Chapter 14. Biological Rhythms, Sleep, and Dreaming
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By David Levine People with depression or other mental illnesses often report trouble sleeping, daytime drowsiness and other sleep-related issues. Now a growing body of research is showing that treating sleep problems can dramatically improve psychiatric symptoms in many patients. Much of the latest work illustrates how sleep apnea, a common chronic condition in which a person repeatedly stops breathing during sleep, may cause or aggravate psychiatric symptoms. In past years sleep apnea has been linked to depression in small studies and limited populations. Now a study by the Centers for Disease Control and Prevention strengthens that connection. The CDC analyzed the medical records of nearly 10,000 American adults with sleep apnea. Men diagnosed with this disorder had twice the risk of depression—and women five times the risk—compared with those without sleep apnea. Writing in the April issue of Sleep, lead author Anne G. Wheaton and her colleagues speculate that in addition to interrupting sleep, the oxygen deprivation induced by sleep apnea could harm cells and disrupt normal brain functioning. Treating this disorder shows promise for reducing symptoms of depression, a recent study at the Cleveland Clinic suggests. In the experiment, patients went to bed wearing a mask hooked up to a machine that increases air pressure in their throat. The increased pressure prevents the airway from collapsing, which is what causes breathing to cease in most cases of this disorder. Using this machine, psychiatrist Charles Bae and his colleagues treated 779 patients who had been diagnosed with sleep apnea. After an average of 90 days of sleeping with the machine, all the patients scored lower on a common depression survey than before the treatment—regardless of whether they had a prior diagnosis of depression or were taking an antidepressant. The data were presented in June at the SLEEP 2012 conference in Boston. © 2012 Scientific American
Keyword: Sleep; Aggression
Link ID: 17550 - Posted: 11.28.2012
The long-held view that a full moon or even a new moon triggers psychological problems has been debunked by a study from Montreal. Researchers at the University of Laval's School of Psychology evaluated patients visiting Montreal's Sacré-Coeur Hospital and Hôtel-Dieu de Lévis between March 2005 and April 2008 and found no correlation between anxiety disorders and the phases of the moon — despite, it seems, what 80 per cent of nurses and 64 per cent of doctors surveyed believe. These researchers analyzed 771 individuals who had shown up at the emergency room with chest pains for which no medical cause could be determined. Psychological evaluations indicated many were suffering anxiety, panic attacks, mood disorders or suicidal thoughts. The time of their visit was then correlated with the phase of the moon at that moment. "We observed no full-moon or new-moon effect on psychological problems," said lead researcher Genevieve Belleville whose study is published in General Hospital Psychiatry. The study went on to suggest that health professionals may think there are more mental problems during a full-moon phase due to "self-fulfilling prophecies." © CBC 2012
Keyword: Biological Rhythms; Aggression
Link ID: 17541 - Posted: 11.27.2012
By ANAHAD O'CONNOR Health officials are warning parents not to use a special device designed to help keep babies in certain positions as they sleep. The device, called a sleep positioner, has been linked to at least 13 deaths in the last 15 years, officials with two federal agencies said on Wednesday. “We urge parents and caregivers to take our warning seriously and stop using these sleep positioners,” Inez Tenenbaum, the chairman of the Consumer Product Safety Commission, said in a statement. The sleep positioner devices come primarily in two forms. One is a flat mat with soft bolsters on each side. The other, known as a wedge-style positioner, looks very similar but has an incline, keeping a child in a very slight upright position. Makers of the devices claim that by keeping infants in a specific position as they sleep, they can prevent several conditions, including acid reflux and flat head syndrome, a deformation caused by pressure on one part of the skull. Many are also marketed to parents as a way to help reduce a child’s risk of sudden infant death syndrome, or SIDS, which kills thousands of babies every year, most between the ages of 2 months and 4 months. But the devices have never been shown in studies to prevent SIDS, and they may actually raise the likelihood of sudden infant death, officials say. One of the leading risk factors for sudden infant death is placing a baby on his or her stomach at bedtime, and health officials have routinely warned parents to lay babies on their backs. They even initiated a “Back to Sleep” campaign in the 1990s, which led to a sharp reduction in sudden infant deaths. Copyright 2012 The New York Times Company
