Scientists have figured out why your skin tenses up and your teeth chatter when an icy blast of wintry wind whips past: The brain’s wiring system monitors the temperature of the skin and decides when the shivering should commence. Shivering is one of the many automatic and subconscious functions that the body performs to regulate itself. Other so-called homeostatic functions include the adjustment of breathing rates, blood pressure, heart rate and weight regulation. Shivering is essentially the body's last-ditch effort to keep itself warm. "Shivering, which is actually heat production in skeletal muscles, requires quite a bit of energy and is usually the last strategy the body uses to maintain its internal temperature to survive in a severe cold environment," said Oregon Health & Science University research fellow Kazuhiro Nakamura. Nakamura and his colleagues studied rats and traced the shivering sensory pathway from the rodents' skin to specialized cells in a portion of the brain called the lateral parabrachial nucleus. These cells can then transmit information to another part of the brain, the preoptic area, which decides when the body should start shivering. © 2007 LiveScience.com

Keyword: Miscellaneous
Link ID: 11116 - Posted: 06.24.2010

Jennifer Viegas, Discovery News -- Treatments for depression range from medicines that can come with scary side effects to electric shock therapy, but a new paper suggests a simple cold shower might sometimes cure, and even prevent, the debilitating mood disorder. Cleanliness may be a pleasant side effect, but the key lies in the water temperature. The study's author, Nikolai Shevchuk, believes the biological explanation revolves around a part of the brainstem known, appropriately enough, as the locus ceruleus, or "blue spot." Shevchuk, who formulated the theory while working in the Department of Radiation Oncology at Virginia Commonwealth University School of Medicine, told Discovery News that short, cold showers may stimulate the blue spot, which is the brain's primary source of noradrenaline -- a chemical that could help mediate depression. "The possible antidepressant effect may also have to do with the mild electroshock delivered to the brain by a cold shower, because of the unusually high density of cold receptors in the skin," he added, explaining that these nerve endings are 3-10 times higher in density than those registering warmth. © 2007 Discovery Communications, LLC.

Keyword: Depression
Link ID: 11115 - Posted: 06.24.2010

Heidi Ledford Animals need to get oxygen to their brain during long dives.ALAMYMarine mammals have an uncanny ability to remain awake and alert while holding their breath during long dives. New research shows that this might be thanks to high concentrations of oxygen-binding proteins in the brain. The proteins, called globins, could help these mammals to remain active long after blood oxygen levels sink low enough to cause a human to black out. Some marine mammals can spend more than 90 minutes under water, altering their physiology to make the most of their limited oxygen supply. Their heartbeats slow down, and blood flow is prioritized to the brain by mobilizing oxygen stores in muscles and constricting blood vessels leading to peripheral tissues. They can also suppress their shivering instinct in cold waters, allowing their body temperature to drop, again conserving oxygen (see Seals don't shiver in chilly waters). These changes are similar to those seen in hibernation, leading some to speculate that diving mammals enter a sort of torpor. But Terrie Williams, a marine-mammal physiologist at the University of California at Santa Cruz, has observed mammals during their dives and knows that they often remain active. "They’re alert, their eyes are moving around watching you," says Williams. "These are not animals that appear to be asleep or hibernating. They’re on top of their game." © 2007 Nature Publishing Group

Keyword: Stroke
Link ID: 11114 - Posted: 06.24.2010

CHICAGO - A mutation in a single gene may raise one's risk of developing amyotrophic lateral sclerosis (ALS), also know as Lou Gehrig's disease, by as much as 30 percent, offering a potential new target for drug research, Dutch scientists said on Sunday. They said a variant in the DPP6 gene may give rise to ALS in people without a family susceptibility to the untreatable and fatal disease. Familial ALS, which accounts for 10 percent of all cases of the disease, has been linked with mutations in a number of other genes. Researchers have had less luck finding a gene associated with non-familial, sporadic ALS, which accounts for 90 percent of ALS cases. But researchers at the University Medical Center Utrecht said a SNP or single-letter change in the genetic code of the DPP6 gene is "consistently and strongly associated with susceptibility to amyotrophic lateral sclerosis in different populations of European ancestry." The DPP6 gene controls an enzyme found mostly in the brain that has been linked with spinal cord injury in rats. (c) Reuters 2007.

