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 BP6e: 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 BP6e: 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 BP6e: 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 BP6e: 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

There was nothing sweet about Kaitlyn Terrana's 16th birthday. And she has virtually no recollection of her last birthday, her 17th, either. She slept through both of them. At a time when the teenager should be living each day to the fullest, she is trapped in a roughly six-week cycle in which she has no choice but to take to her bed, slumbering for about 10 days at a time. Kaitlyn has developed an extremely rare condition called Kleine-Levin syndrome, or KLS, and it is stealing her life away. "Kind of like the day before, I start feeling really tired and it's really hard for me to focus in class," she says from her home in Winona, Ont., near Hamilton. "And then after that, I'm just gone for 10 days. I have to sleep, I can't stay awake." Her mom, Kathy Terrana, has to closely monitor Kaitlyn when she experiences one of these sleeping periods, saying her daughter can't be left alone. "In the beginning of her episodes, she starts off being very, very tired," she says. "By late evening I can usually tell that, yes, she is starting an episode, because she doesn't talk, she doesn't converse with anybody. "It's not very nice to say, but it's almost like she's a walking zombie, because when they're in their episodes they can be walking around but they don't know what's going on around them. So there's no empathy, there's no feeling whatsoever. She's in a complete fog." © CBC 2012

Related chapters from BP6e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 17348 - Posted: 10.09.2012

By James Gallagher Health and science reporter, BBC News Too many people may be damaging their health by self-medicating with sleeping pills, according to the Royal Pharmaceutical Society. It said half of people with insomnia diagnosed themselves and took medication without seeking medical advice. However, the society said insomnia was often part of other physical or mental health problems which needed treating. The warning was based on the findings of a survey of 2,077 people. Insomnia is difficulty in getting to sleep, staying asleep or getting enough good quality sleep night after night. One in three people in the UK are thought to have bouts of insomnia. It can be caused by psychiatric problems such as depression, anxiety disorders and schizophrenia. Other illnesses including heart disease, Alzheimer's disease and hormonal problems can also disturb the normal pattern of sleep. In the survey, 30% of people said they had taken sleeping pills for more than a month without getting advice while 14% had gone six months. One pharmacist, Paul Johnson, said: "It's worrying that so many people are overusing sleeping remedies. "They can be effective for short-term treatment of mild insomnia but should not be taken for long periods without advice because they can hide a serious health problem which could get worse if it remains untreated. BBC © 2012

Related chapters from BP6e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 17309 - Posted: 09.27.2012

By DAVID K. RANDALL SOMETIME in the dark stretch of the night it happens. Perhaps it’s the chime of an incoming text message. Or your iPhone screen lights up to alert you to a new e-mail. Or you find yourself staring at the ceiling, replaying the day in your head. Next thing you know, you’re out of bed and engaged with the world, once again ignoring the often quoted fact that eight straight hours of sleep is essential. Sound familiar? You’re not alone. Thanks in part to technology and its constant pinging and chiming, roughly 41 million people in the United States — nearly a third of all working adults — get six hours or fewer of sleep a night, according to a recent report from the Centers for Disease Control and Prevention. And sleep deprivation is an affliction that crosses economic lines. About 42 percent of workers in the mining industry are sleep-deprived, while about 27 percent of financial or insurance industry workers share the same complaint. Typically, mention of our ever increasing sleeplessness is followed by calls for earlier bedtimes and a longer night’s sleep. But this directive may be part of the problem. Rather than helping us to get more rest, the tyranny of the eight-hour block reinforces a narrow conception of sleep and how we should approach it. Some of the time we spend tossing and turning may even result from misconceptions about sleep and our bodily needs: in fact neither our bodies nor our brains are built for the roughly one-third of our lives that we spend in bed. © 2012 The New York Times Company

Related chapters from BP6e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 17292 - Posted: 09.25.2012

