By Melissa Hogenboom Science reporter, BBC News Smaller animals tend to perceive time in slow-motion, a new study has shown. This means that they can observe movement on a finer timescale than bigger creatures, allowing them to escape from larger predators. Insects and small birds, for example, can see more information in one second than a larger animal such as an elephant. The work is published in the journal Animal Behaviour. "The ability to perceive time on very small scales may be the difference between life and death for fast-moving organisms such as predators and their prey," said lead author Kevin Healy, at Trinity College Dublin (TCD), Ireland. The reverse was found in bigger animals which may miss things that smaller creatures can rapidly spot. In humans, too, there is variation among individuals. Athletes, for example, can often process visual information more quickly. An experienced goalkeeper would therefore be quicker than others in observing where a ball comes from. The speed at which humans absorb visual information is also age-related, said Andrew Jackson, a co-author of the work at TCD. "Younger people can react more quickly than older people, and this ability falls off further with increasing age." The team looked at the variation of time perception across a variety of animals. They gathered datasets from other teams who had used a technique called critical flicker fusion frequency, which measures the speed at which the eye can process light. BBC © 2013

Keyword: Attention; Vision
Link ID: 18651 - Posted: 09.16.2013

By JAN HOFFMAN When Vinnie Richichi started watching the Pittsburgh Steelers’ home opener against the Tennessee Titans last Sunday, he was feeling great. After all, the Steelers had won their first home game six years in a row. Then things indeed went south. “The worse they looked, the more I kept going to the fridge,” recalled Mr. Richichi, a co-host of a sports talk show on KDKA-FM in Pittsburgh. “First a couple of Hot Pockets. By the second quarter I threw in a box of White Castle hamburgers. As the game progressed, I just went through the refrigerator: the more fear, the more emotion, I’m chomping down. But I’m not going near the salad or the yogurt. If it doesn’t have 700 calories, I’m going right past it.” The aftereffect of the Steelers’ ignominious defeat by a score of 16-9 clung to Mr. Richichi on Monday, when he rejected his regular breakfast of yogurt and strawberries in favor of a bagel sandwich with sausage, eggs, cheese, peppers and hot sauce. Then, his mood hardly improved after spending four hours on the air railing and commiserating with Steelers’ fans, he had pizza for lunch. “My weight goes up and down with my teams, “ said Mr. Richichi. “My team does well? I’m 40, 50 pounds lighter.” Mr. Richichi’s eating habits, joined at the waistline with the N.F.L., were reflected in a recent study that investigated whether a football team’s outcome had an effect on what fans ate the day after a game. Although the study did not look at weight fluctuations, researchers found that football fans’ saturated-fat consumption increased by as much as 28 percent following defeats and decreased by 16 percent following victories. The association was particularly pronounced in the eight cities regarded as having the most devoted fans, with Pittsburgh often ranked No. 1. Narrower, nail-biting defeats led to greater consumption of calorie and fat-saturated foods than lopsided ones. Copyright 2013 The New York Times Company

Keyword: Obesity; Aggression
Link ID: 18650 - Posted: 09.16.2013

by Andy Coghlan A girl who does not feel physical pain has helped researchers identify a gene mutation that disrupts pain perception. The discovery may spur the development of new painkillers that will block pain signals in the same way. People with congenital analgesia cannot feel physical pain and often injure themselves as a result – they might badly scald their skin, for example, through being unaware that they are touching something hot. By comparing the gene sequence of a girl with the disorder against those of her parents, who do not, Ingo Kurth at Jena University Hospital in Germany and his colleagues identified a mutation in a gene called SCN11A. This gene controls the development of channels on pain-sensing neurons. Sodium ions travel through these channels, creating electrical nerve impulses that are sent to the brain, which registers pain. Overactivity in the mutated version of SCN11A prevents the build-up of the charge that the neurons need to transmit an electrical impulse, numbing the body to pain. "The outcome is blocked transmission of pain signals," says Kurth. To confirm their findings, the team inserted a mutated version of SCN11A into mice and tested their ability to perceive pain. They found that 11 per cent of the mice with the modified gene developed injuries similar to those seen in people with congenital analgesia, such as bone fractures and skin wounds. They also tested a control group of mice with the normal SCN11A gene, none of which developed such injuries. © Copyright Reed Business Information Ltd.

