Researchers at Melbourne's Howard Florey Institute have discovered how the brain prioritises pain and thirst in order to survive - a mechanism that helps elite athletes to 'push through the pain barrier'. The Florey's Dr Michael Farrell and colleagues discovered that pain sensitivity is enhanced when people are thirsty. The scientists also found that a part of the brain is uniquely activated when pain and thirst are experienced together, suggesting these regions may act as an integrative centre that has a special role in modifying pain senses. Dr Farrell used PET (Positron Emission Tomography) scans to examine changes in brain activity. The 10 individuals participating in the study were given saline injections to stimulate mild thirst and thumb pressure to induce mild pain. Although the level of thumb pressure remained constant throughout the tests, as people became thirstier, they felt more pain. Dr Farrell said the regions of the brain (the pregenual cingulate cortex and ventral orbitofrontal cortex) activated together during thirst and pain acted like a priority switch.

Keyword: Pain & Touch
Link ID: 8469 - Posted: 01.31.2006

By ANAHAD O'CONNOR THE FACTS Is there any link between childbirth and the lunar cycle? Many ancient cultures looked upon the moon as a sign of fertility, and since Roman times people have blamed full moons for all sorts of human behaviors, hence the word lunacy, from the Latin word for moon. But as mysterious and alluring as the link between full moons and births may sound, scientific studies suggest that it is more romance than reality. Over the years, more than a dozen different studies in several countries have looked for a connection, and almost all have found none. One of the most recent, published last year in The American Journal of Obstetrics and Gynecology, examined about 564,000 births across 62 lunar cycles in North Carolina between 1997 and 2001. The lunar cycle, the study found, had no predictable influence on deliveries or birth complications at all. Copyright 2006 The New York Times Company

Keyword: Biological Rhythms
Link ID: 8468 - Posted: 01.31.2006

By HENRY FOUNTAIN You can shout until you're hoarse, but you can't shout until you're deaf. One reason, scientists think, is a phenomenon called corollary discharge signaling. When your brain sends a signal to various muscles to speak, a copy of the signal goes to the auditory system, desensitizing it so it doesn't get overloaded. That's the idea, anyway. But very little is known about how corollary discharges work. Now James F. A. Poulet and Berthold Hedwig of the University of Cambridge in England have found a key to the puzzle. They studied crickets, however, not humans. "Crickets have a very simple nervous system and make very loud noises," said Dr. Poulet, who is now at the Federal Polytechnical School of Lausanne in Switzerland. Crickets do chirp very loudly — sound pressure levels have been measured at more than 100 decibels — yet they don't deafen themselves. Several years ago, Dr. Poulet and Dr. Hedwig discovered that at the precise instant a cricket moved its forewing muscles to create a chirp, its auditory neurons became inhibited, or desensitized, presumably by some chemical neurotransmitter. "We knew that the inhibition was being generated somewhere in the nervous system, but we didn't know where," Dr. Poulet said. Copyright 2006 The New York Times Company

Keyword: Hearing
Link ID: 8467 - Posted: 06.24.2010

By RONI RABIN Candace Talmadge was determined to get through menopause without using hormones, and she tried just about every alternative treatment she could find, like soy tablets, herbs and acupuncture, a chiropractor and even an anti-anxiety medication. "There are always risks to any medication you take, whether it's traditional or nontraditional," said Ms. Talmadge, 51, an author from Lancaster, Tex. "But I've been going through hell. I think my doctor's attitude was, 'Do the benefits for you, right now, outweigh the risks?' " Three and a half years after a landmark study stunned physicians by finding that hormone therapy had serious risks and did not prevent heart disease in postmenopausal women, many women continue to turn to hormones for relief. Many gynecologists continue to prescribe them as a first-line therapy for severe menopausal symptoms. Debates over the study's findings remain heated, with doctors divided between those who believe in the power of hormone therapy to protect the heart and relieve menopausal symptoms and those who think that any heart benefits have been discredited. Copyright 2006 The New York Times Company