Keyword: Sleep; Aggression
Link ID: 17531 - Posted: 11.24.2012
by Greg Miller Hitting the wall in the middle of a busy work day is nothing unusual, and a caffeine jolt is all it takes to snap most of us back into action. But people with certain sleep disorders battle a powerful urge to doze throughout the day, even after sleeping 10 hours or more at night. For them, caffeine doesn't touch the problem, and more potent prescription stimulants aren't much better. Now, a study with a small group of patients suggests that their condition may have a surprising source: a naturally occurring compound that works on the brain much like the key ingredients in chill pills such as Valium and Xanax. The condition is known as primary hypersomnia, and it differs from the better known sleep disorder narcolepsy in that patients tend to have more persistent daytime sleepiness instead of sudden "sleep attacks." The unknown cause and lack of treatment for primary hypersomnia has long frustrated David Rye, a neurologist at Emory University in Atlanta. "A third of our patients are on disability," he says, "and these are 20- and 30-year-old people." Rye and colleagues began the new study with a hunch about what was going on. Several drugs used to treat insomnia promote sleep by targeting receptors for GABA, a neurotransmitter that dampens neural activity. Rye hypothesized that his hypersomnia patients might have some unknown compound in their brains that does something similar, enhancing the activity of so-called GABAA receptors. To try to find this mystery compound, he and his colleagues performed spinal taps on 32 hypersomnia patients and collected cerebrospinal fluid (CSF), the liquid that bathes and insulates the brain and spinal cord. Then they added the patients' CSF to cells genetically engineered to produce GABAA receptors, and looked for tiny electric currents that would indicate that the receptors had been activated. © 2010 American Association for the Advancement of Science
Keyword: Sleep
Link ID: 17530 - Posted: 11.24.2012
By NICHOLAS BAKALAR Everyone yawns. And we start yawning even before we are born. Now, using ultrasound video recordings, researchers have worked out a technique to distinguish prenatal yawns from the simple mouth openings that we also engage in well before birth. For the study, published on Wednesday in PLoS One, scientists scanned 15 healthy fetuses, eight girls and seven boys, at 24, 28, 32 and 36 weeks’ gestation. They distinguished yawns from jaw openings by the timing of the action and shape of the fetuses’ mouths. In all, they counted 56 yawns and 27 non-yawn mouth openings. By 36 weeks, the yawning had completely disappeared. Why fetuses yawn is unclear — for that matter, it is unclear why adults yawn. In any case, the study’s lead author, Nadja Reissland, a developmental psychologist at Durham University in England, said that yawning in a fetus is different from yawning in adults. “When you see a fetus yawning, it’s not because it’s tired,” she said. “The yawning itself might have some kind of function in healthy development. Fetuses yawn, and then as they develop they stop yawning. There’s something special in yawning.” Copyright 2012 The New York Times Company
Keyword: Development of the Brain; Aggression
Link ID: 17529 - Posted: 11.24.2012
By Simon J Makin “One hundred repetitions three nights a week for four years – sixty-two thousand four hundred repetitions make one truth.” These are the thoughts of Bernard Maxwell as he reflects on The World State’s sleep-teaching technique, hypnopaedia, in Aldous Huxley’s Brave New World, before concluding: “Idiots!” Huxley was using the idea to explore social conditioning and control in a dystopian future, rather than what we might call “useful” learning, but the promise of effortless learning while we sleep is an idea that refuses to go away, as evidenced by the continued existence of dubious sleep learning “courses”. The possibility was dismissed scientifically in the 1950s after an experiment showing that people who were played the answers to a list of questions while they slept could not recall any of them the next day, unless they had also shown electrical brain activity indicating they were waking up. But evidence is now growing that the sleeping brain can, in fact, be taught in certain, limited ways. The most striking demonstration of this comes from a recent study published in Nature Neuroscience, in which people learned to associate sounds with smells while they were asleep. Pleasant and unpleasant odours were paired with different sounds played to sleeping participants and their “sniff responses” were measured. Pleasant smells provoked stronger sniffs and when the sounds paired with these smells were later played alone they still provoked stronger sniffs than those that had been paired with unpleasant odours. This was true both while the participants were still asleep and after they awoke and, unsurprisingly, they had no awareness of having learned anything. This is a limited form of learning known as conditioning, famous since Pavlov and his dog, and it can’t be used for learning anything as complex as, say, language vocab. © 2012 Scientific American
