By David Malakoff To sleep, perchance to dream--and maybe not get devoured? When it comes to how much shuteye animals get in the wild, fear and food matter most. Researchers have spent decades trying to understand the confusing array of sleep patterns found in mammals. A donkey typically snoozes for just 3 hours a day, for instance, and armadillos and bats can be dead to the world for 20 hours a day. To explain the differences, scientists have offered a slew of theories, ranging from the idea that smaller animals need more sleep to conserve energy and maintain body temperature to the need to avoid predators. It's been hard to sort out which of these ideas have legs, however. In part, that's because many sleep studies take place in artificial laboratory settings, coloring the results. And there are relatively few studies of sleep habits in the wild; wiring up sleep monitors to free-ranging animals can be difficult (ScienceNOW, 14 May). In one of the most comprehensive efforts yet to tackle the question, a team led by evolutionary biologist Isabella Capellini of Durham University in the U.K. spent 2 years combing through the scientific literature and stockpiling information on the sleep habits of more than 150 mammals. Then they used statistical tools to see what factors best explained the sleep habits of about 60 of the best studied creatures. © 2008 American Association for the Advancement of Science.

Keyword: Sleep; Evolution
Link ID: 11851 - Posted: 06.24.2010

By Lauren Cahoon "Watch out!" It's a simple phrase, but researchers have long debated whether nonhuman primates use something like it. A new study indicates that they do: Even when not threatened themselves, African blue monkeys warn neighbors of nearby predators. However, some skeptics maintain that the animals are acting out of fear, not concern for others. Blue monkeys (Cercopithecus mitis stuhlmanni) have two predator-specific calls: the "hack," a low, gagging sound that warns about eagles, and the "pyow," which sounds a bit like a laser gun and warns about more general dangers on the ground, such as leopards. When a monkey sounds a particular alarm, its neighbors know to look out for that predator. Although listeners clearly understand the warnings, many scientists think that hack and pyow reflect only a basic, emotional response--a scream of fear rather than a "Hey you, look out!" That's not what Klaus Zuberbühler noticed in a Ugandan nature reserve. The psychologist at the University of St. Andrews in Fife, U.K., and colleagues played recordings of hacks and pyows from a loudspeaker near blue monkey troops, which are usually made up of a lead male and about 10 to 40 females and young. The recorded sounds prompted the lead male to follow up with his own alarm call, and he typically repeated the cry about 23 times. However, if a female or baby was close to the loudspeaker--the "predator"--the males gave an average of 42 cries. It didn't matter how close the male was to the danger; he sounded the red-alert alarm only when the females and young appeared to be at risk. © 2008 American Association for the Advancement of Science.

Keyword: Animal Communication; Language
Link ID: 11850 - Posted: 06.24.2010

Jennifer Viegas -- Just as humans tune into individual radio stations, an unusual Chinese frog can shift its hearing from one frequency to another in order to selectively choose what it hears, according to a paper published in this week's Proceedings of the National Academy of Sciences. The frog, Odorrana tormota, is the only known animal in the world that can manipulate its hearing system to select particular frequencies. Humans appear to possess a modicum of control, but our system is slow compared to that of the frog and we cannot, with precision, tune our ears to match sounds. The rare amphibian likely evolved its hearing talent out of necessity, since its environment is so noisy. "Their calling sites are on the steep banks of a fast-flowing body of water -- the Tao Hua Creek (at Huangshan Hot Springs in central China)," co-author Albert Feng told Discovery News. Feng, a professor of molecular and integrative physiology at the University of Illinois at Urbana-Champaign, added that the site is especially noisy after spring showers. He pointed out that humans often cannot hear well over heavy rains either. © 2008 Discovery Communications, LLC.

Keyword: Hearing; Attention
Link ID: 11849 - Posted: 06.24.2010

Abbott Alison Severely depressed patients who do not respond to conventional therapy may be helped by deep brain stimulation (DBS), according to the most-extensive study to date of the experimental procedure. In a clinical trial in Toronto, Canada, 12 out of 20 patients who had stimulating electrodes placed in a brain area called the subcallosal cingulated gyrus showed significant improvement in their depression, with seven of them going into full remission. The benefits lasted at least a year, according to the results published this week in the journal Biological Psychiatry1. Patients in the study had failed to respond to cognitive therapy, antidepressant drugs and electroconvulsant therapy. The research team published results of DBS on their first six patients in 20052. Four of those patients responded well, and were still showing significant improvement after the trial finished six months later. The new research represents the largest trial on DBS for depression to follow patients for a full year. © 2008 Nature Publishing Group

