By ALESSANDRA STANLEY The 10 warning signs listed online by the Alzheimer’s Association include not recognizing oneself in the mirror and giving large amounts of money to telemarketers. Also, Cognitivelabs.com offers free instant memory tests, but the scoring system at the end can be confusing. These tips are offered here because it is almost impossible to watch even a portion of “The Alzheimer’s Project” on HBO without worrying. Many viewers will be tempted to search the Internet or call 877-IS IT ALZ in a sudden panic over blank spells: “Did I already take my Lipitor?” and “That funny blond actress, you know, the one in that old movie about Washington with the guy who was in ‘Picnic’?” (Judy Holliday, “Born Yesterday,” William Holden.) Memory loss is a terrifying prospect, and “The Alzheimer’s Project,” a sober, deeply affecting four-documentary series on HBO that begins on Sunday, seeks to comfort and encourage those whose worst fears turn out to be true. The project was made in collaboration with the National Institute on Aging of the National Institutes of Health, which provided scientific information and guidance, but the filmmakers had the final word on editing. And HBO chose as its marketing motto “HOPELESS,” printed with a big purple X over the “LESS.” The message conveyed by “The Alzheimer’s Project” is that a breakthrough — in prevention and treatment, and even possibly a cure — is at hand. Copyright 2009 The New York Times Company

Keyword: Alzheimers
Link ID: 12836 - Posted: 06.24.2010

by Ewen Callaway In addition to checking blood pressure and heart rate, doctors may want to test their patients' IQs to get a good measure of overall health. A new study of 3654 Vietnam War veterans finds that men with lower IQs are more likely to suffer from dozens of health problems – from hernias, to ear inflammation, to cataracts – compared with those showing greater intelligence. This offers tantalising – yet preliminary – evidence that health and intelligence are the result of common genetic factors, and that low intelligence may be an indication of harmful genetic mutations. "It poses the question to epidemiologists: why is it that intelligence is a predictor for things that seem so very far removed from the brain," says Rosalind Arden, a psychologist at King's College London, who led the study. Lifestyle choices One obvious counter-argument is that intelligent people make healthier choices. "You could say: 'look, brighter people make better health decisions – they give up smoking when they find it's bad for you, they take up exercise when they find out its good for you, and they eat a lot of salad'," Arden says. That's probably true, she says, yet her team found that indicators of healthy living, such as a low body mass index and not smoking, do not correlate with overall health of veterans as well as several tests of intelligence. © Copyright Reed Business Information Ltd.

Keyword: Intelligence; Evolution
Link ID: 12835 - Posted: 06.24.2010

By Gisela Telis As anyone with a busy schedule can attest, intending to do something and actually doing it are two different things. But your brain doesn't make such neat distinctions, according to a new study. Researchers have found that when you wave at someone, for example, the intention to move your hand creates the feeling of it having moved, not the physical motion itself. The discovery sheds new light on how the brain tracks what the body does. Although neuroscience has revealed much about how the brain processes experiences, the origin of intention has remained a mystery. Past studies linked it to the posterior parietal cortex and the premotor cortex, two regions of the brain also associated with motion and awareness of movement, but each region's role and how they work together remained unclear. Neuroscientist Angela Sirigu of the Centre de Neuroscience Cognitive in Bron, France, became intrigued by the posterior parietal's role in willed actions when working with patients who had injured that part of their brains. The patients couldn't define when they began to want to move, says Sirigu, because they couldn't monitor their own intention. Sirigu joined researchers at the University of Lyon in France and neurosurgeon Carmine Mottolese of Lyon's Hôpital Pierre Wertheimer to take advantage of a common operating room practice. As part of their preparation for surgery, neurosurgeons sometimes electrically stimulate the brains of their patients, who are awake under local anesthetic, to map the brain and minimize surgical complications. During brain tumor surgery on seven patients, Mottolese stimulated their frontal, parietal, and temporal brain regions, and Sirigu's team asked the patients to describe what they felt. © 2009 American Association for the Advancement of Science

