By CARL ZIMMER Last month, a bird known as a bar-tailed godwit took flight from Alaska and headed south. A day later, it was still flapping its way over the Pacific. An airplane pilot would have a hard time staying awake after 24 hours of flight (the Federal Aviation Administration allows pilots to fly just eight hours in a row). But the godwit kept flying for an additional week. After eight days and 7,200 miles, it landed in New Zealand, setting a record for nonstop flight. “If they spend so many hours flying,” said Ruth M. Benca of the University of Wisconsin, “where do they find the time to sleep?” Bird sleep is so mysterious that scientists are considering several answers, all intriguing. The godwit may have managed to stay awake for the entire journey. Or it may have been able to sleep while flying. Or, as Dr. Benca and other scientists suspect, its brain may have been in a bizarre state of semilimbo that they do not understand. Bird brains produce patterns of electrical activity that look strikingly like human brains during sleep, a remarkable similarity considering that birds and their brains have been on a separate evolutionary course from mammals for 300 million years. But similarities reach just so far. The amount of sleep birds need can change drastically through the year. Birds may be able to put parts of their brains to sleep while keeping others awake. They may be able to adjust sleep in the course of minutes, even seconds. By figuring out the mysteries of bird sleep, scientists hope to understand some universal rules of sleep. Copyright 2007 The New York Times Company

Keyword: Sleep; Evolution
Link ID: 10875 - Posted: 06.24.2010

By STEPHANIE SAUL Your dreams miss you. Or so says a television commercial for Rozerem, the sleeping pill. In the commercial, the dreams involve Abraham Lincoln, a beaver and a deep-sea diver. Not the stuff most dreams are made of. But if the unusual pitch makes you want to try Rozerem, consider that it costs about $3.50 a pill; gets you to sleep 7 to 16 minutes faster than a placebo, or fake pill; and increases total sleep time 11 to 19 minutes, according to an analysis last year. If those numbers send you out to buy another brand, consider this, as well: Sleeping pills in general do not greatly improve sleep for the average person. American consumers spend $4.5 billion a year for sleep medications. Their popularity may lie in a mystery that confounds researchers. Many people who take them think they work far better than laboratory measurements show they do. An analysis of sleeping pill studies found that when people were monitored in the lab, newer drugs like Ambien, Lunesta and Sonata worked better than fake pills. But the results were not overwhelming, said the analysis, which was published this year and financed by the National Institutes of Health. Copyright 2007 The New York Times Company

Keyword: Sleep
Link ID: 10874 - Posted: 10.23.2007

By BENEDICT CAREY The task looks as simple as a “Sesame Street” exercise. Study pairs of Easter eggs on a computer screen and memorize how the computer has arranged them: the aqua egg over the rainbow one, the paisley over the coral one — and there are just six eggs in all. Most people can study these pairs for about 20 minutes and ace a test on them, even a day later. But they’re much less accurate in choosing between two eggs that have not been directly compared: Aqua trumped rainbow but does that mean it trumps paisley? It’s hazy. It’s hazy, that is, until you sleep on it. In a study published in May, researchers at Harvard and McGill Universities reported that participants who slept after playing this game scored significantly higher on a retest than those who did not sleep. While asleep they apparently figured out what they didn’t while awake: the structure of the simple hierarchy that linked the pairs, paisley over aqua over rainbow, and so on. “We think what’s happening during sleep is that you open the aperture of memory and are able to see this bigger picture,” said the study’s senior author, Matthew Walker, a neuroscientist who is now at the University of California, Berkeley. He added that many such insights occurred “only when you enter this wonder-world of sleep.” Copyright 2007 The New York Times Company

Keyword: Sleep; Learning & Memory
Link ID: 10873 - Posted: 06.24.2010

By GINA KOLATA As every sleep researcher knows, the surest way to hear complaints about sleep is to ask the elderly. “Older people complain more about their sleep; they just do,” said Dr. Michael Vitiello, a sleep researcher who is a professor of psychiatry and behavioral sciences at the University of Washington. And for years, sleep scientists thought they knew what was going on: sleep starts to deteriorate in late middle age and steadily erodes from then on. It seemed so obvious that few thought to question the prevailing wisdom. Now, though, new research is leading many to change their minds. To researchers’ great surprise, it turns out that sleep does not change much from age 60 on. And poor sleep, it turns out, is not because of aging itself, but mostly because of illnesses or the medications used to treat them. “The more disorders older adults have, the worse they sleep,” said Sonia Ancoli-Israel, a professor of psychiatry and a sleep researcher at the University of California, San Diego. “If you look at older adults who are very healthy, they rarely have sleep problems.” Copyright 2007 The New York Times Company

