Brain Awareness Video Contest

Does Sleep Brainwash Us?

  • Published23 Oct 2023
  • Source BrainFacts/SfN

The brain’s self-cleaning system is different from other organs in the body. Scientists have long been puzzled by how the brain is able to get rid of waste. However, the discovery of the glymphatic system revealed how and when the brain achieves a good power wash: during our sleep.

This is a video from the 2023 Brain Awareness Video Contest.

Created by Kunsh Sharma and Vivin Sudharsan.




The brain doesn't have a traditional way of getting rid of waste and keeping itself clean. Scientists have always been puzzled by this. However, recent discoveries have uncovered the glymphatic system that removes harmful waste during sleep. Almost consider this “brainwashing.”

Brainwashing? Yes, you heard me, “brain-washing.” Not like controlling your mind. But literally washing your brain.

Let’s start from the basics. We all know that our body has a defense mechanism that protects us from infections, diseases, and other abnormalities in the body. We call this the lymphatic system, but there is a slight variation in the brain.

The glymphatic system is similar to the lymphatic system, but has a "g" in front of it, which stands for its glial cell dependency. 

You see, glial cells help support, connect, and protect the neurons in the brain. And are sometimes referred to as the “glue” of the nervous system. There are several types of glial cells that all play a part in this so-called “brainwashing.”

More importantly, 2 different types of fluids that circulate in the brain are used. Cerebrospinal fluid, or CSF, and interstitial fluid, or ISF.

CSF is like an invisible helmet, protecting our brain from mechanical damage. It’s made in a specialized tissue known as the choroid plexus in between the lateral, third, and fourth ventricles of the brain. Before any waste reaches the brain, the choroid plexus filters out the plasma from the blood and produces CSF to circulate through the ventricles, then surrounds the brain and spinal cord.

CSF now travels into spaces around cells to provide vital nutrients to the brain cells, and in the process, blends with interstitial fluid.

Interstitial fluid is simply fluid found in the spaces around cells and comes from substances that leak from blood capillaries.

Once CSF and ISF blend in with each other, they pick up any toxic substances and reroute them down through the CSF drainage system, which goes into the lymphatic circulation.

But you mentioned sleep. Where does that play a part in the glymphatic system?

In recent research, during sleep, the brain’s extracellular space expands, which results in decreased resistance to CSF and ISF flow, allowing for a smoother clearance of the brain’s metabolic waste. And scientists have discovered that the glymphatic system clears 80-90% more waste during deep sleep than wakefulness.

Ok, that’s great and all, sleep flushes out the toxins in your brain, we’ve known this but can a lack of sleep lead to any consequences?

According to the amyloid-beta hypothesis, the clumps of amyloid-beta and tau proteins can trigger neurodegenerative diseases such as Alzheimer’s and even dementia if it’s not cleared, so scientists propose that efficient sleep is essential for a healthy mind and body.

Ok, then can you give us some tips for efficient sleep?

No, I can’t. In fact, I interviewed Dr. Russel J. Reiter, a lead professor at the University of Texas, San Antonio, who has dedicated his entire life’s work to sleep and melatonin, and he gave some tips.

Dr. Russel Reiter: I think the most important thing is to get as much sleep as you can and do it regularly every night.

Dr. Russel Reiter: Our officiality was determined by the rising and the setting of the sun and we have subverted all of that, not depending on that at all, but doing our own thing. And our own thing is not healthy, period.

Dr. Russel Reiter: But sustained, regular, uniform exercise is certainly very good. Whether time-of-day dependent would change your circadian basis, I don't know. But all these things are under consideration, and I think we'll pay dividends eventually.

Wow, after your explanation, I now truly understand why sleeping plays a huge role in the glymphatic system for eliminating waste in the brain and preventing neurodegenerative diseases. I’ll definitely use Dr. Reiter’s tips for creating a balanced sleep schedule and the statistic about prioritizing deep sleep in my everyday life. Thank you!

No problem!

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