Keyword: Miscellaneous
Link ID: 12834 - Posted: 06.24.2010

by Ewen Callaway Free will, or at least the place where we decide to act, is sited in a part of the brain called the parietal cortex, new research suggests. When a neurosurgeon electrically jolted this region in patients undergoing surgery, they felt a desire to, say, wiggle their finger, roll their tongue or move a limb. Stronger electrical pulses convinced patients they had actually performed these movements, although their bodies remained motionless. "What it tells us is there are specific brain regions that are involved in the consciousness of your movement," says Angela Sirigu (pdf format), a neuroscientist at the CNRS Cognitive Neuroscience Centre in Bron, France, who led the study. Brain stimulation Sirigu's team, including neurosurgeon Carmine Mottolese, performed the experiments on seven patients undergoing brain surgery to remove tumours. In all but one case, the cancers were located far from the parietal cortex and other areas that Mottolese stimulated. One patient's tumour sat near the parietal cortex, but did not interfere with the experiments, Sirigu says. And because the patients were awake during the surgery, they could answer questions. "Did you move?" a researcher asked a 76-year-old man after lightly zapping a point on his parietal cortex. "No. I had a desire to roll my tongue in my mouth," he responded. © Copyright Reed Business Information Ltd

Keyword: Miscellaneous
Link ID: 12833 - Posted: 06.24.2010

By Lindsay Lyon How the body got there was a mystery. More than 12 hours earlier, the man had emerged from successful back surgery. Now, clad only in underwear, he was outside, dead, wedged between a generator and a wall. He was six floors below the hospital rooftop. Had he jumped to his death? Had he been pushed? Neither, medical investigators concluded. He'd gone sleepwalking, and his stroll took an unfortunate turn. "The autopsy showed that there were significant abrasions along this individual's back, which showed that he fell straight down," notes Michel Cramer Bornemann, an expert on sleep problems who is codirector of the Minnesota Regional Sleep Disorders Center in Minneapolis. "Suicide victims don't fall straight down. They jump." Moreover, the man had been barefoot yet not been deterred by the roof's layer of sharp stones. "Sleepwalkers don't sense pain; the sensory neural pathways are essentially off-line," says Cramer Bornemann, who was brought in by a family lawyer investigating the hospital's suggestion that the death was a suicide. Cramer Bornemann heads up Sleep Forensics Associates, a group that lawyers and law enforcement officials have turned to when investigating crimes that may be explained by a sleep problem. Since they've been together—just over two years—he and his two colleagues have fielded approximately 150 requests for case evaluations, some from as far off as New Zealand. Murder, sexual assault, DUI, child abuse, and "suicide" are just a sampling of crimes they've encountered. All have been suspected of involving sleepwalking, sleep driving, or sleep sex, among other so-called parasomnias—inappropriate, unwanted behaviors that arise during sleep. (About one third of those case referrals involve the alleged influence of the sleep aid Ambien, he says.) © 2009 U.S.News & World Report LP

Keyword: Sleep
Link ID: 12832 - Posted: 06.24.2010

By Rebecca Morelle "In the past, people thought birds were stupid," laments the aptly named scientist Christopher Bird. But in fact, some of our feathered friends are far cleverer than we might think. And one group in particular - the corvids - has astonished scientists with extraordinary feats of memory, an ability to employ complex social reasoning and, perhaps most strikingly, a remarkable aptitude for crafting and using tools. Mr Bird, who is based at the department of zoology at Cambridge University, says: "I would rate corvids as being as intelligent as primates in many ways." The corvids - a group that includes crows, ravens, rooks, jackdaws, jays and magpies - contain some of the most social species of birds. And some of their intelligence is played out against the backdrop of living with others, where being intelligent enough to recognize individuals, to form alliances and foster relationships is key. However, group living can also lead to deceptive behaviour - and western scrub jays (Aphelocoma californica ) can be the sneakiest of the bird-bunch. Many corvids will hide stores of food for later consumption, especially during the cold winter months when resources are scarce, but western scrub jays take this one step further. (C)BBC

