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Natasha Gilbert The eye-catching plumage of some male songbirds has long been explained as a result of sexual selection: brighter males compete more successfully for mates, so evolution favours their spread. Females, by contrast, remain drab. A new study turns this explanation on its head. Sexual-selection pressures drive females to evolve dull feathers more strongly than they drive males to become colourful, argues James Dale, an evolutionary ecologist at Massey University in Auckland, New Zealand. That surprising conclusion is based on a data set of plumage colour in nearly 6,000 songbirds, which Dale and his colleagues built. They used their data to ask how various potential evolutionary factors drive male and female plumage colour. If a particular songbird species was polygynous (that is, the males had more than one mate), displayed a large difference in size between males and females, and left care of the young mainly up to the females, then the researchers judged that sexual selection was likely to be an important factor in that species' evolution. The study, published in Nature1, found that sexual selection does play an important role in creating colour differences between male and female plumage. But the contrast is largely driven by females evolving to become drab. “Females are the chief architect of the difference,” says Dale. © 2015 Nature Publishing Group

Keyword: Sexual Behavior; Evolution
Link ID: 21605 - Posted: 11.05.2015

Laura Sanders Blood tells a story about the body it inhabits. As it pumps through vessels, delivering nutrients and oxygen, the ruby red liquid picks up information. Hormones carried by blood can hint at how hungry a person is, or how scared, or how sleepy. Other messages in the blood can warn of heart disease or announce a pregnancy. When it comes to the brain, blood also seems to be more than a traveling storyteller. In some cases, the blood may be writing the script. A well-fed brain is crucial to survival. Blood ebbs and flows within the brain, moving into active areas in response to the brain’s demands for fuel. Now scientists have found clues that blood may have an even more direct and powerful influence. Early experiments suggest that, instead of being at the beck and call of nerve cells, blood can actually control them. This role reversal hints at an underappreciated layer of complexity — a layer that may turn out to be vital to how the brain works. The give-and-take between brain and blood appears to change with age and with illness, researchers are finding. Just as babies aren’t born walking, their developing brain cells have to learn how to call for blood. And a range of age-related disorders, including Alzheimer’s disease, have been linked to dropped calls between blood and brain, a silence that may leave patches of brain unable to do their jobs. © Society for Science & the Public 2000 - 2015

Keyword: Brain imaging
Link ID: 21604 - Posted: 11.05.2015

Doubts are emerging about one of our leading models of consciousness. It seems that brain signals thought to reflect consciousness are also generated during unconscious activity. A decade of studies have lent credence to the global neuronal workspace theory of consciousness, which states that when something is perceived unconsciously, or subliminally, that information is processed locally in the brain. In contrast, conscious perception occurs when the information is broadcast to a “global workspace”, or assemblies of neurons distributed across various brain regions, leading to activity over the entire network. Proponents of this idea, Stanislas Dehaene at France’s national institute for health in Gif-sur-Yvette, and his colleagues, discovered that when volunteers view stimuli that either enter conscious awareness or don’t, their brains show identical EEG activity for the first 270 milliseconds. Then, if perception of the stimuli is subliminal, the brain activity peters out. However, when volunteers become conscious of the stimuli, there is a sudden burst of widespread brain activity 300 ms after the stimulus. This activity is characterised by an EEG signal called P3b, and has been called a neural correlate of consciousness. Brian Silverstein and Michael Snodgrass at the University of Michigan in Ann Arbor, and colleagues wondered if P3b could be detected during unconscious processing of stimuli. © Copyright Reed Business Information Ltd.