Keyword: Sleep; Aggression
Link ID: 17522 - Posted: 11.21.2012
By Linda Carroll It took almost two years for Nicole Delien’s family to find someone who could explain the mysterious illness that was making their little girl “sleep” for as long as 64 days. During those excruciating 21 months doctors diagnosed everything from West Nile to epilepsy. Some even suggested that Nicole’s parents might be drugging her or somehow manipulating her sleep – an accusation that led to a report to Child Protective Services. Finally, when the family was at their wits end, they found Dr. Michael Rancurello at Allegheny General Hospital in Pittsburgh, who diagnosed Nicole, 17, with an exceedingly rare disorder called Kleine-Levin Syndrome. Rancurello wasn’t an expert in the syndrome, but by chance he’d already treated several patients with the disorder that periodically sends patients into a strange state in which they alternate between long stretches of actual sleep and periods of semi conscious delirium. Nicole was 6 years old when contracted a virus that seems to have sparked her condition. “In the beginning we thought she had the flu because she had flu-like symptoms and a high fever,” Vicki Delien, Nicole’s mom, told TODAY’s Savannah Guthrie. “But then she just became, as the days progressed, more confused and lethargic. We didn’t know what was going on. “ © 2012 NBCNews.com
Keyword: Sleep; Aggression
Link ID: 17521 - Posted: 11.21.2012
By Ferris Jabr After Thanksgiving dinner, many people start to feel a little drowsy. Turkey typically gets the blame. It supposedly contains high levels of tryptophan, an amino acid that is sold in a purified form to help people fall asleep. But turkey contains about the same amount of tryptophan as chicken, beef and other meats. If Thanksgiving drowsiness is not about the main course, what is responsible? It may have more to do with the side dishes. To understand, we first need to digest a little food chemistry. To start, we get tryptophan and other essential amino acids from all the protein in our diet, not just from meat. These amino acids swim through the bloodstream, nourishing our cells. Brain cells convert tryptophan into a chemical called serotonin. This neurotransmitter helps regulate sleep and appetite and high levels of serotonin are associated with calm and relaxation. But tryptophan and other amino acids can’t access brain cells on their own—instead, teams of proteins transport amino acids across the blood-brain barrier. As it turns out, Thanksgiving side dishes probably make it easier for tryptophan to get inside the brain. © 2012 Scientific American,
Keyword: Sleep
Link ID: 17520 - Posted: 11.21.2012
By Alyssa A. Botelho When Jerry Berrier dreams, he hears and touches and smells and talks, but he doesn’t see. Blind since birth, he rarely remembers his dreams, however, because his sleep has been so poor. At 15, Berrier had both of his eyes removed and lost the little light perception he had as a child. Ever since, the Everett resident, now 60, has battled a vicious sleep cycle — a few days of sleep followed by weeks of hardly any. The bouts of sleeplessness come suddenly and subside without warning. When they hit, Berrier can’t sleep more than a couple hours a night, no matter how tired he is. Though physicians haven’t given him a formal diagnosis, scientists believe he suffers from a rare condition called non-24 sleep-wake disorder, or “non-24.” The chronic condition is characterized by a body clock that is out of synch with the 24-hour cycle of the Earth day. Non-24 can affect those with normal vision, but it especially plagues the totally blind who can’t perceive light, the strongest external signal that keeps the brain’s sleep-wake cycle aligned to the pattern of night and day. Of approximately 100,000 totally blind people in the United States, anywhere from 55 percent to 70 percent of them may suffer from non-24, according to Harvard neuroscientist Steven Lockley, one of the lead researchers in an ongoing clinical trial investigating sleep disorders in the blind. With 25 sites around the country, it’s the largest study of non-24 to date. Berrier is a participant in Boston. The toll of having an internal clock in competition with the 24-hour world can be high, adding another layer of challenge to life without sight. © 2012 NY Times Co.
