Alison Abbott A man with brain damage that makes him clinically blind can navigate an obstacle course, seemingly by using a primitive part of his brain to perceive the objects in his path. This remarkable ability, discovered through a chance observation, is shedding light on a curious phenomenon known as blindsight. The man, known as patient TN, was studied by a multinational team led by Beatrice de Gelder at Tilburg University in The Netherlands and Alan Pegna of the Geneva University Hospitals in Switzerland. The researchers tested TN extensively to confirm that he was completely blind. They used brain imaging to show that there was no activity in his visual cortex, the part of the brain that processes most of the information coming from the retina. They then persuaded TN to set his stick aside and walk down a corridor strewn with lab equipment. He was able to do so flawlessly, despite being unable to consciously see any of the obstacles. Head down and hands loose by his side, he twisted his body to slalom slowly but surely between a camera tripod and a swingbin, and neatly stepped around a random series of smaller items. "At first he was nervous," says de Gelder. "He said he wouldn't be able to do it because he was blind." The scientists broke into spontaneous cheers when he succeeded. The results are reported today in Current Biology1. © 2008 Nature Publishing Group,

Keyword: Vision
Link ID: 12372 - Posted: 06.24.2010

By Sara Coelho What would we do without bees? They give us honey and pollinate hundreds of staple food crops throughout the world. Now it seems that the insects may play yet another role in keeping us well fed: Their buzz protects crops and other plants from caterpillar damage. Caterpillars destroy plants by feeding on leaves, flowers, and fruits. But they have a predator of their own: the wasp. To defend itself, the caterpillar has developed sensory hairs that "feel" the air vibrations caused by the beating of wasp wings. If a wasp approaches, the caterpillar stops moving or drops off the plant for safety. Jürgen Tautz, a biologist at the University of Würzburg in Germany, wondered whether bees, whose wings beat with a similar frequency to those of wasps, would have a similar effect. Tautz and his Würzburg colleague Michael Rostás built two cube-shaped tents in the botanical garden of their university, each enclosing 10 bell pepper plants. They then placed about 10 beet armyworm caterpillars (Spodoptera exigua), a notorious crop pest, on each plant. One tent had a window connected to a beehive, and feeders filled with a sugar solution attracted bees inside. The second tent was closed to the outside world. After about 2 weeks, Tautz and Rostás collected the leaves from the bell pepper plants. © 2008 American Association for the Advancement of Science.

Keyword: Hearing
Link ID: 12371 - Posted: 06.24.2010

The brain protein which has a hand, when defective, in the lethal disease CJD may also be involved in aiding our sense of smell. Mice bred to lack the prion protein could not find buried food or choose between smells. Columbia University scientists said some symptoms of prion disease might be due to the loss of the protein's original role. The study was published in the journal Nature Neuroscience. The prion protein has historically received something of a bad press, being blamed in its misshapen form for degenerative brain diseases in humans and other animals. However, many scientists have been trying to uncover what it actually does when it is behaving correctly. Dr Stuart Firestein's team believe that one of these roles is to help us smell. While his prion-protein free mice were still able to detect scents, they had lost some higher functions which required that smell information to be analysed and processed by the brain. The scientists found changes in the communication between neurons in the nerve cells of the olfactory bulb, part of the forebrain which deals with odours. When the protein was restored to this part of the brain, the ability to discriminate between odours came back. The scientists said that while the discovery had no direct link to the diseases caused by faulty prion proteins, it might help account for some of the symptoms experienced by patients, which might be due to the failure of the proteins to do their normal job properly, rather than the damage caused by accumulation of defective prions. (C)BBC

Keyword: Prions; Chemical Senses (Smell & Taste)
Link ID: 12370 - Posted: 12.22.2008