Keyword: Consciousness
Link ID: 21603 - Posted: 11.05.2015

By Nicholas Bakalar A person with depression is at higher risk for heart disease, and a person with heart disease is at higher risk for depression. The link between the two diseases is complex and not entirely understood. Many of the effects of depression — feeling unable to exercise or eat properly, for example — and the behaviors associated with depression, like smoking and abusing alcohol, are well established risk factors for heart disease. Some studies have suggested that insomnia, another symptom of depression, may also increase the risk for cardiovascular illness. Depression can also make heart disease worse. Heart patients with depression may find it more difficult to take medications and comply with the behavioral demands of living with heart disease. Depression may also have destructive physiological effects on heart rhythm, blood pressure, stress hormone levels and blood clotting, studies have shown. These may be among the reasons why depressed patients with stable cardiovascular disease, or those who have survived a heart attack or had coronary bypass surgery, are at two to three times higher risk of dying than similar patients without depression. Treating depressed heart patients with drugs like Prozac may help. These drugs, known as selective serotonin reuptake inhibitors, or S.S.R.I.’s, in addition to relieving depression, have blood-thinning effects that may be beneficial against heart disease. “It is clear that treatment with an S.S.R.I. reduces cardiac mortality in depressed patients post heart attack,” said Dr. Steven P. Roose, a professor of psychiatry at Columbia. “What is not clear is whether the reduction in mortality results from the antidepressant effect of the medication or the anti-platelet effect of the medication.” © 2015 The New York Times Company

Keyword: Depression; Neuroimmunology
Link ID: 21602 - Posted: 11.05.2015

By DAVE ITZKOFF and BENEDICT CAREY For the first time in more than a year, the widow of the actor Robin Williams is speaking publicly about the circumstances that preceded Mr. Williams’s death, and sharing details about a disease he had when he died. Stories from Our Advertisers In interviews with People magazine and with ABC News, the widow, Susan Schneider Williams, laid the blame for her husband’s suicide in 2014 not on depression but on diffuse Lewy body dementia. “It was not depression that killed Robin,” Mrs. Williams said in the People magazine interview. “Depression was one of let’s call it 50 symptoms and it was a small one.” She added: “This was a very unique case and I pray to God that it will shed some light on Lewy bodies for the millions of people and their loved ones who are suffering with it. Because we didn’t know. He didn’t know.” Parts of an interview with Mrs. Williams were shown Tuesday on ABC’s “Good Morning America,” with further segments scheduled for that evening on the network’s “World News Tonight” and “Nightline” programs, and Friday on its morning talk show “The View.” Robin Williams was one of the most explosively, exhaustingly, prodigiously verbal comedians who ever lived, says film critic A. O. Scott. And the only thing faster than Williams’s mouth was his mind. By Adam Freelander on Publish Date August 12, 2014. Photo by ABC, via Associated Press. Watch in Times Video » Mr. Williams, the stand-up comic and star of “Mork & Mindy,” “Good Morning, Vietnam,” “Good Will Hunting” (for which he won an Oscar) and “Dead Poets Society,” killed himself on Aug. 11, 2014, in the home he shared with Mrs. Williams in Tiburon, Calif. He was 63. © 2015 The New York Times Company

Keyword: Alzheimers; Depression
Link ID: 21601 - Posted: 11.04.2015

Sara Reardon Military-service members can suffer brain injury and memory loss when exposed to explosions in enclosed spaces, even if they do not sustain overt physical injury. A strategy designed to improve memory by delivering brain stimulation through implanted electrodes is undergoing trials in humans. The US military, which is funding the research, hopes that the approach might help many of the thousands of soldiers who have developed deficits to their long-term memory as a result of head trauma. At the Society for Neuroscience meeting in Chicago, Illinois, on 17–21 October, two teams funded by the Defense Advanced Research Projects Agency presented evidence that such implanted devices can improve a person’s ability to retain memories. By mimicking the electrical patterns that create and store memories, the researchers found that gaps caused by brain injury can be bridged. The findings raise hopes that a ‘neuro­prosthetic’ that automatically enhances flagging memory could aid not only brain-injured soldiers, but also people who have had strokes — or even those who have lost some power of recall through normal ageing. Because of the risks associated with surgically placing devices in the brain, both groups are studying people with epilepsy who already have implanted electrodes. The researchers can use these electrodes both to record brain activity and to stimulate specific groups of neurons. Although the ultimate goal is to treat traumatic brain injury, these people might benefit as well, says biological engineer Theodore Berger at the University of Southern California (USC) in Los Angeles. That is because repeated seizures can destroy the brain tissue needed for long-term-memory formation. © 2015 Nature Publishing Group