Keyword: Hormones & Behavior
Link ID: 8466 - Posted: 01.31.2006

Changes in the brain that are important indicators of bipolar disorder are not prominent until young adulthood and are reduced in persons taking mood-stabilizing medications, Yale School of Medicine researchers report this month in Biological Psychiatry. The researchers used magnetic resonance imaging to measure a part of the brain that regulates emotions, the ventral prefrontal cortex, that lies above the eyes. The changes in persons with bipolar disorder were not prominent until young adulthood, suggesting that the illness progresses during the teenage years. Bipolar disorder is also known as manic-depressive illness. "The brain changes were diminished in persons with bipolar disorder who were taking mood-stabilizing medications," said Hilary Blumberg, M.D., associate professor in the Department of Psychiatry and director of Yale's Mood Disorders Research Program. "This brings hope that it may someday be possible to halt the progression of the disorder." Blumberg added, "Research to understand bipolar disorder in youths is especially important because of their high risk for suicide."

Keyword: Schizophrenia; Depression
Link ID: 8465 - Posted: 01.31.2006

PHILADELPHIA When Sylvia the baboon lost Sierra, her closest grooming partner and daughter, to a lion, she responded in a way that would be considered very human-like: she looked to friends for support. According to researchers from the University of Pennsylvania, baboons physiologically respond to bereavement in ways similar to humans, with an increase in stress hormones called glucocorticoids. Baboons can lower their glucocorticoid levels through friendly social contact, expanding their social network after the loss of specific close companions. "At the time of Sierra's death, we considered Sylvia to be the queen of mean. She is a very high-ranking, 23 year-old monkey who was, at best, disdainful of females other than Sierra," said Anne Engh, a postdoctoral researcher in Penn's Department of Biology. "With Sierra gone, Sylvia experienced what could only really be described as depression, corresponding with an increase in her glucocorticoid levels." Engh works with Penn biologist Dorothy Cheney and Robert Seyfarth, a professor in Penn's Department of Psychology. For the last 14 years, Cheney and Seyfarth have followed a troop of more than 80 free-ranging baboons in the Okavango Delta of Botswana. Their research explores the mechanisms that might be the basis of primate social relationships and how such relationships may have influenced the development of human social relationships, intelligence and language. Copyright © 2005, University of Pennsylvania

Keyword: Stress
Link ID: 8464 - Posted: 06.24.2010

Traditional polygraph tests to determine whether someone is lying may take a back seat to functional magnetic resonance imaging (fMRI), according to a study appearing in the February issue of Radiology. Researchers from Temple University Hospital in Philadelphia used fMRI to show how specific areas of the brain light up when a person tells a lie. "We have detected areas of the brain activated by deception and truth-telling by using a method that is verifiable against the current gold standard method of lie detection--the conventional polygraph," said lead author Feroze B. Mohamed, Ph.D., Associate Professor of Radiology at Temple. Dr. Mohamed explained how the standard polygraph test has failed to produce consistently reliable results, largely because it relies on outward manifestations of certain emotions that people feel when lying. These manifestations, including increased perspiration, changing body positions and subtle facial expressions, while natural, can be suppressed by a large enough number of people that the accuracy and consistency of the polygraph results are compromised. "Since brain activation is arguably less susceptible to being controlled by an individual, our research will hopefully eliminate the shortcomings of the conventional polygraph test and produce a new method of objective lie detection that can be used reliably in a courtroom or other setting," Dr. Mohamed said.