By Bruce Bower It’s not mealtime for certain bottlenose dolphins living off Australia’s coast unless they sport cone-shaped sea sponges on their beaks. These mammals are not following a strange, marine-based dress code. Their behavior has been identified as the first clear case of tool use by wild dolphins or whales, a new study concludes. These dolphins dive to the bottom of deep channels and poke their sponge-covered beaks into the sandy ocean floor to flush out small fish that dwell there, says a team led by biologist Janet Mann of Georgetown University in Washington, D.C. Foragers then drop their sponges, gobble up available fish and retrieve the implements for another sweep, the scientists report online December 10 in PLoS ONE. Dolphins hold the sponge with the bottom of their beaks and can sweep away much more sand than they could otherwise. Mann’s team documented this behavior among 41 bottlenose dolphins, most of them female, out of a population of several thousand that inhabits Australia’s Shark Bay. The researchers estimate that sponge-carrying dolphins, or spongers for short, devote at least 17 percent of their time to ferreting out bottom-dwelling fish using these beak-borne prods. “It turns out the brainiacs of the marine world can also be tool-using workaholics, spending more time hunting with tools than any nonhuman animal,” Mann says. Chimpanzees and other nonhuman primates spend a small amount of time using tools. One population of woodpecker finches spends an estimated 10 percent of its time using twigs and cactus spines to pry insects and spiders out of tree holes. © Society for Science & the Public 2000 - 2008

Keyword: Evolution
Link ID: 12369 - Posted: 06.24.2010

By Bruce Bower The brain saves face similarly in chimpanzees and people, and possibly in macaque monkeys as well. Chimps recognize their compatriots’ faces by utilizing many of the same brain regions that have already been linked to people’s ability to identify familiar faces, a new study suggests. Neural regions that enable efficient discrimination of one individual’s face from another’s may have evolved between 8 million and 6 million years ago in a common ancestor of chimps and humans, propose psychobiologist Lisa Parr of Emory University in Atlanta and her colleagues. Similar neural elements of face discrimination also appear in macaques, another study finds, suggesting that this ability evolved even earlier. Parr’s group has already conducted studies indicating that chimps recognize other chimps’ faces nearly as well as people recognize other people’s faces. “For the most part, similar brain regions are responsible for this ability in chimps and humans,” Parr says. In her work, macaques’ proficiency at face recognition falls short of that displayed by chimps. Parr’s new brain-scan investigation, published online December 18 in Current Biology, comes on the heels of evidence that a closer link exists between face-responsive parts of macaque and human brains than was previously suspected. Part of the brain known as the temporal lobe hosts a handful of face-sensitive regions in macaques and people, according to a team led by neuroscientist Doris Tsao of the University of Bremen in Germany. Parr’s group also found largely temporal-lobe responses in chimps. © Society for Science & the Public 2000 - 2008

Keyword: Miscellaneous
Link ID: 12368 - Posted: 06.24.2010

JUDGES in the US are waking up to the potential misuse of brain-scanning technologies. Last month, Judge John Kennedy of the New Jersey Judiciary rallied 50 of his peers to discuss protecting courts from junk neuroscience. In September, an Indian court jailed a murder suspect for life, partly on the basis of a brain scan. Meanwhile Cephos of Tyngsboro, Massachusetts, is one of several US companies that claim to be able to show whether someone is lying using a functional MRI brain scan. Ethical issues aside, many neuroscientists say the scans have not been tested rigorously enough to be admitted in court, and that they could produce false positives. Now judges are coming to the same conclusion. Kennedy's gathering, at the New Jersey Judicial College in Teaneck, agreed that brain scans, if accompanied by the opinion of a medical professional, can reveal if a person is in pain or mentally competent to stand trial, but cannot be used to determine a state of guilt. Scans can reveal if a person is in pain or mentally competent to stand trial, but not guilt No judge in the US has yet accepted fMRI scans in a trial, but Kennedy expects attempts to admit them to increase. "We're taking a peek over the horizon to see what's coming," he says. Such considerations are spurred in part by the "Daubert standard" - a Supreme Court ruling that extended a judge's authority to challenge the credibility of scientific evidence in court. © Copyright Reed Business Information Ltd

