A man with an unusually tiny brain manages to live an entirely normal life despite his condition, which was caused by a fluid build-up in his skull. Scans of the 44-year-old man's brain showed that a huge fluid-filled chamber called a ventricle took up most of the room in his skull, leaving little more than a thin sheet of actual brain tissue (see image, right). “It is hard for me [to say] exactly the percentage of reduction of the brain, since we did not use software to measure its volume. But visually, it is more than a 50% to 75% reduction,” says Lionel Feuillet, a neurologist at the Mediterranean University in Marseille, France. Feuillet and his colleagues describe the case of this patient in The Lancet. He is a married father of two children, and works as a civil servant. The man went to a hospital after he had mild weakness in his left leg. When Feuillet's staff took his medical history, they learned that, as an infant, he had had a shunt inserted into his head to drain away hydrocephalus – water on the brain. The shunt was removed when he was 14. But the researchers decided to check the condition of his brain using computed tomography (CT) scanning technology and another type of scan called magnetic resonance imaging (MRI). They were astonished to see "massive enlargement" of the lateral ventricles – usually tiny chambers that hold the cerebrospinal fluid that cushions the brain. © Copyright Reed Business Information Ltd.

Keyword: Development of the Brain; Brain imaging
Link ID: 10513 - Posted: 06.24.2010

Katharine Sanderson Grey matter in the brains of people with bipolar disorder is destroyed with each manic or depressive episode. This was the finding of an MRI study of 21 patients with bipolar disorder, a mental illness marked by successive episodes of mania followed by deep depression. The patients' brains were scanned at either end of a four-year period, during which time each patient had at least one episode and some as many as six. In all cases, the amount of grey matter in the temporal lobe and the cerebellum decreased compared to the grey matter in control subjects. These areas of the brain are associated with memory and coordination. Patients that had suffered more episodes over the four years had the most marked difference in the amount of grey matter that had disappeared. "It was significantly correlated to the number of episodes," says Andrew McIntosh, from the University of Edinburgh, and lead author of the paper out today in the Journal of Biological Psychiatry1. Everyone loses brain tissue over time, but the process seems to be accelerated in people with some mental conditions, including schizophrenia and Alzheimer's disease. Now bipolar disorder joins this list. Scientists already had a hunch that bipolar disorder was related to a loss of grey matter, says Lars Kessing at the University of Copenhagen — this is the first evidence to prove them right. ©2007 Nature Publishing Group

Keyword: Schizophrenia
Link ID: 10512 - Posted: 06.24.2010

By Jeanna Bryner All modern humans originated in sub-Saharan Africa, according to a new study touted by its funders as the “final blow” against an opposing viewpoint. Not so fast, says one anthropologist who finds flaws in the evidence. Debate over the origins of modern humans has simmered among anthropologists for years, with one theory asserting that Homo sapiens migrated across the world from a single point in Africa. The other theory states that multiple populations of Homo sapiens independently evolved from Homo erectus in regions beyond Africa. The new study, published in the July 19 issue of the journal Nature, delivers what the researchers say could be the final verdict in support of the single point "Out of Africa" theory. “We have combined our genetic data with new measurements of a large sample of skulls to show definitively that modern humans originated from a single area in sub-Saharan Africa,” said lead researcher Andrea Manica of the University of Cambridge. Manica and colleagues took multiple measurements of more than 4,500 male fossil skulls from 105 populations around the globe. They combined the results with data from studies of global genetic variations in humans, finding that both genetic and skull variability decreased with distance from Africa. So populations in southeastern Africa held the highest variability compared with populations in other countries. © 2007 MSNBC.com © 2007 Microsoft