Keyword: Sleep
Link ID: 10872 - Posted: 06.24.2010

By Scott McCredie The photograph, even today, arrests the eye and titillates the mind. It's from the early 20th century, and the young man it shows -- tipping back on the rear legs of his chair -- is using his own legs, splayed in front of him, as a counterbalance. The feat itself isn't that impressive. It's his location, perched high over a cityscape of tall buildings. A wobble would be fatal. What strikes me most about the photo is what it suggests about the extraordinary adaptability of our sense of balance. Here's what I mean: Suppose the photographer grabbed a guy off the street and forced him to change places with the unnamed acrobat in the chair. The results would be predictable: Without a safety net, the new guy would almost certainly fall to his death. That's because his balance system wouldn't have had time to adjust to the specific demands of balancing on two legs of a chair while perched on the edge of a tall building. But if that guy off the street had gone through the same training as the acrobat, chances are he might well eventually become adroit enough to perform the trick. © 2007 The Washington Post Company

Keyword: Miscellaneous
Link ID: 10871 - Posted: 06.24.2010

By Sharon Jayson, You might have guessed it, but now researchers have real proof: Sleep deprivation causes our emotions to go haywire. That's according to the first neurological probe into the emotional brain without sleep. It was carried out by researchers at the University of California-Berkeley and Harvard Medical School. "Most people think that when you're sleep-deprived, what happens to the brain is that it becomes sleepy and less active," says Matthew Walker, assistant professor of psychology at Berkeley and a former Harvard sleep researcher. But Walker says the imaging study published in today's issue of Current Biology found that the brain's emotional centers become "60% more reactive." The study also suggests that lack of sleep elevates activity in the emotional centers of the brain most closely associated with psychiatric disorders such as depression. Walker's team studied 26 people ages 18 to 30 who were divided into two groups. The sleep-deprived group was awake 35 hours; the other group slept normally. Using the brain scans, the researchers showed participants a series of images, from neutral to increasingly negative and disturbing. The responses of both groups showed up as hot spots, but the sleep-deprived evoked stronger responses because the prefrontal area of the brain that normally sends out inhibiting signals wasn't able to keep emotions in check. Copyright 2007 USA TODAY

Keyword: Sleep; Emotions
Link ID: 10870 - Posted: 10.23.2007

The young mice in Clinton Rubin's lab don't look like they're exercising; they're just nosing around a plastic tub looking either for something to eat or a way out. But, these mice will grow up leaner than a similar group of mice elsewhere in the lab. The difference is that these mice are spending 15 minutes a day for 15 weeks being vibrated ever so slightly in a tub that rests on a platform that looks like a giant pizza box attached to electronics. The vibrations are very slight, so slight many people can't feel the vibration, only hear the hum. In tests at his lab at Stony Brook University lab, Rubin and his team showed that after the vibration regimen, the mice had 28 percent less fat in their torsos than another group of the same kind of mice who ate the same amount of food, and had the same amount of exercise. Writing in the Proceedings of the National Academy of Sciences, Rubin explained that the vibrations, "also reduced key risk factors in the onset of type II diabetes." Rubin explains that his interest is in how physical signals – outside influences of mechanical, electrical and thermal signals – can influence the body. While his research has centered on bones, that work has taken a temporary detour into fat because both bone cells and fat cells, along with muscle, come from the same stem cells. Stem cells are special cells the body generates that can then turn into other cells as the body needs them. © ScienCentral, 2000-2007.

