Chapter 8. General Principles of Sensory Processing, Touch, and Pain

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Laura Beil Even though a sprained ankle rarely needs an opioid, a new study of emergency room patients found that about 7 percent of patients got sent home with a prescription for the potentially addictive painkiller anyway. And the more pills prescribed, the greater the chance the prescription would be refilled, raising concerns about continued use. The research adds to evidence that it’s hard for some people to stop taking the pills even after a brief use. State officials in New Jersey recently enacted a law limiting first-time prescriptions to a five-day supply, and other states should consider similar restrictions, says Kit Delgado, an assistant professor of Emergency Medicine and Epidemiology at the University of Pennsylvania. “The bottom line is that we need to do our best not to expose people to opioids,” Delgado says. “And if we do, start with the smallest quantity possible.” The research was presented May 17 at the Society for Academic Emergency Medicine’s annual meeting in Orlando. Previous research has found that the more opioids such as hydrocodone and oxycodone are prescribed, the more likely patients are to keep taking them. But previous studies have been too broad to account for differences in diagnoses — for instance, whether people who received refills kept taking the drug simply because they still were in pain, Delgado says. He and colleagues limited their study to prescriptions written after ankle sprains to people who had not used an opioid in the previous six months. Usually, those injuries aren’t serious and don’t require opioids. |© Society for Science & the Public 2000 - 2017

Keyword: Drug Abuse; Pain & Touch
Link ID: 23638 - Posted: 05.20.2017

By Roman Liepelt and Jack Brooks An amputee struggles to use his new prosthetic limb. A patient with a frontal-lobe brain lesion insists that her left hand has a mind of its own. The alleged criminal claims in court that he did not fire the gun, even though several eyewitnesses watched him do it. Each of these individuals is grappling with two elements of the mind-body connection: ownership, or an ability to separate ourselves from the physical and social environments, and agency, a conviction that we have control over our limbs. We are quick to investigate a sticker placed on our forehead when looking in a mirror, recognizing the foreign object as abnormal. The human brain typically handles these phenomena by comparing neural signals encoding the intended action with those signals carrying sensory feedback. When we are born, we make erratic reaching and kicking movements to map our body and to calibrate our sensorimotor system. During infancy, these movements solidify our self-awareness, and around the time we first walk, we are quick to investigate a sticker placed on our forehead when looking in a mirror, recognizing the foreign object as abnormal. By the age of four, our brains are proficient at distinguishing self and other. In the amputee, the brain lesion patient, and the defendant on trial, the sense of self is disrupted due to discordance between sensory feedback from the limb and the brain’s expectations of how a movement should feel. © 1986-2017 The Scientist

Keyword: Pain & Touch
Link ID: 23625 - Posted: 05.17.2017

By Moheb Costandi Pain in infants is heartbreaking for new parents, and extremely difficult to treat effectively—if at all. Every year an estimated 15 million babies are born prematurely, most of whom will then undergo numerous lifesaving but painful procedures, such as heel pricking or insertion of a thin tube known as a cannula to deliver fluids or medicine. Preterm babies in the intensive care unit are subjected to an average of 11 such “skin-breaking” procedures per day, but analgesia is only used just over one third of the time. We know that repetitive, painful procedures in early infancy can impact brain development negatively—so why is pain in infants so undertreated? One reason is the lack of standard guidelines for administering the drugs. Some analgesics given to adults are unsuitable for infants, and those that can be used often have different effects in children, making dosing a problem. What is more, newborn babies are incapable of telling us how they feel, making it impossible to determine how effective any painkiller might be. Researchers at the University of Oxford may now have overcome this latter challenge, however. They report May 3 in Science Translational Medicine having identified a pain-related brain wave signal that responds to analgesics, and could be used to measure the drugs’ efficacy. Until as recently as the 1980s, it was assumed that newborn babies do not feel pain, and that giving them analgesics would do more harm than good. Although these misconceptions have been cleared up, we still have very little understanding of infant pain, and so treating it is a huge challenge for clinicians. © 2017 Scientific American