Drivers who take certain antidepressants, anti-anxiety or sleeping pills could be at higher risk for motor vehicle collisions. Psychotropic drugs can impair a driver's ability to control a vehicle, but there's been less research on newer drugs used to treat insomnia. To learn more, researchers in Taiwan compared drug use among 5,183 people involved in motor vehicle accidents with a second group of 31,093 people of the same age and gender who went for outpatient care between 2000 and 2009. In Thursday's issue of the British Journal of Clinical Pharmacology, they concluded that those taking two types of antidepressants, sleep aids known as Z-drugs, and benzodiazepines used to treat anxiety and insomnia, face increased risk of motor vehicle accidents compared with people not taking those types of drugs. The antidepressants studied included selective serotonin re-uptake inhibitors or SSRIs like paroxitine or Paxil and fluoxetine or Prozac and tricyclic or TCA antidepressants such as amiptriptyline. "The findings underscore that subjects taking these psychotropic medications should pay increased attention to their driving performance in order to prevent …motor vehicle accidents," lead researcher Hui-Ju Tsai, of the National Health Research Institutes in Zhunan, Taiwan, and co-authors concluded. © CBC 2012

Related chapters from BP6e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 14: Attention and Consciousness
Link ID: 17256 - Posted: 09.13.2012

The U.S. national campaign to reduce the risk of sudden infant death syndrome has entered a new phase and will now encompass all sleep-related, sudden unexpected infant deaths, officials of the National Institutes of Health announced today. The campaign, which has been known as the Back to Sleep Campaign, has been renamed the Safe to Sleep Campaign. The NIH-led Back to Sleep Campaign began in 1994, to educate parents, caregivers, and health care providers about ways to reduce the risk of sudden infant death syndrome (SIDS). The campaign name was derived from the recommendation to place healthy infants on their backs to sleep, a practice proven to reduce SIDS risk. SIDS is the sudden death of an infant under 1 year of age that cannot be explained, even after a complete death scene investigation, autopsy, and review of the infant's health history. Sudden unexpected infant death (SUID) includes all unexpected infant deaths: those due to SIDS, and as well as those from other causes. Many SUID cases are due to such causes as accidental suffocation and entrapment, such as when an infant gets trapped between a mattress and a wall, or when bedding material presses on or wraps around an infant’s neck. In addition to stressing the placement of infants on their backs for all sleep times, the Safe to Sleep Campaign emphasizes other ways to provide a safe sleep environment for infants. This includes placing infants to sleep in their own safe sleep environment and not on an adult bed, without any soft bedding such as blankets or quilts. Safe to Sleep also emphasizes breast feeding infants when possible, which has been associated with reduced SIDS risk, and eliminating such risks to infant health as overheating, exposure to tobacco smoke, and a mother’s use of alcohol and illicit drugs.

Related chapters from BP6e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 17254 - Posted: 09.13.2012

By Elizabeth Quill Half a dozen times each night, your slumbering body performs a remarkable feat of coordination. During the deepest throes of sleep, the body’s support systems run on their own timetables. Nerve cells hum along in your brain, their chitchat generating slow waves that signal sleep’s nether stages. Yet, like buses and trains with overlapping routes but unsynchronized schedules, this neural conversation has little to say to your heart, which pumps blood to its own rhythm through the body’s arteries and veins. Air likewise skips into the nostrils and down the windpipe in seemingly random spits and spats. And muscle fluctuations that make the legs twitch come and go as if in a vacuum. Networks of muscles, of brain cells, of airways and lungs, of heart and vessels operate largely independently. Every couple of hours, though, in as little as 30 seconds, the barriers break down. Suddenly, there’s synchrony. All the disjointed activity of deep sleep starts to connect with its surroundings. Each network — run via the group effort of its own muscular, cellular and molecular players — joins the larger team. This change, marking the transition from deep to light sleep, has only recently been understood in detail — thanks to a new look at when and how the body’s myriad networks link up to form an übernetwork. © Society for Science & the Public 2000 - 2012

Related chapters from BP6e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 17235 - Posted: 09.10.2012

Mo Costandi It sounds like every student's dream: research published today in Nature Neuroscience shows that we can learn entirely new information while we snooze1. Anat Arzi of the Weizmann Institute of Science in Rehovot, Israel, and her colleagues used a simple form of learning called classical conditioning to teach 55 healthy participants to associate odours with sounds as they slept. They repeatedly exposed the sleeping participants to pleasant odours, such as deodorant and shampoo, and unpleasant odours such as rotting fish and meat, and played a specific sound to accompany each scent. It is well known that sleep has an important role in strengthening existing memories, and this conditioning was already known to alter sniffing behaviour in people who are awake. The subjects sniff strongly when they hear a tone associated with a pleasant smell, but only weakly in response to a tone associated with an unpleasant one. But the latest research shows that the sleep conditioning persists even after they wake up, causing them to sniff strongly or weakly on hearing the relevant tone — even if there was no odour. The participants were completely unaware that they had learned the relationship between smells and sounds. The effect was seen regardless of when the conditioning was done during the sleep cycle. However, the sniffing responses were slightly more pronounced in those participants who learned the association during the rapid eye movement (REM) stage, which typically occurs during the second half of a night's sleep. © 2012 Nature Publishing Group

