By BENEDICT CAREY Susan Nolen-Hoeksema, a psychologist and writer whose work helped explain why women are twice as prone to depression as men and why such low moods can be so hard to shake, died on Jan. 2 in New Haven. She was 53. Her death followed heart surgery to correct a congenitally weak valve, said her husband, Richard Nolen-Hoeksema. Dr. Nolen-Hoeksema, a professor at Yale University, began studying depression in the 1980s, a time of great excitement in psychiatry and psychology. New drugs like Prozac were entering the market; novel talking therapies were proving effective, too, particularly cognitive behavior therapy, in which people learn to defuse upsetting thoughts by questioning their basis. Her studies, first in children and later in adults, exposed one of the most deceptively upsetting of these patterns: rumination, the natural instinct to dwell on the sources of problems rather than their possible solutions. Women were more prone to ruminate than men, the studies found, and in a landmark 1987 paper she argued that this difference accounted for the two-to-one ratio of depressed women to depressed men. She later linked rumination to a variety of mood and behavior problems, including anxiety, eating disorders and substance abuse. “The way I think she’d put it is that, when bad things happen, women brood — they’re cerebral, which can feed into the depression,” said Martin Seligman, a professor of psychology at the University of Pennsylvania, who oversaw her doctoral work. “Men are more inclined to act, to do something, plan, beat someone up, play basketball.” © 2013 The New York Times Company

Keyword: Depression; Sexual Behavior
Link ID: 17679 - Posted: 01.14.2013

By Consumers Union of United States, More than 5 million people in the United States have Alzheimer’s disease, an insidious disorder that gradually destroys the brain, robbing people of the ability to remember, complete everyday tasks and function on their own. Several drugs are approved to treat it, including donepezil (Aricept and its generic cousins) and memantine (Namenda). But they don’t work well for most people, according to a report from Consumer Reports Best Buy Drugs. In fact, the report concluded that none of the drugs could be recommended as a Best Buy. The decision was based in part on a large-scale analysis by the federal Agency for Healthcare Research and Quality published in April 2010. It found that the drugs didn’t delay the onset of Alzheimer’s or improve or maintain mental function. An earlier review by the American College of Physicians and the American Academy of Family Physicians, published in 2008, reached similar conclusions. Besides not being very effective, Alzheimer’s medication can cause side effects. While most are relatively minor, such as nausea, vomiting, diarrhea, dizziness, muscle cramps and tremors, they could be debilitating in older people with dementia who can’t communicate their discomfort. In rare cases, the drugs can cause a slowed heartbeat, gastrointestinal bleeding and possibly even convulsions or seizures. They’re also expensive: An average monthly prescription can range from $177 to more than $400. © 1996-2013 The Washington Post

Keyword: Alzheimers
Link ID: 17678 - Posted: 01.14.2013

By Susan Milius Imagining tiny creatures infiltrating human brains is creepy enough. But Marion Vittecoq knows she has been invaded. Her inner companions may be just hanging out — or they may be subtly changing her personality, manipulating her behavior or altering her risk of disease. Yet she doesn’t sound particularly upset. Not once in the course of a phone conversation and many e-mails did Vittecoq recommend wearing tinfoil hats or mention mind control by the CIA, the United Nations or little green men beaming rays from the moons of Uranus. She studies the ecology of parasites, especially the one-celled Toxoplasma gondii, which coincidentally is the creature that has invaded her brain. She doesn’t see it as an extra-ordinary intrusion. The parasite has wormed its way into an estimated one-third of people on the planet. In France, where Vittecoq works at both a CNRS national research lab in Montpellier and the Tour du Valat research center in Arles, nearly one-third to about one-half of adults carry hitchhiking T. gondii. CNRS research colleague Frédéric Thomas is also infected, and also doesn’t fret about it. In the United States, almost one in four residents over the age of 12 has the infection. In other parts of the world, rates are as high as 95 percent. An unlucky minority of these infected people become quite ill. Most, however, don’t even know that their muscles and brains carry the parasite. © Society for Science & the Public 2000 - 2013

