Chapter 10. Biological Rhythms and Sleep

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By Katie Moritz If you’re like a lot of people all over the world, you have a hard time sleeping. Maybe you’ve tried apps that promote sleep, or going without electronics for the hours leading up to bedtime, or supplements like melatonin or magnesium. But have you tried thinking differently about your waking life? Research suggests that having a purpose in life leads to a better night’s sleep. Picture in your mind your biggest interests and your loftiest goals. Pursuing those could help you get better shut-eye. A research team at the Northwestern University Feinberg School of Medicine looked at the sleep habits of more than 800 older adults—though they said the results are likely applicable to everyone—and found that the ones who reported having a purpose in life have fewer sleep disturbances like sleep apnea and restless leg syndrome and sleep better over a long period. Purpose pbs rewire“Helping people cultivate a purpose in life could be an effective drug-free strategy to improve sleep quality, particularly for a population that is facing more insomnia,” said Jason Ong, one of the study’s authors and an associate professor of neurology at the Feinberg School of Medicine, to the university. “Purpose in life is something that can be cultivated and enhanced through mindfulness therapies.” In the Northwestern study, the people who felt their lives had meaning were 63 percent less likely to have sleep apnea, 52 percent less likely to have restless leg syndrome and had better sleep quality. Poor sleep quality is defined by having trouble falling and staying asleep and feeling tired during the day.

Keyword: Sleep; Depression
Link ID: 23967 - Posted: 08.17.2017

By NICHOLAS BAKALAR Children who sleep less may be at increased risk for Type 2 diabetes, researchers report. Earlier studies found a link between shorter sleep and diabetes in adults, but the connection has been little studied in children. British researchers studied 4,525 9- and 10-year olds from varying ethnic backgrounds. On average, their parents reported they slept 10 hours a night, with 95 percent sleeping between eight and 12 hours. The study, in Pediatrics, found that the less sleep, the more likely the children were to have higher body mass indexes, higher insulin resistance and higher glucose readings. All three are risk factors for Type 2 diabetes. Over all, increasing weekday sleep duration by an hour was associated with a 0.2 lower B.M.I. and a 3 percent reduction in insulin resistance. The reasons for the link remain unclear, but the researchers suggest that poor sleep may affect appetite regulation, leading to overeating and obesity. This observational study could not establish cause and effect. Still, the senior author, Christopher G. Owen, a professor of epidemiology at St. George’s University of London, said that for children, the more sleep the better — there is no threshold. “Increasing sleep is a very simple, low-cost intervention,” he said. “We should be doing our utmost to make sure that children sleep for an adequate amount of time.” © 2017 The New York Times Company

Keyword: Sleep; Obesity
Link ID: 23957 - Posted: 08.15.2017

By MALIA WOLLAN ‘‘Don’t startle the person,’’ says Charlene Gamaldo, the medical director at the Johns Hopkins Center for Sleep. Sleepwalkers exist in a semiwakeful state and can become testy and disoriented when forced to come to full consciousness. Instead, speak to them in a quiet voice and lead them gently back to their bed. In most cases, they’ll settle easily and in the morning remember nothing of their nighttime ambulations. To determine whether you’re dealing with a sleepwalker, as opposed to, say, a night owl (or someone with another, more worrisome form of parasomnia), watch for open eyes, a blank expression, physical clumsiness and a lack of reactivity. ‘‘They look zoned out,’’ Gamaldo says. Sleepwalkers tend to perform tasks from memory, including texting, shopping online, cooking and even driving and having sex, all with a noticeably odd flair. ‘‘They may get up and eat a raw TV dinner,’’ Gamaldo says. Researchers attribute a surge in sleepwalking in the 21st century to a rise in the use of hypnosedative sleeping medications. A popular hotel chain in the United Kingdom even issued sleepwalker-care guidelines to staff members after noting a sevenfold increase in sleepwalking patrons over one year, 95 percent of whom were men wandering out of their rooms naked. Other triggers include stress, genetics, fatigue, heat and what Gamaldo calls ‘‘poor sleep hygiene,’’ or loud, overly bright bedrooms filled with TVs and digital devices. To protect a sleepwalker in your home, make it as safe and soporific as possible. Keep him or her away from stairs and sharp objects. ‘‘The bedroom should be uncluttered,’’ Gamaldo says. © 2017 The New York Times Company