Keyword: Sleep; Aggression
Link ID: 17514 - Posted: 11.20.2012
By Wynne Parry and LiveScience The realm of sleep and dreams has long been associated with strangeness: omens or symbols, unconscious impulses and fears. But this sometimes disturbing world of inner turmoil, fears and desires is grounded in our day-to-day experience, sleep researchers say. "The structure and content of thinking looks very much like the structure and content of dreaming. They may be the product of the same machine," said Matthew Wilson, a neuroscientist at MIT and a panelist at the New York Academy of Sciences discussion "The Strange Science of Sleep and Dreams" on Friday (Nov. 9). His work and others' explores the crucial link between dreams and learning and memory. Dreams allow the brain to work through its conscious experiences. During them, the brain appears to apply the same neurological machinery used during the day to examine the past, the future and other aspects of a person's (or animal's) inner world at night. Memory is the manifestation of this inner world, Wilson said. "What we remember is the result of dreams rather than the other way around," he said. His work, and that of fellow panelist Erin Wamsley, a sleep scientist at Beth Israel Medical Center/Harvard Medical School, focuses on the relationship between memory and dreams in non-REM sleep. Vivid dreams often occur during REM sleep, named for the rapid eye movement associated with it, however, non-REM sleep also brings dreams but they are more fragmentary. © 2012 Scientific American
Keyword: Sleep
Link ID: 17479 - Posted: 11.13.2012
Mo Costandi General anaesthetics induce a coma-like state within seconds, allowing patients to be operated on without feeling pain or discomfort. Yet very little is known about how these drugs work. Now research published today in the Proceedings of the National Academy of Sciences1 shows that they change the activity of specific regions of the brain and make it difficult for the different parts to talk to each other. Neuroscientist Laura Lewis of the Massachusetts Institute of Technology in Cambridge and her colleagues used microelectrodes to measure the activity of single cells and networks of neurons in the brains of three people who were about to undergo neurosurgery for epilepsy. Each patient was given a single dose of the general anaesthetic propofol, and their ability to respond to auditory stimuli was used to determine when they slipped into unconsciousness. The researchers found that loss of consciousness coincided with the rapid onset of brain waves known as slow oscillations. “We were surprised to find that slow oscillations began so abruptly,” says Lewis. “Their onset was sudden, and precisely timed to when patients lost consciousness.” The oscillations started at different times in different regions of the cerebral cortex, and individual neurons became markedly less active overall, with their activity spiking at the same time as the slow oscillations in that region. © 2012 Nature Publishing Group
Keyword: Sleep
Link ID: 17460 - Posted: 11.06.2012
By OLIVER SACKS HALLUCINATIONS are very startling and frightening: you suddenly see, or hear or smell something — something that is not there. Your immediate, bewildered feeling is, what is going on? Where is this coming from? The hallucination is convincingly real, produced by the same neural pathways as actual perception, and yet no one else seems to see it. And then you are forced to the conclusion that something — something unprecedented — is happening in your own brain or mind. Are you going insane, getting dementia, having a stroke? In other cultures, hallucinations have been regarded as gifts from the gods or the Muses, but in modern times they seem to carry an ominous significance in the public (and also the medical) mind, as portents of severe mental or neurological disorders. Having hallucinations is a fearful secret for many people — millions of people — never to be mentioned, hardly to be acknowledged to oneself, and yet far from uncommon. The vast majority are benign — and, indeed, in many circumstances, perfectly normal. Most