Keyword: Evolution
Link ID: 10511 - Posted: 06.24.2010

By NICHOLAS WADE Imagine you keep waking up with a fierce urge to move your legs, each time further eroding your sleep quota and your partner’s patience. You have restless legs syndrome, a quaintly named disorder whose sufferers may get more respect now that its genetic basis has been identified. Two independent teams, one in Germany and one in Iceland, have identified three variant sites on the human genome which predispose people to the condition. The advance should help scientists understand the biological basis of the disorder, which could lead to new ideas for treatment. The new findings may also make restless legs syndrome easier to define, resolving disputes about how prevalent it really is. The disorder is a “case study of how the media helps make people sick,” two researchers at Dartmouth Medical School, Steven Woloshin and Lisa Schwartz, wrote recently in the journal PLoS Medicine. They argued that its prevalence had been exaggerated by pharmaceutical companies and uncritical newspaper articles, and that giving people diagnoses and powerful drugs were serious downsides of defining the elusive syndrome too broadly. Discovery of the genetic basis of the disorder “puts restless legs syndrome on a firmer footing,” said Dr. Christopher Earley, a physician at Johns Hopkins University who treats the malady. Copyright 2007 The New York Times Company

Keyword: Sleep
Link ID: 10510 - Posted: 06.24.2010

By Constance Holden People who can't follow a movie when someone else is talking can blame their genes. The ability--or inability--to listen to more than one thing at once is largely inherited, according to a study of twins. The finding could help scientists better understand disorders that involve problems in auditory processing. A few years ago, scientists at the National Institute on Deafness and Other Communication Disorders (NIDCD) in Bethesda, Maryland, discovered that being "tune-deaf" is mostly determined by genes. Now, NIDCD geneticist Robert Morell and colleagues have gauged the heritability of several other auditory abilities by rounding up 194 pairs of same-sex identical and fraternal twins at the annual Twins Day Festival in Twinsburg, Ohio. In a trailer on the site, twins were given auditory tests that involved piping a different sound into each ear simultaneously. Such dichotic listening tasks are often used for studying brain asymmetry. In the competing words test, subjects had to identify two monosyllables, such as "ma" and "ka," one presented to each ear. A more difficult version, the consonant-vowel-consonant test, required subjects to identify two similar-sounding words, such as "bit" and "get." To estimate the genetic contribution to performance, the researchers compared the scores of the fraternal twins, who share, on average, 50% of their genes, with those of the identical twins, who share 100% of their genes. The ability to identify the competing words turned out to be the most heritable. The scientists estimated the genetic contribution at 73%--comparable to the heritability of height or of Type I diabetes, they report in the August issue of Human Genetics. © 2007 American Association for the Advancement of Science

Keyword: Hearing; Genes & Behavior
Link ID: 10509 - Posted: 06.24.2010

Michael Hopkin Neuroscientists have found that people who experience a strong dose of pleasure at the thought of an upcoming reward are more susceptible to the placebo effect. The research shows how the placebo effect, in which patients perceive a benefit from a medical treatment despite it having no genuine therapeutic activity, hinges on the brain's 'reward centre' — a region that predicts our future expectations of positive experiences, and which is also implicated in gambling and drug addiction. Greater activity in this brain region, called the nucleus accumbens, is linked to a stronger placebo effect, the new research shows. This kind of mechanistic understanding of how the brain reacts to placebo treatments could help doctors to boost the effect, argues Jon-Kar Zubieta of the University of Michigan, Ann Arbor, who led the research. "This is driving the idea that you can manipulate the placebo effect, to increase it for therapeutic treatment," he says. Conversely, reducing or eliminating variations in the placebo effect could improve the accuracy of medical trials, which evaluate the effects of new therapies against that of a placebo. Reducing the variation in placebo effects among different volunteers could help to standardize trial results. ©2007 Nature Publishing Group

Keyword: Pain & Touch
Link ID: 10508 - Posted: 06.24.2010

Stephen Pincock, ABC Science Online — If sucking on a slice of lemon sends shudders down your spine, blame your genes. Researchers have found that our ability to taste sourness is strongly influenced by genetic factors. Paul Wise, a researcher from Monell Chemical Senses Center in Philadelphia, and colleagues publish their results in the journal Chemical Senses. The U.S. and Australian team compared the abilities of 74 pairs of identical twins and 35 sets of non-identical twins to taste saltiness and sourness. Because identical twins have nearly identical genes and fraternal twins share about half their genes, genetically speaking, scientists often use twin studies to figure out how much genes affect individual characteristics. In this case, the twins were asked to taste cups of water containing small amounts of sour citric acid, or salt. The researchers kept increasing the concentration of the solution until the twins could recognize the taste. © 2007 Discovery Communications