Keyword: Sleep
Link ID: 23951 - Posted: 08.12.2017

Thomas Cronin We humans are uncommonly visual creatures. And those of us endowed with normal sight are used to thinking of our eyes as vital to how we experience the world. Vision is an advanced form of photoreception – that is, light sensing. But we also experience other more rudimentary forms of photoreception in our daily lives. We all know, for instance, the delight of perceiving the warm sun on our skin, in this case using heat as a substitute for light. No eyes or even special photoreceptor cells are necessary. But scientists have discovered in recent decades that many animals – including human beings – do have specialized light-detecting molecules in unexpected places, outside of the eyes. These “extraocular photoreceptors” are usually found in the central nervous system or in the skin, but also frequently in internal organs. What are light-sensing molecules doing in places beyond the eyes? Vision depends on detecting light All the visual cells identified in animals detect light using a single family of proteins, called the opsins. These proteins grab a light-sensitive molecule – derived from vitamin A – that changes its structure when exposed to light. The opsin in turn changes its own shape and turns on signaling pathways in photoreceptor cells that ultimately send a message to the brain that light has been detected. © 2010–2017, The Conversation US, Inc.

Keyword: Biological Rhythms; Vision
Link ID: 23947 - Posted: 08.11.2017

By Philip Jaekl In 1959, two French scientists, Michel Jouvet and François Michel, recorded strange patterns of neural activity in the brainstem of sleeping cats. The brain waves seemed remarkably synced to rapid eye movement (REM) sleep, which University of Chicago researchers had connected with dreaming six years earlier. These new brain activity patterns seemed as though they might also correspond with dreaming. In the 1960s, Jouvet and collaborators showed that cats with a lesion introduced into that same brainstem area—the pons—exhibited odd behavior. Cats displayed REMs as though they were asleep, while reacting to nonexistent prey or predators, pouncing, or hiding. Humans can also experience REMs while dreaming, hallucinating, or even recalling deeply emotional memories while awake. But do humans also exhibit the same patterns of neural activity—dubbed PGO waves? The waves are so named because they are generated in a part of the brain stem called the pons, and propagate to the lateral geniculate nuclei of the brain—relay stations in the thalamus for incoming visual information—and then to the occipital lobe, where most visual processing takes place. Studies have suggested that this neural pathway is crucial for functions ranging from basic ones such as the control of eye muscle movements to more-complex phenomena, including visual experiences during dreams and in hallucinations, memory consolidation, and even psychotic behavior. Researchers have recently proposed that a common thread shared by these phenomena is the overriding of retinal visual input by internally created visual experiences (Front Hum Neuro,, 2017). © 1986-2017 The Scientist

Keyword: Sleep; Vision
Link ID: 23940 - Posted: 08.10.2017

Amy Maxmen Despite strides in maternal medicine, premature birth remains a vexing problem for obstetricians worldwide. But an analysis of medical records from almost 3 million pregnant women in California1 suggests that a surprisingly simple intervention — better sleep — might help to address the issue. Researchers found that women who had been diagnosed with insomnia or sleep apnea were about twice as likely as women without sleep disorders to deliver their babies more than six weeks early. “It seems obvious, but strangely this study has not been done before,” says Laura Jelliffe-Pawlowski, an epidemiologist at the University of California, San Francisco (UCSF), and an author of the research, which was published on 8 August in the journal Obstetrics and Gynecology1. “Seeing this relationship is important because we are just starved for interventions that can make a difference.” Public-health experts say that better treatment for pregnant women with serious sleep disorders could save babies' lives, and do so with approaches that avoid the use of medication. Every year, 15 million babies worldwide are born prematurely — more than three weeks before the typical full-term pregnancy of 40 weeks. These children have less time to develop in the womb, and 1.1 million will die from birth-related complications. Many others are left with hearing impairment, learning disabilities, cerebral palsy and other health issues. © 2017 Macmillan Publishers Limited,

