Researchers are trying to figure out why sleep is important
Deep-Brain Oscillations during Sleep Reveals a Beautiful Biological System, says Dr. Maiken Nedergaard
The consequences of not getting enough sleep are harmful, as the average adult spends 20 years of their life sleeping. But surprisingly little is known about why it’s necessary. The tools that scientists can use to understand the function of sleep was not available in the past. These include optogenetics, which involves directing laser light to specific neurons to wake a person or put them into deep sleep, and focused ultrasound, which has emerged in the past five years as a way to view the deep-brain neural oscillations that occur during sleep.
People who listened to the pink noise had lowerCortisol levels, and reduced parasympathetic activity, when compared with those who did not. During sleep, parasympathetic activity gives the cardiovascular system a much-needed break. “We know that if you don’t sleep well, your heart rate and blood pressure go up and you are at greater risk for cardiovascular disease,” Zee says.
In 2020, researchers found that hydra, a freshwater polyp with no brain, also enter a languid state at night11. These creatures show a need for sleep homeostasis as well, resting longer the day after being sleep deprived.
Franks disputes this characterization and maintains that his results directly contradict Nedergaard’s. He said his data couldn’t be reconciled with her conclusions about clearance during sleep because he showed that the brain was retained at higher concentrations during sleep.
Nedergaard says that sleep is the period in which our brain doesn’t rest but does all the work. The glial cells clean our brains when it’s quiet and they also do what other organs do when we are awake. It’s a function of the brain that’s probably not compatible with wakefulness.”
She says that every time the heart beats, the arteries expand and fluid moves into the brain. There is a very beautiful biological system. The paper reported that the interstitial space in mice grew by about 60% when they were sleeping. This increased the exchange of fluid and the clearance of, which was linked to.
Sleep is thought to not only help memories to take root, but also clear the brain of anything superfluous. Neuroscientist Maiken Nedergaard at the University of Rochester in New York, has a theory of how that cleaning occurs.
“We asked them to remember word pairs during the day and then they slept,” says co-author Phyllis Zee, a neurologist and sleep-medicine specialist at the Feinberg School of Medicine in Chicago, Illinois. Overall, Zee says, those that had pink-noise stimulation performed almost 30% better on memory tests than did those who listened to the control sounds.
Source: Sleep is essential — researchers are trying to work out why
Does Sleep Impair Genes’ Functions? A New Mechanism for Fat Propagation in Flies that are Sleep Deprived of Sleep
For decades, the main purpose of sleep was thought to be maintaining brain health. Babies and teenagers sleep for such long periods of time, according to this theory, because there is so much brain development going on at those stages.
In rats, most genes seem to be upregulated while the animals are awake and downregulated during sleep. The functions of genes that are upregulated while sleep deprivation takes place. The study found that fruit flies that were sleep deprived had overexpression of genes that affected metabolism and levels of the Hormone dopamine6.
In mice, the same thing happened. When the animals were deprived of sleep and then allowed to sleep for a few minutes, they stopped expressing their genes for fat metabolism. Organelles called mitochondria sense this nutrient deficiency and signal cellular enzymes to make ROS to stimulate the proliferation of cells in the gut that are better at absorption, Rogulja says. After just one day of sleep restriction, Rogulja could detect the presence of fats in the mice’s guts. After five days, their guts were filled with fat although their bodies were starved of nutrients.
Source: Sleep is essential — researchers are trying to work out why
Sleep is essential — research is trying to explain why: A study by Vaccaro and Hermitia I. The gut of flies
“We looked at tissues all over the body,” Vaccaro says. We looked at the brain and didn’t see anything. The one tissue that showed the most damage when the flies started to die was in the gut.”
In order to find markers of aging in insects, Vaccaro decided to look for sleep deprivation and death in flies. She and her colleagues found that the concentrations of reactive oxygen species (ROS) in the guts of flies were at their highest when the animals started dying. Small amounts of ROS are beneficial — they regulate the body’s immune response and help cells to defend against pathogens. These molecules accumulate to toxic levels, but without sleep.
A person may feel fatigued and need to fall asleep if the brain is further from its critical point. The closer the brain is to its most critical point, the more likely a person will stay awake.