of us have experienced them from time to time, during a fever or with the sensory monotony of a desert or empty road, or sometimes, seemingly, out of the blue. Many of us, as we lie in bed with closed eyes, awaiting sleep, have so-called hypnagogic hallucinations — geometric patterns, or faces, sometimes landscapes. Such patterns or scenes may be almost too faint to notice, or they may be very elaborate, brilliantly colored and rapidly changing — people used to compare them to slide shows. At the other end of sleep are hypnopompic hallucinations, seen with open eyes, upon first waking. These may be ordinary (an intensification of color perhaps, or someone calling your name) or terrifying (especially if combined with sleep paralysis) — a vast spider, a pterodactyl above the bed, poised to strike. © 2012 The New York Times Company
Keyword: Sleep; Aggression
Link ID: 17452 - Posted: 11.05.2012
By Laura Sanders Devoid of any external time cues, monkeys can still tell time. Animals learned to move their eyeballs once every second, a completely internal timing feat made possible by the rhythmic behavior of small groups of nerve cells, researchers propose online October 30 in PLOS Biology. Time is often measured with clues from the environment, says study coauthor Geoffrey Ghose of the University of Minnesota in Minneapolis. A quick glance at a clock indicates that your meeting will start soon, and a look outside at a low sun tells you that it’s time to leave work. But some time-telling abilities rely on purely internal processes — just a feeling that minutes, hours or days have ticked by, Ghose says. Ghose and Blaine Schneider, also of the University of Minnesota, studied this internal sensation of time by creating a situation in which two monkeys had to generate their own pattern without any outside help. The animals were trained to switch their gaze rhythmically between a red dot and a blue dot on a computer screen once every second, a job that looks like “they’re watching an extremely boring tennis match,” Ghose says. After a while, the monkeys got good, on average just tens of milliseconds off their tempo. Meanwhile, the researchers used electrodes to eavesdrop on the behavior of neurons in a part of the brain called the lateral intraparietal area. Earlier monkey studies found that neurons there build up activity with time, firing messages more and more frequently as the milliseconds tick by. © Society for Science & the Public 2000 - 2012
Keyword: Biological Rhythms; Aggression
Link ID: 17442 - Posted: 11.03.2012
by Douglas Heaven Timing is everything. But exactly how the brain keeps time, which it does very well, has been something of a mystery. One widely held theory suggests that a single brain region acts as a centralised timekeeper – possibly in the basal ganglia or cerebellum. However, a study now suggests that timekeeping is decentralised, with different circuits having their own timing mechanisms for each specific activity. The finding could help explain why certain brain conditions affect our sense of timing, and even raise the possibility of artificially manipulating time perception. Geoffrey Ghose and Blaine Schneider, at the University of Minnesota in Minneapolis, investigated timing in the brain by training two rhesus macaques to perform tasks in which they moved their eyes between two dots on a screen at regular 1-second intervals. There were no external cues available to help them keep track of time. After three months, the monkeys had learned to move their eyes between the two dots with average intervals of 1.003 and 0.973 seconds, respectively. The researchers then used electrodes to record brain activity across 100 neurons in the lateral intraparietal cortex – associated with eye movement – while the monkeys performed the task. The activity of these neurons decreased during the interval between each eye movement, and the rate of decrease correlated with the monkeys' timing. Using this information, Ghose and Schneider were able to predict the interval between eye movements by measuring the preceding decay rate. © Copyright Reed Business Information Ltd.
