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By ANAHAD O'CONNOR Chronic sleep loss has many downsides, among them weight gain, depression and irritability. But now scientists have found a new one: It also weakens your tolerance for pain. In recent studies, researchers have shown that losing sleep may disrupt the body’s pain signaling system, heightening sensitivity to painful stimuli. Though it is not clear why, one theory is that sleep loss increases inflammation throughout the body. Catching up on sleep if you are behind may reduce inflammation. Scientists believe this could have implications for people with chronic pain. It could also have an impact on the effects of painkillers, which appear to be blunted after chronic sleep loss. In one study published in the journal Sleep, scientists at the sleep disorders and research center at Henry Ford Hospital in Detroit recruited 18 healthy adults and split them into two groups. One was allowed to sleep for an average of nine hours, while the other averaged two fewer hours of sleep each night. To assess pain thresholds, the researchers measured how long the subjects were able to hold a finger to a source of radiant heat. After four nights, the group that was allowed to sleep the longest was able to withstand the painful stimuli much longer, by about 25 percent on average. Several studies in the past have had similar findings, including one in 2006 that showed that one night of cutting sleep in half could significantly reduce a person’s threshold for physical pain. Copyright 2012 The New York Times Company

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 5: The Sensorimotor System
Link ID: 17612 - Posted: 12.18.2012

One in five U.S. adults shows signs of chronic sleep deprivation, and a shortage of sleep has been linked to health problems as different as diabetes and Alzheimer’s disease. Recent studies have found some interesting connections between illness and what is happening in our brains as we snooze. One in five U.S. adults shows signs of chronic sleep deprivation © 1996-2012 The Washington Post

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 17575 - Posted: 12.04.2012

By BENEDICT CAREY Subtle breathing problems during sleep may play a larger role in causing insomnia than the usual suspects, like stress and the need for a bathroom, a small study of poor sleepers suggests. The report, published in the current issue of the journal Sleep, found that chronic insomniacs woke an average of about 30 times a night, and that a brief respiratory problem — a drop in the volume of oxygen inhaled, due to a narrowed airway, for instance — preceded about 90 percent of those interruptions. None of the people had any idea they had breathing problems during sleep. The study is hardly conclusive, experts said, because it included only 20 people and had no control group of normal sleepers for comparison. But these experts said that it was worth following up, because it challenged the predominant theory of insomnia as a problem of “hyper-arousal,” in which the body idles on high psychologically and physiologically. Earlier studies have linked measures of hyper-arousal to delays in falling asleep and problems nodding off after interruptions. But the theory does not satisfactorily explain what prompts awakenings in the first place. The new study compared chronic insomniacs’ opinions about why they awoke at night with data from a sleep test monitoring breathing and brain waves — and does provide a possible explanation. “It is a striking finding that by no means can be discounted,” said Dr. Michael J. Sateia, a professor of psychiatry and sleep medicine at Dartmouth College’s school of medicine, who was not involved in the research. Still, he added, “we know arousal can in and of itself promote instability of the upper airway,” and it is not always clear which comes first. Copyright 2012 The New York Times Company

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 17574 - Posted: 12.04.2012

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

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 17550 - Posted: 11.28.2012

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

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 13: Memory, Learning, and Development
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

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 17530 - 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

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 13: Memory, Learning, and Development
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

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
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,

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and 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.

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 7: Vision: From Eye to Brain
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

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and 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

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and 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

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 17452 - Posted: 11.05.2012

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

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and 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

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 13: Memory, Learning, and Development
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.

Related chapters from BP7e: Chapter 17: Learning and Memory; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 10: Biological Rhythms and Sleep
Link ID: 17422 - 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

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and 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

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 13: Memory, Learning, and Development
Link ID: 17403 - Posted: 10.22.2012

Results of a new study presented at Neuroscience 2012, the annual meeting of the Society of Neuroscience, has suggested the right hemisphere of the brain performs important tasks during its resting state, implying different end results for left-handed people and right-handed people, who use the right and left sides of their brains differently. Findings showed that when resting, the right hemisphere of the brain communicates more with itself and the left side of the brain, than when the left hemisphere talks to itself and communicates to the right side of the brain, regardless of participants' dominant hand. Neuroscientists did note that right-handed people used their left hemisphere at a higher rate, and vice versa. The authors of this study say that during rest, the right hemisphere is "doing important things, we don't yet understand." The activities that are being processed by the right hemisphere could be storing and processing acquired information, daydreaming, or similar creative tasks. Andrei Medvedev, Ph.D., an assistant professor in the Center for Functional and Molecular Imaging at Georgetown explains: The researchers had 15 participants connect to near-infrared spectroscopy (NIRS) equipment. This inexpensive and moveable technology uses light to calculate changes in oxygenated hemoglobin inside the body. Participants wore a hat that contained optical fibers delivering infrared light to the outermost layers of the brain and then assessed the light that bounced back. Through this method, the device could see which parts of the brain are active and communicate at the highest rate, based on heightened use of oxygen in the blood and elevated simultaneous occurrence of their activities.

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 19: Language and Hemispheric Asymmetry
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 15: Language and Our Divided Brain
Link ID: 17397 - Posted: 10.20.2012

Mo Costandi Scientists have learned how to discover what you are dreaming about while you sleep. A team of researchers led by Yukiyasu Kamitani of the ATR Computational Neuroscience Laboratories in Kyoto, Japan, used functional neuroimaging to scan the brains of three people as they slept, simultaneously recording their brain waves using electroencephalography (EEG). The researchers woke the participants whenever they detected the pattern of brain waves associated with sleep onset, asked them what they had just dreamed about, and then asked them to go back to sleep. This was done in three-hour blocks, and repeated between seven and ten times, on different days, for each participant. During each block, participants were woken up ten times per hour. Each volunteer reported having visual dreams six or seven times every hour, giving the researchers a total of around 200 dream reports. Most of the dreams reflected everyday experiences, but some contained unusual content, such as talking to a famous actor. The researchers extracted key words from the participants’ verbal reports, and picked 20 categories — such as 'car', 'male', 'female', and 'computer' — that appeared most frequently in their dream reports. Kamitani and his colleagues then selected photos representing each category, scanned the participants’ brains again while they viewed the images, and compared brain activity patterns with those recorded just before the participants were woken up. © 2012 Nature Publishing Group

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 17396 - Posted: 10.20.2012