Keyword: Chemical Senses (Smell & Taste); Genes & Behavior
Link ID: 10507 - Posted: 06.24.2010

Roxanne Khamsi A single protein in the brain seems to exert significant influence over feelings of despair, according to a new study in mice. Rodents engineered to have higher levels of the protein coped better with the frustrating challenges presented to them in the experiment. Researchers speculate that the protein – called delta-FosB – might also help the human brain handle stressful situations better In the experiments, Olivier Berton at the University of Texas Southwestern Medical Center in Dallas, Texas, and his colleagues exposed mice to a test involving mild but painful electric shocks from a wire mesh at the bottom of a cage. The scientists observed how hard each mouse worked to avoid the shocks. Then, brain biopsies revealed that the mice that tried the hardest to escape the shocks had the highest levels of delta-FosB. Next, researchers created mice that overproduce delta-FosB. They did this by injecting a harmless virus loaded with extra copies of the genetic code for delta-FosB into the animals' brains. The team also injected the harmless virus without the extra genetic code into another set of mice, which served as a control group. Both groups of mice showed the same levels of physical activity when left in standard laboratory cages. But the mice responded very differently when challenged by repeated electric shocks. Two days in a row, the scientists placed the mice for an hour in cages that intermittently transmitted such shocks. On the third day, the animals had access to a tiny escape door. © Copyright Reed Business Information Ltd.

Keyword: Depression
Link ID: 10506 - Posted: 06.24.2010

By Josh White The Army plans to begin a program today to educate every soldier about traumatic brain injury and post-traumatic stress disorder. The rare effort to break the perceived stigma within the military on mental health problems comes as increasingly more troops return from battle with serious but undiagnosed conditions. Senior Army leaders are using a "chain-teaching" method to reach all U.S. soldiers, including more than 150,000 who are facing combat in Iraq and Afghanistan, within 90 days. Such a technique extends down the chain of command, with commanders educating their subordinates until individual soldiers are taught by their platoon leaders. Lt. Gen. James L. Campbell, director of the Army staff, said yesterday that the impetus is a growing recognition that brain injuries and mental trauma are real problems that affect soldiers, their families and the general readiness of the Army. But many soldiers have been reluctant to seek help because of a perceived stigma, he said, and others have fallen through the system's cracks and have been overlooked. "We want to try to educate our soldiers and our leaders . . . to be able to recognize the symptoms and then to be aware of the treatment options that are available," Campbell said. "There is a huge culture issue here, and it is this: that those leaders or soldiers who seek help could be perceived as being weak. And the whole thrust behind this program is that if you are in fact someone who needs help, that your desire to get that help is not perceived as a weakness but rather as a strength, as a personal courage to do it." © 2007 The Washington Post Company

Keyword: Brain Injury/Concussion; Stress
Link ID: 10505 - Posted: 06.24.2010

Leigh Dayton, A STUDY of newborn babies and preschoolers has revealed that language may be the root of prejudice - and the way to avoid it. US and French researchers have found that the language babies hear spoken in their first six months of life leads to a preference for speakers of that language. The preference is so entrenched that by age five youngsters prefer playmates who not only speak the same language but do so with the same accent. A key implication of the findings - reported in the US publication Proceedings of the National Academy of Science - is that children exposed to different languages grow into more tolerant adults than their monolingual mates. Linguist Stephen Crain of Sydney's Macquarie University tended to agree: "I've always thought it would be beneficial to expose our children to more than one language," he said. "If they no longer have a prejudice against people who don't sound the same as they, they may be more accepting of people from different backgrounds who don't sound the same," Professor Crain said. Cognitive psychologist Elizabeth Spelke of Harvard University in Cambridge, Massachusetts, conducted a series of experiments with Harvard doctoral student Katherine Kinzler and Emmanuel Dupoux of the National Centre for Scientific Research (CNRS) in Paris. Copyright 2007 News Limited.