Keyword: Intelligence; Evolution
Link ID: 12831 - Posted: 05.07.2009

Neuroscientists claim growing pains Leading neuroscientists are warning that difficulties with a staple laboratory product may be costing time and money. The scientists say that variation between batches of a growth medium designed to sustain neurons in culture can, in their experience, cause experiments to fail or give low-quality results because of the poor survival and maturation of cells. The growth medium in question is a particular formulation of B27, a mixture of proteins, hormones and vitamins, produced by laboratory supplies company Invitrogen of Carlsbad, California, now a division of Life Technologies. In 2004, a group of neuroscientists including Beth Stevens, now at Harvard Medical School, in Boston, Massachusetts, and Johannes Hell of the University of Iowa, Iowa City, told Invitrogen that they thought the B27 medium was producing poor results following a change in the product's ingredients. The company says that it remedied the problem, and that the number of complaints it received from scientists fell to "negligible levels". "Things were improved," says Stevens, "but over the next few years it became clear there is still a lot of variation in quality control." Hell estimates that his lab spends about US$50,000 per year on culturing neurons. "If you get mediocre cultures, that money is wasted," he says. So Hell and other colleagues developed an alternative growth medium called Neuronal Supplement 21 (NS21), which they unveiled last year (Y. Chen et al. J. Neurosci. Meth. 171, 239–247; 2008). Hell points out that NS21 is not a commercial product; the researchers who use it prepare it in their own laboratories. © 2009 Nature Publishing Group,

Keyword: Development of the Brain
Link ID: 12830 - Posted: 06.24.2010

by Alan Boyle A songbird's brain may be programmed to gravitate toward a particular kind of tune, even if it's been taught from infancy to sing to the beat of a different warbler, researchers say. They go on to suggest that a similar neural mechanism might be behind the way our brains handle language. "I think we humans, and songbirds, are probably born with some innate predisposition to communicate in a particular way," Olga Feher, a biologist at The City College of New York, told me this week. The findings from Feher and her colleagues appear in this week's issue of the journal Nature. The experiments suggest that phenomena rooted in a species' culture - for example, singing for birds, using language for people - may be rooted in a species' genome as well. "People have theorized long and hard about how the evolutionary process applies to culture," another co-author of the study, Partha Mitra of Cold Spring Harbor Laboratory, said in a news release. "This experiment takes culture and puts it into a laboratory setting. We've tested some questions, asked by others over many years, in a mathematically and experimentally crisp manner and come up with a concrete answer." The experimenters started out by raising zebra finches in isolation, in soundproof boxes. For decades, scientists have known that an isolated songbird's innate song is different from the song that is "learned" from its feathered tutors as it grows up. In fact, different genes come into play as a songbird's song matures. So does the classic zebra finch song emerge merely as a cultural norm among the songbird set, or is there some sort of hard-wired inevitability about the tune? © 2009 msnbc.com

Keyword: Language; Learning & Memory
Link ID: 12829 - Posted: 06.24.2010

By Jessica Knoblauch One night in February, high school principal Matthew Smith got a frightening wake-up call. The local fire department alerted him that the home of a student at Agua Fria High School was contaminated with liquid mercury that apparently had been taken from a science classroom. The next day, emergency crews descended on the school in haz-mat suits, discovering a toxic trail of mercury vapors in classrooms, locker rooms, and buses. The high school, in Avondale, Ariz., was shut down for a week so it could be decontaminated. The homes of six students were tainted with mercury, two so severely that the families had to be relocated for 11 days, according to the Environmental Protection Agency. The total cleanup is expected to reach hundreds of thousands of dollars. The mercury mess in Arizona was only the latest in thousands of incidents where children are exposed to elemental mercury, a poison that can damage the brain, trigger respiratory failure and cause other serious health problems. Power plants are typically cast as the usual suspects of mercury contamination, since they emit mercury into the air, where it spreads globally. But many children are exposed to toxic levels of mercury much closer to home. Mercury spills inside schools and houses, often unreported, can release vapors into the air for weeks, even years. © 1996-2009 Scientific American Inc.

