Incredible!See how quality sleep can help clean your brain

               

           

The brain, whether you give it credit or not, that soft gelatinous mass hanging in your skull is the center for life as you might be aware of it. At this moment, your brain is invariably maintaining your breathing and heart rate, while changing these black squiggles  into coherent words and thoughts.

The brain appears be a workhorse and a hungry one at that. While accounting for around 2% of the average adult’s weight, it accounts for 20% of its energy requirements, more than any other organ.

You could give your brain a mental compliment and then have a thought about how meta that was.

It is fascinating; Neuroscience research is booming. Growing interest and funding for neuroscience research has brought about a multiplying fields of interdisciplinary neuroscience that varies from clinical studies in neurodegenerative and behavioral disorders to basic science studies including brain structure and function at the molecular level– and all this is for good purpose.

Neuroscience research has grown steadily over time. Sources: Yeung et al., 2017, Frontiers in Neuroscience.

In 2014, only nine common neurological diseases (Alzheimer’s and other dementias, chronic lower back pain, stroke, TBI, migraines, epilepsy, MS, TSCI, and Parkinson’s) could approximately cost the American people nearly 800 billion dollars, a figure that has only increased over time. And despite the abundance of sensationalist reporting that might suggest otherwise, there is currently no ideal solution for a sick brain. Yet the research does indicate that quality sleep, among other factors, generally can boost brain health and we’re only just starting to understand the reason.

       

      

Penetrating into the black box of sleep

Sleep is very mysterious. Even today, we can’t totally for sure state  the real evolutionary function of sleep. Yet surely, it must be essential as most mammals die after more than a week of total sleep-deprivation. So what is really happening behind the scenes?

With the exception of a few brief exciting and oftentimes unusual dreams in REM sleep, our experience of sleep appears rather not exciting. While Drake and friends might think they are ‘out like a light’ when they fall asleep, the light is, in fact, still very much on. The “sleeping” brain is still working, sending electrochemical signals any on measuring electrical activity on the surface of the brain using EEG or measuring blood flow using fMRI. These tools are popular since they are non-invasive, but they lack the detail that would come from analyzing a brain sample after death.

The advances in newer Methodists like a two-photon microscopy allow highly-penetrant, in-vivo imaging in a precise focal plane. In other words, you might look through the skull to see some microscopic brain structures in alive, sleeping subjects in real-time. How neat can they appear?

These methods have helped sleep researchers to make some truly breathtaking discoveries, but first, let’s take time to analyse some relevant Neurophysiology 101.

• Neurons: they are classic nervous system cells that propagate electrochemical signals through action potentials and release of neurotransmitters
• Glia: they are  non-neuronal nervous system cells that keep neurons healthy
• CSF or cerebrospinal fluids: they are fluids in which  your brain is suspended. 
• Arteries: they are blood vessels conveying blood toward an organ
• Veins:they are blood vessels conveying blood away from an organ

Making divided traffic and discovering a new way

In a beautifully-designed experiment published in 2012, scientists injected a fluorescent tracer into the CSF of mice to follow its flow. Interestingly, the tracer appeared to be following the network of arteries conveying fresh blood to the brain.

However, the tracer was not in the arteries, just close to them. What they simply discovered was that the CSF was flowing in the space between the outer walls of the arteries and the surrounding glial cells. If you can imagine introducing a smaller pipe into a larger pipe, allowing two distinct fluids to flow in parallel along the same network, you’ve started understanding periarterial flow.

In addition to the pressure gradient that allows the fluid to move, the pulses of blood in your arteries also might help push the CSF along.

This CSF moves into the water surrounding cells, or interstitial fluid, and washes over them, supplying nutrients and clearing away harmful cellular waste products. It then moves through perivenous spaces, which surround veins, to be deposited into lymphatic vessels where the waste is filtered out.

This, in fact, is the glymphatic (glial lymphatic) system and it works

as the brain’s sewer system. Surprisingly, it was discovered only seven years ago by Dr. Maiken Nedergaard’s group at the University of Rochester Medical Center

Why sleep matters

Maybe, the most surprising fact about the glymphatic system is that it is only active during sleep. The perivascular tunnels are tightened during wakefulness,reducing CSF flow; this change is likely mediated by norepinephrine, a neuromodulator which is abundant only in wakefulness.

Several studies have shown that as you sleep, the glymphatic system is clearing your brain of neurotoxic substances that have accumulated throughout the day, including amyloid-beta, the protein that forms the characteristic plaques in Alzheimer’s. In a vicious cycle, impaired glymphatic function increases the accumulation of amyloid-beta, which in turn reduces its CSF influx through the glymphatic system.

And indeed glymphatic efficiency is impaired in the brains of current models of Alzheimer’s disease and generalized aging, even if  the possibility of an unusual relationship presents a less-clear, chicken-or-egg-first kind of question.

Fortunately, more people are coming up to confirm the idea that sleep is not a luxury. There is strong evidence for how sleep van influence learning, obesity, hypertension, insulin sensitivity, and you don’t need a peer-reviewed article to convince you that sleep affects your mood.

For many young people, not having adequate sleep is no longer a humblebrag for an industrious work ethic, but rather a mark of neglect for one’s well-being. Yet, while surveys reveal that Americans 

are getting slightly more weekday sleep than in previous years, only 10% of respondents said they give  priority to sleep over fitness, work, or their hobbies.