Keyword: Sleep; Development of the Brain
Link ID: 23937 - Posted: 08.09.2017

By Ben Guarino A sleeping brain can form fresh memories, according to a team of neuroscientists. The researchers played complex sounds to people while they were sleeping, and afterward the sleepers could recognize those sounds when they were awake. The idea that humans can learn while asleep, a concept sometimes called hypnopedia, has a long and odd history. It hit a particularly strange note in 1927, when New York inventor A. B. Saliger debuted the Psycho-phone. He billed the device as an “automatic suggestion machine.” The Psycho-phone was a phonograph connected to a clock. It played wax cylinder records, which Saliger made and sold. The records had names like “Life Extension,” “Normal Weight” or “Mating.” That last one went: “I desire a mate. I radiate love … My conversation is interesting. My company is delightful. I have a strong sex appeal.” Thousands of sleepers bought the devices, Saliger told the New Yorker in 1933. (Those included Hollywood actors, he said, though he declined to name names.) Despite his enthusiasm for the machine — Saliger himself dozed off to “Inspiration” and “Health” — the device was a bust. But the idea that we can learn while unconscious holds more merit than gizmos named Psycho-phone suggest. In the new study, published Tuesday in the journal Nature Communications, neuroscientists demonstrated that it is possible to teach acoustic lessons to sleeping people. © 1996-2017 The Washington Post

Keyword: Sleep; Learning & Memory
Link ID: 23936 - Posted: 08.09.2017

By Matthew Hutson Every year, tens of millions of Americans toss and turn with chronic sleep disorders. But diagnosis isn’t easy: It usually means sleeping in a lab entangled in gadgets that track breathing, heart rate, movement, and brain activity, followed by expert analysis of the data. Now, a new technique that uses machine learning and radio signals can get rid of the sleep lab—and the expert. First, an in-home device bounces radio waves—similar to those in cellphones and Wi-Fi routers—off the sleeper, measuring the returning signal. Then, the system builds on previous radio-frequency sleep monitoring by using three machine-learning algorithms to analyze breathing and pulse and identify the stage of sleep: light, deep, REM, or wakefulness. One algorithm uses a type of neural network common in image recognition to parse the spectrograms, or snapshots, of the data; another uses a type of neural net typically employed in tracking temporal patterns to look at the dynamics of sleep stages; a third refines the analysis to make it more generalizable across people and environments. Researchers trained the tool on about 70,000 30-second sleep intervals and tested it on about 20,000. Measured against an electroencephalogram system that was about as proficient as humans, the system identified sleep stages with 80% accuracy, versus 64% for the previous best radio frequency method, the researchers will report tomorrow at the International Conference on Machine Learning in Sydney, Australia. If the system makes it to market, doctors might soon be able to diagnose you in their sleep. © 2017 American Association for the Advancement of Science.