Keyword: Pain & Touch
Link ID: 23576 - Posted: 05.05.2017

Douglas Fox Six times a day, Katrin pauses whatever she's doing, removes a small magnet from her pocket and touches it to a raised patch of skin just below her collar bone. For 60 seconds, she feels a soft vibration in her throat. Her voice quavers if she talks. Then, the sensation subsides. The magnet switches on an implanted device that emits a series of electrical pulses — each about a milliamp, similar to the current drawn by a typical hearing aid. These pulses stimulate her vagus nerve, a tract of fibres that runs down the neck from the brainstem to several major organs, including the heart and gut. The technique, called vagus-nerve stimulation, has been used since the 1990s to treat epilepsy, and since the early 2000s to treat depression. But Katrin, a 70-year-old fitness instructor in Amsterdam, who asked that her name be changed for this story, uses it to control rheumatoid arthritis, an autoimmune disorder that results in the destruction of cartilage around joints and other tissues. A clinical trial in which she enrolled five years ago is the first of its kind in humans, and it represents the culmination of two decades of research looking into the connection between the nervous and immune systems. For Kevin Tracey, a neurosurgeon at the Feinstein Institute for Medical Research in Manhasset, New York, the vagus nerve is a major component of that connection, and he says that electrical stimulation could represent a better way to treat autoimmune diseases, such as lupus, Crohn's disease and more. Several pharmaceutical companies are investing in 'electroceuticals' — devices that can modulate nerves — to treat cardiovascular and metabolic diseases. But Tracey's goal of controlling inflammation with such a device would represent a major leap forward, if it succeeds. © 2017 Macmillan Publishers Limited

Keyword: Neuroimmunology; Pain & Touch
Link ID: 23573 - Posted: 05.04.2017

Laura Sanders An electrode on top of a newborn’s scalp, near the soft spot, can measure when the baby feels pain. The method, described online May 3 in Science Translational Medicine, isn’t foolproof, but it brings scientists closer to being able to tell when infants are in distress. Pain assessment in babies is both difficult and extremely important for the same reason: Babies don’t talk. That makes it hard to tell when they are in pain, and it also means that their pain can be more easily overlooked, says Carlo Bellieni, a pediatric pain researcher at the University Hospital Siena in Italy. Doctors rely on a combination of clues such as crying, wiggling and facial grimacing to guess whether a baby is hurting. But these clues can mislead. “Similar behaviors occur when infants are not in pain, for example if they are hungry or want a cuddle,” says study coauthor Rebeccah Slater of the University of Oxford. By relying on brain activity, the new method promises to be a more objective measurement. Slater and colleagues measured brain activity in 18 newborns between 2 and 5 days old. Electroencephalography (EEG) recordings from electrodes on the scalp picked up collective nerve cell activity as babies received a heel lance to draw blood or a low-intensity bop on the foot, a touch that’s a bit like being gently poked with a blunt pencil. One electrode in particular, called the Cz electrode and perched on the top of the head, detected a telltale neural spike between 400 and 700 milliseconds after the painful event. This brain response wasn’t observed when these same babies received a sham heel lance or an innocuous touch on the heel. |© Society for Science & the Public 2000 - 2017

Keyword: Pain & Touch; Development of the Brain
Link ID: 23566 - Posted: 05.04.2017

Amber Dance Biologist Leo Smith held an unusual job while an undergraduate student in San Diego. Twice a year, he tagged along on a chartered boat with elderly passengers. The group needed him to identify two particular species of rockfish, the chilipepper rockfish and the California shortspine thornyhead. Once he’d found the red-orange creatures, the passengers would stab themselves in the arms with the fishes’ spines. Doing so, the seniors believed, would relieve their aching arthritic joints. Smith, now at the University of Kansas in Lawrence, didn’t think much of the practice at the time, but now he wonders if those passengers were on to something. Though there’s no evidence that anything in rockfish venom can alleviate pain — most fish stings are, in fact, quite painful themselves — some scientists suspect fish venom is worth a look. Studying the way venom molecules from diverse fishes inflict pain might help researchers understand how nerve cells sense pain and lead to novel ways to dull the sensation. Smith is one of a handful of scientists who are studying fish venoms, and there’s plenty to investigate. An estimated 7 to 9 percent of fishes, close to 3,000 species, are venomous, Smith’s work suggests. Venomous fishes are found in freshwater and saltwater, including some stingrays, catfishes and stonefishes. Some, such as certain fang blennies, are favorites in home aquariums. Yet stinging fishes haven’t gotten the same attention from scientists as snakes and other venomous creatures. |© Society for Science & the Public 2000 - 2017