Keyword: Depression; Schizophrenia
Link ID: 17677 - Posted: 01.12.2013

Experts are questioning whether diet drinks could raise depression risk, after a large study has found a link. The US research in more than 250,000 people found depression was more common among frequent consumers of artificially sweetened beverages. The work, which will be presented at the American Academy of Neurology's annual meeting, did not look at the cause for this link. Drinking coffee was linked with a lower risk of depression. People who drank four cups a day were 10% less likely to be diagnosed with depression during the 10-year study period than those who drank no coffee. But those who drank four cans or glasses of diet fizzy drinks or artificially sweetened juice a day increased their risk of depression by about a third. Lead researcher Dr Honglei Chen, of the National Institutes of Health in North Carolina, said: "Our research suggests that cutting out or down on sweetened diet drinks or replacing them with unsweetened coffee may naturally help lower your depression risk." But he said more studies were needed to explore this. BBC © 2013

Keyword: Depression; Obesity
Link ID: 17676 - Posted: 01.12.2013

By SABRINA TAVERNISE WASHINGTON — For two decades, millions of Americans have taken Ambien to help them sleep at night. But for years, the Food and Drug Administration has gotten complaints that people felt drowsy the morning after taking the medicine or its successors, and sometimes got into car accidents. On Thursday the agency said that women should be taking half as much, after laboratory studies and driving tests confirming the risks of drowsiness. The new recommendation applies to drugs containing the active ingredient zolpidem, by far the most widely used sleep aid. Using lower doses means less of the drug will remain in the blood in the morning hours, and will reduce the risk that people who use it will be impaired while driving. Sleeping pills have boomed in popularity with the increasingly frantic pace of modern American life. According to IMS, a health care information and technology company, about 60 million prescriptions were dispensed in 2011, up about 20 percent since 2006. About 40 million were for products containing zolpidem. The agency’s announcement was focused on women because they take longer to metabolize the drug than men. An estimated 10 percent to 15 percent of women will have a level of zolpidem in their blood that could impair driving eight hours after taking the pill, while only about 3 percent of men do, said Dr. Robert Temple, an official in the agency’s Center for Drug Evaluation and Research. © 2013 The New York Times Company

Keyword: Sleep; Sexual Behavior
Link ID: 17675 - Posted: 01.12.2013

Sujata Gupta Two things are thought to be crucial for evolutionary adaptation: genetic diversity and long periods of time, in which advantageous mutations accumulate. So how do invasive species, which often lack genetic diversity, succeed so quickly? Some ecologists are beginning to think that environmental, or ‘epigenetic’, factors might be modifying genes while leaving the genome intact. “There are a lot of different ways for invasive species to do well in novel environments and I think epigenetics is one of those ways,” says Christina Richards, an evolutionary ecologist at the University of South Florida in Tampa. Although biomedical researchers have been investigating the links between epigenetics and human health for some time, evolutionary biologists are just beginning to take up the subject. Richards, who helped to organize a special symposium on ecological epigenetics at a meeting of the Society for Integrative and Comparative Biology (SICB) in San Francisco this month, says that the field has the potential to revolutionize the study of evolutionary biology. The nascent field of ecological epigenetics has plenty of challenges standing in its way. The genomes of most wild animals and plants have not been sequenced so ecologists can’t pinpoint which genes have been modified. And, because they tend to work outside of controlled laboratory conditions, researchers have trouble linking those gene modifications to behavioural changes. © 2013 Nature Publishing Group

Keyword: Epigenetics; Evolution
Link ID: 17674 - Posted: 01.12.2013

by Michael Balter Are crows mind readers? Recent studies have suggested that the birds hide food because they think others will steal it -- a complex intuition that has been seen in only a select few creatures. Some critics have suggested that the birds might simply be stressed out, but new research reveals that crows may be gifted after all. Cracks first began forming in the crow mind-reading hypothesis last year. One member of a research team from the University of Groningen in the Netherlands spent 7 months in bird cognition expert Nicola Clayton's University of Cambridge lab in the United Kingdom studying Western scrub jays, a member of the crow family that is often used for these studies. The Groningen team then developed a computer model in which "virtual jays" cached food under various conditions. In PLOS ONE, they argued that the model showed the jays' might be moving their food—or recaching it—not because they were reading the minds of their competitors, but simply because of the stress of having another bird present (especially a more dominant one) and of losing food to thieves. The result contradicted previous work by Clayton's group suggesting that crows might have a humanlike awareness of other creatures' mental states—a cognitive ability known as theory of mind that has been claimed in dogs, chimps, and even rats. In the new study, Clayton and her Cambridge graduate student James Thom decided to test the stress hypothesis. First, they replicated earlier work on scrub jays by letting the birds hide peanuts in trays of ground corn cobs—either unobserved or with another bird watching—and later giving them a chance to rebury them. As in previous studies, the jays recached a much higher proportion of the peanuts if another bird could see them: nearly twice as much as in private, the team reports online today in PLOS ONE. © 2010 American Association for the Advancement of Science