Keyword: Depression
Link ID: 11848 - Posted: 06.24.2010

The one-year results from a new surgical approach that targets tough-to-treat depression show a significant benefit, according to Canadian researchers. Deep brain stimulation, in which electrical impulses are sent through electrodes that are implanted in the section of the brain called the subcallosal cingulate gyrus, was shown to offer relief from depression in 60 per cent of patients, say researchers at Toronto Western Hospital. These patients, who suffered from major depressant disorder, a severe form of depression that is unresponsive to other treatments, were able to reduce their medication as symptoms improved. "Our research confirmed that 60 per cent of patients have shown a clinically significant response to the surgery and the benefits were sustained for at least one year," said Dr. Andres Lozano, neurosurgeon at Krembil Neurosciences Centre, Toronto Western Hospital, in a release. The therapy appears to change the metabolic activity of what's known as the depression circuit. This means that, in effect, the brain is rewired, altering the cycle of depression. In the study, researchers found that one month after surgery, 35 per cent of patients responded well to the therapy, with 10 per cent of patients entering remission. Six months after surgery, 60 per cent of patients responded well to the surgery and 35 per cent were in remission. © CBC 2008

Keyword: Depression
Link ID: 11847 - Posted: 06.24.2010

By NATALIE ANGIER For the bubbleheaded young Narcissus of myth, the mirror spun a fatal fantasy, and the beautiful boy chose to die by the side of a reflecting pond rather than leave his “beloved” behind. For the aging narcissist of Shakespeare’s 62nd sonnet, the mirror delivered a much-needed whack to his vanity, the sight of a face “beated and chopp’d with tann’d antiquity” underscoring the limits of self-love. Whether made of highly polished metal or of glass with a coating of metal on the back, mirrors have fascinated people for millennia: ancient Egyptians were often depicted holding hand mirrors. With their capacity to reflect back nearly all incident light upon them and so recapitulate the scene they face, mirrors are like pieces of dreams, their images hyper-real and profoundly fake. Mirrors reveal truths you may not want to see. Give them a little smoke and a house to call their own, and mirrors will tell you nothing but lies. To scientists, the simultaneous simplicity and complexity of mirrors make them powerful tools for exploring questions about perception and cognition in humans and other neuronally gifted species, and how the brain interprets and acts upon the great tides of sensory information from the external world. They are using mirrors to study how the brain decides what is self and what is other, how it judges distances and trajectories of objects, and how it reconstructs the richly three-dimensional quality of the outside world from what is essentially a two-dimensional snapshot taken by the retina’s flat sheet of receptor cells. They are applying mirrors in medicine, to create reflected images of patients’ limbs or other body parts and thus trick the brain into healing itself. Mirror therapy has been successful in treating disorders like phantom limb syndrome, chronic pain and post-stroke paralysis. Copyright 2008 The New York Times Company

Keyword: Pain & Touch; Vision
Link ID: 11846 - Posted: 06.24.2010

By Belle Elving I can't tell right from left. It hasn't been a serious problem. Except that night on a freeway heading into San Francisco when, befuddled by an "Exit Left" sign, I hit the brakes and got totaled by a really fast sports car. Or the day I directed a footsore family of tourists 180 degrees away from the White House. Or the time I assembled an Ikea bookcase with the dowel holes for the shelves on the outside. Or the countless times I've annoyed my husband by telling him "Turn, um, left. No wait, I'm sorry . . ." It's a mild disability that has not seriously limited my options in life. Of course, a career in air traffic control would have been unwise. Synchronized swimming and ballroom dancing were not in the cards. (Playing cards is a bit of a problem, actually. I'm never sure which way to pass them.) But I'm usually fine driving alone. I know which way I want to turn; I just don't know what to call it. On the upside, it's delightful to discover others who share this condition, including, as it happens, the editor of the Health section and the editor who wrote the accompanying medical misadventure story. And we are not that small a group. John R. Clarke, a professor of surgery at Drexel University in Philadelphia, estimates that about 15 percent of the population faces some degree of left/right challenge. Eric Chudler, a neuroscientist at the University of Washington in Seattle, puts the figure a bit higher, having found that more than 26 percent of college students and 19 percent of college professors acknowledge having difficulty telling left from right -- occasionally, frequently or always. © 2008 The Washington Post Company