Keyword: Pain & Touch; Genes & Behavior
Link ID: 18649 - Posted: 09.16.2013

By PAULINE W. CHEN, M.D. One afternoon at a school not far from the hospital where I was working, a teacher opened a utility closet and found a staff member passed out on the floor. He was clutching a small bloody mass in one hand, a sharp knife in the other, she reported, a red stain spreading rapidly at his middle. He had amputated his genitals. Once he’d been brought to our emergency room and resuscitated, the man refused further treatment. Doctors and nurses, concerned that if they waited any longer to reattach the severed part the surgery might not work, took the necessary steps to deem him mentally incompetent to make such decisions. “The guy was seriously nuts,” I remember one of the doctors saying afterward. “He kept screaming that he didn’t want ‘it’ back.” For days after the successful operation, the gruesome story was all anyone at the hospital could discuss. Most of us chalked it up to his being “certifiable,” and several wondered if maybe they should have skipped the surgery. “After all,” said one clinician, “isn’t that what he wanted?” But in all the chatter none of us mentioned a key part of the patient’s story: the unbearable suffering that must have pushed him to commit so brutal an act. In fact, anyone overhearing our conversations might have been hard pressed to find any of the warmth and sensitivity we routinely displayed toward patients with cancer, AIDS or heart disease. I remembered the man and our reactions this past week while reading “Falling Into the Fire: A Psychiatrist’s Encounters With the Mind in Crisis,” a thought-provoking new book by Dr. Christine Montross. Of all the afflictions that fall upon us, few remain as misunderstood and stigmatized as those that affect the mind. Copyright 2013 The New York Times Company

Keyword: Schizophrenia; Depression
Link ID: 18648 - Posted: 09.16.2013

By Tina Hesman Saey About 10 percent of people prefer using their left hand. That ratio is found in every population in the world and scientists have long suspected that genetics controls hand preference. But finding the genes has been no simple task, says Chris McManus, a neuropsychologist at University College London who studies handedness but was not involved in the new research. “There’s no single gene for the direction of handedness. That’s clear,” McManus says. Dozens of genes are probably involved, he says, which means that one person’s left-handedness might be caused by a variant in one gene, while another lefty might carry variants in an entirely different gene. To find handedness genes, William Brandler, a geneticist at the University of Oxford, and colleagues conducted a statistical sweep of DNA from 3,394 people. Statistical searches such as this are known as genome-wide association studies; scientists often do such studies to uncover genes that contribute to complex diseases or traits such as diabetes and height. The people in this study had taken tests involving moving pegs on a board. The difference in the amount of time they took with one hand versus the other reflected how strongly left- or right-handed they were. A variant in a gene called PCSK6 was most tightly linked with strong hand preference, the researchers report in the Sept. 12 PLOS Genetics.. The gene has been implicated in handedness before, including in a 2011 study by the same research group. PCSK6 is involved in the asymmetrical positioning of internal organs in organisms from snails to vertebrates. © Society for Science & the Public 2000 - 2013