Related chapters from BP6e: 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: 17208 - Posted: 08.27.2012

By Christine Gorman More than 25 years later details of the attack are still shocking: Sometime after 2 A.M. one Sunday morning in May 1987, Kenneth James Parks, then 23, left his house in a Toronto suburb and drove 23 kilometers to the apartment of his wife's parents. He got out of the car, pulled a tire iron out of the trunk and let himself into the older couple's home with a key they had given him. Once inside, he struggled with and choked his father-in-law, Dennis Woods, until the older man fell unconscious and then struggled with and beat his mother-in-law, Barbara Ann Woods, stabbing her to death with a knife from her kitchen. Parks then got back into his car, drove to a nearby police station and announced to the startled officers on duty, "I think I have killed some people." For several hours before the Toronto man left his home, however, and throughout the course of the attack, Parks was asleep and therefore not criminally responsible for his actions, according to five doctors and the defense lawyer at his 1988trial for the murder of Barbara Ann and the attempted murder of Dennis. After deliberating for nine hours, the jury agreed and Parks was set free. Although prosecutors at the time considered the defense "ludicrous" and appealed the judge's decision to allow the jury to consider a sleepwalking defense, the Canadian Supreme court upheld the original ruling in 1992. Even the sleep specialist who was first brought in as a consultant on the case was initially skeptical that a sleepwalker could have undertaken such a series of complex behaviors—including safely driving through three traffic lights and portions of an express highway—before attacking anyone. After all, most people who strike out in their sleep usually injure themselves or the person sleeping next to them—not someone 23 kilometers away. But further examination showed that the tragedy was not, as it had first seemed, a clear-cut case of murder. © 2012 Scientific American,

Related chapters from BP6e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 11: Emotions, Aggression, and Stress
Link ID: 17194 - Posted: 08.22.2012

By DOUGLAS QUENQUA Moleendo Stewart can’t say for sure what’s caused his lifelong sleeping problems. But he has his suspicions. There’s the childhood spent in loud, restless neighborhoods in Miami. “You hear people shooting guns all night, dealing drugs,” said Mr. Stewart, 41, who lives in the East Flatbush section of Brooklyn. He also cites his weight, 260 pounds, down from a peak of 310. Sleep experts would point to another factor working against Mr. Stewart: He is a black man. The idea that race or ethnicity might help determine how well people sleep is relatively new among sleep researchers. But in the few short years that epidemiologists, demographers and psychologists have been studying the link, they have repeatedly come to the same conclusion: In the United States, at least, sleep is not colorblind. Non-Hispanic whites get more and better-quality sleep than people of other races, studies repeatedly show. Blacks are the most likely to get shorter, more restless sleep. What researchers don’t yet know is why. “We’re not at a point where we can say for certain is it nature versus nurture, is it race or is it socioeconomics,” said Dr. Michael A. Grandner, a research associate with the Center for Sleep and Neurobiology at the University of Pennsylvania. But when it comes to sleep, “there is a unique factor of race we’re still trying to understand.” © 2012 The New York Times Company

Related chapters from BP6e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 11: Emotions, Aggression, and Stress
Link ID: 17193 - Posted: 08.22.2012

Sleep apnea, a disorder characterized by snoring and daytime sleepiness that has been linked to cardiovascular disease, has primarily been viewed as a male problem, but a new Swedish study suggests the sleep disorder is also a common problem among women. Dr. Karl A Franklin of Umea University Hospital in Sweden and colleagues noted in the study released Wednesday that there have been only a few epidemiological studies conducted in women, and the frequency of the disorder in women "is still uncertain." Obstructive sleep apnea, in which a person has short pauses in breathing during sleep, may be caused by a temporary collapse of the airway. The gaps in breathing can last 10 to 30 seconds, and may occur dozens or hundreds of times each night. For their study, Franklin and the other Swedish researchers investigated 400 women from a population-based random sample of 10,000 women aged 20 to 70. The women answered a questionnaire and were monitored overnight. Obstructive sleep apnea was found in 50 per cent of the women subjects, with 14 per cent of them having a severe form of the disorder. Treatment for obstructive sleep apnea: For mild to moderate apnea, the best treatment is continuous positive airway pressure (CPAP). © CBC 2012