Keyword: ALS-Lou Gehrig's Disease ; Genes & Behavior
Link ID: 11113 - Posted: 12.18.2007

By RICHARD A. FRIEDMAN, M.D. In a few days, the winter solstice will plunge us into the longest and darkest night of the year. Is it any surprise that we humans respond with a holiday season of relentless cheer and partying? It doesn’t work for everyone, though. As daylight wanes, millions begin to feel depressed, sluggish and socially withdrawn. They also tend to sleep more, eat more and have less sex. By spring or summer the symptoms abate, only to return the next autumn. Once regarded skeptically by the experts, seasonal affective disorder, SAD for short, is now well established. Epidemiological studies estimate that its prevalence in the adult population ranges from 1.4 percent (Florida) to 9.7 percent (New Hampshire). Researchers have noted a similarity between SAD symptoms and seasonal changes in other mammals, particularly those that sensibly pass the dark winter hibernating in a warm hole. Animals have brain circuits that sense day length and control the timing of seasonal behavior. Do humans do the same? In 2001, Dr. Thomas A. Wehr and Dr. Norman E. Rosenthal, psychiatrists at the National Institute of Mental Health, ran an intriguing experiment. They studied two patient groups for 24 hours in winter and summer, one group with seasonal depression and one without. Copyright 2007 The New York Times Company

Keyword: Depression; Biological Rhythms
Link ID: 11112 - Posted: 06.24.2010

Carl Zimmer, New York Times The word "big" doesn't do justice to whales. Humpback whales can weigh up to 40 tons. Fin whales have been known to reach 80 tons. Blue whales, the biggest animals to have ever lived, reach 160 tons - the same mass as about 2,000 grown men or 5 million grown mice. It takes a lot of food to build such giant bodies, but how exactly the biggest whales get so much has long been a mystery. "We don't have much of a sense of these animals in their natural environments," said Nick Pyenson, a biologist at UC Berkeley. For decades, whale experts had only indirect clues. "It's primarily from dead animals or from a few people standing on a ship seeing whales come to the surface," he said. With so little information, scientists have struggled to make sense of several enigmas about the biggest whales. "It's always been a mystery why they have really short dives for their body size," Pyenson said. The bigger a marine mammal is, the longer it should be able to dive for food, because it has more muscle tissue in which it can store oxygen. Other species follow this pattern, but the biggest whales do not. Pyenson and his colleagues may have solved some of the gastronomical mysteries of these leviathans by creating the first detailed biomechanical model of a feeding fin whale. In essence, they have created the world's biggest gulp. © 2007 Hearst Communications Inc.

Keyword: Obesity
Link ID: 11111 - Posted: 06.24.2010

By John Cannon The Cuvier's beaked whale is a master of the ocean's crushing depths. It can dive as deep as 2 kilometers in search of prey, the deepest known for any mammal. So scientists have been at a loss to explain why, in response to naval sonar testing, this champion cetacean sometimes succumbs to the same decompression sickness that afflicts scuba divers. A new mathematical model suggests that, by replicating the sounds of a predator, sonar forces the whale to adopt a risky diving pattern. Researchers have suspected a link between sonar testing and whale deaths for nearly 20 years. In 2000, the U.S. Navy said its sonar exercises led six beaked whales to fatally beach themselves in the Bahamas, and stranded whales have died near sonar-testing sites in at least five other cases since then. It hasn't been clear how the sonar disorients the animals and causes such strandings, but some marine biologists suspect that the intense sound waves force whales to shoot to the surface, and they've found evidence that tiny nitrogen bubbles expand in the whales' tissues and damage vital organs (ScienceNOW, 9 October 2003). The same thing happens when scuba divers surface too quickly--a condition known as the bends. But a whale holds its breath when diving, preventing nitrogen buildup, so the theory didn't seem to hold water. A group led by marine biologist Peter Tyack of Woods Hole Oceanographic Institution in Massachusetts suspected that whales alter their diving behavior in some other way. Whales make repeated shallow dives when trying to evade predators. The team wondered whether such behavior could be risky, especially because naval sonar--which is similar in frequency to the calls of the beaked whale's most feared adversary, the killer whale--could be forcing the whales to adopt a similar diving pattern. © 2007 American Association for the Advancement of Science.