Keyword: Laterality; Genes & Behavior
Link ID: 18647 - Posted: 09.14.2013

Emily Underwood Jackie Murphy didn't worry that her son Fintan was a late talker, at least at first. Her other two children had been slow to say their first words, so it was only when the former California nurse noticed that her 20-month-old wasn't responding to his name, or even reacting to loud noises, that she became concerned. "One day, I dropped a toy xylophone behind him and he didn't even flinch," she says. "That's when I knew something was wrong." Fintan didn't have a hearing problem—he had autism, his mom finally learned after more than 6 months of searching for a diagnosis. A few months later, Murphy enrolled Fintan in the Autism Phenome Project at the MIND Institute at the University of California (UC), Davis, a long-term assessment of children, as many as 1800, aimed at teasing out subtypes of the complex disorder. Murphy also became a research subject, donating a blood sample. One of the project's researchers, Melissa Bauman, soon informed Murphy that her blood had tested positive for antibodies that react to fetal brain proteins. Bauman asked her to donate more blood for studies exploring the provocative idea that some of Murphy's antibodies had slipped through the placenta and into Fintan's developing brain, affecting its maturation. At that point, Murphy says, she and her husband made a big decision: Fearing that the immune proteins in her blood would harm another baby, they decided that she would not again get pregnant. Many more women could face a similarly difficult choice. In July, immunologist Judy Van de Water and her team at UC Davis, which includes Bauman and Daniel Braunschweig, bolstered the hypothesis that maternal antibodies cause some autism with two studies, including one showing autismlike symptoms in monkeys injected with such antibodies. And women may soon be able to check whether they have the suspect antibodies: California company Pediatric Bioscience announced that it is moving forward with a new diagnostic test, based on patented antibody screening techniques licensed from Van de Water and UC Davis. © 2013 American Association for the Advancement of Science

Keyword: Autism; Neuroimmunology
Link ID: 18646 - Posted: 09.14.2013

By Philip Yam If you’re a fan of optical illusions and perceptual tricks, check out this AsapSCIENCE video. As usual, producers Michael Moffitt and Gregory Brown do a great job distilling the essential ideas and presenting them in a fun, entertaining and informative way. Here, they show you how your brain judges brightness and color in context. Visit their YouTube channel to see more (including a frequency test for your ears). You can also check out our compilation of the 169 best illusions (ia sampling of them is on our site) as well as our Illusions Chasers blog, by Susana Martinez-Conde and Steven Macknik, which explore illusions each week. © 2013 Scientific American

Keyword: Vision
Link ID: 18645 - Posted: 09.14.2013

Insect leg cogs a first in animal kingdom Philip Ball If you are a young plant hopper, leaping one metre in a single bound, you need to push off with both hind legs in perfect unison or you might end up in a spin. Researchers have discovered that this synchrony is made possible by toothed gears that connect the two legs when the insects jump. Zoologists Malcolm Burrows and Gregory Sutton at the University of Cambridge, UK, say that this seems to be the first example in nature of rotary motion with toothed gears. They describe their findings today in Science1. When the insect jumps, the cog teeth join so that the two legs lock together, ensuring that they thrust at exactly the same time (see video above and image at left). “The gears add an extra level of synchronization beyond that which can be achieved by the nervous system,” says Burrows. Infant plant hoppers, known as nymphs, can take off in just 2 milliseconds, reaching take-off speeds of almost 4 metres a second (see video below). For motions this rapid, some mechanical device is needed to keep the legs synchronized and to avoid lopsided jumps that might lead to the insects spinning out of control. The problem does not, however, arise in all jumping insects: whereas the attachments of plant hoppers' hind legs are adjacent to each other, the legs of grasshoppers and fleas attach to opposite the sides of the body and move in parallel planes. This helps to stabilize the insects and even enables them to jump one-legged. © 2013 Nature Publishing Group