Keyword: Learning & Memory; Robotics
Link ID: 21600 - Posted: 11.04.2015

Your sense of smell might be more important than you think. It could indicate how well your immune system is functioning, a study in mice suggests. Evidence of a connection between the immune system and the olfactory system – used for sense of smell – has been building for some time. For instance, women seem to prefer the scent of men with different immune system genes to their own. Meanwhile, other studies have hinted that the robustness of your immune system may influence how extraverted you are. To investigate further, Fulvio D’Acquisto at Queen Mary University of London and his colleagues studied mice missing a recombinant activating gene (RAG), which controls the development of immune cells. Without it, mice lack a working immune system and some genes are expressed differently, including those involved in the olfactory system. “That rang bells, because people with immune deficiencies often lose their sense of smell,” says D’Acquisto. Systemic lupus erythematosus, an autoimmune disease in which the immune system mistakenly attacks tissues in the skin, joints, kidneys, brain, and other organs, is one such example. His team measured how long it took mice to find chocolate chip cookies buried in their cages. Those missing RAG took five times as long as normal mice. They also failed to respond to the scent of almond or banana, which mice usually find very appealing – although they did still react to the scent of other mice. Further study uncovered abnormalities in the lining of their noses; physical evidence that their sense of smell might be disrupted. © Copyright Reed Business Information Ltd.

Keyword: Chemical Senses (Smell & Taste); Neuroimmunology
Link ID: 21599 - Posted: 11.04.2015

Scientists have come up with a questionnaire they say should help diagnose a condition called face blindness. Prosopagnosia, as doctors call it, affects around two in every 100 people in the UK and is the inability to recognise people by their faces alone. In its most extreme form, people cannot even recognise their family or friends. Milder forms, while still distressing, can be tricky to diagnose, which is why tests are needed. People with prosopagnosia often use non-facial cues to recognise others, such as their hairstyle, clothes, voice, or distinctive features. Some may be unaware they have the condition, instead believing they have a "bad memory for faces". But prosopagnosia is entirely unrelated to intelligence or broader memory ability. One [anonymous] person with prosopagnosia explains: "My biggest problem is seeing the difference between ordinary-looking people, especially faces with few specific traits. "I work at a hospital with an awful lot of employees and I often introduce myself to colleagues with whom I have worked several times before. I also often have problems recognising my next-door neighbour, even though we have been neighbours for eight years now. She often changes clothes, hairstyle and hair colour. When I strive to recognise people, I try to use technical clues like clothing, hairstyle, scars, glasses, their dialect and so on." Doctors can use computer-based tests to see if people can spot famous faces and memorise and recognise a set of unfamiliar faces. And now Drs Richard Cook, Punit Shah and City University London and Kings College London have come up with a 20-item questionnaire to help measure the severity of someone's face blindness. © 2015 BBC

Keyword: Attention
Link ID: 21598 - Posted: 11.04.2015

By Christof Koch Artificial intelligence has been much in the news lately, driven by ever cheaper computer processing power that has become effectively a near universal commodity. The excitement swirls around mathematical abstractions called deep convolutional neural networks, or ConvNets. Applied to photographs and other images, the algorithms that implement ConvNets identify individuals from their faces, classify objects into one of 1,000 distinct categories (cheetah, husky, strawberry, catamaran, and so on)—and can describe whether they see “two pizzas sitting on top of a stove top oven” or “a red motorcycle parked on the side of the road.” All of this happens without human intervention. Researchers looking under the hood of these powerful algorithms are surprised, puzzled and entranced by the beauty of what they find. How do ConvNets work? Conceptually they are but one or two generations removed from the artificial neural networks developed by engineers and learning theorists in the 1980s and early 1990s. These, in turn, are abstracted from the circuits neuroscientists discovered in the visual system of laboratory animals. Already in the 1950s a few pioneers had found cells in the retinas of frogs that responded vigorously to small, dark spots moving on a stationary background, the famed “bug detectors.” Recording from the part of the brain's outer surface that receives visual information, the primary visual cortex, Torsten Wiesel and the late David H. Hubel, both then at Harvard University, found in the early 1960s a set of neurons they called “simple” cells. These neurons responded to a dark or a light bar of a particular orientation in a specific region of the visual field of the animal. © 2015 Scientific American

