Sleep is what biologists consider a primary biological need, something that no animal can live without, just like water and food. The average person spends one third of their lifespan, in this subconscious — and exceptionally vulnerable — state; and yet, the exact purpose of sleep eludes us.
In the last two decades, we have seen enormous leaps in our understanding of sleep, however. We know that sleep plays a significant role in learning and memory, with all the brain activity patterns associated with newly-acquired information being “replayed” during certain phases of sleep to combine it.
It’s also clear that sleep is vital for maintaining good overall brain health, and that protracted periods of sleep deprivation may have severe consequences. Sleep disturbances are related to neurodegenerative diseases and psychiatric disorders, so maintaining good sleep habits probably reduces one’s risk of developing such conditions.
The mind does most of its housekeeping while we sleep, and a single housekeeping duty in particular — waste disposal. The brain disposes of its own waste through the glymphatic system, which is thought to consist of a network of vessels which runs together with blood vessels in the scalp and drains waste-filled cerebrospinal fluid in the organ.
Waste products removed away by this system comprise insoluble clumps of misfolded proteins which are deposited into the brain; these happen as a normal part of the aging process and also in neurodegenerative diseases. Alzheimer’s disease, for instance, is associated with the deposition of two such proteins: amyloid-beta, which aggregates to produce plaques around brain cells, and tau, which forms tangles in them.
The glymphatic system works best while we sleep, which explains why sleep disturbances have been linked to neurodegenerative diseases. Poor sleep habits probably reduces the efficiency of the brain’s waste disposal process, so the insoluble protein clumps which would typically be removed away during sleep, stay in place. Prolonged periods of sleep can result in these clumps accumulating to toxic levels, and these, in turn, can worsen sleep problems at a vicious level.
We’ve all had late or sleepless nights, and many people probably consider this to be completely harmless, though we know from experience that losing sleep has remarkable effects on our mental skills and well-being. Sleep deprivation makes us moody and irritable, and impairs brain functions like memory and decision-making. It also negatively impacts the rest of the body — it impairs the operation of the immune system, for instance, making us more prone to infection.
Better brain imaging today enables researchers to analyze exactly how sleep deprivation affects brain function. One study, published in 2009, revealed that sleep deprivation alters functional connections between the adrenal gland and the brain’s reward- and emotion-processing centers, impairing so-called executive functions. As a result, we become hypersensitive to rewarding stimuli, our psychological responses are improved, and we begin acting irrationally.
The most recent of these studies demonstrates that one night of sleep deprivation results in the deposition of amyloid-beta plaques in areas of the brain which are affected in Alzheimer’s disease. Earlier research had revealed that circulating amyloid-beta levels fluctuate with the sleep-wake cycle in mice, which sleep deprivation significantly increases amyloid-beta levels from the animals’ brains, but it was not clear if these findings also apply to people.
Ehsan Shokri-Kojori of the National Institutes of Health and his colleagues may now have resolved this issue. They injected 20 healthy participants using a radioactive tracer that binds to amyloid-beta, also utilized positron emission tomography (PET) to see where the tracer was dispersed in their brains, once after a night of relaxed sleep and after one night of sleep deprivation.
What’s more, study participants with the biggest increases in amyloid-beta levels also reported worse moods the day after.
“We didn’t ascertain the extent to which the elevated amyloid levels subside,” says Shokri-Kojori,”but it’s likely that sleep will clear away these consequences, particularly when amyloid-beta is in the soluble form.”
He adds the caveat that they did not distinguish between the soluble and insoluble forms of this protein, however. “We don’t know whether these changes are lasting, but consistently higher levels of amyloid-beta would likely increase the risk of plaque formation.”
How can lack of sleep affect your brain in short-term? Likewise, what occurs in our brains when we don’t get adequate sleep for a prolonged period?
Lack of sleep can affect your brain and lead to a range of cognitive, attention, and emotional deficits. Everybody knows that sleep is critical for our brains and bodies to function at their very best. Otherwise, why would we be spending one third of our lives doing this? Chronic sleep deprivation puts us in a greater risk of various ailments and long-term health conditions like hypertension, cardiovascular disease, obesity, diabetes and mental health issues such as anxiety and depression, to name just a couple.
Additionally, it has been amply demonstrated that the lack of sleep has a negative impact on your brain and overall our cognitive performance. At the cognitive degree, the lack of sleep effects on the brain include impairments on our ability to concentrate, make judgements, combine information and learn new things.
However, while the impact of sleep and the lack of it on our cognitive performance is very well documented, much less is still known about how sleep affects the mind on the cellular level.
However, as brain science quickly advances, more and more studies appear that begin to fill that gap. Listed below are just four of the most prominent studies lately and their findings which looked closely in our sleep deprived brains.
Sleep Allows Your Brain Cells to Fix Themselves
A study published earlier this year discovered that sleep is vital for the brain’s ability to repair itself. More specifically, scientists discovered that during sleep fundamental DNA repair processes take place in the brain.
In the course of the research, the researchers from Bar-Ilan University observed zebrafish, species that are characterized with transparent heads. With the usage of a microscope, the researchers were able to discover the mind of the zebrafish during sleeping and waking, and required time-lapsed images of individual neurons. They were subsequently able to find that during sleep the process of DNA repair kicked off in their brains, reversing the DNA damage gathered during the day.
According to the researchers, human brain cells also regularly accumulate DNA damage not only from exposure to radiation and other undesirable ailments but also as a consequence of the normal brain activity. Sleep permits for these cells to be mended.