Keyword: Laterality
Link ID: 11845 - Posted: 06.24.2010

By Nikhil Swaminathan Researchers have discovered early blood markers in people genetically predisposed to develop Huntington's disease, a mysterious neurodegenerative disorder. These signs may provide future targets for staving off or even preventing symptoms from developing. Huntington's disease, which affects an estimated 30,000 Americans, kills neurons (nerve cells), which leads to cognitive difficulties, a loss of movement control and emotional distress. A carrier typically does not experience symptoms until he or she is in her 30s or 40s, and lives an average of 15 to 20 years once they show up. Patients ultimately die of heart failure, pneumonia or choking triggered by the disorder. Children with a parent who has the disease have a 50 percent chance of inheriting the mutated huntingtin gene that causes it. In other neurodegenerative diseases, such as Parkinson's—which primarily affects a person's motor abilities—scientists know that nerve cells begin to die long before symptoms appear. Researchers wondered if the same was true in Huntington's. Previous research indicated this was the case in mice, but this is the first study to document presymptomatic dysfunction in humans. "In gene carriers, before they show signs of the disease, the neurodegeneration process has already started," says Sarah Tabrizi, a neurologist at University College London and coauthor of the study, which appears in The Journal of Experimental Medicine. "This indicates that the process of neuronal dysfunction which goes on to neuronal degeneration is theoretically rescuable." © 1996-2008 Scientific American Inc

Keyword: Huntingtons
Link ID: 11844 - Posted: 06.24.2010

By Andrea Lu It's 4 a.m. and you're stumbling to the bathroom, regretting that bottle of water you chugged before bed. This early morning trip to the loo may seem like a simple response to a full bladder, but new research in rats suggests that your bladder may actually be influencing various brain areas, including those responsible for memory and concentration. Frequent trips to the bathroom are a regular annoyance for one of every six people in the United States. They have a condition known as overactive bladder, which sometimes results from an obstruction--an enlarged prostate, for example--that makes the bladder muscles contract involuntarily. Patients have a recurrent urge to urinate, a feeling that disrupts their sleep. Normally, when the bladder fills, it sends a signal to the Barrington's nucleus, a brain region that controls bladder contraction and urination. But the Barrington's nucleus also sends signals to the locus ceruleus, an area important in arousal and attention. Could an overactive bladder somehow be changing the way the brain works? Researchers led by neuroscientist Rita Valentino of The Children's Hospital of Philadelphia in Pennsylvania mimicked an obstructed bladder in a group of male rats by surgically narrowing the outlets from the organ. After 2 to 4 weeks, the researchers measured electrical activity in the Barrington's nucleus and the locus ceruleus. The Barrington's nucleus showed less activity in response to bladder filling in obstructed rats than in normal rats, which could explain the loss of bladder control in people with overactive bladder, the team reports online today in the Proceedings of the National Academy of Sciences. © 2008 American Association for the Advancement of Science.

Keyword: Sleep
Link ID: 11843 - Posted: 06.24.2010

Ewen Callaway Human-frog hybrids might reveal the neurological secrets of autism. By fusing cells from the preserved brains of deceased autistic patients with the eggs of a carnivorous African frog called Xenopus, scientists have started investigating the way the brain cells of people with autism behave. The frog eggs work a little like human neurons and the hybrid cells act as a surrogate of a living brain with the condition. "It's almost as if you were studying a neuron in the human brain," says Ricardo Miledi, a neurobiologist at the University of California, Irvine, who developed the approach and has previously used Xenopus eggs to study epilepsy. Miledi's earlier work has suggested that some brain cells of epilepsy patients have trouble sensing a molecule that helps damp down neuron activity. The proteins in question, called neurotransmitter receptors, sense the chemicals that neurons use to communicate, and Miledi thinks that problems with these proteins underlie epilepsy and other disorders Some researchers blame autism on a malfunction in mirror neurons, cells that play a vital role in understanding the actions of others people. To see if abnormalities in neurotransmitter signalling also underlie autism, Miledi's team collected brain samples from six deceased autistic patients, aged eight to 39. They fused brain-cell membranes, which house neurotransmitter receptors, together with Xenopus egg membranes. As a control, they did the same thing with brain cells from patients with no history of mental disorder. © Copyright Reed Business Information Ltd.