Keyword: Biological Rhythms
Link ID: 17438 - Posted: 10.31.2012
By Laura Sanders Anesthesiologists aren’t totally lying when they say they’re going to put you to sleep. Some anesthetics directly tap into sleep-promoting neurons in the brain, a study in mice reveals. The results may help clarify how drugs that have been used around the world for decades actually put someone under. “It’s kind of shocking that after 170 years, we still don’t understand why they work,” says study coauthor Max Kelz of the University of Pennsylvania in Philadelphia. Most neurons in the brain appear to be calmed by anesthetics, says neuropharmacologist and anesthesiologist Hugh Hemmings Jr. of Weill Cornell Medical College in New York City. But the new results, published online October 25 in Current Biology, show that two common anesthetics actually stimulate sleep-inducing neurons. “It’s unusual for neurons to be excited by anesthetics,” Hemmings says. In the study, Kelz, Jason Moore, also of the University of Pennsylvania, and colleagues studied the effects of the anesthetics isoflurane and halothane. Mice given the drugs soon became sleepy, as expected. Along with this drowsiness came a jump in nerve cell activity in a part of the brain’s hypothalamus called the ventrolateral preoptic nucleus, or VLPO. Not all neurons in the VLPO are the same. Some are involved in kicking off sleep, while neighboring neurons don’t seem to play a role. The anesthetics affected only the VLPO neurons that promote sleep, Moore and his colleagues found. © Society for Science & the Public 2000 - 2012
Keyword: Sleep
Link ID: 17425 - Posted: 10.27.2012
By Daisy Yuhas We're all familiar with the feeling—waking up from a restless night only to realize that this will be a very long, sleepy day. Recent research reveals that honeybees are also sensitive to sleep deprivation, and although a cup of coffee may give you a morning buzz, the bees aren't so lucky. Neurobiologists at the Free University of Berlin have found that sleepy bees fail to remember lessons learned the day before, a finding that could help scientists discover the neural processes involved in sleep and memory formation. They present their research October 25 in the Journal of Experimental Biology. "We started with the idea that we could look for a neural substrate of learning and memory in bees, since they have a wonderful memory, can be easily trained, and we know their brain well at the neuronal level," says study co-author Randolf Menzel. After characterizing how honeybees find their way home when released in a new location, the scientists captured and then released bees in unfamiliar territory some 600 meters from their hive. In addition to tracking how long the bees needed to return home, the researchers monitored bee sleep. Bees take brief naps throughout the day in addition to longer periods of nocturnal sleep. (Snoozing bees are easy to spot because their antennae droop.) The scientists made their observations both by watching bees in person and by tracking their activity via radio-frequency devices that they glued onto some of the insects. © 2012 Scientific American
Keyword: Sleep; Aggression
Link ID: 17424 - Posted: 10.27.2012
by Sara Reardon Sleeping helps us reset our brains and calm our emotions. Perhaps it can do more, though: if sleepers are exposed to odours they associate with bad memories, it appears they can lose the fear those memories bring. Previous studies have shown that sleep helps eliminate fear in general. But whether it is possible to focus this effect through the careful use of odours has not been tested in humans. Katherina Hauner and Jay Gottfried of Northwestern University in Evanston, Illinois, exposed subjects to four pictures of faces and a series of inoffensive smells such as mint. When one of the faces appeared, the volunteers got a painful electric shock. Afterwards, the researchers measured the amount of electricity conducted by the subjects' skin – a measure that goes up when afraid, because the sweat produced is a good conductor. The researchers found that conductance spiked whenever the volunteers saw the face associated with the shock. They then let half the subjects sleep, and exposed this group to variable amounts of the odour that had been presented along with the "painful" face. The next day, these volunteers were much less afraid of the face – and those with the least fear were those that had received the highest exposure to the odour while asleep. Brain scans also showed that brain areas associated with fear and with memory were less active after this exposure. © Copyright Reed Business Information Ltd.