Keyword: Brain imaging; Stress
Link ID: 12367 - Posted: 06.24.2010

Led Zeppelin's immortal song Dazed and Confused might well have been a clinical observation on the state of their audience's brains, say Australian researchers who have found over-enthusiastic head-banging can cause mild brain injury. In a study published in this week's Christmas issue of the British Medical Journal, two University of New South Wales (UNSW) researchers concluded that head-banging to a typical heavy metal tempo could cause mild traumatic brain injury or concussion, and neck injury, particularly as the tempo of the music and angle of movement increased. "Clearly it's a serious issue," says Prof. Andrew McIntosh, co-author and professor of biomechanics at UNSW. "If you observe people after concerts, they clearly look dazed, confused and incoherent, so something must be going on and we wanted to look into it." Beats per minute After careful observation of the behaviour of heavy metal concert-goers, McIntosh and honours student Declan Patton constructed a theoretical head-banging model to better understand the mechanics of the practice. They also spoke to a focus group of local musicians to identify 10 popular songs to head-bang to. © CBC 2008

Keyword: Brain Injury/Concussion
Link ID: 12366 - Posted: 06.24.2010

By Amy Norton NEW YORK (Reuters Health) - Older adults might want to take an interest in their grandchildren's' video games, if early research on the brain benefits of gaming is correct. In a study of 40 adults in their 60s and 70s, researchers found that those who learned to play a strategy-heavy video game improved their scores on a number of tests of cognitive function. Men and women who trained in the game for about a month showed gains in tests of memory, reasoning and the ability to "multi-task." The findings suggest that video games that keep players "on their toes" might help older adults keep their brains sharp, the researchers report in the journal Psychology and Aging. This is the first published study to suggest as much, so it's important not to overstate the findings, said senior researcher Dr. Arthur F. Kramer, a professor of psychology at the University of Illinois at Urbana-Champaign. Still, he told Reuters Health, the results are "very promising," as they suggest that strategy-based video games can enhance reasoning, memory and other cognitive abilities that often decline with age. © 2008 Reuters

Keyword: Alzheimers; Learning & Memory
Link ID: 12365 - Posted: 06.24.2010

By Coco Ballantyne A little over a year ago, a 25-year-old woman visited University Hospital Birmingham in England complaining of frequent 10-second bouts of nausea and lightheadedness, which was sometimes so intense it caused her to pass out. "She was very thin, she was pale, a very sensible young woman," says Una Martin, a clinical pharmacologist at the hospital assigned to the case shortly after the woman's first visit. She had no history of smoking, heavy drinking or psychiatric disorders. Strangely, her fainting episodes coincided with eating sandwiches and drinking fizzy beverages. By the time Martin saw her, the woman had been bounced from one physician to the next and hospitalized twice, once in 2001 and once in 2007—but her condition remained a mystery. "She felt she had been passed from doctor to doctor [and] was beginning to feel it was all in her head," Martin says. Some of the physicians she had visited thought she was suffering from petit mal seizures—brief epileptic brain episodes characterized by loss of consciousness but without the violent shaking associated with the larger grand mal seizures. Yet neurological tests showed no evidence of epilepsy. Martin suspected there might be something wrong with the patient's heart, so she sent her patient home with an external loop electrocardiogram recorder, a device worn on the wrist or waist to monitor heart rhythm for extended periods of time. Whenever the young woman felt lightheaded, she would press a button on the device, causing it to record one to two minutes of heart activity. After monitoring her heart for a week, the woman returned the device to Martin who interpreted the results. © 1996-2008 Scientific American Inc.

Keyword: Miscellaneous
Link ID: 12364 - Posted: 06.24.2010

by Sunita Reed You may have seen robotic fish, robotic dogs, and even robotic roaches. But you’ve probably never seen a robotic lizard that does four-legged pushups. Its creator is evolutionary ecologist Terry Ord. Ord’s interest in lizards and other animals began as a child growing up in Australia, where his family spent weekends and holidays on their property in Australia’s bush country. “Amongst the rock outcrops around the house, lizards defended territories with elaborate performances of pushups and other displays,” Ord recalls. “The spectacle evidentially had a lasting impression because I would devote my PhD research to deciphering what exactly it was they were saying to each other.” As a researcher, Ord spent weeks at a time observing the male yellow-chinned anole lizard. He noticed that it defended its territory against other males with two types of displays. One is the subtle headbob. The other display is done with the flap of skin under its chin called a dewlap. When extended, it looks like an inflated bright yellow balloon. These two actions comprise the information-rich message that means, “I’m tough, so back off!” But sometimes the lizards would do exaggerated four-legged pushups before they gave this regular message. Was it just another way of flexing their muscles or was it an alert signal that the mostly silent lizards used to get their neighbor’s attention before “talking”? Ord suspected the latter was the case, and decided that the best way to talk to a lizard…was to be a lizard. Ord was at University of California at Davis and worked with Judy Stamps on this project. He now works at Harvard as well. ©2008 ScienCentral