Related chapters from BP6e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 8: Hormones and Sex
Link ID: 17170 - Posted: 08.16.2012

by Michael Marshall You may think you can cope without sleep, but you have nothing on male pectoral sandpipers. Some of these birds can go more than a fortnight with hardly any sleep – the most extreme case of uninduced sleep deprivation known in any animal. What's more, the males that sleep the least father the most offspring, suggesting they benefit from their lack of slumber. Pectoral sandpipers (Calidris melanotos) breed on the Arctic tundra of Asia and North America. Males don't help with childcare – instead they try to mate with as many females as possible. Bart Kempenaers of the Max Planck Institute for Ornithology in Seewiesen, Germany and colleagues fitted radio tags to 149 birds – accounting for most of a population living near Barrow in Alaska. This showed that males were highly active during periods when females were fertile. One male was active 95 per cent of the time for 19 days. The team then fitted 29 of the males with devices that recorded their brain activity, something never done before with a wild bird. This allowed them to look at the active males' sleep patterns. They found that the males that slept the least slept more deeply, but calculations show that this wouldn't make up for the sleep they missed, says team member Niels Rattenborg. © Copyright Reed Business Information Ltd

Related chapters from BP6e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 8: Hormones and Sex
Link ID: 17146 - Posted: 08.11.2012

By ANAHAD O'CONNOR For Lisa Hanson, a stay-at-home mother in San Francisco, the alarm that used to rouse her out of sleep most mornings was the sound of her toddler. “He wakes up at 5:30 screaming sometimes,” she said. “It would jolt me awake, and then I’d be miserable and groggy all morning because I’d be woken up when I’m in my deepest sleep.” But last month, Ms. Hanson started using a new program, the Renew SleepClock, an iPhone app that keeps track of her sleep. Its makers, GEAR4, say that the app uses radio sensors to detect breathing patterns and movements at night, then uses that information to wake a person at the lightest point of sleep, the optimal time to wake up. The theory is that awaking from light sleep, as opposed to the deep stages of sleep, helps reduce so-called sleep inertia, the cloud of grogginess and impaired alertness that makes people desperately want to crawl back into bed. The app also acts as a sort of sleep adviser, giving Ms. Hanson guidance about the amount of shut-eye to shoot for and ways to get there. “Since I’ve been using it, I do feel better,” Ms. Hanson said. “It’s waking me up in a more ideal stage of sleep and helping me have that much better of a day.” The Renew SleepClock, which costs $199, is the latest addition to a new generation of smartphone apps designed to analyze and improve sleep patterns. While experts have warned for years that gadgets like smartphones are increasingly disrupting sleep by keeping us connected 24/7, these programs claim to do the opposite. Two other products that have gained followings are the WakeMate ($59.99), a wristband worn at night that wirelessly transmits data to the user’s smartphone, and the Zeo Sleep Manager-Mobile ($99), which uses a sensor-equipped headband to collect data about the user’s sleep habits. Copyright 2012 The New York Times Company

Related chapters from BP6e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 17022 - Posted: 07.11.2012

By Morgen E. Peck Anyone who has pulled an all-nighter knows it is possible to be tired without being sleepy. The body slows and concentration slips, even as thoughts spin toward a manic blur. It feels as though the sleep-deprived brain is actually becoming more active. And indeed it is, according to a recent study in the journal Cerebral Cortex. Marcello Massimini, a neurophysiologist at the University of Milan in Italy, found that the brain becomes more sensitive as the day wears on. The experiment, he explains, is like poking a friend in the ribs to see how high he jumps. Massimini prodded brain cells in the frontal cortex with a jolt of electricity, delivered via noninvasive transcranial magnetic stimulation. Then he observed how the rest of the brain responded, comparing results from subjects who had been awake for two, eight, 12 or 32 hours. “I'm sure if you bump your friend when he's sleep-deprived, he's going to jump higher,” he says. The sleep-deprived brain, it turns out, also gets jumpy, responding to the electrical jolt with stronger, more immediate spikes of activity. The results jibe with a widely held theory that while we are awake, our neurons are constantly forming new synapses, or connections to other neurons, which ramps up the activity in our brain. Many of these connections are irrelevant, but the only way to prune them is by shutting down for a while. The theory explains why it is difficult to cram new information into a sleepy brain. But it also helps to explain some unusual medical observations: epileptics are more likely to have seizures the longer they stay awake, and severely depressed patients with abnormally low brain activity sometimes improve after skipping sleep. “You keep them awake for one night, and, incredibly, they get better,” Massimini says. © 2012 Scientific American,