Among the study’s authors, Professor Lior Applebaum, clarified why this complex procedure takes place while we sleep, by comparing it into fixing potholes in the road. He said:”Roads accumulate wear and tear, especially during daytime hours, and it’s most convenient and efficient to fix them during the nighttime, when there is traffic that is light .”
The researchers believe that this finding might explain the essential function of sleep for all animals with neural system including humans.
Lack of Sleep and Effects on Brain Cells
This study was conducted on mice, whose brain is known to be surprisingly like the human brain. The mice were put on a program like the one that is utilized by men and women who work night shifts or long hours. In each 24 hour period, the mice got just 4 to 5 hours of sleep.
The results were astonishing. After just three days of this schedule, the sleep-deprived mice lost 25 percent of brain cells within the brain stem cells, the harm that seemed to become irreversible.
According to the study’s authors, because of the connection between the brains of mice and humans, it is very possible that the human mind suffers from the same reduction of neurons when deprived of sufficient sleep. This is something that researchers planned to further research by conducting autopsies of night shift employees.
Sleep Helps Brain ‘Detox’
Another study printed in Science, found that through sleep a sort of detox process occurs in brain, as it gets rid of harmful waste products, such as some that have been associated with Alzheimer’s and dementia.
The analysis was conducted by researchers at the University of Rochester Medical Center (URMC) who utilized high-tech imaging to look into the brains of mice and found that their brains behaved very differently when asleep and awake. Specifically, the waste elimination process happened ten times quicker when the mice had been sleeping, flushing out poisonous protein amyloid-beta that’s associated with Alzheimer’s.
The clean up process observed by the investigators happens with the help of the cerebrospinal fluid which flows through the spaces between nerves flushing waste into the circulatory system. During sleep, the researchers discovered that the brain cells contract, leaving more space for the cerebrospinal fluid to do its job far more effectively.
Sleep Enables Brain Cells to Communicate Effectively
In research on the lack of sleep effects on brain printed recently in Nature Medicine, researchers found a neurological explanation to the mental sluggishness that is so familiar to some people who’ve ever had to take an exam, drive a vehicle or perform any other cognitively demanding activity while sleep deprived. Particularly, the study authors found that lack of sleep effects on brain include severe impairments on the ability of brain cells to communicate efficiently.
From the study, 12 participants that were planning to undergo surgery for epilepsy (unrelated to the study) had electrodes implanted into their brains and were requested to stay up the whole night. Many times throughout the night, researchers asked them to categorize images of faces, places and animals as quickly as possible. They discovered that as people became drowsier, their reactions got slower. The researchers monitored the brain activity during the same time, paying particular attention to neurons in the temporal lobe, which modulate visual memory and perception. They could see that the lack of sleep effects on the brain include slowed down reaction time because of the less effective communication between brain cells.
This of course has direct consequences in everyday activities like driving, and consequently may have a fatal effect. “Intense fatigue exerts a similar effect on the mind to drinking too much,” Fried said. “Nevertheless no legal or health care criteria exist for identifying overtired drivers on the road the exact same way we target drunk drivers.”
The lack of sleep effects on the brain may compromise health, performance, and security, are common among people who work extended hours, such as military and medical personnel. Sleep shortages also have been connected to the growth of some chronic conditions, such as diabetes, obesity, and cardiovascular disease.
Even though most men and women experience occasional sleep deprivation and recognize its effects on their disposition and behavior, there is limited scientific understanding of lack of sleep affects the brain.
By studying which genes were turned on across the brain, the investigators discovered that a “molecular anatomical touch” of sleep deprivation that entails many areas from the forebrain, including the neocortex, amygdala, and hippocampus. Together, these regions mediate cognitive, psychological, and memory functions that are impaired by sleep deprivation. These findings can contribute to remedies which can help improve sleep quality and reduce issues arising from sleep deprivation.
Thorough investigations of 209 brain regions revealed a novel set of genes not previously associated with sleep deprivation, such as genes associated with the stress response and the regulation of different genes. One gene, neurotensin, has been associated with schizophrenia and is influenced by antipsychotic drugs.
Researchers and clinicians now concur that good sleep habits are a pillar of the neuroprotective lifestyle, and there’s supporting evidence that improving sleep may have enormous benefits for our total well-being. One recent study of more than 7,500 British university students revealed that digital cognitive behavioral treatment for insomnia not only enhanced the pupils’ sleep, but additionally decreased the level of delusions and hallucinations they experienced.
“We are now able to consider sleep as a therapeutic goal,” says study co-author Russell Foster, director of the Sleep and Circadian Neuroscience Institute of the University of Oxford.
The most recent findings, presented at the SLEEP 2018 conference in Baltimore in June, reveal that a daytime light intervention improves mood and sleep in Alzheimer’s sufferers, adding more substance to the notion of using sleep to treat both psychiatric and neurological conditions.
Sleep Deprived Society
Yet, many people remain largely unaware of the importance of sleep. Some experts argue that we are living in a sleep-deprived society, where large sections of the population do not get sufficient rest and have unhealthy sleep patterns — such as night shift workers with intermittent schedules, busy career-driven individuals and parents who sleep less than 8 hours and school children who do not go to bed early enough and begin their day as early as 7:30 am.
Sleep is the most effective cognitive enhancer we’ve got, but we are doing an extremely bad job translating this information across to people of how important it is for our overall well being. Children should be taught at a young age to see the value of sleep in the way that they are taught to value nutrition and fitness.
In addition, studies on lack of sleep effects on the brain are not conclusive enough and there needs to be more research done on the topic to support the conclusions that have been made in recent studies to address unanswered questions.