Keyword: Miscellaneous
Link ID: 18644 - Posted: 09.14.2013

By Philip Yam New Hampshire health officials announced last week that hospitals in three New England states may have accidentally exposed 15 people to prions, the infectious protein that ravages the brain and leaves it full of holes. Evidently, the hospitals involved used surgical tools that had previously been deployed on a patient who officials suspect later died from a particular prion infection called sporadic Creutzfeldt-Jakob disease (CJD). As disturbing as the revelation was, it pales in comparison with the announcement in 2002, when the University of Pittsburgh Medical Center Presbyterian announced that up to 4,000 patients might have been exposed to the prion. Both incidents show that the hospital transmission of prion diseases remains an ever-present possibility, if thankfully a very unlikely one. Prions are unusual pathogens distinct from parasites, fungi, bacteria and viruses. They are misfolded proteins that can transform healthy proteins into sickly versions, leading to the death of cells. Particularly abundant in the brain, they took center stage in the late 1980s, during the mad cow outbreak in the U.K. People who ate beef from infected cows ran the risk of contracting a variant of CJD. The panic brought to light the range of prion diseases that can affect humans and animals, including one that develops spontaneously. Called sporadic CJD, this spontaneous form strikes about one in every million people each year for no apparent reason. What’s more, the brain tissue from the unlucky few can infect healthy brains—hence, the worry over surgical transmission. © 2013 Scientific American

Keyword: Prions
Link ID: 18643 - Posted: 09.14.2013

By Melissa Healy It's a question that has long fascinated and flummoxed those who study human behavior: From whence comes the impulse to dream? Are dreams generated from the brain's "top" -- the high-flying cortical structures that allow us to reason, perceive, act and remember? Or do they come from the brain's "bottom" -- the unheralded brainstem, which quietly oversees such basic bodily functions as respiration, heart rate, salivation and temperature control? At stake is what to make of the funny, sexual, scary and just plain bizarre mental scenarios that play themselves out in our heads while we sleep. Are our subconsious fantasies coming up for a breath of air, as Sigmund Freud believed? Is our brain consolidating lessons learned and pitching out unneeded data, as neuroscientists suggest? Or are dreams no more meaningful than a spontaneous run of erratic heartbeats, a hot flash, or the frisson we feel at the sight of an attractive passer-by? A study published this week in the journal Brain suggests that the impulse to dream may be little more than a tickle sent up from the brainstem to the brain's sensory cortex. The full dream experience -- the complex scenarios, the feelings of fear, delight or longing -- may require the further input of the brain's higher-order cortical areas, the new research suggests. But even people with grievous injury to the brain's prime motivational machinery are capable of dreams, the study found.

Keyword: Sleep
Link ID: 18642 - Posted: 09.14.2013

By GRETCHEN REYNOLDS As readers of this column know, short, intense workouts, usually in the form of intervals that intersperse bursts of hard effort with a short recovery time, have become wildly popular lately, whether the sessions last for four minutes, seven minutes or slightly longer. Studies have found that such intense training, no matter how abbreviated, usually improves aerobic fitness and some markers of health, including blood pressure and insulin sensitivity, as effectively as much longer sessions of moderate exercise. What has not been clear, though, is whether interval training could likewise also aid in weight control. So for a study published online in June in The International Journal of Obesity, researchers at the University of Western Australia in Perth and other institutions set out to compare the effects of easy versus exhausting exercise on people’s subsequent desire to eat. To do so, they recruited 17 overweight but otherwise healthy young men in their 20s or 30s and asked them to show up at the university’s exercise physiology lab on four separate days. One of these sessions was spent idly reading or otherwise resting for 30 minutes, while on another day, the men rode an exercise bike continuously for 30 minutes at a moderate pace (equivalent to 65 percent of their predetermined maximum aerobic capacity). A third session was more demanding, with the men completing 30 minutes of intervals, riding first for one minute at 100 percent of their endurance capacity, then spinning gently for 4 minutes. The final session was the toughest, as the men strained through 15 seconds of pedaling at 170 percent of their normal endurance capacity, then pedaled at barely 30 percent of their maximum capacity for a minute, with the entire sequence repeated over the course of 30 minutes. Copyright 2013 The New York Times Company