Keyword: Neurotoxins; Development of the Brain
Link ID: 12828 - Posted: 06.24.2010

Eric Bland -- "The alleles of my Major Histocompatibility Complex are completely opposite from yours," might not sound like pillow talk, but it is the literal basis for the "chemistry" many couples have. Two companies, Basisnote and Scientific Match, are developing technology to match couples based on the genetic components of the human immune system -- and their odor. Studies have linked odor to immune systems and shown that people are most likely to be attracted to the smells of those who have different histocompatibility genes than their own. While those who have similar immune systems tend to not be attracted to each others' odors. "The MHC helps signal whether I find someone attractive or not," said August Hammerli of the Switzerland based Basisnote. "What we have developed is a saliva assay that measures a person's MHC and how they might react to another individual's MHC profile." It works like this. Clients order a test online and receive it two days later. Then they simply swab their cheeks and put the sample into a machine. Ten minutes later out pops a code of 0's and 1's. Hammerli won't say how many 0's or 1's, or how many different chemicals are being tested. A client enters their unique code at Basisnote's Web site, and the software matches them to a person with a completely different immune system. © 2009 Discovery Communications, LLC.

Keyword: Sexual Behavior; Chemical Senses (Smell & Taste)
Link ID: 12827 - Posted: 06.24.2010

By Alissa Quart We don't want to be normal," Will Hall tells me. The 43-year-old has been diagnosed as schizophrenic, and doctors have prescribed antipsychotic medication for him. But Hall would rather value his mentally extreme states than try to suppress them, so he doesn't take his meds. Instead, he practices yoga and avoids coffee and sugar. He is delicate and thin, with dark plum polish on his fingernails and black fashion sneakers on his feet, his half Native American ancestry evident in his dark hair and dark eyes. Cultivated and charismatic, he is also unusually energetic, so much so that he seems to be vibrating even when sitting still. I met Hall one night at the offices of the Icarus Project in Manhattan. He became a leader of the group—a "mad pride" collective—in 2005 as a way to promote the idea that mental-health diagnoses like bipolar disorder are "dangerous gifts" rather than illnesses. While we talked, members of the group—Icaristas, as they call themselves—scurried around in the purple-painted office, collating mad-pride fliers. Hall explained how the medical establishment has for too long relied heavily on medication and repression of behavior of those deemed "not normal." Icarus and groups like it are challenging the science that psychiatry says is on its side. Hall believes that psychiatrists are prone to making arbitrary distinctions between "crazy" and "healthy," and to using medication as tranquilizers. "For most people, it used to be, 'Mental illness is a disease—here is a pill you take for it'," says Hall. "Now that's breaking down." Indeed, Hall came of age in the era of the book "Listening to Prozac." He initially took Prozac after it was prescribed to him for depression in 1990. But he was not simply depressed, and he soon had a manic reaction to Prozac, a not uncommon side effect. In his frenetic state, Hall went on to lose a job at an environmental organization. He soon descended into poverty and started to hear furious voices in his head; he walked the streets of San Francisco night after night, but the voices never quieted. © 2009 Newsweek, Inc.