Keyword: Vision; Robotics
Link ID: 21597 - Posted: 11.03.2015

Alison Abbott Europe’s troubled Human Brain Project (HBP) has secured guarantees of European Commission financing until at least 2019 — but some scientists are still not sure that they want to take part in the mega-project, which has been fraught with controversy since its launch two years ago. On 30 October, the commission signed an agreement formally committing to fund the HBP past April 2016, when its preliminary 30-month ‘ramp-up’ phase ends. The deal also starts a process to change the project’s legal status so as to spread responsibility across many participating institutions. The commission hopes that this agreement will restore lost confidence in the HBP, which aims to better understand the brain using information and computing technologies, primarily through simulation. Last year, hundreds of scientists signed a petition claiming that the project was being mismanaged and was running off its scientific course; they pledged to boycott it if their concerns were ignored. Since then, the HBP has been substantially reformed along lines recommended by a mediation committee. It has dissolved its three-person executive board, which had assumed most of the management power. And it has committed to including studies on cognitive neuroscience (which the triumvirate had wanted to eliminate). It also opened up for general competition some €8.9 million ($US10 million) of cash previously allocated only to project insiders, and in September selected four major projects in systems and cognitive neuroscience proposed by different groups around Europe. © 2015 Nature Publishing Group

Keyword: Brain imaging
Link ID: 21596 - Posted: 11.03.2015

Nicole Fisher , We know that the brain is neuroplastic — adapts to changes in behavior, environment, thinking and emotions — and may even rewire itself in certain ways. Life experience also teaches us that the tongue is a learning tool that shapes our brain. During early development, babies test everything by placing it in their mouths. As children age they stick out their tongues when concentrating on tasks such as drawing. Even as adults we let our tongue tell us about the world around us through eating, drinking and kissing. During basketball games, some players stick out their tongues while shooting. Now, knowing that there is such a rich nerve connection to the brain, scientists and doctors are turning to the tongue as a way to possibly stimulate the brain for neural retraining and rehabilitation after traumatic injuries or disease. The team at Helius Medical Technologies believe combining physical therapy with stimulation of the tongue may improve impairment of brain function and associated symptoms of injury. “We have already seen that stimulation of various nerves can improve symptoms of a range of neurological diseases. However, we believe the tongue is a much more elegant and direct pathway for stimulating brain structures and inducing neuroplasticity. We are focused on investigating the tongue as a gateway to the brain to hopefully ease the disease of brain injury,” said Dr. Jonathan Sackier, CMO at Helius. It has been argued by some that the era of small molecule is gone. Instead, recognition that the entire body is a closed electrical circuit, is leading to new therapeutic modalities that are known in certain circles as “electroceuticals.”

Keyword: Brain Injury/Concussion; Chemical Senses (Smell & Taste)
Link ID: 21595 - Posted: 11.03.2015