Keyword: Intelligence; Stress
Link ID: 17673 - Posted: 01.12.2013

Some animals are more eloquent than previously thought and have a communication structure similar to the vowel and consonant system of humans, according to new research. Studying the abbreviated call of the mongoose, researchers at the University of Zurich have found they are the first animals to communicate with sound units that are even smaller than syllables and yet still contain information about who is calling and why. Usually, animals can only produce a limited number of distinguishable sounds and calls due to their anatomy. While whale and bird songs are a little more complex than most animal sounds — in that they are repeatedly combined with new arrangements — they don’t pattern themselves after human syllables with their combination of vowels and consonants. Studying wild banded mongooses in Uganda, behavioural biologists discovered that the calls of the animals are structured and contain different information — a sound structure that has some similarities to the vowel and consonant system of human speech. Banded mongooses live in the savannah regions of the Sahara. They are small predators that live in groups of around 20 and are related to the meerkat. The scientists recorded calls of the mongoose and made acoustic analyses of them. The calls, which last between 50 and 150 milliseconds, could be compared to one "syllable," the researchers found. © CBC 2013

Keyword: Language; Evolution
Link ID: 17672 - Posted: 01.12.2013

Fran Lowry Salivary gland biopsy appears to be a diagnostic test for Parkinson's disease, a new study suggests. A biopsy of the submandibular gland that shows the presence of the abnormal protein alpha-synuclein is highly indicative of Parkinson's, as distinct from other neurodegenerative disorders that can mimic the disease, said lead study author, Charles Adler, MD, PhD, from the Mayo Clinic Arizona, Scottsdale, Arizona. "There is currently no diagnostic test for Parkinson's disease in living patients. The only way to make the diagnosis is at autopsy, when you can see an abnormal protein, alpha-synuclein, in certain brain regions," Dr. Adler, a fellow of the American Academy of Neurology, told Medscape Medical News. Their preliminary findings were released January 10; full results will be presented at the American Academy of Neurology's 65th Annual Meeting in San Diego. Dr. Adler and his team have been working on determining whether there is evidence of alpha-synuclein in other organs of the body so that they could develop a diagnostic test in living patients. "We previously published the fact that the submandibular gland has one of the densest concentrations of alpha-synuclein in an organ outside the brain. When we tested this in an autopsy study of 28 Parkinson's disease patients, we found that all 28 of them had alpha-synuclein in the submandibular gland," he said. The discovery led the researchers to biopsy the submandibular gland in living patients with Parkinson's disease to see whether this protein was present. If it was, then the biopsy could potentially be used as a diagnostic test, they reasoned. © 1994-2013 by WebMD LLC

Keyword: Parkinsons
Link ID: 17671 - Posted: 01.12.2013

by Sara Reardon In the dark expanses of the Sonoran desert in the US, a terrifying creature stalks the night, searching for fresh meat. Anything will do: crickets, rodents, tarantulas – the nastier the better. Even the poisonous scorpion cannot escape the savage monster's little pink paws. It fights bravely, stinging its attacker on the nose. To no avail. The mouse ignores the painful venom and cruelly breaks the scorpion's tail by pummelling it into the ground, then bites its head and feasts on its flesh. Throwing its head back, the murderous animal howls at the moon. No, it's not the mythical Chupacabra. It's the southern grasshopper mouse (Onychomys torridus), the only carnivorous mouse in North America. Its unique biology and resistance to scorpion venom may one day help researchers treat human pain disorders. But for now, it's just after blood. Natural born killer From the day they are born, grasshopper mice are natural killers. Even pups born and raised in captivity quickly figure out how to take down prey much larger than themselves. They appear to learn some of their aggression from their fathers: pups raised with two parents are more likely to bully other mice and attack insects more viciously than those raised by single mothers (Behavioral Biology, DOI: 10.1016/S0091-6773(77)91933-2) © Copyright Reed Business Information Ltd.