Keyword: Obesity
Link ID: 10869 - Posted: 06.24.2010

Results of a new study may one day help scientists learn how to enhance a naturally occurring mechanism in the brain that promotes resilience to psychological stress. Researchers funded by the National Institutes of Health's National Institute of Mental Health (NIMH) found that, in a mouse model, the ability to adapt to stress is driven by a distinctly different molecular mechanism than is the tendency to be overwhelmed by stress. The researchers mapped out the mechanisms — components of which also are present in the human brain — that govern both kinds of responses. In humans, stress can play a major role in the development of several mental illnesses, including post-traumatic stress disorder and depression. A key question in mental health research is: Why are some people resilient to stress, while others are not? This research indicates that resistance is not simply a passive absence of vulnerability mechanisms, as was previously thought; it is a biologically active process that results in specific adaptations in the brain's response to stress. Vulnerability was measured through behaviors such as social withdrawal after stress was induced in mice by putting them in cages with bigger, more aggressive mice. Even a month after the encounter, some mice were still avoiding social interactions with other mice — an indication that stress had overwhelmed them — but most adapted and continued to interact, giving researchers the opportunity to examine the biological underpinnings of the protective adaptations.

Keyword: Stress
Link ID: 10868 - Posted: 06.24.2010

The power of the mind has been overestimated when it comes to fighting cancer, US scientists say. They said they found that a patient's positive or negative emotional state had no direct bearing on cancer survival or disease progression. The University of Pennsylvania team followed more than 1,000 patients with head and neck cancer. But experts said the Cancer journal study should not deter people from adopting a "fighting spirit". Indeed, a positive outlook can help patients cope with gruelling cancer therapies and resume a "normal" life, a spokeswoman for Macmillan Cancer Support said. Seeking emotional support may be beneficial to cancer patients, said the researchers. Lead author Dr James Coyne said: "If cancer patients want psychotherapy or to be in a support group, they should be given the opportunity. There can be lots of emotional and social benefits. But they should not seek such experiences solely on the expectation that they are extending their lives. The hope that we can fight cancer by influencing emotional states appears to have been misplaced." In the study, a patient's emotional status had no bearing on survival, regardless of gender, tumour site or disease stage. Julia Frater, of Cancer Research UK, said: "People with cancer can feel under pressure to cope well with their disease and treatment and to stay on top of things. They are often urged to feel positive. "These results should reassure them that if they don't feel like this, it's okay. Many people do feel worried or low following a diagnosis and this isn't likely to affect the outcome of their treatment." (C)BBC

Keyword: Neuroimmunology; Emotions
Link ID: 10867 - Posted: 10.22.2007

By Fergus Walsh A gene therapy trial for the fatal disorder Duchenne muscular dystrophy (DMD) is about to begin in London. In a world first, a small group of patients will be injected with an experimental drug which it is hoped will extend their lives. DMD, which affects boys, is caused by a single faulty gene, and results in progressive muscle wasting. The injection contains a "molecular patch" targeting the faulty gene so that it should work again. At first, minute quantities of the drug will be used - to check it is safe. If it works the drug will effectively knit together the key damaged section of DNA, allowing it to begin producing a protein that keeps the muscles strong. The hope is it could slow, or even halt the progression of muscle wasting, and give some patients the chance of living into old age. Animal trials of the drug have proved highly successful. If it works in humans, patients would need regular infusions of the drug. Lead researcher Professor Francesco Muntoni, of Imperial College London, has high hopes. He said: "It will be truly life changing, and life extending for these people. "Maybe this will not be a complete cure, but it could definitely buy a lot of time for these children." Professor Muntoni describes the gene therapy as like a piece of molecular velcro which will form a temporary repair. (C)BBC

Keyword: Muscles; Genes & Behavior
Link ID: 10866 - Posted: 10.22.2007

Donald Wilson In 2004 the Nobel Prize in Physiology or Medicine went to Linda B. Buck and Richard Axel for their research showing that there is a huge family of genes that encode proteins called olfactory receptors. Their findings, published in 1991, opened many doors toward understanding the function of the olfactory system. One important observation was that individual olfactory sensory neurons typically express just one of those genes. Thus, signals coming from a given neuron provide information about odors that activate the specific receptor protein expressed by that cell. A single receptor protein, however, appears to bind (or recognize) many different odors. Thus, rather than having neurons that respond selectively to coffee or vanilla or Bordeaux, most individual cells (via their receptors) respond to submolecular features of the volatile chemicals coming from those objects. For example, an olfactory sensory receptor neuron may respond to a hydrocarbon chain of a particular length or a specific functional group like an alcohol or aldehyde. This means that any given sensory neuron will respond to many different odors as long as they share a common feature. The brain (specifically, the olfactory bulb and olfactory cortex) then looks at the combination of sensory neurons activated at any given time and interprets that pattern in the context of previous patterns that have been experienced and other kinds of available information. The interpreted pattern is what you perceive as smell. Olfactory sensory neurons, which sit in the mucus in the back of the nose and relay data into the brain via axons (fingerlike projections that transmit information out from the cell body), do not live forever. In fact, they are one of the increasingly large number of neuron types that are known to die and be replaced throughout life. © 1996-2007 Scientific American, Inc.