Keyword: Schizophrenia; Depression
Link ID: 12826 - Posted: 06.24.2010

By JOHN TIERNEY Imagine that you have ditched your laptop and turned off your smartphone. You are beyond the reach of YouTube, Facebook, e-mail, text messages. You are in a Twitter-free zone, sitting in a taxicab with a copy of “Rapt,” a guide by Winifred Gallagher to the science of paying attention. The book’s theme, which Ms. Gallagher chose after she learned she had an especially nasty form of cancer, is borrowed from the psychologist William James: “My experience is what I agree to attend to.” You can lead a miserable life by obsessing on problems. You can drive yourself crazy trying to multitask and answer every e-mail message instantly. Or you can recognize your brain’s finite capacity for processing information, accentuate the positive and achieve the satisfactions of what Ms. Gallagher calls the focused life. It can sound wonderfully appealing, except that as you sit in the cab reading about the science of paying attention, you realize that ... you’re not paying attention to a word on the page. The taxi’s television, which can’t be turned off, is showing a commercial of a guy in a taxi working on a laptop — and as long as he’s jabbering about how his new wireless card has made him so productive during his cab ride, you can’t do anything productive during yours. Why can’t you concentrate on anything except your desire to shut him up? And even if you flee the cab, is there any realistic refuge anymore from the Age of Distraction? Copyright 2009 The New York Times Company

Keyword: Attention; Vision
Link ID: 12825 - Posted: 06.24.2010

By Caitlin Gibson Leah's voice was calm on the phone. I'm on my way home, she said. Sarah died this morning. In the steady tone my best friend would use to say she had a flat tire or was late for class, Leah explained that she was about to board a flight to join her family as they prepared for her little sister's funeral. Leah had known on some level that this might happen. She'd read the books, done the research and understood that girls with eating disorders got better, or they didn't. She saw Sarah as what she was: the everygirl of her illness, not immune because she was smart and beautiful, popular and athletic. But the knowledge that it might happen did nothing to prepare Leah. Her false serenity lasted until the funeral, where she sat beside her parents in the synagogue and greeted a seemingly endless line of mourners. I took my place behind her, next to her aunt. Person after person shuffled forward to offer tearful embraces, and Leah's cocoon suddenly collapsed. The piercing cry that tore from her throat silenced the room. Leah's aunt and I lunged forward in the instinctive way that one body answers another: our palms pressed against her back, fingers wrapped around her shoulders. Leah's scream subsided into a whimper, then quiet. The day shuddered on. A growing consensus suggests that for young people with eating disorders, the sooner the problem is identified and aggressively treated, the better the chance of recovery. © 2009 The Washington Post Company

Keyword: Anorexia & Bulimia
Link ID: 12824 - Posted: 06.24.2010

By RONALD PIES, M.D. Harry was one of the lucky ones. After a lifetime of schizophrenia — hallucinations, hospitalizations and all the attendant miseries — he was a genuinely new man. This was about 20 years ago, and clozapine — then viewed as a miracle antipsychotic drug — seemed to have wrought some deep, transforming magic. True, he had put on 20 pounds and complained of mild drowsiness. But the crippling fears and fearsome voices had been quieted. We were able to discharge him from the hospital and arrange for placement in a neighborhood residence. At his first outpatient appointment, Harry looked cheerful. He seemed to be adjusting to a life of relative normalcy. This was more than I had hoped for, given his disease and its devastation. When the German psychiatrist Emil Kraepelin described what we now recognize as schizophrenia, he called it “dementia praecox” — premature dementia. For decades, the condition was thought to have an inevitable downhill course, much as we still see with Alzheimer’s disease. Even during my residency in the early 1980s, most of us were gloomy about schizophrenia. We now believe that schizophrenia comprises several different disease processes and often has a more benign course. We have begun to speak not only of remission, but even of recovery — and hope. Copyright 2009 The New York Times Company