Keyword: Aggression; Neurotoxins
Link ID: 17670 - Posted: 01.12.2013

By Laura Sanders At birth, some infants are already saddled with brains that carry features of Alzheimer’s disease and schizophrenia. Newborns who carry certain versions of genes already show brain shrinkage reminiscent of that in adults with brain illnesses, a study of 272 newborn babies reveals. The new results, published online January 2 in Cerebral Cortex, illuminate what happens to the brain in the earliest stages of life, says neuroscientist Jay Giedd of the National Institute of Mental Health in Bethesda, Md., who was not involved in the study. “As we go through life, there are so many uncontrollable factors,” he says. “This is a way to see gene influences before the world steps in.” Until this study, scientists didn’t have a good idea of whether certain brain signatures — such as reduced volume in parts of the brain — were present from birth or whether they accumulated over a lifetime, says study coauthor Rebecca Knickmeyer of the University of North Carolina at Chapel Hill. To test this, Knickmeyer and her colleagues looked for the influence of 10 versions of seven genes on newborns’ brains. The researchers chose genes that affect how the brain grows and develops. These gene variants have also been linked to adult brain diseases, such as the ε4 version of the ApoE gene, which triples the risk of getting Alzheimer’s, and a version of the COMT gene, which has been implicated in schizophrenia. © Society for Science & the Public 2000 - 2013

Keyword: Alzheimers; Schizophrenia
Link ID: 17669 - Posted: 01.12.2013

By MARY PILON and KEN BELSON The former N.F.L. linebacker Junior Seau had a degenerative brain disease linked to repeated head trauma when he committed suicide in the spring, the National Institutes of Health said Thursday. The findings were consistent with chronic traumatic encephalopathy, a degenerative brain disease widely connected to athletes who have absorbed frequent blows to the head, the N.I.H. said in a statement. Seau is the latest and most prominent player to be associated with the disease, which has bedeviled football in recent years as a proliferation of studies has exposed the possible long-term cognitive impact of head injuries sustained on the field. “The type of findings seen in Mr. Seau’s brain have been recently reported in autopsies of individuals with exposure to repetitive head injury,” the N.I.H. said, “including professional and amateur athletes who played contact sports, individuals with multiple concussions, and veterans exposed to blast injury and other trauma.” Since C.T.E. was diagnosed in the brain of the former Eagles defensive back Andre Waters after his suicide in 2006, the disease has been found in nearly every former player whose brain was examined posthumously. (C.T.E. can be diagnosed only posthumously.) Researchers at Boston University, who pioneered the study of C.T.E., have found it in 33 of the 34 brains of former N.F.L. players they have examined. The N.I.H. began its examination of Seau’s brain tissue in July. In addition to being reviewed by two federal neuropathologists, Seau’s brain was reviewed by three outside neuropathology experts who did not have knowledge of the source of the tissue. Upon initial examination “the brain looked normal,” according to the N.I.H. It was not until doctors looked under the microscope and used staining techniques that the C.T.E. abnormalities were seen. © 2013 The New York Times Company

Keyword: Brain Injury/Concussion
Link ID: 17668 - Posted: 01.12.2013

Elderly people with dementia should be prescribed antipsychotics carefully, say Ontario doctors who found men are at higher risk of hospitalization and death than women when the treatment begins. Researchers focused on new prescriptions of a class of drugs called atypical antipsychotics that are used to manage behaviour problems associated with dementia. "It tells us a little bit more about drug therapy and perhaps what might be affecting women and men differently," said Dr. Paula Rochon, a senior scientist at Toronto's Women College Hospital. In Wednesday's issue of the Journal of the American Geriatric Society, Rochon and her co-authors said of 21,526 older adults with dementia in Ontario who started taking the medications, about seven per cent of the women and nearly 11 per cent of the men died or were hospitalized during the 30 days after the treatment started. Little is known about how drugs may affect men and women differently after the age of 85, says Dr. Paula Rochon. "While younger women may be more likely than younger men to experience an adverse drug event, our results suggest that the incidence of serious events in the elderly is reversed and that older men are more likely than older women to experience a serious event related to atypical antipsychotic initiation," the study's authors concluded. © CBC 2013