Keyword: Chemical Senses (Smell & Taste); Neurogenesis
Link ID: 10865 - Posted: 06.24.2010

By JASCHA HOFFMAN Has the Clean Air Act done more to fight crime than any other policy in American history? That is the claim of a new environmental theory of criminal behavior. In the early 1990s, a surge in the number of teenagers threatened a crime wave of unprecedented proportions. But to the surprise of some experts, crime fell steadily instead. Many explanations have been offered in hindsight, including economic growth, the expansion of police forces, the rise of prison populations and the end of the crack epidemic. But no one knows exactly why crime declined so steeply. The answer, according to Jessica Wolpaw Reyes, an economist at Amherst College, lies in the cleanup of a toxic chemical that affected nearly everyone in the United States for most of the last century. After moving out of an old townhouse in Boston when her first child was born in 2000, Reyes started looking into the effects of lead poisoning. She learned that even low levels of lead can cause brain damage that makes children less intelligent and, in some cases, more impulsive and aggressive. She also discovered that the main source of lead in the air and water had not been paint but rather leaded gasoline — until it was phased out in the 1970s and ’80s by the Clean Air Act, which took blood levels of lead for all Americans down to a fraction of what they had been. “Putting the two together,” she says, “it seemed that this big change in people’s exposure to lead might have led to some big changes in behavior.” Copyright 2007 The New York Times Company

Keyword: Neurotoxins; Aggression
Link ID: 10864 - Posted: 06.24.2010

Rex Dalton Fossils can shed light on when bats developed the ability to echo-locate.GETTYThe most primitive bat ever discovered is finally being scientifically reported, years after the first fossil was found and snapped up by a private collector. The 52.5-million-year-old bat unusually had a claw on all five digits of each limb, earning it the nickname '20-clawed bat'. Its anatomy shows that it captured its prey without the use of echolocation — the strongest evidence yet that some bats flew before this skill evolved. Bats are thought to have evolved from flightless tree-dwelling creatures, and also developed specialized echolocation to detect their small prey at night. Which came first has been a matter of some debate. “This tells us there was flight before echolocation,” says Nancy Simmons, the chief mammal curator at the American Museum of Natural History in New York. “So the question we have to answer now is: how did it catch its prey?” Simmons and her colleagues reported on two individual fossils of the new bat late last week in a lecture at the 67th annual meeting of the Society of Vertebrate Paleontology (SVP) in Austin, Texas. The team has submitted an article naming and fully describing the species to a scientific journal. Bats today make up about 20% of living mammals. There are an estimated 1,100 species, with new ones reported regularly. The previous oldest bat found is from the same place and age as the new species, but the new find has more primitive features. © 2007 Nature Publishing Group

Keyword: Hearing; Evolution
Link ID: 10863 - Posted: 06.24.2010

By Benjamin Lester For young men from the Maasai tribe of Kenya, spearing an elephant is part of the transition to manhood. The farmers of the Kamba tribe pose no threat to elephants, however. New research shows that wary pachyderms in Kenya's Amboseli National Park have learned to distinguish between the two groups based on odors and colors. The findings demonstrate the animals' ability to accurately classify threats from indirect cues. The Maasai are a cattle-herding Kenyan tribe who habitually wear red or other deep, rich colors. Although the practice is now illegal, young Maasai continue to spear elephants as a rite of passage. Other ethnic groups in the area do not harass elephants, and researchers working in the park noticed that the local herds reacted differently to Maasai than to these groups. To determine how the elephants discern a Maasai from a Kamba, evolutionary psychologists Lucy Bates and Richard Byrne, both of the University of St. Andrews in Fife, U.K., and colleagues recruited male volunteers from both tribes and gave them red clothes to wear for 5 days. The team then placed the fragrant garments upwind and out of sight of 18 different elephant family groups. Both types of clothing elicited more of a response--tensing, sniffing the air, and moving away--than did unworn duds of the same color, but the reaction to Maasai smells was much stronger. In a paper published online 18 October in Current Biology, the team reports that the animals moved away 27% faster and 65% farther from the Maasai scents than from Kamba odors. "If they got a whiff of the Maasai, they would just be running away," says Byrne. © 2007 American Association for the Advancement of Science.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 10862 - Posted: 06.24.2010