Keyword: Stress; Brain imaging
Link ID: 8463 - Posted: 01.31.2006

By Rossella Lorenzi, Discovery News Abraham Lincoln may have carried a genetic mutation responsible for the neurological disorder ataxia, according to U.S. researchers who screened descendants of the 16th president. Laura Ranum, a genetics professor at the University of Minnesota, and colleagues discovered that a type of ataxia, called Spinocerebellar ataxia type 5 (SCA5), is linked to a mutation in an amino-acid protein which plays an important role in maintaining the health of nerve cells. The gene breakthrough was made thanks to DNA from the Lincoln family: the researchers identified the mutation in an 11-generation family descended from the president's paternal grandparents, Capt. Abraham Lincoln and Bathsheba Herring. Overall, Ranum examined and collected DNA samples from 299 Lincoln family members and found that about a third have ataxia. "We are excited about this discovery because it provides a genetic test that will lead to improved patient diagnoses and gives us new insight into the causes of ataxia and other neurodegenerative diseases, an important step towards developing an effective treatment," Ranum said in a statement. © 2006 Discovery Communications Inc.

Keyword: Movement Disorders; Genes & Behavior
Link ID: 8462 - Posted: 06.24.2010

Stu Hutson The curative properties of stem cells may rely on prions, a new study suggests, the type of protein made infamous by mad cow disease. Prions are a special class of protein that can change the shape and function of other proteins around them. While these are found throughout any mammal’s body, the understanding of their biological role is limited. What is known is that prions that become misshapen, through some unknown process, can result in BSE (bovine spongiform encephalopathy) – mad cow disease – and its equivalents in other animals. Researchers at the Whitehead Institute in Cambridge, Massachusetts, US, have now found that adult stem cells in bone marrow gradually lose their ability to regenerate without their normal complement of membrane-bound prions. Stem cells are primitive cells which have the potential to divide endlessly, and the ability to differentiate into any cell type in the body – offering hope for future therapies. Andrew Steele, Cheng Cheng Zhang and colleagues used radiation to deplete the bone marrow of mice genetically engineered to not produce the prion proteins. The animals’ marrow regenerated quickly at first, but eventually slowed to a stop. The marrow also lost its regenerative abilities when transplanted into normal mice. © Copyright Reed Business Information Ltd

Keyword: Prions; Stem Cells
Link ID: 8461 - Posted: 06.24.2010

Highly analytical people, such as scientists who fall for each other, may be more likely to produce children with autism, an expert has argued. Professor Simon Baron-Cohen, of the University of Cambridge, said the phenomenon may help explain the recent rise in diagnoses. He believes the genes which make some analytical may also impair their social and communication skills. A weakness in these areas is the key characteristic of autism. It is thought that around one child in every 100 has a form of autism - the vast majority of those affected are boys. The number of diagnoses seems to be on the increase, but some argue this is simply because of a greater awareness of the condition. In a paper published in the journal Archives of Disease of Childhood, Professor Baron-Cohen labels people such as scientists, mathematicians and engineers as 'systemizers'. They are skilled at analysing systems - whether it be a vehicle, or a maths equation - to figure out how they work. But they also tend to be less interested in the social side of life, and can exhibit behaviour such as an obsession with detail - classic traits associated with autism. Professor Baron-Cohen argues that systemizers are often attracted to each other - and thus more likely to pass 'autism' genes to their offspring. He cited a survey of 1,000 members of the National Autistic Society which found fathers and grandfathers of children with autistic spectrum conditions are twice as likely to work in a systemizing profession. In addition, students in the natural sciences have a higher number of relatives with autism than do students in the humanities, and mathematicians have a higher rate of autistic spectrum conditions compared with the general population. (C)BBC

Keyword: Autism; Genes & Behavior
Link ID: 8460 - Posted: 01.30.2006

Andrew D. M. Smith Languages are constantly changing—being endlessly reinvented and reworked by the people who use them. In his compelling new book, The Unfolding of Language, Guy Deutscher argues that the same simple processes that underlie the rich and dynamic variety of modern human languages can also explain the initial emergence of complex language from its primitive beginnings. Deutscher, a specialist in ancient Semitic languages and a lecturer in linguistics at the University of Leiden in the Netherlands, notes that people have always complained about the state of their language, bemoaning its misuse (departures from "proper" language) and its degeneration from a once-glorious past into an error-ridden, chaotic mess. Even Cicero grumbled that the Latin of his time had deteriorated from that of the previous century. Deutscher explains that such complaints are depressingly inevitable, because "decay . . . is the aspect of change that is by far the most easily observable." But he also shows that, beneath the surface, the linguistic forces that conspire to erode language are closely related to the more elusive, but just as ineluctable, forces of renewal and reconstruction. Deutscher illuminates his absorbing analysis of humanity’s "greatest invention" with a detailed investigation of what he identifies as the three main forces of change: economy, expressiveness and analogy. The first of these, economy, occurs because speakers are intrinsically lazy and therefore seldom inclined to expend more effort in pronunciation than is absolutely necessary for the listener to understand their meaning. © Sigma Xi, The Scientific Research Society