Keyword: Hearing
Link ID: 11110 - Posted: 06.24.2010

By Benjamin Lester Thirsty old folks drink less water than parched whippersnappers because their brains are more easily satisfied, according to a new study. The findings suggest that the brain's satiation mechanisms malfunction as we age and might help explain why seniors are at greater risk for dehydration. Feelings of thirst stem from two main changes in the blood: a higher concentration of salts and a lower concentration of water. Ordinarily, the feeling of thirst prompts us to drink enough water to restore a balance. However, researchers have known for several years that older people tend to drink less, and the reason has remained unclear. Curious about whether the fault lay in the brain, a team led by neuroscientists from the University of Melbourne in Australia induced thirst in 10 men in their 20s and in 12 men in their 60s or 70s by injecting them with a salty solution. The scientists then spied on the subjects' brains using positron emission tomography, which measures changes in blood flow. The salt cocktail prompted similar feelings of thirstiness in the young and old subjects, as well as similar changes in cerebral blood flow. However, the older men drank nearly 50% less water than did the younger men. A possible explanation showed up in the brain scans. In the older subjects, blood flow to a brain region called the anterior midcingulate cortex--a regulatory area that was previously linked to feelings of thirst--decreased much more per sip than it did in the younger group. © 2007 American Association for the Advancement of Science.

Keyword: Development of the Brain
Link ID: 11109 - Posted: 06.24.2010

It's your snapshot of the Statue of Liberty. It's just like a thousand others taken that day, but this one is yours. So, you upload it to an Internet-based photo sharing service for everyone to see. Among those who might see your photo and thousands of similar photographs are computer scientists who have created a computer program to combine tourist photos to create accurate 3-D models of such places as the Statue of Liberty or Notre Dame Cathedral. "The images can be quite general," says Steve Seitz, Associate Professor in the University of Washington's Department of Computer Science and Engineering. He adds, "They can be day or night. They can be almost any viewpoint you want. There could be lots of people in the foreground obstructing the architecture and it will still work pretty well." "What the algorithm (computer program) is doing is it's taking a set of photos, trying to figure out which parts of the photos overlap with each other," Seitz says. Photographs turn the three-dimensional or 3-D world into a flat two-dimensional or 2-D representation. This program reverses the process. "To produce a reconstruction we have to figure out for every 2-D position in the image what its 3-D coordinates are," Seitz explains. © ScienCentral, 2000-2007.

Keyword: Vision
Link ID: 11108 - Posted: 06.24.2010

Jennifer Viegas, Discovery News -- Most snakes give off a subtle odor that's akin to gamey fried chicken, but it is a useful smell to rock squirrels and California ground squirrels, which chew shed rattlesnake skins and then lick their fur with their snake-scented spit, according to a new study. The rather indelicate ritual likely helps squirrels fool their rattlesnake arch nemeses. The discovery may represent the first documented instance of a vertebrate self-applying a chemical from a foreign source in order to defend itself against predators. The squirrels don't even seem to like the taste or texture of rattlesnake skin. "As far as we can tell, they do not consume the skin and at times we would see pieces of the skin stuck onto the squirrels' fur after they licked their bodies," lead author Barbara Clucas told Discovery News. Clucas, a scientist in the Animal Behavior Graduate Group at the University of California at Davis, and her colleagues witnessed the behavior while studying squirrels and rattlesnakes at Lake Solano County Park in California and at Caballo Lake State Park, New Mexico. Similar to how a person might always apply scent onto certain select areas, the squirrels typically twist to the side, lick their flanks and then grab their tail with their forepaws and lick the tail from its base to its tip. Like a big powder puff, the tail might help to waft the rattlesnake scent into the air. © 2007 Discovery Communications, LLC.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 11107 - Posted: 06.24.2010