Related chapters from BP6e: 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: 16991 - Posted: 07.02.2012

By Susan Carnell One of the strangest findings to emerge from the world of obesity science lately is that people who sleep less tend to weigh more. But until recently, we have been stifling our yawns and scratching our heads about why: Does lack of sleep alter our biology? Or does it affect our eating behavior? Now two brain-imaging reports suggest the answer is both. The first study, published in March in the Journal of Clinical Endocrinology & Metabolism, looked at the effects of one night of no sleep. The second, published in April in the American Journal of Clinical Nutrition, tested the impact of nearly a week of more commonly experienced levels of sleep deprivation (four hours of sleep for six nights). Both studies used functional MRI to measure brain activation as their subjects viewed food pictures—analogous to being bombarded with a stream of McMuffin ads after a long night of working (or partying). Each study discovered that sleep loss caused areas within a key motivation network, including the striatum and anterior cingulate cortex, to go into overdrive at the mere sight of food. The same circuit perks up when addicts view images of their substance of choice. “Calories are energy, and your brain subconsciously knows they will wake you up,” says Marie-Pierre St-Onge of Columbia University, lead investigator of the April study. She likens the superresponsive sleep-poor brain to that of someone who has lost weight on a drastic diet—devouring the first snack you can get your hands on is a “no-brainer.” © 2012 Scientific American

Related chapters from BP6e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 13: Homeostasis: Active Regulation of Internal States
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 16960 - Posted: 06.25.2012

By Ferris Jabr In the 18th century Carl Linnaeus named them lemurs, after the Latin lemures—spirits of the dead, wandering ghosts. He knew the primates roamed Madagascar’s forests at night, their large eyes brimming with moonlight, their shrill cries crashing through the treetops. One of the smallest lemurs on the island, the fat-tailed dwarf lemur, resembled a phantom in another way: it completely vanished for seven months each year. For a long time, no one understood where the fat-tailed dwarf lemur went—a remote part of the island? the spirit world?—or what it was doing all that time, but scientists had a hunch. Perhaps the lemur was hibernating. If so, it would be the only primate in the world—and one of the only tropical mammals—to do so. Given Madagascar’s climate, however, it made sense that a lemur might hibernate to survive annual periods of drought. In general, Madagascar has two seasons: the hot, wet season from November to April, and the cooler, dry season from April through October. The deciduous forests on the west coast, where many fat-tailed dwarf lemurs live, offer no open sources of water during the dry season and only fibrous fruits bereft of sugar. Perhaps, scientists reasoned, the fat-tailed dwarf lemur hunkered down and waited for the rains to return, slowing its metabolism and dropping its body temperature. It could survive off of nutrients stored in its tail, which always grew plumper as the dry season drew closer. © 2012 Scientific American

Related chapters from BP6e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 16939 - Posted: 06.20.2012

By Charles Q. Choi Sleep should be the great equalizer. Whatever differences might divide us during the day, the nonconsciousness that comes with nighttime should be one thing we all have in common. It ain't necessarily so. Scientists have now found significant differences exist in how people sleep in the U.S. depending on race, ethnicity and country of origin, suggesting genetic or cultural differences in shut-eye patterns. This line of research could help identify how these disparities might affect health and find better ways to improve sleep. One study looked at sleep data gathered from more than 430,000 people in the U.S. between 2004 and 2010 as part of the National Health Interview Surveys, which the U.S. Centers for Disease Control and Prevention conducts annually to monitor the country's well-being. They found that foreign-born respondents were generally more likely to sleep the recommended healthy six to eight hours each night as compared with native-born Americans. "This study is particularly interesting, because it goes to show that the unhealthy American lifestyle includes more than a poor diet and lack of exercise—it also means unhealthy sleep patterns, and this can lead to important health consequences," says sleep researcher Michael Grandner at the University of Pennsylvania, who did not take part in this research. "It seems like foreign-born Americans may be protected by not adopting this unhealthy lifestyle." © 2012 Scientific American

Related chapters from BP6e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 16935 - Posted: 06.20.2012