By Michelle Roberts Health editor, BBC News online Brain training - playing online games that give memory and reasoning skills a workout - is beneficial for older people, a large-scale study has concluded. Researchers at King's College London found the mental exercises kept minds sharp and helped people with everyday skills such as shopping and cooking. Nearly 7,000 people aged 50 and over signed up for the six-month experiment, launched by BBC TV's Bang Goes The Theory. Longer studies are now beginning. The volunteers were recruited from the general population by a partnership between the BBC, the Alzheimer's Society and the Medical Research Council. As far as the investigators were aware, none had any problems with memory or cognition when they signed up to the experiment. Some of the volunteers were encouraged to play online brain training games for 10 minutes at a time, as often as they wished. The others - the control group - were asked to do simple internet searches. The researchers tested the subjects on a series of medically recognised cognitive tests at baseline and then again at three months and six months to see if there was any detectable difference between the groups. The researchers found after six months, those who played "brain training" games for reasoning and problem-solving kept their broader cognitive skills better than those who did not. The benefit appeared to kick in when people played the games at least five times a week. And people over 60 who played these games reported better scores for carrying out essential everyday tasks, the Journal of Post-acute and Long Term Care Medicine reports. © 2015 BBC

Keyword: Learning & Memory; Development of the Brain
Link ID: 21594 - Posted: 11.03.2015

By SINDYA N. BHANOO Some kinds of itching can be caused by the lightest of touches, a barely felt graze that rustles tiny hairs on the skin’s surface. This type of itch is created via a dedicated neural pathway, a new study suggests. The finding, which appears in the journal Science, could help researchers better understand chronic itchiness in conditions like eczema, diabetic neuropathy, multiple sclerosis and some cancers. The study also may help researchers determine why certain patients do not respond well to antihistamine drugs. “In the future, we may have some way to manipulate neuron activity to inhibit itching,” said Quifu Ma, a neurobiologist at Harvard University and one of the study’s authors. In the study, Dr. Ma and his colleagues inhibited neurons that express a neuropeptide known as Y or NPY in mice. When these neurons were suppressed and the mice were poked with a tiny filament, they fell into scratching fits. Normally, mice would not even respond to this sort of stimuli. “We start to see skin lesions — they don’t stop scratching,” Dr. Ma said. “It’s pretty traumatic.” The neurons only seem related to itches prompted by light touching, known as mechanically induced itches. Chemical itches, like those caused by a mosquito bite or an allergic reaction, are not transmitted by the same neurons. © 2015 The New York Times Company

Keyword: Pain & Touch
Link ID: 21593 - Posted: 11.03.2015

by Bethany Brookshire Cheese is a delicious invention. But if you saw the news last week, you might think it’s on its way to being classified as a Schedule II drug. Headlines proclaimed “Say cheese? All the time? Maybe you have an addiction,” “Cheese really is crack” and “Your cheese addiction is real.” Under the headlines, the stories referred to a study examining the addictive properties of various foods. Pizza was at the top. The reason? The addictive properties of cheese, which the articles claim contains “dangerous” opiate-like chemicals called casomorphins. But you can’t explain away your affinity for cheese by saying you’re addicted. The study in those stories, published earlier this year in PLOS ONE, did investigate which foods are most associated with addictive-like eating behaviors. Pizza did come out on top in one experiment. But the scientists who did the research say this has little to do with the delicious dairy products involved. Instead, they argue, the foods we crave the most are those processed to have high levels of sugars and fat, and it’s these ingredients that leave us coming back for another slice. The cheese? “I was horrified by the misstatements and the oversimplifications … and the statements about how it’s an excuse to overeat,” says Ashley Gearhardt of the University of Michigan in Ann Arbor, who led the study. “Liking is not the same as addiction. We like lots of things. I like hip-hop music and sunshine and my wiener dog, but I’m not addicted to her. I eat cheese every day. That’s doesn’t mean you’re addicted or it has addictive potential.” © Society for Science & the Public 2000 - 2015