Heidi Ledford A mathematical competition between two rhesus macaques and fourteen undergraduates has revealed a new similarity between monkeys and college students: their ability to handle basic addition. In the battle of man versus macaque, students bested the monkeys for overall accuracy at 94% to 76%. But response times during a computerized test of addition were approximately the same in the two groups. Both groups were more likely to stumble as the magnitude of the sums increased. Such similarities, researchers say, suggest an evolutionary continuity between basic mathematical skills in humans and other primates. The results are published this week in PLoS Biology 1. The fact that monkeys can handle basic arithmetic is not in itself new, as it had been suggested by previous work. If monkeys watch as lemons are placed behind a screen, for example, they will stare longer at the fruit if the screen is lifted to reveal an incorrect sum of lemons2. Their apparent surprise when the number of lemons revealed isn't what was expected suggests the presence of rudimentary mathematical ability, says Jessica Cantlon of Duke University in Durham, North Carolina. © 2007 Nature Publishing Group

Keyword: Intelligence
Link ID: 11106 - Posted: 06.24.2010

BUFFALO, N.Y. - Firefighters waited in the hospital's hallways, the campfire smell of their last call still heavy on their turnout gear. Word had spread quickly among the Buffalo department's ranks. Donny Herbert wasn't doing well. It was February 2006, but as Linda Herbert watched her husband slip away, it was as if the sun was finally setting on a day that dawned more than a decade earlier. Four days after Christmas in 1995, Herbert had nearly died in a roof collapse that robbed his brain of oxygen. He was without air for more than six minutes when he was trapped in the attic of a burning house. Colleagues pulled him from the rubble and he survived, but barely. For most of the next 9 1/2 years, he was minimally conscious, unaware of his surroundings and unable to communicate. Until one day. That single day — April 30, 2005 — means everything to Linda Herbert and her family, and it's the subject of a new book. That was the day when her husband suddenly awoke. "Where's Linda?" he asked. It appeared an experimental combination of brain-stimulating drugs begun two years earlier had sparked something. © 2007 MicrosoftMSN

Keyword: Miscellaneous
Link ID: 11105 - Posted: 06.24.2010

"Portable monitoring may be used as an alternative to polysomnography (a diagnostic sleep test) for the diagnosis of obstructive sleep apnea in patients with a high pretest probability of moderate to severe obstructive sleep apnea," read the guidelines. Most sleep apnea tests take place in a sleep clinic under the careful watch of a licensed medical practitioner. Sleep apnea is a disorder in which a person stops breathing repeatedly while asleep. These gaps in breathing or "apneas" usually last 10 to 30 seconds and can occur many times throughout the night, according to the Canadian Lung Association. Untreated, the condition can lead to serious health problems, such as an increased risk of heart attack or stroke, accidents, and premature death. The home tests are portable devices the wearer sleeps in. They are composed of a recording device, sensors, belts and other cables. A sleep specialist reviews the data gathered overnight and makes a diagnosis and develops a treatment plan. The tests are recommended for adults aged 18 to 65 who have been assessed by a certified sleep practitioner who has deemed them at risk of the condition. People who have not had a medical practitioner recommend such a test should not take one, according to the guidelines. © CBC 2007

Keyword: Sleep
Link ID: 11104 - Posted: 06.24.2010

By LISA SANDERS, M.D. “I’m sorry, Nonnie,” the slender 9-year-old girl said. “I tried to get to the bathroom.” She was pale, her lips trembled and her thin face was streaked with tears and vomit. “Don’t you worry about it, baby girl.” Her grandmother’s soft twang was as warm as a hug as she quickly wiped down the floor. “You can’t help it when you’re sick.” And she had been sick — for nearly six months. Last March, the child got some kind of terrible stomach bug. Her grandmother, with whom she was currently living, called the pediatrician. He said there was a flu going around and that she would probably be fine in a day or two. But over the next several days, nothing the little girl ate or drank would stay down. When she didn’t get better, the grandmother took the child to the doctor’s office. After one look at the girl, he sent her to the emergency room at a local hospital. The doctors there had her airlifted to Children’s Hospital in nearby Birmingham, Ala. The girl was badly dehydrated and spent the better part of the next week in the I.C.U. It seemed as if they ran a million tests, her grandmother told me. But none of them gave the doctors the answer they sought. They sent her home. After a couple of days, the girl was fine — running, laughing, playing with her little brother, eating as if there were no tomorrow. But a few weeks later, the nausea came back, and so did the vomiting and diarrhea. She went back to the pediatrician. He said it was probably a virus, but a couple of days later she ended up in a nearby hospital again. It was a cycle that was repeated many times over the next several months. Copyright 2007 The New York Times Company