Keyword: Sleep
Link ID: 23932 - Posted: 08.09.2017

By Ariana Eunjung Cha By now, the connection between sleep and weight gain has been well established. Numerous studies have provided evidence that sleeping too little — less than five hours — messes with your hormones, slows down your metabolism and reprograms your body to eat more. But just how serious are the consequences in terms of numbers? A new study published in PLOS One takes a stab at this question by studying the relationship between sleep duration and a number of quantifiable factors: waist circumference, blood pressure, lipids, glucose, thyroid hormones and other important measures of a person's metabolic profile. The research, led by the Leeds Institute of Cardiovascular and Metabolic Medicine and the School of Food Science and Nutrition, involved 1,615 people ages 19 to 65 in Great Britain. The most striking suggestion was that getting insufficient sleep may make you go up a clothing size. People in the study who were sleeping an average of six hours each night had waist measurements about 1.2 inches (or 3 centimeters) more than those getting nine hours of sleep a night. Those with less sleep also weighed more. The relationship between more sleep and smaller waists and a lower body mass index (BMI) appeared to be almost linear, as shown below. The findings appear to contradict other studies that show that too much sleep — nine hours or more — might have a similar impact on the body as too little sleep. This new study appears to show that waist circumference and BMI are lowest for those with 12 hours of sleep. The theory of why this relationship exists has to do with two hormones that help tell you when to eat and when to stop. Less sleep upsets the balance, making you eat more. Combine that with the slower metabolism that people with lack of sleep appear to have it's no wonder that people are prone to becoming larger and gaining weight. © 1996-2017 The Washington Post

Keyword: Sleep; Obesity
Link ID: 23903 - Posted: 08.01.2017

By Helen Thomson Have you recently arrived at work naked or turned up for an exam without revising? If you want to avoid having nightmares like these, it might be best to get less than 9 hours’ sleep a night. People often have nightmares following upsetting events, and research into nightmares has mostly focused on people with conditions like post-traumatic stress disorder (PTSD). But most people get nightmares at some point, prompting Stephanie Rek at the University of Oxford and her colleagues to perform one of the largest ever studies of nightmares in the general population. Discover the new science of sleep and dreaming: Learn more at New Scientist Live in London The team recruited 846 people through media advertisements and databases of people interested in sleep studies, and asked them to complete an online survey. The participants were asked questions such as how many nightmares they had experienced over the past two weeks, and how bad they were. These answers contributed to an overall score on a “nightmare severity scale”. Each volunteer was also assessed for PTSD and asked about other aspects of their life, such as recent divorces or legal trouble, their tendency to worry, how much sleep they get and how much alcohol they drink. © Copyright New Scientist Ltd.

Keyword: Sleep
Link ID: 23894 - Posted: 07.29.2017

By Tara Bahrampour Older patients who become disoriented or confused after surgery are more than three times more likely to develop dementia later, a new study has found. The report, published Friday by the British Journal of Anaesthesia, assesses the effects of post-operative delirium (POD) on people 65 and older who were cognitively normal before their operations. Of 1,152 such patients, 9.5 percent met criteria for mild cognitive impairment or dementia a median of nine months after surgery. The frequency of being diagnosed with MCI or dementia after surgery was much higher – 33.3 percent – among those who had experienced post-operative delirium, compared with 9 percent among those who had not. While earlier studies have showed a relationship between POD and dementia, this is the first to look entirely at subjects who showed no cognitive decline in pre-surgery assessments, said David Warner, an anesthesiologist at Mayo Clinic in Rochester, Minnesota and the study’s senior author. Delirium is defined by an acute state of confusion, inattention, disorganized thinking, and a fluctuating mental state. Older patients are more likely than younger ones to develop it after surgery, as are people with lower education levels and those who undergo vascular procedures. Further study is needed to determine whether delirium contributes to later cognitive decline or is an indicator of some underlying factor that made people more likely to develop dementia, Warner said. © 1996-2017 The Washington Post

Keyword: Alzheimers
Link ID: 23888 - Posted: 07.28.2017

By Alice Klein FOR decades, new parents have been warned against sharing a bed with their babies. While snuggling up with your newborn may seem like the most natural thing in the world, prevailing medical advice says this increases the risk of sudden infant death syndrome (SIDS), sometimes called cot death. Instead, doctors say your little ones should sleep in a separate crib in your bedroom. On the other side of the argument are anthropologists and proponents of “attachment parenting”, who believe that infant-parent separation is unnatural and at odds with our evolutionary history. They favour not just room-sharing but bed-sharing – putting them in direct conflict with paediatric advice. This debate was recently reignited by a study suggesting that room-sharing for up to nine months reduces a baby’s sleep, which in theory could have future health consequences. So what’s a sleep-deprived parent to do? Our ancestors slept in direct contact with their young in order to protect them, just as other primates do today, says Helen Ball at Durham University, UK. “Babies respond to close contact – their breathing, blood oxygen and heart rate are on a more even keel.” In Asia and Africa, most babies still share their parents’ beds (see map). But in the West, bed-sharing fell during the industrial revolution as increased wealth let people afford separate rooms and value was placed on teaching early independence. © Copyright New Scientist Ltd.