Keyword: Language; Emotions
Link ID: 10504 - Posted: 07.18.2007

By David Biello No animal compares to humans when it comes to studying populations over time. Easy to track and occasionally living in relative isolation, Homo sapiens is the only species that keeps detailed records. That is why biologist Virpi Lummaa of the University of Sheffield in England started in 1998 to comb through Finnish church records from two centuries ago for clues about the influence of evolution on reproduction. "I always wanted to work on primates," Lummaa says. "But if I wanted to collect a similar data set on wild chimps, I would be struggling. I've decided to study another primate in the end." The 33-year-old Finnish biologist, aided by genealogists, has pored through centuries-old tomes (and microfiche) for birth, marriage and death records, which ended up providing glimpses of evolution at work in humanity's recent ancestors. Among them: that male twins disrupt the mating potential of their female siblings by prenatally rendering them more masculine; mothers of sons die sooner than those of daughters, because rearing the former takes a greater toll; and grandmothers are important to the survival of grandchildren. "I'm trying to understand human reproductive behavior from an evolutionary perspective," Lummaa says. Most recently, Lummaa and her colleagues studied the effect of males on their female twins. Of 754 twins born between 1734 and 1888 in five towns in rural Finland, girls from mixed-gender pairs proved 25 percent less likely to have children, had at least two fewer children, and were more than 15 percent less likely to marry than those born with a sister. This impact remained the same regardless of social class and other cultural factors and even if the male twin died within three months of birth, leaving the female twin to be reared as if she was an only child, the researchers reported in Proceedings of the National Academy of Sciences USA. © 1996-2007 Scientific American, Inc.

Keyword: Hormones & Behavior
Link ID: 10503 - Posted: 06.24.2010

Kerri Smith 'Southpaw', 'goofy', or just plain 'lefty' are some of the many names that left-handers have been called. In certain societies, the aversion can go so far that some left-handers are forced to write with their right hand, regardless of their natural tendencies. Now, a study of such 'converted' left-handers has found that the way their brains are organized, and how hard particular regions work, changes as a result of this switch. Some areas of the brain continue to look like those of a practising lefty, whereas other areas switch to the patterns of a righty, the research reveals. "The question now is, 'do converts suffer because of this extra attention that they exert?'," says Stefan Klöppel of University College London, who led the work. The answer to that is as yet unknown. The hand used to write with is generally controlled by the opposite side of the brain — in right-handed people, movement-related areas on the left side of the brain are more active when they move the fingers of their right hand. But converting from being left-handed to right-handed doesn't simply move brain activity to the other half of the brain, Klöppel and his colleagues found. ©2007 Nature Publishing Group

Keyword: Laterality
Link ID: 10502 - Posted: 06.24.2010

Your ability to listen to a phone message in one ear while a friend is talking into your other ear — and comprehend what both are saying — is an important communication skill that’s heavily influenced by your genes, say researchers of the National Institute on Deafness and Other Communication Disorders (NIDCD), one of the National Institutes of Health. The finding, published in the August 2007 issue of Human Genetics, may help researchers better understand a broad and complex group of disorders — called auditory processing disorders (APDs) — in which individuals with otherwise normal hearing ability have trouble making sense of the sounds around them. “Our auditory system doesn’t end with our ears,” says James F. Battey, Jr., M.D., Ph.D., director of the NIDCD. “It also includes the part of our brain that helps us interpret the sounds we hear. This is the first study to show that people vary widely in their ability to process what they hear, and these differences are due largely to heredity.” The term “auditory processing” refers to functions performed primarily by the brain that help a listener interpret sounds. Among other things, auditory processing enables us to tell the direction a sound is coming from, the timing and sequence of a sound, and whether a sound is a voice we need to listen to or background noise we should ignore. Most people don’t even realize they possess these skills, much less how adept they are at them. Auditory processing skills play a role in a child’s language acquisition and learning abilities, although the extent of that relationship is not well understood.