Keyword: Drug Abuse
Link ID: 21592 - Posted: 11.02.2015

By Simon Makin Most people have felt depressed or anxious, even if those feelings have never become debilitating. And how many times have you heard someone say, “I'm a little OCD”? Clearly, people intuitively think that most mental illnesses have a spectrum, ranging from mild to severe. Yet most people do not know what it feels like to hallucinate—to see or hear things that are not really there—or to have delusions, persistent notions that do not match reality. You're psychotic, or you're not, according to conventional wisdom. Evidence is growing, however, that there may be no clear dividing line. Psychiatrists have long debated whether psychosis exists on a spectrum, and researchers have been investigating the question for more than a decade now. A 2013 meta-analysis, combining much of the existing data, by Jim van Os of Maastricht University in the Netherlands and Richard Linscott of the University of Otago in New Zealand, found the prevalence of hallucinations and delusions in the general population was 7.2 percent—much higher than the 0.4 percent prevalence of schizophrenia diagnoses found in recent studies. Now the most comprehensive epidemiological study of psychotic experiences to date, published in July in JAMA Psychiatry, has given researchers the most detailed picture yet of how many people have these experiences and how frequently. The results strongly imply a spectrum—and suggest that the standard treatment for a psychotic episode might be due for an overhaul. After ruling out experiences caused by drugs or sleep, the researchers determined that 5.8 percent of the respondents had psychotic experiences. Two thirds of these people had had only one type of episode, with hallucinations being four times more common than delusions. © 2015 Scientific American

Keyword: Schizophrenia
Link ID: 21591 - Posted: 11.02.2015

By Jennie Baird Last week’s news that Sesame Street was introducing the first autistic Muppet was met in my house with a resounding, “Huh?” “But there already is an autistic Muppet,” my high-functioning 14-year-old said. “Fozzie Bear.” I had never thought of Fozzie that way, but my son had a point. Fozzie is not good at taking social cues; he doesn’t read a room well and he tends to monologue and perseverate (to repeat himself long after the need has passed). He interprets figurative language as literal — remember that fork in the road in “The Muppet Movie?” He has a verbal tic he falls back on, “wokka-wokka.” And he hates to be separated from his hat for no obvious reason. I’ve tested this theory on friends and have seen the light bulb of recognition go off every time. Of course Fozzie has autism! One friend, a mother whose son is also on the spectrum even told me her family had the exact same conversation. Sesame Street hopes children will identify with their new character Julia, described as a “friend who has autism,” and appearing, for now, only in the book “We’re Amazing 1-2-3!” There is no question, the mere presence of Julia is a positive development. But she also introduces a rarely discussed complication of autism. Let’s call it the Fozzie Conundrum. I’m particularly sensitive to the Fozzie Conundrum now that my son attends regular honors classes in a regular public high school. Naturally sociable and charismatic — and with eight years of support and interventions from a team of terrific teachers and therapists at specialized schools — he can easily “pass” as a regular, funny, quirky teenager. © 2015 The New York Times Company

Keyword: Autism
Link ID: 21590 - Posted: 11.02.2015

? Joanne Silberner Each year, nearly three times as many Americans die from suicide as from homicide. More Americans kill themselves than die from breast cancer. As Thomas Insel, longtime head of the National Institute of Mental Health, prepared to step down from his job in October, he cited the lack of progress in reducing the number of suicides as his biggest disappointment. While the homicide rate in the US has dropped 50 percent since the early 1990s, the suicide rate is higher than it was a decade ago. "That to me is unacceptable," Insel says. It hasn't been for lack of trying. The US has a national suicide hotline and there are suicide prevention programs in every state. There's screening, educational programs, and midnight walks to raise awareness. Yet over the last decade or so, the national suicide rate has increased. In 2003, the suicide rate was 10.8 per 100,000 people. In 2013, it was 12.6. An effort that began in Detroit in 2001 to treat depression, the most common cause of suicide, is offering hope. With a relentless focus on finding and treating people with depression, the Henry Ford Health System has cut the suicide rate among the people in its insurance plan dramatically. The story of the health system's success is a story of persistence, confidence, hope and a strict adherence to a very specific approach. © 2015 npr