Keyword: Hormones & Behavior; Anorexia & Bulimia
Link ID: 11103 - Posted: 06.24.2010

By Rachael Moeller Gorman Richard Wrangham has tasted chimp food, and he doesn’t like it. “The typical fruit is very unpleasant,” the Harvard University biological anthropologist says of the hard, strangely shaped fruits endemic to the chimp diet, some of which look like cherries, others like cocktail sausages. “Fibrous, quite bitter. Not a tremendous amount of sugar. Some make your stomach heave.” After a few tastings in western Uganda, where he works part of the year on his 20-year-old project studying wild chimpanzees, Wrangham came to the conclusion that no human could survive long on such a diet. Besides the unpalatable taste, our weak jaws, tiny teeth and small guts would never be able to chomp and process enough calories from the fruits to support our large bodies. Then, one cool fall evening in 1997, while gazing into his fireplace in Cambridge, Mass., and contemplating a completely different question—“What stimulated human evolution?”—he remembered the chimp food. “I realized what a ridiculously large difference cooking would make,” Wrangham says. Cooking could have made the fibrous fruits, along with the tubers and tough, raw meat that chimps also eat, much more easily digestible, he thought—they could be consumed quickly and digested with less energy. This innovation could have enabled our chimp­like ancestors’ gut size to shrink over evolutionary time; the energy that would have gone to support a larger gut might have instead sparked the evolution of our bigger-brained, larger-bodied, humanlike forebears. © 1996-2007 Scientific American Inc.

Keyword: Evolution
Link ID: 11102 - Posted: 06.24.2010

PROVIDENCE, R.I. - One operation went awry after an experienced brain surgeon insisted to a nurse he knew what side of the head to operate on — but got it wrong. Another time, a doctor-in-training cut into the wrong side of a patient's head after skipping a pre-op checklist. In a third case, the chief resident started brain surgery in the wrong place, and the nurse didn't stop him. All three mistakes happened at the same hospital in less than a year — Rhode Island Hospital, the state's most prestigious medical center and a teaching hospital for the Ivy League's Brown University. That was startling enough, but just as surprising was that the errors happened despite an explicit set of required operating-room precautions adopted by the medical profession a few years ago to prevent "wrong-site surgery" mistakes. Those measures include the use of checklists, "time-outs" to double-check everything is correct, and indelible markers to show the surgeon where to cut. "The problem's not going away," said Peter Angood, vice president and chief patient safety officer at the Joint Commission, an independent organization that accredits most of the nation's hospitals. "Organizations don't like to do this. It's complicated for them to do. Surgeons tend to resist it. Copyright 2007 The Associated Press

Keyword: Miscellaneous
Link ID: 11101 - Posted: 06.24.2010

Brian Vastag In 2000, researchers in Canada reported a possible breakthrough in the treatment of type 1 diabetes. By transfusing insulin-producing cells from donated pancreases into patients, the researchers provided what looked like cures. Within a week after the procedure, all of the first six patients were liberated from daily insulin injections. For a time, the team that developed the procedure, at the University of Alberta in Edmonton, appeared to have succeeded where many others had failed. But after a year or two, the transplants began to falter. Last year, the latest report on the Edmonton protocol found that of 36 patients, 21 initially were able to ditch their insulin needles. Two years after transplantation, though, 16 of those patients were back on insulin. Another report on 65 patients found that only 6 were insulin-independent at 5 years post-transplant. While ultimately disappointing, the Edmonton protocol is "clearly orders of magnitude better than previous attempts at [pancreatic-cell] transplantation," two diabetes researchers wrote in 2006 in the New England Journal of Medicine. Since the 1970s, researchers had been implanting pancreatic cells from cadavers into type 1 diabetes patients with little luck. By the mid-1990s, after some 450 transplants worldwide, the success rate hovered at a dismal 2 percent. ©2007 Science Service.