Keyword: Hearing; Genes & Behavior
Link ID: 10501 - Posted: 06.24.2010

It was hailed as the "trust" hormone, then the "mind-reading" hormone. Now it seems oxytocin may also help people with social phobia to interact. Markus Heinrichs at the University of Zurich, Switzerland, and colleagues are studying 70 people with generalised social phobia, characterised by overwhelming anxiety and self-consciousness in social situations. Half an hour before undergoing standard cognitive behavioural therapy, which is designed to alter negative thoughts and behaviour, the patients were given a dose of oxytocin by nasal spray. Preliminary results suggest oxytocin improved their readiness to interact in role-playing and their confidence in tackling social challenges outside the sessions, says Heinrichs, who will present his results at the World Congress of Neuroscience in Melbourne, Australia, this week. In a separate study, Heinrichs and colleagues report that oxytocin reduces the response of the amygdala - a brain region involved in the fear response - to pictures of fearful, happy or angry faces (Biological Psychiatry, DOI: 10.1016/j.biopsych.2007.03.025). This may explain why patients are more ready to engage in social situations, Heinrichs believes. © Copyright Reed Business Information Ltd

Keyword: Hormones & Behavior; Emotions
Link ID: 10500 - Posted: 06.24.2010

By DAVID TULLER For decades, people suffering from chronic fatigue syndrome have struggled to convince doctors, employers, friends and even family members that they were not imagining their debilitating symptoms. Skeptics called the illness “yuppie flu” and “shirker syndrome.” But the syndrome is now finally gaining some official respect. The Centers for Disease Control and Prevention, which in 1999 acknowledged that it had diverted millions of dollars allocated by Congress for chronic fatigue syndrome research to other programs, has released studies that linked the condition to genetic mutations and abnormalities in gene expression involved in key physiological processes. The centers have also sponsored a $6 million public awareness campaign about the illness. And last month, the C.D.C. released survey data suggesting that the prevalence of the syndrome is far higher than previously thought, although these findings have stirred controversy among patients and scientists. Some scientists and many patients remain highly critical of the C.D.C.’s record on chronic fatigue syndrome, or C.F.S. But nearly everyone now agrees that the syndrome is real. “People with C.F.S. are as sick and as functionally impaired as someone with AIDS, with breast cancer, with chronic obstructive pulmonary disease,” said Dr. William Reeves, the lead expert on the illness at the C.D.C., who helped expose the centers’ misuse of chronic fatigue financing. Copyright 2007 The New York Times Company

Keyword: Neuroimmunology; Stress
Link ID: 10499 - Posted: 06.24.2010

By NICHOLAS BAKALAR Certain kinds of carbohydrates may play a role in the development of age-related macular degeneration, an incurable degenerative eye disease that is a leading cause of blindness in older adults. A new study has found that eating carbohydrate-rich food with a high glycemic index — a measure of a food’s potential to raise blood glucose levels — is associated with the development of the disorder. The glycemic index is a measure of how fast carbohydrates are metabolized — the faster they are broken down into glucose, the higher the glycemic index. Simple carbohydrates, like those in cakes and cookies, cheese pizza, white bread or other foods sweetened with sugar or corn syrup, are quickly metabolized by the cells, while the complex carbohydrates in brown rice, barley and many other vegetables are broken down more slowly. Heavy consumption of foods with a high glycemic index has been implicated in the development of diabetes, cardiovascular disease and some cancers, according to background information in the paper, which appears in the July issue of The American Journal of Clinical Nutrition. The researchers examined 4,099 people ages 55 to 80 enrolled in a larger long-term study of eye health. Each participant had 20/32 vision in at least one eye, and the lens of the eye had to be clear enough to allow good photographs that could be used to diagnose macular degeneration. Copyright 2007 The New York Times Company

Keyword: Vision
Link ID: 10498 - Posted: 06.24.2010

Researchers say they may have worked out why the obese are more prone to asthma than those of normal weight. The link between the two conditions is well-established, but the relationship is ill-understood. Now scientists at King's College London say they have pinned down a protein which contributes to inflammation of the lungs as well as increasing hunger. The study in the Proceedings of the National Academy of Sciences said further research was now needed. The researchers investigated molecules produced by Th2 cells - specialised cells belonging to the immune system which can inflame the lungs and contribute to the development of asthma. But these cells also produce a protein known as PMCH which is known to increase appetite. "These findings may provide a mechanistic link between allergic inflammation, asthma and obesity," the researchers wrote. Several European and American studies have found a link between obesity and asthma which cannot be explained by weight gain brought on by the inactivity asthma encourages. In many cases, the obesity precedes the asthma. One study of 330,000 patients published earlier this year found that for every normal weight person with asthma, there were 1.5 who were overweight or obese. The latter category effectively ran a 50% greater risk of developing the condition. (C)BBC