Keyword: Alzheimers; Schizophrenia
Link ID: 17667 - Posted: 01.10.2013

Ewen Callaway In the mid-1980s, Paul Moorcraft, then a war correspondent, journeyed with a film crew into Afghanistan to produce a documentary about the fifth anniversary of the Soviet invasion. The trip took them behind Soviet lines. “We were attacked every fucking day by the Russians,” says the colourful Welshman. But the real trouble started later, when Moorcraft tried to tally his expenses, such as horses and local garb for his crew. Even with a calculator, the simple sums took him ten times longer than they should have. “It was an absolute nightmare. I spent days and days and days.” When he finally sent the bill to an accountant, he had not realized that after adding a zero he was claiming millions of pounds for a trip that had cost a couple of hundred thousand. “He knew I was an honest guy and assumed that it was just a typo.” Such mistakes were part of a lifelong pattern for Moorcraft, now director of the Centre for Foreign Policy Analysis in London and the author of more than a dozen books. He hasn't changed his phone number or PIN in years for fear that he would never remember new ones, and when working for Britain's Ministry of Defence he put subordinates in charge of remembering safe codes. In 2003, a mistaken phone number — one of hundreds before it — lost him a girlfriend who was convinced he was out gallivanting. That finally convinced him to seek an explanation. At the suggestion of a friend who teaches children with learning disabilities, Moorcraft contacted Brian Butterworth, a cognitive neuroscientist at University College London who studies numerical cognition. After conducting some tests, Butterworth concluded that Moorcraft was “a disaster at arithmetic” and diagnosed him with dyscalculia, a little-known learning disability sometimes called number blindness and likened to dyslexia for maths. Researchers estimate that as much as 7% of the population has dyscalculia, which is marked by severe difficulties in dealing with numbers despite otherwise normal (or, in Moorcraft's case, probably well above normal) intelligence. © 2013 Nature Publishing Group

Keyword: Attention
Link ID: 17666 - Posted: 01.10.2013

By BENEDICT CAREY Most adolescents who plan or attempt suicide have already received at least some mental health treatment, raising questions about the effectiveness of current approaches to helping troubled youths, according to the largest in-depth analysis to date of suicidal behaviors in American teenagers. Matt Nock, a professor of psychology at Harvard and the lead author of a study on the mental health treatment of troubled young people, said his research showed that “we’ve got a long way to go to do this right.” The study found that 55 percent of adolescents who plan or attempt suicide have already received some therapy. The study, in the journal JAMA Psychiatry, found that 55 percent of suicidal teenagers had received some therapy before they thought about suicide, planned it or tried to kill themselves, contradicting the widely held belief that suicide is due in part to a lack of access to treatment. The findings, based on interviews with a nationwide sample of more than 6,000 teenagers and at least one parent of each, linked suicidal behavior to complex combinations of mood disorders like depression and behavior problems like attention-deficit and eating disorders, as well as alcohol and drug abuse. The study found that about one in eight teenagers had persistent suicidal thoughts at some point, and that about a third of those who had suicidal thoughts had made an attempt, usually within a year of having the idea. © 2013 The New York Times Company

Keyword: Depression; Development of the Brain
Link ID: 17665 - Posted: 01.10.2013

By Susan Milius Male European blackbirds monitored in a lab under simulated city lighting started secreting increased levels of testosterone and growing their sexual organs up to a month earlier in the spring than birds kept in country-style darkness, Davide Dominoni of the Max Planck Institute for Ornithology in Radolfzell, Germany, reported January 6 at the annual meeting of the Society for Integrative and Comparative Biology. Dominoni’s colleagues have found that, outside the lab, male blackbirds flying around Munich undergo this growth surge about three weeks earlier than counterparts in a forest just 40 kilometers out of town. Beginning in December 2010, the researchers exposed captive blackbirds to night light levels typical of urban settings. They estimated those levels by outfitting free-flying blackbirds with light-sensitive devices and averaging the urban light exposure. A winter of lab night light sped up the males’ molting and boosted testosterone levels as well as organ development in spring. Continuing the night light treatment through the next winter left the males reproductively shut down in the spring of 2012. The lab night lights probably kept the birds’ seasonal reproductive clocks from resetting at the end of the first breeding season, Dominoni says. That second-year suppression may not be common in the real world, where birds fly around and experience more variety in night lighting, he says. But he sees the lab breeding shutdown as a sign of how big of an impact artificial light might have. © Society for Science & the Public 2000 - 2013