Keyword: Autism
Link ID: 11842 - Posted: 06.24.2010

John Naish When Don Curran first saw the portrait that Adam Hahn had painted of him, with part of his face a dark blur of confusion, he was delighted. Ten years ago, Curran was working as an airline executive when he was found to have the progressively blinding eye disease, age-related macular degeneration (AMD). Now, thanks to the portrait, the world can understand just how he sees. In AMD the light-sensing cells in the macula, the central area of vision, stop working and eventually die. The disease is thought to be caused by a combination of genes, environmental factors and age. It might seem an incongruous inspiration for visual art, but Hahn was inspired by his late grandmother's experience to paint a series of 17 portraits of AMD sufferers the way they would see themselves. “Grandma had macular degeneration. It was my way of trying to understand how she saw the world and how it affected her,” says Hahn, 29, who studied at Glasgow School of Art. The painting project, now on exhibition in Kent,offered a way to comprehend the mystery of her condition. “While she was alive she never talked about her sight or how it affected her,” he says. “People with macular degeneration don't tend to talk about what they see. I think it's because it's a very personal experience and they don't want other people to know because it might upset them. “The condition is very disabling at the beginning, but people do accept it and get on. With macular degeneration you will always have some degree of vision; you rely on using the peripheral vision that you have left.” Copyright 2008 Times Newspapers Ltd.

Keyword: Vision
Link ID: 11841 - Posted: 06.24.2010

By Jonathan Amos The number of animals used in UK labs for scientific experiments is now more than three million - a level not seen since 1991. Home Office figures show that in 2007, all procedures in England, Wales and Scotland used 3.1 million animals. The year-on-year increase of 6% continues the recent upward trend driven mainly by the use of rodents in genetics experiments. Mice and rats constitute more than 80% of all animals used in laboratories. The remainder involve primarily fish, birds, and reptiles/amphibians. Dogs, cats, horses and non-human primates receive special protection under the Animals (Scientific Procedures) Act 1986. These were used in less than half of 1% of the procedures. Most procedures are for research and drug development; safety testing accounts for much of the rest. The number of animals used in lab experiments peaked in the 1970s with more than five million procedures carried out annually. The statistics then fell rapidly during the 90s and 80s before picking up again at the start of the century. Just over 3.2 million scientific procedures were started in 2007, a rise of about 189,500 (6%) on 2006. The latest rise is the sixth in succession and largely reflects the increasing role of genetically modified animals in research. The use of GM animals – mainly mice - has more than quadrupled since 1995. By adding or knocking out genes in mice, scientists believe they can gain an insight into the molecular flaws in humans that lead to illness. Animal welfare groups have long argued that the numbers – although smaller than they used to be – are still too high. They say that many experiments often give misleading or wholly useless information; and that scientists ought to make better use of alternatives. (C)BBC

Keyword: Animal Rights
Link ID: 11840 - Posted: 06.24.2010

By Liz Szabo Are premature babies born to be shy? New research suggests that children born prematurely are more timid and less likely to get married and have children. Researchers say they're just starting to understand how being born prematurely affects personality. Until 20 to 30 years ago, few premature babies survived. Even today, very small or premature newborns are much more likely to have serious health problems, such as cerebral palsy. But now that doctors can save most preemies — and some of the earliest survivors are reaching adulthood — researchers are accumulating evidence that even those without medical disabilities have more problems socializing or taking risks. Among the findings: • The earlier babies are born, the less likely they are to marry, become parents or earn a high salary, suggests a study of nearly 1 million Norwegians, now ages 20 to 36, in today's New England Journal of Medicine. • In two studies of people in their early 20s in this month's Pediatrics, researchers found that former preemies were less likely to leave home, live with a romantic partner or be sexually active. They were also more inhibited and more apt to obey social conventions. • And three new studies — including the Norwegian paper — find that former preemies are more likely to have symptoms of autism, a condition that affects interpersonal skills. Copyright 2008 USA TODAY,