Keyword: Sleep
Link ID: 23829 - Posted: 07.13.2017

By Linda Geddes Many dangers stalk the bushlands of Tanzania while members of the Hadza people sleep, yet no one keeps watch. There is no need because it seems that natural variation in sleep means there’s rarely a moment when someone isn’t alert enough to raise the alarm. That’s the conclusion of a study that sheds new light on why teenagers sleep late while grandparents are often up at the crack of dawn. Fifty years ago, psychologist Frederick Snyder proposed that animals who live in groups stay vigilant during sleep, by having some stay awake while others rest. However, no one had tested this sentinel hypothesis in humans until now. One way of maintaining this constant vigilance might be by the evolution of different chronotypes – individual differences in when we tend to sleep. This changes as we age, with teenagers shifting towards later bedtimes, and older people towards earlier bedtimes. Would such variability be enough to keep a community safe at night? To investigate, David Samson, then at the University of Toronto in Canada, and his colleagues turned to the Hadza, a group of hunter-gatherers in northern Tanzania. The Hadza sleep in grass huts, each containing one or two adults and often several children. They live in camps of around 30 adults, although several other camps may be close by. Samson recruited 33 adults from two nearby groups of 22 huts and asked them to wear motion-sensors on their wrists to monitor sleep, for 20 days. “It turned out that it was extremely rare for there to be synchronous sleep,” says Samson, now at Duke University in Durham, North Carolina. © Copyright New Scientist Ltd.

Keyword: Sleep; Development of the Brain
Link ID: 23827 - Posted: 07.12.2017

Tina Hesman Saey How well, not how much, people sleep may affect Alzheimer’s disease risk. Healthy adults built up Alzheimer’s-associated proteins in their cerebral spinal fluid when prevented from getting slow-wave sleep, the deepest stage of sleep, researchers report July 10 in Brain. Just one night of deep-sleep disruption was enough to increase the amount of amyloid-beta, a protein that clumps into brain cell‒killing plaques in people with Alzheimer’s. People in the study who slept poorly for a week also had more of a protein called tau in their spinal fluid than they did when well rested. Tau snarls itself into tangles inside brain cells of people with the disease. These findings support a growing body of evidence that lack of Zs is linked to Alzheimer’s and other neurodegenerative diseases. Specifically, “this suggests that there’s something special about deep, slow-wave sleep,” says Kristine Yaffe, a neurologist and psychiatrist at the University of California, San Francisco who was not involved in the study. People with Alzheimer’s are notoriously poor sleepers, but scientists aren’t sure if that is a cause or a consequence of the disease. Evidence from recent animal and human studies suggests the problem goes both ways, Yaffe says. Lack of sleep may make people more prone to brain disorders. And once a person has the disease, disruptions in the brain may make it hard to sleep. Still, it wasn’t clear why not getting enough shut-eye promotes Alzheimer’s disease.

Keyword: Sleep; Alzheimers
Link ID: 23824 - Posted: 07.11.2017

Ian Sample Science editor The secret to a good night’s sleep later in life is having a good reason to get up in the morning, according to US researchers who surveyed people on their sleeping habits and sense of purpose. People who felt they had a strong purpose in life suffered from less insomnia and sleep disturbances than others and claimed to rest better at night as a result, the study found. Jason Ong, a neurologist who led the research at Northwestern University in Chicago, said that encouraging people to develop a sense of purpose could help them to keep insomnia at bay without the need for sleeping pills. More than 800 people aged 60 to 100 took part in the study and answered questions on their sleep quality and motivations in life. To assess their sense of purpose, the participants were asked to rate statements such as: “I feel good when I think of what I’ve done in the past and what I hope to do in the future.” According to Ong, people who felt their lives had most meaning were less likely to have sleep apnea, a disorder that makes the breathing shallow or occasionally stop, or restless leg syndrome, a condition that compels people to move their legs and which is often worse at night. Those who reported the most purposeful lives had slightly better sleep quality overall, according to the study in the journal Sleep Science and Practice. © 2017 Guardian News and Media Limited