Keyword: Pain & Touch; Neurotoxins
Link ID: 23515 - Posted: 04.20.2017

Laurel Hamers Earth’s magnetic field helps eels go with the flow. The Gulf Stream fast-tracks young European eels from their birthplace in the Sargasso Sea to the European rivers where they grow up. Eels can sense changes in Earth’s magnetic field to find those highways in a featureless expanse of ocean — even if it means swimming away from their ultimate destination at first, researchers report in the April 13 Current Biology. European eels (Anguilla anguilla) mate and lay eggs in the salty waters of the Sargasso Sea, a seaweed-rich region in the North Atlantic Ocean. But the fish spend most of their adult lives living in freshwater rivers and estuaries in Europe and North Africa. Exactly how eels make their journey from seawater to freshwater has baffled scientists for more than a century, says Nathan Putman, a biologist with the National Oceanic and Atmospheric Administration in Miami. The critters are hard to track. “They’re elusive,” says study coauthor Lewis Naisbett-Jones, a biologist now at the University of North Carolina at Chapel Hill. “They migrate at night and at depth. The only reason we know they spawn in the Sargasso Sea is because that’s where the smallest larvae have been collected.” |© Society for Science & the Public 2000 - 2017.

Keyword: Animal Migration
Link ID: 23492 - Posted: 04.14.2017

David Cyranoski For decades, scientists have wondered how animals can navigate huge distances using the weak signals of Earth’s magnetic field. So, interest was piqued in 2015 when two teams released papers in quick succession describing the functions of a protein found in animals that seemed to sense magnetic fields. But the claims have proved controversial, and questions have been piling up. The basic science behind the discovery was reported by Xie Can, a biophysicist at Peking University in Beijing, and his colleagues. In a paper in Nature Materials1, they claimed that a protein in animal cells forms a structure that responds to magnetic fields, and so might help in navigation. In the same year, a group led by Zhang Sheng-jia, then at Tsinghua University in Beijing, had published a paper in Science Bulletin2 reporting that the same protein could offer a powerful means of controlling brain cells. An academic battle has long raged between Xie and Zhang, but mounting evidence has cast doubt on both of their discoveries. Several researchers have challenged Xie’s claims that the protein reacts to magnetic fields. And last month, Xie co-authored a paper in Frontiers in Neural Circuits3 disputing Zhang’s work on the protein’s potential to magnetically control cells. This has all given rise to serious questions about the role of the molecule at the centre of the dispute. In their 2015 paper1, Xie and his colleagues reported that a protein called IscA1 forms a complex with another protein, Cry4, that explains how organisms pick up magnetic cues. The study found that this complex incorporates iron atoms, which gives it magnetic properties, and has a rod-like shape that aligns with an applied magnetic field. © 2017 Macmillan Publishers Limited

Keyword: Animal Migration
Link ID: 23452 - Posted: 04.05.2017

By STEPH YIN It’s a small fish, only a couple of inches long, and its bright colors make it pop in the Pacific coral reefs it calls home. The first thing that makes this fish peculiar is the striking pair of large lower canines it sports. But when attacked by a predator, this fish, part of a group called fang blennies,does something even more strange. A predator that puts this fang blenny in its mouth would experience a “violent quivering of the head,” according to George Losey, a zoologist who observed this species up close in a series of feeding experiments in the 1970s. Then the predator would open its jaws and gills. The little blenny would swim away, unscathed. A study published on Thursday in Current Biology now lays bare the details of the fish’s unusual defense mechanism: Unlike most venomous fish, which inject toxins through their fins, fang blennies deliver venom through their bite. Furthermore, fang blenny venom does not appear to produce potent pain, at least in mice. Instead, it causes a sudden drop in blood pressure, which might temporarily stupefy predators. “This is one of the most in-depth studies of how venom functions in any particular group of fish,” said Matthew Davis, an assistant professor of biology at St. Cloud State University in Minnesota, who did not participate in the research. A CT scan of Meiacanthus grammistes, a venomous fang blenny species. Anthony Romilio The authors of the study took a multipronged approach to studying venomous fang blennies. First, they imaged the jaws of fang blennies collected from around the Pacific and Indian Oceans to confirm what scientists long suspected: Not all fang blennies have venom glands at the base of their teeth. © 2017 The New York Times Company