Keyword: Sleep; Aggression
Link ID: 17422 - Posted: 10.25.2012
By Katherine Harmon Getting seven to eight solid hours of sleep each night might seem an almost impossible luxury to many people. But not getting enough sleep is known to impair mental function and increase the risk for heart disease, among other ill effects. Accumulating evidence also suggests that even short-term, partial sleep deprivation could pave the way for weight gain and other negative metabolic consequences. More than 28 percent of adults in the U.S. report that they get less than six hours of sleep a night, with this cumulative deprivation becoming more common in the past three decades. And now that more than 35 percent of U.S. adults are currently obese, researchers have been searching for potential links between the two conditions, in hopes of reducing the increasing health and economic burden of obesity. Establishing lack of sleep as a risk factor for weight gain could have important clinical and public health effects, possibly allowing people to make simple lifestyle changes to improve their metabolic health. A new report, published online October 24 in the Journal of the Academy of Nutrition and Dietetics, reviews 18 carefully controlled laboratory studies that tested human subjects' physiological and behavioral responses to sleep deprivation as they relate to metabolic health. Reena Mehra, an associate professor of medicine who studies sleep and health at Case Western Reserve University School of Medicine and who was not involved in the new analysis, notes that the new paper is "a well done review of the experimental data." © 2012 Scientific American
Keyword: Obesity; Aggression
Link ID: 17419 - Posted: 10.25.2012
By Scicurious Picture this: the prince has won his way past the dragon, past the huge walls of briars. He paces slowly through the sleeping castle, toward the tower where the princess lies, in a deep, deep sleep. Finally he sees her, leans over her lovely form… …and gently inserts a probe into her brain, letting a yellow light activate her locus coeruleus. Within moments, the princess awakes. Now THAT’S a kiss. I’ll admit, this post isn’t about sleeping beauty. Instead, it’s about sleep-wake transitions, and how they might work. And the answer involves an up and coming molecule, hypocretin (aka orexin), and an area of the brain called the locus coeruleus (LC). And it involves mice, who are little sleeping beauties in their own way. We’ll start with hypocretin (or orexin*). Hypocretin is a small peptide released from the hypothalamus of the brain. It’s a very recently discovered molecule (published in 1998), and has been enjoying a recent explosion in popularity, due to its interesting involvement in drug addiction and feeding behavior, and its very clear role in sleep. You see, hypocretin controls sleep/wake cycles by mediating what we call “arousal” (which is not that, though it’s that, too). Neurons that produce hypocretin are silent while you are asleep, but burst of firing and the release of hypocretin from these neurons comes immediately before wakefulness. And hypocretin is such a strong mediator of sleep/wake transitions that loss of hypocretin produces some very striking narcolepsy. © 2012 Scientific American
Keyword: Sleep
Link ID: 17411 - Posted: 10.23.2012
By ERIC NAGOURNEY There are any number of reasons you might be up at 2 in the morning instead of snuggled asleep in bed. Maybe you are finishing some work — an article, say, that you owe the editor of that new Booming blog. Maybe you are one of those people who decided to have a baby at an age when parents would once have been making their last tuition payments. Or maybe the condo you bought over that all-night bowling alley was so cheap for a reason. But there could be another explanation. Maybe you are not asleep because you can’t sleep. As baby boomers age, many may find that a basic act they once took for granted (or intentionally neglected) has become a lot more complicated. They are finding it harder to get to sleep or stay asleep, and they may feel the consequences during the day. “The older we get, the more likely we are to develop sleep problems,” said Dr. William C. Kohler, a Florida sleep specialist and a past official of the American Academy of Sleep Medicine. This is not to say that trouble sleeping is inevitable. “Healthy aging is not necessarily associated with poor sleep,” said Dr. Nathaniel F. Watson, a director of the University of Washington Medicine Sleep Center. “Some people have this sense that ‘Oh, I’m just going to sleep badly when I get older, because that’s what happens to everybody.'” That said (and you knew this was coming), even in the absence of illness, as people age, the “sleep architecture,” as Dr. Watson put it, tends to change. They spend less time in deep non-REM sleep. And all the while, their old circadian rhythm is shifting ever earlier for reasons no one really understands. © 2012 The New York Times Company
Keyword: Sleep; Aggression
Link ID: 17403 - Posted: 10.22.2012