Keyword: Sleep; Attention
Link ID: 23819 - Posted: 07.11.2017

By Linda Geddes BILLIONS of dollars have been spent in search of treatments for psychiatric conditions and brain disorders, when a cheap and effective drug may have been right under our noses: light. Now hospitals are turning to light to treat depression, strokes and Parkinson’s disease, using it to hit the reset button on our internal clocks. From green light soothing the pain of migraine, to blue light reducing organ damage during surgery, recent small studies have uncovered some intriguing effects of this therapy. But apart from easing seasonal affective disorder, we’ve been slow to embrace light as a serious contender for treating neurological conditions. We’ve known for 15 years that a special kind of receptor in our eyes transmits information directly to the body’s master clock, as well as other brain areas that control mood and alertness. These cells are particularly responsive to bluish light, including sunlight. These receptors enable light to act as a powerful reset switch, keeping the clock in our brain synced to the outside world. But this clock can fall out of sync or weaken as part of ageing or a range of disorders – a problem doctors are now starting to treat with light. Most hospitals have small windows and 24-hour lighting, both of which might exacerbate health problems. To tackle this, several hospitals in Europe and the US are installing dynamic “solid state” lighting, which changes like daylight over the course of a day. Such lights can, for example, shine bright whitish-blue in the morning, grow warmer and dimmer throughout the day, and turn orange or switch off at night. © Copyright New Scientist Ltd.

Keyword: Biological Rhythms; Stroke
Link ID: 23808 - Posted: 07.06.2017

By NICHOLAS BAKALAR Poor sleep may be an indication of increased risk for Alzheimer’s disease, a new study of older people suggests. Researchers studied 101 cognitively normal people, average age 63, who completed well-validated sleep questionnaires. They analyzed their spinal fluid for the presence of indicators of the plaques and tangles that are characteristic of Alzheimer’s. The study is in Neurology. After controlling for age, a family history of Alzheimer’s, the ApoE gene that increases Alzheimer’s risk and other factors, they found that poor sleep quality, sleep problems and daytime sleepiness were associated with increased spinal fluid indicators of Alzheimer’s disease. The reason for the association is unclear, but at least one animal study found that during sleep the brain’s capacity to clear toxins like beta amyloid, the toxic protein that forms plaques in the brains of those with Alzheimer’s, improves. It may be that poor sleep interferes with this process in people, too. “Not everyone with sleep problems is destined to develop Alzheimer’s disease,” said the senior author, Barbara B. Bendlin, an associate professor of medicine at the University of Wisconsin School of Medicine and Public Health. “We’re looking at groups of people, and over the whole group we find the association of poor sleep with the markers of Alzheimer’s. But when you look at individuals, not everyone shows that pattern.” © 2017 The New York Times Company