Keyword: Obesity
Link ID: 18641 - Posted: 09.14.2013

By Gary Stix New types of drugs for schizophrenia, depression and other psychiatric disorders are few and far between—and a number of companies have scaled back or dropped development of this class of pharmaceuticals. One exception stands out. Ketamine, the anesthetic and illegal club drug, is now being repurposed as the first rapid-acting antidepressant drug and has been lauded as possibly the biggest advance in the treatment of depression in 50 years. A few trials by large pharma outfits are now underway on a new, purportedly improved and, of course, more profitable variant of ketamine, which in its current generic drug form does not make pharmaceutical marketing departments salivate. Some physicians have decided they simply can’t wait for the lengthy protocols of the drug approval process to be sorted out. They have read about experimental trials in which a low-dose, slow-infusion of ketamine seems to produce what no Prozac-like pill can achieve, lifting the black cloud in hours, not weeks. With nothing to offer desperate, sometimes suicidal patients, physicians have decided against waiting for an expensive, ketamine lookalike to arrive and have started writing scripts for the plain, vanilla generic version that has been used for decades as an anesthetic. Ketamine, it seems, has captivated a bunch of white coats with the same grassroots energy that has propelled the medical marijuana movement. © 2013 Scientific American

Keyword: Depression; Drug Abuse
Link ID: 18640 - Posted: 09.12.2013

by Andy Coghlan Normal adult cells have been reprogrammed to become stem cells inside live mice for the first time. As stem cells can be coaxed into developing into almost any kind of cell, being able to prompt this behaviour in the body could one day be used to repair ailing organs including the heart, liver, spinal cord and pancreas. "By doing it in situ, the cells are already there in the tissue, in the right position," says Manuel Serrano at the Spanish National Cancer Research Centre in Madrid, and co-leader of the new work. The technique overcomes the difficulties inherent in making cells outside the body, grafting them into people, and then of potential rejection. It opens up new clinical opportunities, say the researchers. Since 2006, when Nobel-prizewinning researcher Shinya Yamanaka first made adult cells return to a stem-cell-like state of being pluripotent – able to turn into almost any cell type – all such induced pluripotent stem (iPS) cells have been made in vitro. This is done by taking a sample of adult cells, such as skin cells, and treating them with four proteins that rewind the cells back to an embryonic-like state. Serrano genetically altered mice to give them extra copies of the four genes that produce these proteins: Oct, Sox2, Klf4 and c-Myc. The genes were programmed to kick into action when exposed to doxycycline, an antibiotic. © Copyright Reed Business Information Ltd.

Keyword: Stem Cells; Regeneration
Link ID: 18639 - Posted: 09.12.2013

Associated Press It's the ape equivalent of Google Maps and Facebook. The night before a big trip, Arno the orangutan plots his journey and lets others know where he is going with a long, whooping call. What he and his orangutan buddies do in the forests of Sumatra tells scientists that advance trip planning and social networking aren't just human traits. A new study of 15 wild male orangutans finds that they routinely plot out their next-day treks and share their plans in long calls, so females can come by or track them, and competitive males can steer clear. The researchers closely followed the males as they traveled on 320 days during the 1990s. The results were published Wednesday in the journal PLoS One. Typically, an orangutan would turn and face in the direction of his route and let out a whoop, sometimes for as long as four minutes. Then he'd go to sleep and 12 hours later set on the heralded path, said study author Carel van Schaik, director of the Anthropological Institute at the University of Zurich. "This guy basically thinks ahead," van Schaik said. "They're continuously updating their Google Maps, so to speak. Based on that, they're planning what to do next." The apes didn't just call once - they kept at it, calling more than 1,100 times over the 320 days. © 2013 The Hearst Corporation

Keyword: Animal Migration; Animal Communication
Link ID: 18638 - Posted: 09.12.2013