Home heating systems are familiar to Hanken. A drop in a room’s temperature below the set point causes the heater to turn on, restoring the environment to the desired level of warmth.
“This was like a light bulb for me a long time ago,” Hengen says. If you keep on letting machine learning learn, it will show catastrophic forgetting, and the wheels will come off. It just doesn’t work.
Source: Sleep is essential — researchers are trying to work out why
The aging of the brain: how many hours does it take to lose sleep? A neuroscientist’s look at the impacts of low daytime light exposure
What is the most important function of the brain? It could be tempting to say a specific task such as avoiding predators or finding food. But none of these roles is possible if the brain’s cellular machinery isn’t functioning reliably. Indeed, it is maintaining that reliability that might well be the main purpose of sleep, says Keith Hengen, a neuroscientist at Washington University in St. Louis, Missouri.
“We started looking at lifespan and saw that the moment when sleep-deprived animals would start dying was pretty much always the same,” Rogulja says. They began dying after they lost about 90% of their sleep. Those studies were in flies and mice — but the implications for other animals, including humans, was intriguing.
She expected the questions would take a long time to answer. But in six months, Rogulja’s postdoctoral assistant, Alexandra Vaccaro, found a tantalizing clue.
The data showed that those with the top 25% of the group had a 30% higher risk of major depressive disorder, 27% higher odds of self-harm, 21% higher odds of psychosis, and 23% higher risk of generalized anxiety disorder than did the bottom 25%. Those with the highest daytime light exposure had a lower risk of mental illness compared to those in the lowest level of light exposure. The associations persisted even after excluding night-shift workers from the analysis, or accounting for other factors such as physical activity and cardiometabolic health.
The Effects of Soft Rocking on Early Morning Lecture Attendance in Mice and Flies during Pre-Prepartum Insomnia
People who received therapist-assisted cognitive behavioural therapy for insomnia, which is delivered over the phone and by e-mail from the start of pregnant through to three months after the birth, saw the greatest reduction in insomnia. However, a mechanized ‘responsive bassinet’, which plays white noise and rocks back and forth when an infant cries, did not improve participants’ postpartum insomnia. The participants got a booklet explaining sleep hygiene.
The mechanism underpinning these effects is not clear. Excessive napping could reflect inadequate night-time sleep, which could indicate conditions such as obstructive sleep apnoea. The risk of cardiovascular disease can be influenced by daytime naps.
A study has confirmed what most students and lecturers have long suspected: early morning lectures are poorly attended, and the few who do attend are so sleep-deprived that no one is learning much anyway.
Around one in five adults in the United States use alcohol to help them get to sleep. Researchers at Brown University and E. P. Bradley Hospital, both in Providence, Rhode Island, found that a pre-sleep tipple delays the onset and decreases the total amount of rapid eye movement (REM) sleep, but these effects lessen over consecutive nights of drinking.
One hour before lights out, 30 healthy adults aged 22 to 57 were given a drink that contained either a mixer or a mixer plus alcohol, which was designed to bring them to a blood alcohol level of 0.08 milligrams per litre — around four drinks for the average man. The participants were wired up to polysomnography machines to record their brain activity throughout the night. The groups were switched over to the opposite drink type during the last three nights of the experiment.
The soporific effects of being gently rocked are well known in humans, mice and even fruit flies that have been specifically engineered to stay awake. Sho Inami and Kyunghee Koh at Thomas Jefferson University in Philadelphia, Pennsylvania, have shown that this vibration-induced sleep has the same beneficial cognitive effects as natural, uninduced sleep.
Another group of flies that had been genetically engineered to develop Alzheimer’s disease, which is known to interfere with healthy sleep, were placed in the vibrating tubes for longer stretches of time to see what effect the induced sleep had on disease markers. The researchers found that the flies that were vibrated to sleep slept better than those that were not and that they had less amyloid andtau in the brain.
A study on fruit flies found that when they were deprived of sleep, they started dying as soon as they reached the end of their life span. Researchers also found that a sleep-deprived fruit fly had less amyloid andtau in its brain, a protein that is known to cause Alzheimer’s Disease. The flies that slept were placed in vibrating tubes.