Keyword: Biological Rhythms; Sexual Behavior
Link ID: 17664 - Posted: 01.10.2013

by Gretchen Vogel All you graying, half-deaf Def Leppard fans, listen up. A drug applied to the ears of mice deafened by noise can restore some hearing in the animals. By blocking a key protein, the drug allows sound-sensing cells that are damaged by noise to regrow. The treatment isn't anywhere near ready for use in humans, but the advance at least raises the prospect of restoring hearing to some deafened people. When it comes to hearing, hair cells in the inner ear, so named for their bristlelike appearance, keep the process humming along, converting mechanical vibrations caused by sound waves into nerve impulses. Unfortunately for people, loud noises can overwork and destroy the cells. And once they're gone, they're gone: Birds and fish can regenerate the inner ear hair cells, but mammals cannot. Researchers have been looking for ways to reactivate the regenerative potential that other species enjoy. In 2005, scientists used gene therapy to prompt the growth of hair cells in the inner ears of adult guinea pigs, which restored some hearing. However, the drug approach would potentially be much easier to use in the clinic, says Albert Edge, a stem cell biologist at the Massachusetts Eye and Ear Infirmary in Boston. He and his colleagues had previously found that a class of drugs called gamma-secretase inhibitors could prompt the growth of hair cells from inner ear stem cells growing in the lab. The lab also showed that the drugs worked by blocking the signaling of the Notch protein, which helps determine which cells become hair cells and which become support cells during ear development. © 2010 American Association for the Advancement of Science

Keyword: Hearing; Regeneration
Link ID: 17663 - Posted: 01.10.2013

By Bruce Bower Babies may start to learn their mother tongues even before seeing their mothers’ faces. Newborns react differently to native and foreign vowel sounds, suggesting that language learning begins in the womb, researchers say. Infants tested seven to 75 hours after birth treated spoken variants of a vowel sound in their home language as similar, evidence that newborns regard these sounds as members of a common category, say psychologist Christine Moon of Pacific Lutheran University in Tacoma, Wash., and her colleagues. Newborns deemed different versions of a foreign vowel sound to be dissimilar and unfamiliar, the scientists report in an upcoming Acta Paediatrica. “It seems that there is some prenatal learning of speech sounds, but we do not yet know how much,” Moon says. Fetuses can hear outside sounds by about 10 weeks before birth. Until now, evidence suggested that prenatal learning was restricted to the melody, rhythm and loudness of voices (SN: 12/5/09, p. 14). Earlier investigations established that 6-month-olds group native but not foreign vowel sounds into categories. Moon and colleagues propose that, in the last couple months of gestation, babies monitor at least some vowels — the loudest and most expressive speech sounds — uttered by their mothers. © Society for Science & the Public 2000 - 2013

Keyword: Language; Development of the Brain
Link ID: 17662 - Posted: 01.08.2013

Taking beta-blocker drugs may cut the risk of dementia, a trial in 774 men suggests. The medication is used to treat high blood pressure, a known risk factor for dementia. In the study, which will be presented at the American Academy of Neurology's annual meeting in March, men on beta-blockers were less likely to have brain changes suggestive of dementia. Experts say it is too early to recommend beta-blockers for dementia. The findings are preliminary and larger studies in men and women from different ethnicities are needed to see what benefit beta-blockers might offer. People with high blood pressure are advised to see their doctor and get their condition under control to prevent associated complications like heart disease, stroke and vascular dementia. Having high blood pressure may damage the small vessels that supply the brain with blood. Blood carries essential oxygen and nourishment to the brain and without it, brain cells can die. Vascular dementia is the second most common cause of dementia after Alzheimer's disease and can occur if blood flow to the brain is reduced. Other research in a much larger sample of men - 800,000 in all - suggests another type of blood pressure drug known as an angiotensin receptor blocker (ARB) may cut dementia risk, including Alzheimer's disease, by as much as 50%. BBC © 2013

Keyword: Alzheimers
Link ID: 17661 - Posted: 01.08.2013

By KENNETH CHANG Mosquito bite? Poison ivy? Dry skin? Fuzzy sweater? Everyone has an itch to scratch. Why we and other animals itch remains something of a mystery. But now researchers at Johns Hopkins and Yale in the United States and several universities in China have found a key piece of the puzzle, identifying sensory neurons in mice that are dedicated to relaying itchy sensations from the top layers of skin to the spinal cord. “Our study, for the first time, shows the existence of itch-specific nerves,” said Xinzhong Dong, a professor of neuroscience at the Johns Hopkins University School of Medicine and the senior author of a paper about the findings in the journal Nature Neuroscience. Scientists have debated for decades whether separate circuitry existed for itchiness or whether its signals passed through the same nerves used to transmit pain. Earlier data — suppressing pain with morphine can cause chronic itching, for example — indicated some overlap between the two sensations. But the fact that evolution also produced dedicated itch nerves in mice — and almost certainly in people as well — suggests that itching serves an important role in survival and is not just a byproduct of the pain nerves. © 2013 The New York Times Company

Keyword: Pain & Touch
Link ID: 17660 - Posted: 01.08.2013