Keyword: Alzheimers; Sleep
Link ID: 23806 - Posted: 07.06.2017

Blood samples from infants who died of Sudden Infant Death Syndrome (SIDS) had high levels of serotonin, a chemical that carries signals along and between nerves, according to a study funded in part by the National Institutes of Health. The finding raises the possibility that a test could be developed to distinguish SIDS cases from other causes of sleep-related, unexpected infant death. The study, led by Robin L. Haynes, Ph.D., of Boston Children’s Hospital and Harvard Medical School, appears in the Proceedings of the National Academy of Sciences. NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) provided funding for the work. SIDS is the sudden death of an infant under one year of age that remains unexplained after a complete autopsy and death scene investigation. In the current study, researchers reported that 31 percent of SIDS infants (19 of 61) had elevated blood levels of serotonin. In previous studies, the researchers reported multiple serotonin-related brain abnormalities in SIDS cases, including a decrease in serotonin in regions involved in breathing, heart rate patterns, blood pressure, temperature regulation, and arousal during sleep. Taken together, the researchers wrote, the findings suggest that an abnormality in serotonin metabolism could indicate an underlying vulnerability that increases SIDS risk and that testing blood samples for serotonin could distinguish certain SIDS cases from other infant deaths. However, they caution that more research is needed. NICHD’s Safe to Sleep campaign provides information on ways to reduce the risk of SIDS and other sleep-related causes of infant death.

Keyword: Sleep; Development of the Brain
Link ID: 23804 - Posted: 07.04.2017

By Kerry Grens Until a little more than a decade ago, doctors had few options to treat newborns whose brains were deprived of oxygen or blood at birth, a condition known as perinatal hypoxic-ischemic encephalopathy, or HIE. If babies could be stabilized and kept breathing, physicians and nurses could offer only supportive care and had to watch and wait to see how much brain damage their patients would suffer. “This was a disease where we had no treatment that worked, and [around] 60 percent of these babies were either dying or had a disability,” says Rosemary Higgins, a program scientist at the National Institute of Child Health and Human Development. In 2005, research findings reshaped the field. Higgins and other neonatologists reported the results of a couple of large clinical trials testing the effects of so-called cooling therapy on brain damage. Hundreds of babies suffering from HIE—the effects on the brain of oxygen deprivation during delivery, due to umbilical cord problems, the placenta coming away from the uterus too soon, or other complications—had their temperatures chilled from roughly 37 °C to about 33 °C for 72 hours, then slowly rewarmed (in one study it was whole-body cooling, in the other it was just the head). Although many babies still died of the brain damage or ended up with a severe disability, more fared better in the treatment groups than in the control groups (New Engl J Med, 353:1574-84; The Lancet, 365:663-70). “Cooling was a landmark discovery for this disease,” Higgins says. Finally, doctors (and their patients) weren’t completely helpless. The intervention used in these studies reduced the number of newborns dying or enduring a severe disability to below 50 percent. © 1986-2017 The Scientist

Keyword: Sleep; Development of the Brain
Link ID: 23787 - Posted: 06.29.2017

By Diana Kwon Across the animal kingdom, nearly all creatures sleep or display sleep-like states. The roundworm, Caenorhabditis elegans, does not sleep in a typical day-night cycle like humans and many other animals. Instead, these worms catch most of their z’s while transitioning from one larval stage to another, during a period called lethargus. When these creatures fall asleep, most of their neurons become inactive spontaneously, suggesting that sleep—at least in worms—is a passive state of the brain, according to a study published today (June 22) in Science. “The condition between sleep to wakefulness is probably one of the most drastic changes that our brains undergo,” says Manuel Zimmer, a neuroscientist at the Research Institute of Molecular Pathology at the Vienna Biocenter in Austria. “How a brain can switch between such drastically different states is not really understood.” To investigate this process, Zimmer and colleagues examined the brains of C. elegans. These worms do indeed have primitive brains, yet their nervous system comprises only 302 neurons, making it much easier to tackle than, say, the human brain, with billions of neurons, or even the fly brain, which has around 100,000 nerve cells. Using transgenic worms engineered with a fluorescent indicator that becomes active in response to high calcium levels in neurons (a proxy for neural activity), the researchers imaged the C. elegans brain during the transitions between sleep and wake states by adjusting oxygen levels. Because these soil-dwelling creatures live among low levels of oxygen (10 percent), atmospheric oxygen concentrations (21 percent) induce hyperactivity and wakefulness. © 1986-2017 The Scientist

Keyword: Sleep
Link ID: 23775 - Posted: 06.26.2017