Keyword: Obesity; Hormones & Behavior
Link ID: 11100 - Posted: 06.24.2010

Philip Ball What did you say? Gerbils might hear sounds as babies do.PhotodiscIf you say something to a gerbil, will it understand? Two researchers have succeeded in training gerbils to recognize human vowel sounds, and have found that they can easily distinguish, say, an 'oo' (as in 'you') from an 'ee' (as in 'me'). Joan Sinnott and Kelly Mosteller of the University of South Alabama in Mobile know, of course, that gerbils are never going to understand the semantics of human speech; they're not trying to train the gerbils to understand words or sentences. Instead, the work will feed into their interest in how humans discriminate between sounds at a very basic level, as infants do before those sounds become part of a known language. A good animal model would provide a useful way of looking at this question. Sinnott says she began by testing monkeys, but found that they were too smart: "They can hear all the human phonemes [basic speech sounds] I have tested, even the difficult ones," she says. So she switched to gerbils. In their experiments, the researchers presented Mongolian gerbils with two feeder cups: one to the right and one to the left. One vowel sound, pre-recorded and played back repeatedly at intervals of one second, signals that the food is in the left-hand cup. A different vowel sound indicates food in the right-hand cup. The gerbils could learn this rule relatively quickly in tests with pairs of ten different vowel sounds, the researchers say. © 2007 Nature Publishing Group

Keyword: Hearing
Link ID: 11099 - Posted: 06.24.2010

The immune system helps to prune excess connections between neurons in the developing brains of young mice, according to scientists funded by the National Institute on Drug Abuse (NIDA), part of the National Institutes of Health (NIH). The study, published in the December 14 issue of the journal Cell, sheds critical new light upon a fundamental process, while hinting at a likely mechanism behind neurodegenerative diseases like glaucoma and Alzheimer’s disease. Shortly after birth, the mammalian brain contains vast numbers of connections, or synapses, between neurons — many more than will be needed in adulthood. Scientists have known for years that the developing brain follows a use it or lose it rule: inactive connections are pruned away during childhood and adolescence. However, the molecular mechanism underlying this pruning process has remained one of the biggest mysteries in neurobiology. Now, Dr. Beth Stevens and Dr. Ben Barres of the Stanford University School of Medicine and their colleagues report that a protein used by the immune system to destroy bacteria is also needed by the young brain to target and destroy unwanted synapses. "From the fetal period through early adulthood, the developing brain is constantly fine-tuning its synaptic connections. These results provide new insight into this vital process," said Dr. Nora Volkow, NIDA director. "Eventually, research like this, into the fundamental mechanisms of brain development, will help us understand why a child’s brain is so vulnerable to environmental factors, including addictive drugs."

Keyword: Development of the Brain; Neuroimmunology
Link ID: 11098 - Posted: 06.24.2010

Peter Kenter, CanWest News Service Policing of roads and traffic has come a long way since the early days of the automobile. It all started with a few simple suggestions such as, "Just keep it away from people, all right?" or "Drive this thing like it was a horse." Then it gradually developed into something more complex, featuring high-tech enforcement devices such as radar guns and red light cameras. You probably think it ends with omnipresent video surveillance gradually creeping across the landscape to monitor every nuance of our driving behaviour. Unfortunately, an emerging branch of law enforcement known as "neuro law" makes that look like kids stuff. Neurological testing equipment that peers deep inside our brains may one day coerce drivers to convict themselves of their own malfeasance. Futuristic traffic court could consist of some shaky-cam footage representing exactly what drivers saw when the alleged traffic violation took place. Researchers at Vanderbilt University in Nashville are working on ways to determine not only what we did but how we felt about it at the time we did it. Data gathering often relies on having subjects think about complex philosophical problems and measuring brain chemistry while they do it. Exempli gratia: You control a gate arm that can shut one gate at a time. A car with malfunctioning brakes is careening toward a group of innocent pedestrians and you must choose whether to: a) shut the first gate and save the lives of five innocent people or b) shut the second gate and save the life of a single pedestrian. Most subjects instantly decide to protect the larger group. © 2007 CanWest Interactive

Keyword: Stress; Brain imaging
Link ID: 11097 - Posted: 06.24.2010