain is literally consuming its own synapses and signaling is constantly getting disrupted, how can we expect to maintain strong long-term potentiation (LTP) and continue to learn? 

The takeaway is simple: good sleep clears toxins, supports learning, and prevents your brain from over-pruning itself. So next time you’re tempted to pull an all-nighter, remember you’re probably just better off sleeping. Get your rest! Your brain depends on it.

Citations:

Allendorf, D., Popescu, A., & Brown, G. C. (2019). How the brain eats itself. The Biochemist, 41(1), 32–35. https://doi.org/10.1042/BIO04101032

Chen, P., Ban, W., Wang, W., You, Y., & Yang, Z. (2023). The Devastating Effects of Sleep Deprivation on Memory: Lessons from Rodent Models. Clocks & Sleep, 5(2), 276–294. https://doi.org/10.3390/clockssleep5020022

Crew, B. (2018, May 29). The Brain Literally Starts Eating Itself When It Doesn’t Get Enough Sleep. ScienceAlert. https://www.sciencealert.com/your-brain-starts-eating-itself-due-to-lack-of-sleep

Puigdellívol, M., & Brown, G. C. (2024). Stopping the aged brain from eating itself. Aging (Albany NY), 16(9), 7508–7510. https://doi.org/10.18632/aging.205887

Tavernarakis, N. (2020). Regulation and Roles of Autophagy in the Brain. https://doi.org/10.1007/978-3-030-32633-3_5