Kerri Smith Researchers delving into the DNA of Neanderthal remains have found the human form of a gene crucial for the development of language. The result indicates that this modern form of the gene could have appeared much earlier than previously thought — in the ancestors of humans and Neanderthals. However, the presence of this gene alone does not guarantee that Neanderthals actually spoke to each other using anything that we would classify as a language. Studies of their anatomy haven’t answered this question either: a bone in the Neanderthal throat called the hyoid resembles the human form, but the inner ear appears different. It is extremely difficult to extract nuclear DNA from such ancient samples, so the study is an impressive technical achievement. But the group cannot rule out entirely the possibility that their results are due to contamination of the samples with modern human DNA. One of the first studies of Neanderthal DNA1, published in Nature in 2006, was reanalysed this year and it was claimed that a large chunk could have been modern human DNA, not Neanderthal2. In the new study, Johannes Krause of the Max-Planck Institute for Evolutionary Anthropology in Leipzig, Germany and an international team of colleagues took DNA from two Neanderthal males whose bones were found in a cave in Northern Spain. © 2007 Nature Publishing Group

Keyword: Language; Genes & Behavior
Link ID: 10861 - Posted: 06.24.2010

By Steve Mitchell A new study has identified brain cells that play a key role in ensuring that we rise and shine when the alarm clock buzzes. The findings could lead to a better understanding of sleep disorders. People with narcolepsy--a condition marked by falling asleep at inappropriate times--have fewer neurons that produce a small protein called hypocretin, also known as orexin (ScienceNOW, 29 January). So scientists had a hunch that these neurons, which are located in the hypothalamus region of the brain, play a role in transitioning from sleep to wake states, but their exact function had been difficult to pin down. Now, a team led by neuroscientist Luis de Lecea of Stanford University in Palo Alto, California, has literally shed some light on the problem. The researchers used a virus to insert the gene that encodes a light-sensing protein into hypocretin-producing neurons in the brains of mice. This enabled them to activate the neurons by shining a laser deep into the brain via fiber optics. When the cells were activated, sleeping mice woke faster than animals that did not have their neurons stimulated, the researchers report online today in Nature. Further experiments indicated that hypocretin is key in stimulating the transition from asleep to awake. Mice given a compound that blocks the action of hypocretin, for example, woke up more slowly upon activation of the neurons than did mice given a placebo. Knockout mice that lacked the gene for hypocretin also had a delay in waking up, although they still awoke faster than normal mice that did not have their neurons stimulated, suggesting that additional chemicals are involved in the process. "The hypocretin-producing neurons are very important in switching from sleep to wakefulness," de Lecea says, noting that the findings help explain the sleep disorders in narcoleptics who are deficient in these types of cells. © 2007 American Association for the Advancement of Science.

Keyword: Sleep; Biological Rhythms
Link ID: 10860 - Posted: 06.24.2010

Matt Kaplan Men have it tough: they age faster and die younger than women. Now research suggests that this trait could be linked to humankind’s ancestral breeding habits. Several explanations have been proposed for the lifespan difference between men and women. It could be a result of the ageing effects of testosterone. Or it could be thanks to evolutionary forces: having the men die early might ease pressure on valuable resources, for example, helping the overall success of the species. Or perhaps it has something to do with mating behaviour. Casual observations had previously suggested that polygyny is a common characteristic among species in which males die younger than females, including red deer, lions and elephant seals. In more monogamous species, including Bewick’s swans and meerkats, a gender-related lifespan difference is not seen. So Tim Clutton-Brock and Kavita Isvaran of Cambridge University pulled together data sets in which measures of survival and descriptions of breeding were available for both sexes, to see whether this observation holds true. In monogamous species, they found no consistent sex differences in breeding lifespans, annual rates of mortality or rates of ageing. But the more polygynous a species was, the more short-lived the male was likely to be, and the shorter their duration of effective breeding, the team reports in Proceedings of the Royal Society of London B 1. © 2007 Nature Publishing Group –