Keyword: Development of the Brain; Emotions
Link ID: 11839 - Posted: 06.24.2010

Fleur Britten Is your memory so perforated that you fear early-onset Alzheimer’s? Your attention so centrifugal that you’ve self-diagnosed attention deficit hyperactivity disorder (ADHD)? Perhaps you don’t have time to sleep, or maybe you would just like to function as a super-you. The sci-fi solution we have all been waiting for is already here, and it’s circulating in student unions and school. These days, the kids are all on “smart drugs”. A group of pharmaceuticals designed for sufferers of narcolepsy, Alzheimer’s and ADHD, smart drugs are increasingly being used “off label” (unsupervised, as a lifestyle choice) by healthy people, who procure them from online pharmacies, friendly physicians and illicit prescription sales. “This stuff is being passed around all the time,” says one male A-level student with something of a smart-drug habit — “this stuff” largely being Ritalin, usually prescribed for children with ADHD, and Modafinil, which is used to treat narcolepsy. Students are rejoicing and cramming for exams with smart-drug- fuelled all-nighters. One told me that he buys his from a mate who sells on his larger-than-necessary prescription; another offered to put me in touch with her “very kind doctor”. The government, meanwhile, is sweating. It recently commissioned a report on brain science that concluded more work is needed. What students and the government both know is that in Ritalin improves attention, memory and cognitive flexibility in healthy subjects; Modafinil improves attention, memory, planning and decision- making and leaves you in a state of wakefulness without the wired bit, liability of addiction or “obvious toxic effects”. So what’s not to like? Copyright 2008 Times Newspapers Ltd.

Keyword: ADHD; Learning & Memory
Link ID: 11838 - Posted: 06.24.2010

A drug once used to treat hayfever "significantly improves" symptoms in patients with mild to moderate Alzheimer's disease, research suggests. Dimebon was once licensed in Russia as an antihistamine but was taken off the market when better drugs came along. Now US researchers have found it can improve memory, behaviour and ability to conduct simple activities like eating in patients with dementia. Experts were cautiously optimistic about The Lancet study findings. In the trial of 183 people who all had untreated mild to moderate dementia, which was carried out in Russia, half were given 20 mg of dimebon 20 three times a day while the rest were given a dummy pill. After six months, all were given tests such as memorising a list of words and performing simple tasks. Those taking the drug scored four points lower on a scale designed to measure severity of Alzheimer's disease - meaning they were less badly affected. Patients taking the drug scored better than they did at the start of the study but patients taking the placebo got worse over the six-month period. In a smaller group of patients who continued with the trial for a further six months there was an even greater seven-point gap between those on dimebon and those on placebo. It is not clear exactly how the drug works but it has been shown in animals to have a protective effect on nerve cells in the brain. Study leader Dr Rachelle Doody, from Baylor College of Medicine in Houston, Texas, said the ongoing improvement seen in the study was particularly important. "At present no approved therapies for mild to moderate Alzheimer's disease have shown increasing improvement over 12 months." (C)BBC

Keyword: Alzheimers
Link ID: 11837 - Posted: 07.19.2008

The amount of sleep postmenopausal women get — either too little or too much — could affect their risk of having a stroke, suggests new research. The study, conducted by researchers at the University of North Carolina, found that sleeping longer — nine hours to be exact — increased the risk of stroke in post-menopausal women by 60 to 70 per cent over those who slept seven hours. "After accounting for all common clinical conditions predictive of stroke, we found this increase was statistically significant: sleeping nine hours or more is strongly associated with increased risk of ischemic stroke," said lead author Jiu-Chiuan Chen, assistant professor of epidemiology at the University of North Carolina's School of Public Health in Chapel Hill, in a release. Sleeping less than six hours meant the women were 14 per cent more at risk of stroke than those sleeping seven hours. The 93,676 women in the study — who were between 50 and 79 years old and enrolled at 40 U.S. clinical centres — were asked how many hours they slept at night. The researchers said because women usually get less, rather than more, sleep, the risk of stroke stemming from sleep deprivation is likely of more concern than the one caused by oversleeping. © CBC 2008

Keyword: Stroke; Sleep
Link ID: 11836 - Posted: 06.24.2010

By Steve Mitchell The repetitive behavior of obsessive-compulsive disorder (OCD), such as excessive hand-washing or turning the lights on and off multiple times before leaving a room, sounds like the product of a mind in overdrive. But it may actually be the result of an underactive brain, according to a new study. If scientists had to single out a part of the brain responsible for OCD, they'd point to the orbitofrontal cortex. The region, located behind the eyes, helps us make decisions and keeps compulsive behaviors, such as gambling and excessive drinking, in check. Some studies have found abnormalities in this region in people with OCD, but its role in the disorder is unclear. Samuel Chamberlain, a psychiatrist at the University of Cambridge in the U.K., hoped brain scans would help. He and colleagues monitored 14 OCD patients, 12 unaffected relatives, and 15 people without a family history of the disorder as they engaged in a task intended to stimulate the orbitofrontal cortex. As a functional magnetic resonance imaging machine measured blood flow to various parts of their brains, the participants viewed two superimposed images--a face over a house, for example--on a screen and had to figure out through trial and error which images were "correct" and which ones were "incorrect," as determined by the researchers. Once the subjects caught on to which image was the right choice, the researchers switched it up and made the other image the correct choice. That forced the participants to change their newly acquired habit, something previously shown to activate the orbitofrontal cortex. But although normal subjects exhibited the expected activity in this region, those with OCD and their relatives showed reduced activity, even though their performance on the task was normal, the researchers report in tomorrow's issue of Science. © 2008 American Association for the Advancement of Science.