By GINA KOLATA It is the scourge of many a middle-aged man: he starts getting a pot belly, using lighter weights at the gym and somehow just doesn’t have the sexual desire of his younger years. The obvious culprit is testosterone, since men gradually make less of the male sex hormone as years go by. But a surprising new answer is emerging, one that doctors say could reinvigorate the study of how men’s bodies age. Estrogen, the female sex hormone, turns out to play a much bigger role in men’s bodies than previously thought, and falling levels contribute to their expanding waistlines just as they do in women’s. The discovery of the role of estrogen in men is “a major advance,” said Dr. Peter J. Snyder, a professor of medicine at the University of Pennsylvania, who is leading a big new research project on hormone therapy for men 65 and over. Until recently, testosterone deficiency was considered nearly the sole reason that men undergo the familiar physical complaints of midlife. The new frontier of research involves figuring out which hormone does what in men, and how body functions are affected at different hormone levels. While dwindling testosterone levels are to blame for middle-aged men’s smaller muscles, falling levels of estrogen regulate fat accumulation, according to a study published Wednesday in The New England Journal of Medicine, which provided the most conclusive evidence to date that estrogen is a major factor in male midlife woes. And both hormones are needed for libido. “Some of the symptoms routinely attributed to testosterone deficiency are actually partially or almost exclusively caused by the decline in estrogens,” said Dr. Joel Finkelstein, an endocrinologist at Harvard Medical School and the study’s lead author, in a news release on Wednesday. © 2013 The New York Times Company

Keyword: Obesity; Hormones & Behavior
Link ID: 18637 - Posted: 09.12.2013

By Melanie Tannenbaum I can remember exactly where I was twelve years ago when I learned why the sky was starting to fill with smoke about 30 miles to the west. Though I live in Illinois now, I’m originally from Long Island. In September 2001, I was just beginning the 9th grade at Friends Academy, my new high school in Locust Valley. I had just started getting to know the people who would become my closest friends over the next four years. I was on my way to Computer Programming when I ran into Molly, a girl on my bus. “Hey, did you hear?” Molly asked, somewhat casually. “No, what’s up? Oh, is Maggie taking the bus today?!” I asked excitedly. Maggie was Molly’s adorable baby sister, whose expeditions onto our bus were rare (but exciting) events. “No…apparently something really big just happened in the city. They’re canceling class right now and calling an all-school assembly in the Dolan Center. You didn’t hear?” “Oh, no, but thank God. I didn’t finish my math homework last night and I didn’t have time to do it on the bus, this is awesome,” I said with a smile. “Do you have any idea why they’re canceling class, though?!” I had no idea at the time how much I would cringe for the rest of my life whenever I looked back and thought about my first reaction to hearing that “something big” was going on in the city. © 2013 Scientific American,

Keyword: Learning & Memory
Link ID: 18636 - Posted: 09.12.2013

By Susan Milius Mice in the wild have no problem dining where someone else has pooped. Animals with higher standards of hygiene, reported in earlier studies, may not face the same dangers as small, hungry creatures scurrying around the woods. Feeding among feces of your own species raises the risk of catching nasty intestinal parasites, explains behavioral ecologist Patrick T. Walsh of University of Edinburgh. So far most tests of fecal avoidance have focused on hoofed animals. Horses, cows, sheep, reindeer and even wild antelopes tend not to graze in heavily poop-dotted areas. White-footed and deer mice, however, show no such daintiness of manners in a test in the woods, Walsh and his colleagues report in the September Animal Behaviour. Wild mice may have more immediate problems, like starvation or predators that domesticated--or just plain bigger--animals don’t. For the wild mice, Walsh says, fecal avoidance may be “a luxury.” Learning whether and when animals avoid poop helps clarify how parasites spread, an issue important for the health of both wildlife and people. So far no one has tested fecal avoidance for mice feeding in the lab, but research has shown that female lab mice tend to avoid the urine of parasite-infected males. To see whether mice in the wild dodge parasite risks, Amy Pedersen, a coauthor of the study also at Edinburgh, designed an experiment with a long plastic box divided into zones, some of which had mouse droppings in them. In the experiment, researchers tested more than 130 wild Peromyscus mice, of either the leucopus or maniculatus species, held captive for less than a day in the mountains of Virginia. © Society for Science & the Public 2000 - 2013