Keyword: Schizophrenia
Link ID: 12823 - Posted: 06.24.2010

Scientists have uncovered genetic evidence suggesting the sleep disorder narcolepsy is linked to a fault in the immune system's "foot soldier" cells. It suggests these T-cells may cause the condition by attacking cells in the sleep centres of the brain. Narcolepsy, which causes extreme daytime sleepiness and sudden muscle weakness, has previously been linked to a malfunctioning immune system. The Stanford University research appears in the journal Nature Genetics. Narcolepsy is a mysterious, uncommon condition that can be very distressing for those who have it. It can trigger "sleep attacks" without any warning during any normal activity. In addition, some people can experience "cataplexy", where strong emotions such as anger, surprise, or laughter can trigger an instant loss of muscle strength, which, in some cases, can cause collapse. There is currently no cure for narcolepsy, only ways to minimise symptoms such as taking frequent, brief naps evenly spaced throughout the day. The condition has previously been linked to depletion of cells deep in the regulatory regions of the brain. But lead researcher Dr Emmanuel Mignot said while previous research had only suggested a link with a fault in the immune system, the latest study provided firm evidence. The Stanford team carried out an extensive genetic analysis to identify specific areas of the genome which appeared to be linked to the condition. They pinpointed three specific genetic variants in the same gene in people with European and Asian ancestry that appeared to be associated with an increased susceptibility for narcolepsy. The gene in question plays a key role in the functioning of an important receptor used by T-cells to recognise foreign proteins in the body. (C)BBC

Keyword: Narcolepsy; Neuroimmunology
Link ID: 12822 - Posted: 05.05.2009

Drinking water which contains the element lithium may reduce the risk of suicide, a Japanese study suggests. Researchers examined levels of lithium in drinking water and suicide rates in the prefecture of Oita, which has a population of more than one million. The suicide rate was significantly lower in those areas with the highest levels of the element, they wrote in the British Journal of Psychiatry. High doses of lithium are already used to treat serious mood disorders. But the team from the universities of Oita and Hiroshima found that even relatively low levels appeared to have a positive impact of suicide rates. Levels ranged from 0.7 to 59 micrograms per litre. The researchers speculated that while these levels were low, there may be a cumulative protective effect on the brain from years of drinking this tap water. At least one previous study has suggested an association between lithium in tap water and suicide. That research on data collected from the 1980s also found a significantly lower rate of suicide in areas with relatively high lithium levels. The Japanese researchers called for further research in other countries but they stopped short of any suggestion that lithium be added to drinking water. The discussion around adding fluoride to water to protect dental health has proved controversial - criticised by some as mass involuntary medication. In an accompanying editorial, Professor Allan Young of Vancouver's Institute for Mental Health said "this intriguing data should provoke further research." (C)BBC

Keyword: Depression
Link ID: 12821 - Posted: 05.02.2009

By NICHOLAS WADE Locations for the Garden of Eden have been offered many times before, but seldom in the somewhat inhospitable borderland where Angola and Namibia meet. A new genetic survey of people in Africa, the largest of its kind, suggests, however, that the region in southwest Africa seems, on the present evidence, to be the origin of modern humans. The authors have also identified some 14 ancestral populations. The new data goes far toward equalizing the genetic picture of the world, given that most genetic information has come from European and Asian populations. But because it comes from Africa, the continent on which the human lineage evolved, it also sheds light on the origins of human life. “I think this is an enormously impressive piece of work,” said Alison Brooks, a specialist on African anthropology at George Washington University. The origin of a species is generally taken to be the place where its individuals show the greatest genetic diversity. For humans, when the new African data is combined with DNA information from the rest of the world, this spot lies on the coast of southwest Africa near the Kalahari Desert, the research team, led by Sarah A. Tishkoff of the University of Pennsylvania, said in this week’s issue of Science. Dr. Brooks, who spent many years in the area, said that it had some trees but that it also had deep sand and was not particularly garden-like. The area is a homeland of the Bushmen or San people, whose language is distinguished by its many click sounds. Copyright 2009 The New York Times Company