Keyword: Aggression; Sexual Behavior
Link ID: 12363 - Posted: 06.24.2010

By Sara Coelho When a teammate crashes into you playing soccer, you're likely to experience some pain. But if an opposing player hits you with the same amount of force, you'll hurt a lot more. That's the conclusion of a new study that finds that pain caused intentionally feels much worse than pain perceived as accidental. While thinking about the debate over the torture of prisoners at Guantanamo Bay, psychologist Kurt Gray of Harvard University wondered whether the intent to deliver pain mattered. "Perhaps without this malicious intention, torture would not hurt as much," he says. Gray and Harvard colleague Daniel Wegner tested the hypothesis on 43 student volunteers, most of them female. Each volunteer was paired with a partner, who, unbeknownst to the volunteer, was a part of the research team. The volunteers were asked to perform several tasks chosen by the partner from a pair of options. One of the choices was between gauging the pain of electric shocks delivered by a stimulator tied to the volunteer's wrist (on a scale of 1 to 7) and evaluating the relative pitch of different sounds. In one set of experiments, the partner selected the painful task whenever the shock or pitch choice came up; as a result, the volunteers felt that the partner was intentionally harming them. In the other set of experiments, the volunteers still received electric shocks, but they were told that the partner was not responsible. © 2008 American Association for the Advancement of Science.

Keyword: Pain & Touch
Link ID: 12362 - Posted: 06.24.2010

By Erik Stokstad The movie Jurassic Park gave advanced, birdlike dinosaurs a fearsome reputation--swift, intelligent, and deadly. Now it turns out that they had a softer side. Researchers report that males in three species were stay-at-home dads that incubated the eggs in their nests. There's plenty of evidence to suggest that dinos baby-sat their offspring. A predatory dinosaur called Oviraptor, for example, was discovered in the Gobi Desert in 1993, its fossilized remains protecting a brood of eggs. In addition, dinosaurs' closest living relatives, birds and crocodiles, display nesting behavior: Female crocs guard the eggs, whereas in birds the gender of the stay-at-home-parent depends on the species. But whether male or female dinos had nest duty has remained a mystery. For the new research, paleontologist David Varricchio of Montana State University in Bozeman compared three species of birdlike dinosaurs--Oviraptor, Citipati, and Troodon--with birds and crocodiles. All three types of dinosaurs were found on nests, and those nests contain large clutches of eggs, as many as 30 each. Varricchio and his colleagues investigated whether they could discern the nesting behavior from the relationship of the clutch size and the animal's body size. Measurements in 433 living birds and crocodiles revealed that, for a given body size, species in which males took care of the nest tended to have the largest clutches. The next-largest clutches were cared for by mothers. Mom-dad partnerships had the smallest clutches. Extrapolated to dinosaurs, the data revealed a pattern of paternal care in the ancient beasts. © 2008 American Association for the Advancement of Science.

Keyword: Sexual Behavior
Link ID: 12361 - Posted: 06.24.2010

by Ewen Callaway For a 22-year-old woman known as AW, denim evokes feelings of depression, disgust and worthlessness. Corduroy causes confusion, and silk provides utter contentment. She is one of two people known to experience a newly discovered form of synaesthesia, where textures give rise to strong emotions. HS, another young woman who experiences tactile-emotion synaesthesia, gets no kick out of denim. Fleece and dry leaves disgust her, while the touch of tennis balls, fresh leaves and sand are heaven. Other forms of synaesthesia include numbers and letters that evoke colours, shapes that evoke tastes shapes and colours with their very own fragrances. AW and HS's sensations, unusual though they may seem, are an extreme form of the positive feelings most people associate with a soft blanket or the aversion to sharp knives and jagged rocks, says V. S. Ramachandran, a neuroscientist at the University of California, San Diego. "We have an affinity for fur because when were evolving in the ice age, we needed coats," he says. "This is the architecture on which [tactile-emotion synaesthesia] is built." A mental mishmash between touch and emotion could underlie metaphors such as sharp criticism and a rough night, he says. "Synaesthesia is a quirky example of a mechanism we all have for generating metaphors," he says. © Copyright Reed Business Information Ltd