Keyword: Obesity; Neuroimmunology
Link ID: 10497 - Posted: 07.17.2007

Heidi Ledford Getting sick often means getting tired too. Now researchers have tracked down how the chemical responsible for such drowsiness works. The culprit is a small protein called tumour necrosis factor alpha (TNF-alpha), named for its anti-tumour properties. This compound was known to trigger inflammation in response to infection and some chronic diseases such as rheumatoid arthritis and multiple sclerosis. And it was known to be linked — somehow — to fatigue. Cancer patients treated with TNF-alpha sometimes report severe lethargy, for example. And patients with a sleep disorder called sleep apnea sometimes report less daytime sleepiness after receiving a drug that interferes with TNF-alpha. But precisely how the protein was affecting sleep habits was unclear. Thomas Birchler, an immunologist at the University Hospital of Zurich in Switzerland, and his colleagues administered TNF-alpha to mice and then monitored the expression of genes involved in the biological clock, the internal timekeeper that tells us when to go to sleep and when to wake up. They found that the genes were expressed in their normal rhythm, rising and falling at designated points during the day. But the overall level of expression of some of these genes was reduced in mice that received the drug. "The oscillations were still in rhythm," says Birchler. "But the output of the clock genes was much reduced." © 2006 Nature Publishing Group

Keyword: Sleep; Neuroimmunology
Link ID: 10496 - Posted: 06.24.2010

Louis Buckley It seems that some chimps surprisingly use less energy walking on two feet than they do loping around on all four limbs. The researchers who discovered the expert walking ability of one chimp say it may help to explain how the earliest humans adapted to standing upright. Chimpanzees normally move about on all fours in a gait known as a 'knucklewalk', says David Raichlen from the University of Arizona in Tucson. "But they can also walk on two legs — when they're carrying things, reaching for fruit, that kind of thing." Raichlen trained five adult chimps to amble on a treadmill using both kinds of locomotion, and he also roped in four humans to strut their stuff at a variety of different speeds. The researchers then measured the amount of oxygen used in each case.1 As expected, chimps were significantly less efficient at walking than humans, using up 75% more energy, irrespective of whether they were walking on two legs or four. This is mainly down to the fact that humans walk using relatively straight legs. This means they can propel themselves along by swinging their rigid appendages, using a minimal amount of muscle. Chimps, on the other hand, generally walk with their knees and hips flexed. ©2007 Nature Publishing Group

Keyword: Evolution
Link ID: 10495 - Posted: 06.24.2010

Colin Barras It used to be easy to separate man from beast. Then we realised animals, too, can experience sophisticated emotions and communicate through language. But there is one thing that is beyond even our closest relatives, chimpanzees. And that is the ability to be spiteful. Keith Jensen and his team at the Max Planck Institute for Evolutionary Anthropology at Leipzig, Germany, conducted experiments in which they placed a food-laden table in front of a caged chimp. Attached to the table was a string the chimp could pull to collapse the table. The chimp resisted the urge to pull the string as long as the food was within its reach. But when the researchers moved the food to the opposite side of the table, the frustrated chimp collapsed the table in 30% of the trials. In a second experiment, the researchers placed a second chimp in a cage at the opposite side of the table. Moving the food across the table now benefited the second chimp at the cost of the first. If the first chimp wanted to be spiteful, it could simply collapse the table and prevent its rival from feeding. But the chimps tested merely showed the same level of frustration as before, collapsing the table 30% of the time. But if the second chimp attempted to move the food closer to itself, by pulling a string of its own, the first chimp reacted angrily, collapsing the table 50% of the time. © Copyright Reed Business Information Ltd.

Keyword: Emotions; Evolution
Link ID: 10494 - Posted: 06.24.2010