Keyword: Depression
Link ID: 21589 - Posted: 11.02.2015

By Hanae Armitage Fake fingerprints might sound like just another ploy to fool the feds. But the world’s first artificial prints—reported today—have even cooler applications. The electronic material, which mimics the swirling designs imprinted on every finger, can sense pressure, temperature, and even sound. Though the technology has yet to be tested outside the lab, researchers say it could be key to adding sensation to artificial limbs or even enhancing the senses we already have. “It’s an interesting piece of work,” says John Rogers, materials scientist at the University of Illinois, Urbana-Champaign, who was not involved in the study. “It really adds to the toolbox of sensor types that can be integrated with the skin.” Electronic skins, known as e-skins, have been in development for years. There are several technologies used to mimic the sensations of real human skin, including sensors that can monitor health factors like pulse or temperature. But previous e-skins have been able to “feel” only two sensations: temperature and pressure. And there are additional challenges when it comes to replicating fingertips, especially when it comes to mimicking their ability to sense even miniscule changes in texture, says Hyunhyub Ko, a chemical engineer at Ulsan National Institute of Science and Technology in South Korea. So in the new study, Ko and colleagues started with a thin, flexible material with ridges and grooves much like natural fingerprints. This allowed them to create what they call a “microstructured ferroelectric skin” The e-skin’s perception of pressure, texture, and temperature all come from a highly sensitive structure called an interlocked microdome array—the tiny domes sandwiched in the bottom two layers of the e-skin, also shown in the figure below. © 2015 American Association for the Advancement of Science

Keyword: Pain & Touch; Robotics
Link ID: 21588 - Posted: 10.31.2015

Laura Sanders A fly tickling your arm hair can spark a maddening itch. Now, scientists have spotted nerve cells in mice that curb this light twiddling sensation. If humans possess similar itch-busters, the results, published in the Oct. 30 Science, could lead to treatments for the millions of people who suffer from intractable, chronic itch. For many of these people, there are currently no good options. “This is a major problem,” says clinician Gil Yosipovitch of Temple University School of Medicine in Philadelphia and director of the Temple Itch Center. The new study shows that mice handle an itch caused by a fluttery touch differently than other kinds of itch. This distinction “seems to have clinical applications that clearly open our field,” Yosipovitch says. In recent years, scientists have made progress teasing apart the pathways that carry itchy signals from skin to spinal cord to brain (SN: 11/22/2008, p. 16). But those itch signals often originate from chemicals, such as those delivered by mosquitoes. All that’s needed to spark a different sort of itch, called mechanical itch, is a light touch on the skin. The existence of this kind of itch is no surprise, Yosipovitch says. Mechanical itch may help explain why clothes or even dry, scaly skin can be itchy. The new finding came from itchy mice engineered to lack a type of nerve cell in their spinal cords. Without prompting, these mice scratched so often that they developed sore bald patches on their skin. © Society for Science & the Public 2000 - 2015

Keyword: Pain & Touch
Link ID: 21587 - Posted: 10.31.2015

Adam Cole Watch a scary movie and your skin crawls. Goose bumps have become so associated with fear that the word is synonymous with thrills and chills. But what on earth does scary have do to with chicken-skin bumps? For a long time, it wasn't well understood. Physiologically, it's fairly simple. Adrenaline stimulates tiny muscles to pull on the roots of our hairs, making them stand out from our skin. That distorts the skin, causing bumps to form. Call it horripilation, and you'll be right — bristling from cold or fear. Charles Darwin once investigated goose bumps by scaring zoo animals with a stuffed snake. He argued for the now accepted theory that goose bumps are a vestige of humanity's ancient past. Our ancestors were hairy. Goose bumps would have fluffed up their hair. When they were scared, that would have made them look bigger — and more intimidating to attackers. When they were cold, that would have trapped an insulating layer of air to keep them warm. We modern humans still get goose bumps when we're scared or cold, even though we've lost the advantage of looking scarier or staying warmer ourselves. And researchers have found that listening to classical music (or Phil Collins), seeing pictures of children or drinking a sour drink can also inspire goose bumps. There's clearly a link with emotion and reward, too. © 2015 npr

Keyword: Pain & Touch; Emotions
Link ID: 21586 - Posted: 10.31.2015