Keyword: Pain & Touch; Neurotoxins
Link ID: 23432 - Posted: 03.31.2017

By Anil Ananthaswamy People who have chronic pain are more likely to experience mood disorders, but it’s not clear how this happens. Now a study in mice has found that chronic pain can induce genetic changes in brain regions that are linked to depression and anxiety, a finding that may lead to new treatments for pain. “At least 40 per cent of patients who suffer from severe forms of chronic pain also develop depression at some point, along with other cognitive problems,” says Venetia Zachariou of the Icahn School of Medicine at Mount Sinai in New York. To see if there might be a genetic link between these conditions, Zachariou and her team studied mice with damage to their peripheral nervous system. These mice show symptoms similar to chronic pain in people – they become hypersensitive to harmless touch, and avoid other situations that might also cause them pain. Until now, pain behaviour in mice had only been studied for at most a week at a time, says Zachariou, whose team monitored their mice for 10 weeks. “At the beginning, we saw only sensory deficits and pain-like symptoms. But several weeks later, the animals developed anxiety and depression-like behaviours.” The team then examined gene activity in three regions in the mouse brains we know are associated with depression and anxiety. Analysing the nucleus accumbens, medial prefrontal cortex, and periaqueductal gray, they found nearly 40 genes where activity was significantly higher or lower than in mice without the nervous system damage. © Copyright Reed Business Information Ltd.

Keyword: Depression; Pain & Touch
Link ID: 23402 - Posted: 03.24.2017

by Laura Sanders Many babies born early spend extra time in the hospital, receiving the care of dedicated teams of doctors and nurses. For these babies, the hospital is their first home. And early experiences there, from lights to sounds to touches, may influence how babies develop. Touches early in life in the NICU, both pleasant and not, may shape how a baby’s brain responds to gentle touches later, a new study suggests. The results, published online March 16 in Current Biology, draw attention to the importance of touch, both in type and number. Young babies can’t see that well. But the sense of touch develops early, making it a prime way to get messages to fuzzy-eyed, pre-verbal babies. “We focused on touch because it really is some of the basis for communication between parents and child,” says study coauthor Nathalie Maitre, a neonatologist and neuroscientist at Nationwide Children’s Hospital in Columbus, Ohio. Maitre and her colleagues studied how babies’ brains responded to a light puff of air on the palms of their hands — a “very gentle and very weak touch,” she says. They measured these responses by putting adorable, tiny electroencephalogram, or EEG, caps on the babies. The researchers puffed babies’ hands shortly before they were sent home. Sixty-one of the babies were born early, from 24 to 36 weeks gestation. At the time of the puff experiment, they had already spent a median of 28 days in the hospital. Another group of 55 babies, born full-term, was tested in the three days after birth. |© Society for Science & the Public 2000 - 2017

Keyword: Pain & Touch; Development of the Brain
Link ID: 23398 - Posted: 03.23.2017

By Jia Naqvi A drug frequently prescribed for pain is no more effective than a placebo at controlling sciatica, a common source of pain in the lower back and leg, according to a study published Wednesday in the New England Journal of Medicine. The researchers at the George Institute for Global Health in Australia followed 209 sciatica patients in Sydney who were randomly assigned to receive either the drug pregabalin, more commonly known as Lyrica, or a placebo. The results showed no significant differences in leg pain intensity between the group on the placebo and that on Lyrica after eight weeks taking the drug or during the rest of the year on follow-up exams. Similarly, there were no differences for other outcomes such as back pain, quality of life and degree of disability. After Lyrica was approved in 2004, it has become the most commonly prescribed medicine for neuropathic pain, which is caused by damage to the nervous system. The drug was ranked as the 19th-highest-earning pharmaceutical in 2015, with worldwide sales rising annually at a rate of 9 percent and sale revenue of more than $3 billion in 2015 in the United States. “We have seen a huge rise in the amount of prescriptions being written each year for patients suffering from sciatica. It’s an incredibly painful and disabling condition, so it’s no wonder people are desperate for relief and medicines such as pregabalin have been widely prescribed,” Christine Lin, one of the authors of the study and an associate professor at the George Institute for Global Health, said in a news release. © 1996-2017 The Washington Post