Keyword: Sexual Behavior; Evolution
Link ID: 10859 - Posted: 06.24.2010

Emma Marris Zebrafish won't be caught napping after a sleepless night.Zebrafish don't nap more during daylight hours when sleep deprived, a new study shows. The work suggests that fish are better able to use light cues to stay awake during the day than mammals, hinting that evolution has produced different systems for regulating sleep in different groups of animals. Every animal sleeps, but many do so in ways that humans would hardly recognize. Cows stand stock still on their four legs; dolphins take a separate nap in each hemisphere of their brains so they can keep swimming. Even fruitflies catch forty winks now and again in their short lives. The way you can tell a zebrafish is asleep, says Emmanuel Mignot at Stanford University in Palo Alto, California, is that its tail droops, it hangs immobile at the bottom of the tank, and it requires more of a prod — a mild electric current will do — to get it swimming than when it is awake. Mignot and his colleagues are keen to keep zebrafish awake to study how sleep — or the lack of it — affects this often-studied fish. No one really understands why people sleep; how sleep evolved is equally mysterious, says Mignot. "Sleep is one of the basic mysteries remaining, in terms of why it has been selected for." To understand that, he is studying sleep in animals from dogs to zebrafish. "It is better to understand how we sleep across evolution, and then we will understand the reason for sleep," he says. © 2007 Nature Publishing Group

Keyword: Sleep; Evolution
Link ID: 10858 - Posted: 06.24.2010

Mark D'Esposito How does the brain organize its work? And how does it heed what it needs to heed? Theories of brain organization focus on two distinct but complementary principles of brain organization: modularity, the existence of brain regions with specialized functions, and network connectivity, the integration of information from various brain regions that results in organized behavior. In the study under review here, the modular and network models appear to play specialized roles in directing the attention of monkeys seeking certain visual targets through either "top-down" or "bottom-up" attentional strategies. In the modules-versus-network debate, modularity is probably the simpler brain model to understand. Clinical observation of individuals with brain damage, as well as brain-imaging studies (functional MRIs, or fMRIs) of healthy individuals, demonstrate that certain brain regions control specific cognitive processes, such as the ability to produce speech. For instance, in patients with nonfluent aphasia, which creates a selective inability to speak, comprehension of spoken language remains intact. In 1861 Paul Broca observed that damage to the left frontal lobe in an autopsied brain had produced nonfluent aphasia. Modern brain-imaging studies of patients with strokes to this area (now known as "Broca's area") confirmed Broca's theory. Moreover, fMRIs of healthy individuals reveal that the left frontal lobe is activated when subjects generate speech. © 1996-2007 Scientific American, Inc.

Keyword: Attention
Link ID: 10857 - Posted: 06.24.2010

The next time you pause to mull over menu selections even after you have decided to order your favorite entrée, it may comfort you to know that you may be behaving that way because your brain is hard-wired to ponder decisions, leaving room for a possible change of mind. New studies have identified a specific neural circuit in the brains of monkeys that is activated when they postpone acting on a decision. The circuit is thought to keep potential choices brewing in memory even after a decision has already been made. The brain may continue to consider the options even after a decision is made because that extra consideration may sometimes result in a change of mind - and a possible reward, such as a tastier meal. The researchers said that their findings could offer important insight into the function of neural circuits that drive the brain's memory and decision-making machinery. The researchers, led by Howard Hughes Medical Institute international research scholar Ranulfo Romo, reported their findings in the October 16, 2007, issue of the Proceedings of the National Academy of Sciences. Romo and his colleagues are at the National Autonomous University of Mexico. In their experiments, the researchers trained monkeys to judge whether, when a pair of vibrations were delivered to their fingertip, the second vibration was at a higher or lower frequency than the first. The animals indicated their choice by pressing a button. During this process, the researchers recorded electrical activity in relevant areas of the monkeys' brains. © 2007 Howard Hughes Medical Institute.

Keyword: Miscellaneous
Link ID: 10856 - Posted: 06.24.2010