Keyword: Language; Evolution
Link ID: 8459 - Posted: 06.24.2010

New study results bolster the controversial hypothesis that certain cases of obesity are contagious. Over the last 20 years, some research has suggested that certain strains of human and avian adenoviruses--responsible for ailments ranging from the chest colds to pink eye--actually make individuals build up more fat cells. Having antibodies to one strain in particular, so-called Ad-36, proved to correlate with the heaviest obese people and in one study, pairs of twins differed in heft depending on exposure to that virus. Now researchers have identified another strain of adenovirus that makes chickens plump. Physiologist Leah Whigham of the University of Wisconsin Madison and her colleagues inoculated young male chickens with three strains of adenovirus--Ad-2, Ad-31 and Ad-37. She and her team then monitored the chickens for three and a half weeks, recording their food intake throughout. Though the infected chickens and non-infected controls consumed the same amount of food and were exposed to the same conditions, chickens carrying Ad-37 were found to have nearly three times as much fat in their guts and more than two times as much fat over their entire body at the end of the three-and-a-half week period. The other two virus strains appeared to have little effect on weight. "Ad-37 is the third human adenovirus to increase adiposity in animals, but not all adenoviruses produce obesity," Whigham and her fellow authors write in their report presenting the findings in the current issue of the American Journal of Physiology. Although it remains unclear exactly how Ad-37 adds fat, it joins a growing list of such viruses, including canine distemper, Ad-5 and Ad-36. © 1996-2006 Scientific American, Inc.

Keyword: Obesity
Link ID: 8458 - Posted: 06.24.2010

Undamaged nerve fibres - not those that are injured - may cause long-term chronic pain, research suggests. Ongoing pain affects one-in-five adults across Europe, and costs an estimated £23 billion a year in lost work days. Inflammation caused by damaged nerve fibres triggered nearby undamaged ones to send signals to the brain, the University of Bristol researchers said. In the journal Neuroscience, they say their finding may aid the development of more effective painkillers. Ongoing pain is a burning or sharp stabbing/shooting pain that can occur spontaneously after nerve injury - unlike "evoked" pain caused, for example, by hitting your thumb with a hammer. It is particularly difficult to live with because it is often impossible to treat with currently available painkillers. Previous research into ongoing pain has tended to focus on the damaged nerve fibres after injury or disease and overlooked the intact fibres. Lead researcher Professor Sally Lawson said: "The cause of this ongoing pain and why it arises spontaneously was not understood before. Now that we know the type of nerve fibres involved, and especially that it is the undamaged fibres that cause this pain, we can examine them to find out what causes them to continually send impulses to the brain. This should help in the search for new analgesics that are effective for controlling ongoing pain." (C)BBC

Keyword: Pain & Touch
Link ID: 8457 - Posted: 01.28.2006

By Justin Gillis The Food and Drug Administration yesterday approved an inhaled form of insulin, the first new way to get that hormone into the body since it was discovered in 1921 -- and a new treatment option for many of the 21 million Americans with diabetes. The approval fulfills an arduous scientific quest that spanned most of the 20th century and spilled over to the 21st. And it marks the biggest change in diabetes treatment in decades, one that doctors hope will lure a fair slice of the American population into their offices to talk about controlling blood sugar. The product poses long-term safety questions, though, and it's not clear yet whether it will be more expensive than standard insulin. Millions of Americans need treatment with insulin but don't get it because it involves frequent, painful needle sticks and injections. About 5 million take the hormone, but a high proportion inject themselves too few times during the day because it's so inconvenient. Doctors hope inhaled insulin will overcome some of that resistance, helping diabetics ward off a slew of medical problems that afflict those who don't control their disease. © 2006 The Washington Post Company