Keyword: Evolution
Link ID: 12820 - Posted: 06.24.2010

By Stephanie Pappas When hunger strikes, do you reach for celery or a candy bar? How well you stick to your diet could depend on the activity of a small region in your forebrain, according to a new study on self-control. The research could open doors to better understanding destructive behaviors such as overeating, drinking, and smoking. Behavioral researchers have long known that self-control is an important component of decision-making. But less is understood about the brain regions involved. Several areas in the forebrain show activity when a person makes tough choices, yet scientists disagree on how these regions work together. How, for example, does the brain weigh the short-term sugar rush of a chocolate bar against the long-term health benefits of a salad? Now, researchers from the California Institute of Technology in Pasadena say they have the answer. The scientists recruited 37 dieters who had been successful in losing or maintaining weight. The volunteers fasted for 3 hours and then entered a functional magnetic resonance imaging machine (fMRI), which measures brain activity. While inside, they viewed pictures of 50 different foods and rated each on a five-point scale for how healthy and tasty they considered it to be. The researchers then picked a food the dieter had rated neutral on both scales and asked the person to choose between that food and each of the 49 other options. Although all of the participants labeled themselves "dieters," about half threw self-control to the wind and went for the tastier treats, while the other half chose the healthier options. © 2009 American Association for the Advancement of Science.

Keyword: Obesity; Attention
Link ID: 12819 - Posted: 06.24.2010

By Virginia Morell Snowball, the dancing sulphur-crested cockatoo, is a big hit on YouTube--and now he's also a scientific sensation. Researchers have shown that the bird, who bobs his head and lifts his legs to the Backstreet Boys' song Everybody, is in fact listening to and following the beat. The findings--detailed in a pair of articles--challenge the notion that only humans have the neural wiring for dancing in time to music. "These are pathbreaking studies," says Bruno Repp, a cognitive psychologist at Haskins Laboratories in New Haven, Connecticut. Aniruddh Patel remembers the first time he saw Snowball on the Internet. A neurobiologist at the Neurosciences Institute in San Diego, California, Patel had argued in an earlier study that our talent for moving synchronously to a rhythmic beat is tied to our ability to learn and mimic sounds. "It seems to be a byproduct of a link between the auditory and motor parts of the brain," he says. That seemed to rule out most animals except humans and parrots. Nevertheless, Patel was stunned to see Snowball's video. "My jaw hit the floor," he says. To see if the cockatoo was actually in the groove and not simply trained, Patel visited Snowball at his Indiana home. He put the bird through the paces of a controlled experiment, speeding up and slowing down the music's tempo. Snowball wasn't fazed. "He adjusted the tempo of his dancing to stay synchronized to the beat," says Patel. To do so, he "must be monitoring the sounds" and changing his bobbing and kicking as the musical beat speeds up or slows down. The same neural abilities are required to imitate sounds, explains Patel, whose team reports its findings online today in Current Biology. © 2009 American Association for the Advancement of Science.

Keyword: Hearing
Link ID: 12818 - Posted: 06.24.2010

by Bob Holmes Remaining vigilant for five days and nights without a break would reduce any human to an incoherent, sleep-deprived daze – but dolphins can string together all-nighters without any detectable mental impairment. Sam Ridgway, a marine mammal biologist at the University of California, San Diego, and his colleagues trained captive dolphins to listen to a series of broadcast sounds. Most of the time, a short beep sounded every 30 seconds, but a few times per hour it was replaced by a slightly longer beep. When that happened, the dolphin had to press a lever for a food reward. Previously, Ridgway's team had shown that dolphins could stay alert and perform this task for up to 120 consecutive hours without any decline in accuracy. However, sleep-deprived humans show their fatigue most quickly in more complex mental tasks rather than such simple physical skills. To see if this is true of dolphins, too, Ridgway's team gave the dolphins a more complex task – in which they had to make different sounds in response to two different visual stimuli – at intervals during the 120-hour vigilance test. Here, too, the dolphins showed no sign of losing their sharpness as the days wore on. The dolphins' remarkable alertness may result from their ability to sleep on one side of the brain at a time. This unihemispheric sleep allows dolphins and other cetaceans to get the benefits of sleep even as they remain aware of their pod mates and predators – and, presumably, experimental sounds, says Ridgway. Journal reference: Journal of Experimental Biology (DOI: 10.1242/jeb.027896) © Copyright Reed Business Information Ltd

Keyword: Sleep; Evolution
Link ID: 12817 - Posted: 06.24.2010