Keyword: OCD - Obsessive Compulsive Disorder; Genes & Behavior
Link ID: 11835 - Posted: 06.24.2010

By Bruce Bower A burst of happiness may impair children’s attention to detailA new study of how mood affects thinking styles presented children with problems such as the one shown above. Participants searched for a houselike shape, left, in the larger drawing of a vehicle, right.Schnall Happy children learn especially well, unless they have to focus on details rather than the big picture. That’s the implication of a new study in which school-age youngsters induced to feel happy lagged behind their sad- or neutral-feeling peers in finding shapes embedded within larger images. This two-part investigation shows for the first time that an experimentally induced good mood undermines children’s ability to perform detail-oriented tasks, report psychologist Simone Schnall of the University of Plymouth in England and her colleagues online and in an upcoming Developmental Science. Earlier studies had indicated that a surge of happiness draws adults’ attention away from the details of a problem but increases both adults’ and children’s creativity and mental flexibility. Schnall hypothesized that positive and negative feelings evolved, in part, to trigger contrasting thinking styles. Happiness signals a sense of personal safety that encourages a relaxed, broad focus on one’s immediate situation. Sadness reflects awareness of a difficult problem or situation, prompting caution and a detailed surveillance of one’s surroundings. © Society for Science & the Public 2000 - 2008

Keyword: ADHD; Emotions
Link ID: 11834 - Posted: 06.24.2010

Ewen Callaway At the base of our brain, where the back of our neck meets our head, may lurk the voice of a 400 million-year-old fish. Chirps, croaks, growls – even the dulcet tones of the human voice – might have a common origin in an ancient brain metronome that coordinates the other-worldly grunts of several modern species of fish. Gulf toadfish and closely related midshipman fish emit low frequency groans to woo females and warn off rivals (see video, top right). Now an evolutionary kinship between these sounds and those produced by other animals has been suggested by researchers. "In these animals their entire social life revolves around making sound and hearing sound," says neurobiologist Andrew Bass, of Cornell University in Ithaca, New York. "Sound is their world." Vertebrates make sounds using precisely timed and coordinated muscle movements and scientists have studied the brain regions that control these movements in animals as diverse as songbirds, frogs, mice and monkeys. But few have examined fish calls, or the relevant brain regions of these animals, Bass says. © Copyright Reed Business Information Ltd.

Keyword: Language; Evolution
Link ID: 11833 - Posted: 06.24.2010

After a sleepless night, anyone - even a fruit fly - can feel a little groggy, and a lot of mystery surrounds what keeps us up at night. Now, thanks to a set of fruit flies that seem to get by with far less dozing than most, a team of Howard Hughes Medical Institute (HHMI) researchers has found a gene absolutely necessary for snoozing. The discovery of the slumber gene, dubbed SLEEPLESS, is reported in the July 18, 2008 issue of the journal Science. The finding, which was made by a group led by HHMI investigator Amita Sehgal and her colleagues at the University of Pennsylvania School of Medicine, could one day help scientists puzzle out some of the root causes of chronic sleep problems. “Sleep serves an essential function, although we don't know what that is,” explained Sehgal. The discovery of SLEEPLESS “allows us to start to get a handle on the mechanisms underlying sleep.” Sleep is a universal requirement, occurring in animals from flies to humans. It is controlled by the body's circadian clock — a roughly 24-hour cycle in the biochemical, physiological and behavioral processes of animals — as well as by an organism's internal equilibrium. A fruit fly can sleep up to 12 hours a day. Without sleep, animals will die. The SLEEPLESS mutants in Sehgal's study live only half as long as a typical fly. “Even the SLEEPLESS animals need sleep — that's probably why they are so short lived,” she said. © 2008 Howard Hughes Medical Institute

Keyword: Sleep; Genes & Behavior
Link ID: 11832 - Posted: 06.24.2010