Keyword: Obesity
Link ID: 8456 - Posted: 06.24.2010

By Karen Heyman Researchers have found a way to use femtosecond lasers to cause strokes deep in the brains of rats. The technique should help researchers create more realistic rodent models of stroke and aid the search for human therapies. There are two basic types of stroke: an ischemic stroke, in which a blood vessel is blocked, and a hemorrhagic stroke, in which a blood vessel ruptures and bleeds out. In both cases, the tissue fed by the vessel dies because it doesn't receive enough oxygen. Existing whole animal stroke models cannot separate these different aspects properly for study. In addition, researchers are seeking to create "microstrokes," in which only one small, individual blood vessel is damaged. An accumulation of microstrokes can cause cognitive deficits that are often confused with the initial symptoms of Alzheimer's disease. To help develop a better rat model for strokes, physicist David Kleinfeld, neurologist Patrick Lyden, and colleagues at the University of California, San Diego, turned to femtosecond lasers. Traditionally used for cutting material such as glass, the lasers create short, high-energy pulses of light. Using the lasers on living brain tissue for the first time, the team found that, when concentrated to a precise point, the femtosecond laser light vaporized tissue in rats, creating either blockages or ruptures in individual blood vessels, depending on the intensity. © 2006 American Association for the Advancement of Science.

Keyword: Stroke
Link ID: 8455 - Posted: 06.24.2010

Susan Milius As the morning mists rose on the slopes of Ecuador's Pasochoa volcano, the burbling of plain-tailed wrens came through the bamboo thickets. Two researchers started their standard procedure of catching wrens, banding them, and letting them go. Soon, however, they were startled when a small cluster of wrens settled into a bush and began singing together. It turned out to be "one of the most complex singing performances yet described in a nonhuman animal," says Nigel Mann. Mann, of the State University of New York at Oneonta, and a colleague had gone to Pasochoa in the summer of 2002 as part of a team that was surveying of the 28-or-so species of the bird genus Thryothorus. That genus is famous for musical duets, in which a male and a female alternate phrases, sometimes so rapidly that it sounds like one song. Ecuador's plain-tailed wrens (Thryothorus euophrys), relatives of North America's Carolina wren, make a rhythmic, bubbling song together. Most other wrens in this genus pair off and fiercely defend a territory. "If [four wrens] actually got within a few feet of each other, they'd be fighting," says Mann. That's why he and Kimberly A. Dingess of Indiana University at Bloomington were so surprised to find several plain-tailed wrens sharing a bush. "It took a few hours of wandering around for us to realize we had a group-living species," Mann says. Copyright ©2006 Science Service.

Keyword: Language; Sexual Behavior
Link ID: 8454 - Posted: 06.24.2010

Why does one person like to skydive or ski off cliffs while someone else is happy reading a book? After studying mouse behavior, scientists now have a clue into a certain gene that may be a factor. Jim Olson of Seattle's Fred Hutchinson Cancer Institute led the team making the discovery. The gene, called neurod2, helps in the formation of a part of the brain called the amygdala. Olson says the gene, "Turns on all the other genes that are needed for a [stem] cell to become a nerve cell [for the brain] instead of some other kind of cell." The amygdala is important in the process of thrill seeking because it is the part of that's brain central to your emotions and your ability to sense danger. It's designed to keep us out of dangerous situations by helping us store in our long-term memory moments that are especially frightening or emotionally stressful. Olson offers his own example of a negative emotional memory from scout camp: he describes counselors sounding a siren at all hours that signaled a water rescue drill. "For almost a year after that, every time I heard a siren I'd get sick to my stomach," he says. Mice normally have two copies of the neurod2 gene. But Olson's team modified mice to have either just one copy or no copies of the gene. As they reported in the journal Proceedings of the National Academy of Sciences, they then studied the mice's behavior as compared with normal mice. © ScienCentral, 2000-2006.