Keyword: Neuroimmunology; Evolution
Link ID: 18635 - Posted: 09.12.2013

By Ben Thomas As Albert Einstein famously said, “No problem can be solved from the same level of consciousness that created it.” The history of science is littered with so-called “intractable” problems that researchers later cracked wide open using techniques their ancestors could hardly imagine. Biologists in the 1950s looked at the staggeringly complex (and beautiful) three-dimensional shapes into which proteins fold and declared that a reliably predictive mathematical model of these convolutions might be unachievable in our lifetimes. But over the past few years, folks with home computers have joined forces to crack many longstanding protein-folding problems using the online game FoldIt. Instead of relying on the number-crunching power of a single supercomputer or network, crowdsourced games like FoldIt translate vast and complex data sets into simple online interfaces that anyone can learn to operate. The crowdsourced astronomy game Galaxy Zoo also depends on an army of “citizen scientists” for classification of stars hundreds of light years away; while Google built its image search technology on an image-labeling game. In fact, every time you “verify your humanity” on a web form by typing out nonsensical reCAPTCHA text, you’re actually helping Google transcribe books from the world’s libraries into a digital format. And now, a worldwide team of neuroscience researchers have begun using this crowdsource approach to crack open one of the greatest problems in any scientific field: The construction of a complete wiring diagram for a mammalian brain. © 2013 Scientific American,

Keyword: Brain imaging
Link ID: 18634 - Posted: 09.12.2013

Amanda Fiegl What's the difference between a spicy meal and being tickled? Not much, from your lips' perspective. A new study reports that Szechuan pepper activates the same nerves that respond to a light physical touch. Researchers at the University College London Institute of Cognitive Neuroscience found that people experienced the same sensation when either Szechuan pepper—a spice used in many types of Asian cuisine—or a machine vibrating at a particular frequency was placed on their lips. "The pepper is sending the same information to the brain as having a buzzer on your lips," the study's lead author, Nobuhiro Hagura, said in an email. The study, published today in Proceedings of the Royal Society B with the wry headline "Food Vibrations," delves into the little-known field of psychophysics, which "describes the relation between physical reality and what we actually perceive," Hagura said. "Our research shows just one interesting example of a case where we perceive something quite different than what is actually there," he said. "In many cases, the difference between perception and reality can be explained by understanding how the nervous system transmits information about the outside world to the brain." Previous studies have shown that other spicy ingredients, such as chili peppers and mustard oils, activate the nerve fibers associated with pain and physical heat. And studies in animals indicated that the spicy chemical in Szechuan pepper—sanshool—acts on the nervous system's "light touch" fibers. So Hagura and his colleagues wanted to find out whether sanshool produces a conscious sensation of touch in humans. © 1996-2013 National Geographic Society.

Keyword: Pain & Touch; Chemical Senses (Smell & Taste)
Link ID: 18633 - Posted: 09.11.2013

By Michele Solis Like truth and beauty, pain is subjective and hard to pin down. What hurts one moment might not register the next, and our moods and thoughts color the experience of pain. According to a report in April in the New England Journal of Medicine, however, researchers may one day be able to measure the experience of pain by scanning the brain—a much needed improvement over the subjective ratings of between one and 10 that patients are currently asked to give. Led by neuroscientist Tor Wager of the University of Colorado at Boulder, researchers used functional MRI on healthy participants who were given heated touches to their arm, some pleasantly warm, others painfully hot. During the painful touches, a scattered group of brain regions consistently turned on. Although these regions have been previously associated with pain, the new study detected a striking and consistent jump in their activity when people reported pain, with much greater accuracy than previous studies had attained. This neural signature appeared in 93 percent of subjects reporting to feel painful heat, ramping up as pain intensity increased and receding after participants took a painkiller. The researchers determined that the brain activity specifically marked physical pain rather than a generally unpleasant experience, because it did not emerge in people shown a picture of a lover who had recently dumped them. Although physical pain and emotional pain involve some of the same regions, the study showed that fine-grained differences in activation separate the two conditions. © 2013 Scientific American

Keyword: Pain & Touch; Brain imaging
Link ID: 18632 - Posted: 09.11.2013