Keyword: Pain & Touch
Link ID: 12360 - Posted: 06.24.2010

By Janet Raloff On December 18, a National Research Council panel told the Environmental Protection Agency that sufficient data exist to begin assessing the potential health risks posed by phthalates, among the most ubiquitous pollutants on the planet. At the same time, the NRC panel strongly recommended that the agency adopt a “paradigm shift” in the way it assesses the chemicals’ toxicity to humans. Instead of evaluating each phthalate compound individually, EPA should begin assessing risks from likely combos of these and related chemicals — even if each chemical works differently, according to the panel’s new report. Phthalates are a widely used family of plasticizers and solvents. Owing to the chemicals’ presence in plastics, cosmetics, personal care products and even medicines, residues of these chemicals show up in everyone throughout the developed world. For more than a decade, studies in rodents have been demonstrating that exposures to phthalates early in life can perturb — in some cases derail — development of an animal’s reproductive organs (SN: 9/2/00, p. 152). Males are most sensitive, largely because these chemicals act as anti-androgens. That is, the chemicals lower concentrations of testosterone, the primary male sex hormone. Especially concerning: In females, phthalates can cross the placenta and pollute the womb. © Society for Science & the Public 2000 - 2008

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 12359 - Posted: 06.24.2010

A newly discovered class of neurons allows rats to identify the borders of their surroundings and helps them to build mental maps. These neurons, called border cells, join three other known classes of neurons that help us to find our way through space: place cells fire when we pass through fixed locations, letting us know where we are; head-direction cells fire when we face particular directions, acting as a compass; and grid cells fire when we're at specific points on a hexagonal grid that the brain superimposes on our surroundings. Neuroscientist Edvard Moser from the Norwegian University of Science and Technology in Trondheim and his colleagues first came across border cells in the entorhinal cortex of rat brains1. While recording the activity from single neurons, the team kept finding neurons that were linked to mental maps but that didn't act like any of the three known classes of mapping neurons. "We ignored them in the beginning," says Moser. Later, however, the researchers realized that they might have found border cells, a theoretically predicted2 class of neurons. Moser and his colleagues refocused their attention on how these neurons reacted as rats ran around small rooms. They found that the border cells would fire when rats approached walls — generally, each border cell was linked with a single wall, but some cells responded to several borders. © 2008 Nature Publishing Group

Keyword: Learning & Memory
Link ID: 12358 - Posted: 06.24.2010

By Susan Watts Doctors fear a new wave of the human form of "mad cow disease" is about to hit Britain, BBC Newsnight has learned. In the UK, 164 people have died of variant CJD, which originally came from cows infected with BSE, and all cases shared a version of a certain gene. But Newsnight has been told of a new case in a separate genetic group. The government's chief adviser on vCJD, Professor Chris Higgins, said estimates were that up to 350 people could become affected by this new type. He told Newsnight the new case had been diagnosed on a clinical basis as vCJD. Such cases can be officially confirmed only if further, more invasive, tests go ahead, such as a brain biopsy. What is of concern to doctors in the new case is that the individual concerned has a particular genetic make-up and it is the first case to appear of that type. There is a key gene linked to vCJD and 42% of the population have a version of that gene, known as MM. The number of human victims peaked in the year 2000 and there are now only a handful of cases a year. It looked like the disease had almost gone away, but this new case is from a group with a version of the gene called MV. This raises fears that the 47% of the population who have this gene are now at risk. Prof Higgins, chairman of the government's Spongiform Encephalopathy Advisory Committee, said: "Given that 160 to 170 MM individuals were infected, we would estimate the number of MV victims would be a maximum of 300 to 350, probably between 50 and 350." (C)BBC