Keyword: Genes & Behavior; Emotions
Link ID: 8453 - Posted: 06.24.2010

Does the sight of a snake make you squirm? Perhaps taking to the air makes you feel faint. Or maybe just the thought of going outside brings you out in a cold sweat. For some, fears are just an inconvenience, but for people who suffer from fear and anxiety disorders, such as post-traumatic stress disorder and phobias, fear can be a major part of their day and even restrict how they live their lives. But even deeply ingrained fears can be unlearned, says New York University psychologist and neuroscientist Liz Phelps. And she's used brain imaging to see what happens in the brain when we gradually confront our fears to "extinguish" them. "It's essentially new learning. Previously you've learned that something is something that you should be afraid of, and now by being exposed to it and not having adverse consequences, you're learning that there really is nothing to be afraid of in this situation," Phelps explains. As featured in Scientific American Mind, Phelp's colleague Joseph LeDoux, who's spent more than 20 years studying how the brain responds to fear. He discovered that a primitive, almond-shaped brain region called the amygdala reacts instantly to a fear stimulus and gets us ready to fight or flee. © ScienCentral, 2000-2006.

Keyword: Emotions
Link ID: 8452 - Posted: 06.24.2010

A new UCLA/Veterans Affairs study implicates defects in the machinery that creates connections between brain cells as responsible for the onset of Alzheimer disease. The defect in PAK enzyme signaling pathways -- vital to creation of these connections, or synapses -- is related to loss of a synapse protein in certain forms of mental retardation, such as Down syndrome. The new finding suggests therapies designed to address the PAK defect could treat cognitive problems in both patient populations. The peer-reviewed journal Nature Neuroscience published the study online Jan. 15. "The emerging lesson is that cognitive problems in Alzheimer disease are related to defects in the machinery controlling neuronal connections, not the lesions observed by pathologists," said principal investigator Greg Cole, professor of medicine and neurology at the David Geffen School of Medicine and Alzheimer Disease Research Center at UCLA, and the Geriatric Research Education and Clinical Center at the Veterans Affairs Greater Los Angeles Health Care System and Sepulveda Ambulatory Care Center. "Our findings show that PAK defects in the brains of Alzheimer patients appear sufficient to directly cause cognitive difficulties." In some families, early-onset Alzheimer disease can be caused by mutations in different genes that all increase the production of a sticky protein called Abeta42 (Ab42). The increase causes the protein to form aggregates, little clusters or long filaments that pile up and make lesions in the brain called plaques.

Keyword: Alzheimers
Link ID: 8451 - Posted: 01.27.2006

Debora MacKenzie The infectious prions that cause Chronic Wasting Disease, an infection similar to BSE that afflicts North American deer and elk have been found in the parts of the animals that people eat. No one knows if CWD can jump to humans, but if it does hunters in affected areas might be at risk. CWD was first diagnosed as a spongiform encephalopathy in captive deer and elk in Colorado in the 1970s, and in wild deer and elk in the region in the 1980s. But in the 1990s it spread widely within the elk farming industry, jumped to wild deer, and now affects two provinces of Canada and 13 US states. Like the related sheep disease scrapie – though unlike BSE – CWD spreads from animal to animal, says Glenn Telling of the University of Kentucky at Lexington, US. Deer housed with infected animals, or fed infected brain experimentally, contract the disease. Because of this there are fears that the CWD prion might be distributed widely in the deer’s tissues – as scrapie is in sheep. Efforts to find the infectious prion in the muscle of infected animals, by seeing whether antibodies to the prion could find any and bind on, have previously failed. But Telling’s lab has now shown that diseased prions can reside in muscle of deer infected with CWD, by using transgenic mice. © Copyright Reed Business Information Ltd.

Keyword: Prions
Link ID: 8450 - Posted: 06.24.2010