Keyword: Prions
Link ID: 12357 - Posted: 12.18.2008

People who snore heavily or have sleep apnea burn more calories when resting when the condition is more severe, researchers have found. In sleep apnea and other sleep-related breathing disorders, the airways become partially or completely blocked during sleep. Signs include frequent snoring and fatigue during the day. Untreated, sleep apnea can lead to serious health problems, such as an increased risk of heart attack or stroke and accidents. In the December issue of the Archives of Otolaryngology (head and neck surgery, including ears, nose and throat), Dr. Eric Kezirian of the University of California, San Francisco, and his colleagues measured resting energy expenditure, or the number of calories burned while resting, for 212 adults suspected of having sleep-related breathing disorders. Obesity is a major risk factor for developing sleep-related breathing problems, and changes in body mass are linked with changes in the severity of sleep-disordered breathing, the researchers noted. "It is unclear whether weight gain is simply a cause of sleep-disordered breathing or whether sleep-disordered breathing may be associated with alterations in energy metabolism that, in turn, lead to weight gain and complicate the treatment of these two disorders that often coexist," the study's authors wrote. © CBC 2008

Keyword: Sleep
Link ID: 12356 - Posted: 06.24.2010

Parents may think that sugar makes children hyperactive, but it's a myth, say researchers who analyzed evidence on this and other festive medical folklore. For the Christmas issue of the British Medical Journal, Dr. Aaron Carroll and Dr. Rachel Vreeman of the Indiana University School of Medicine debunk common holiday myths that have little evidence in scientific studies or online. The pair said they did the study to remind people of the importance of keeping a healthy skepticism. "Only by investigation, discussion, and debate can we reveal the existence of such myths and move the field of medicine forward," they wrote. For example, the idea that sugar from sweets, chocolates and pop makes children hyperactive is most likely in parents' minds, the researchers said, based on their review of at least 12 studies. Parents were so convinced about the myth that when they think their children have been given a drink containing sugar (when it is actually sugar-free) they rated their children's behaviour as more hyperactive. © CBC 2008

Keyword: ADHD
Link ID: 12355 - Posted: 06.24.2010

When I first heard the term “restless leg syndrome” years ago, I thought it was a joke. It’s not an uncommon reaction. Over at the Freakonomics blog, Stephen J. Dubner saw a commercial about the disorder and thought it was a “Saturday Night Live” spoof. But the people who have the problem aren’t laughing. Restless leg syndrome is a neurological disorder characterized by unpleasant sensations in the legs — often described by people as burning or creeping or like insects crawling inside the legs. The condition, which appears to have a genetic basis, creates an uncontrollable urge to move around. The biggest problem with the condition is that lying down and trying to relax makes it worse. The National Institute of Neurological Disorders and Stroke estimates that restless leg syndrome, or R.L.S., affects as many as 12 million Americans. But the number is a source of debate. Some doctors believe the condition is often misdiagnosed as nervousness or insomnia or under-diagnosed, because sufferers don’t seek medical attention. However, two Dartmouth Medical School researchers have questioned whether “disease mongering” by drug companies has led to an increase in R.L.S. diagnoses. They acknowledge that symptoms can be severe enough to be disabling, but wonder if ad campaigns for drugs to treat the condition have convinced otherwise healthy people that they are sick. Copyright 2008 The New York Times Company

Keyword: Sleep
Link ID: 12354 - Posted: 06.24.2010

By BENEDICT CAREY The book is at least three years away from publication, but it is already stirring bitter debates over a new set of possible psychiatric disorders. Is compulsive shopping a mental problem? Do children who continually recoil from sights and sounds suffer from sensory problems — or just need extra attention? Should a fetish be considered a mental disorder, as many now are? Panels of psychiatrists are hashing out just such questions, and their answers — to be published in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders — will have consequences for insurance reimbursement, research and individuals’ psychological identity for years to come. The process has become such a contentious social and scientific exercise that for the first time the book’s publisher, the American Psychiatric Association, has required its contributors to sign a nondisclosure agreement. The debate is particularly intense because the manual is both a medical guidebook and a cultural institution. It helps doctors make a diagnosis and provides insurance companies with diagnostic codes without which the insurers will not reimburse patients’ claims for treatment. Copyright 2008 The New York Times Company

Keyword: Depression; Schizophrenia
Link ID: 12353 - Posted: 06.24.2010