Keyword: Pain & Touch
Link ID: 23395 - Posted: 03.23.2017

By THOMAS FULLER SANTA ROSA, Calif. — In the heart of Northern California’s wine country, a civil engineer turned marijuana entrepreneur is adding a new dimension to the art of matching fine wines with gourmet food: cannabis and wine pairing dinners. Sam Edwards, co-founder of the Sonoma Cannabis Company, charges diners $100 to $150 for a meal that experiments with everything from marijuana-leaf pesto sauce to sniffs of cannabis flowers paired with sips of a crisp Russian River chardonnay. “It accentuates the intensity of your palate,” Mr. Edwards, 30, said of the dinners, one of which was held recently at a winery with sweeping views of the Sonoma vineyards. “We are seeing what works and what flavors are coming out.” Sonoma County, known to the world for its wines, is these days a seedbed of cannabis experimentation. The approval of recreational cannabis use by California voters in November has spurred local officials here to embrace the pot industry and the tax income it may bring. “We’re making this happen,” said Julie Combs, a member of the Santa Rosa City Council, who is helping lead an effort to issue permits to cannabis companies. “This is an industry that can really help our region.” Of the many ways in which California is on a collision course with the Trump administration, from immigration to the environment, the state’s enthusiastic embrace of legalized and regulated marijuana may be one of the biggest tests of the federal government’s power. Attorney General Jeff Sessions has equated marijuana with heroin and, on Wednesday, mentioned cannabis in the context of the “scourge of drug abuse.” © 2017 The New York Times Compan

Keyword: Drug Abuse; Pain & Touch
Link ID: 23379 - Posted: 03.20.2017

By Daniel Barron It was 4 P.M., and Andrew* had just bought 10 bags of heroin. In his kitchen, he tugged one credit-card-sized bag from the rubber-banded bundle and laid it on the counter with sacramental reverence. Pain shot through his body as he pulled a cutting board from the cabinet. Slowly, deliberately, he tapped the bag's white contents onto the board and crushed it with the flat edge of a butter knife, forming a line of fine white powder. He snorted it in one pass and shuffled back to his armchair. It was bitter, but snorting heroin was safer than injecting, and he was desperate: his prescription pain medication was gone. I met Andrew the next day in the emergency room, where he told me about the previous day's act of desperation. I admitted him to control his swelling legs and joint pain. He was also detoxing from opioids. Andrew looked older than his 69 years. His face was wrinkled with exhaustion. A frayed, tangled mop of grizzled hair fell to his shoulders. Andrew had been a satellite network engineer, first for the military, more recently for a major telecommunications company. An articulate, soft-spoken fellow, he summed up his (rather impressive) career modestly: “Well, I'd just find where a problem was and then find a way to fix it.” Yet there was one problem he couldn't fix. “Doctor, I'm always in the most terrible pain,” he said, with closed eyes. “I had no other options. I started using heroin, bought it from my neighbor to help with the pain. I'm scared stiff.” © 2017 Scientific American

Keyword: Pain & Touch; Drug Abuse
Link ID: 23378 - Posted: 03.20.2017

By Jia Naqvi Sixty percent of the calls to poison control centers for help with prescription opioid exposure involved children younger than 5. (Rich Pedroncelli/Associated Press) The phone rings once approximately every 45 minutes — that is how often poison control centers in the United States receive calls about children being exposed to prescription opioids, according to a study published Monday. Over a span of 16 years, from January 2000 until December 2015, about 188,000 calls were placed to poison control centers regarding pediatric and teenage exposure to opioids, the study published in the journal Pediatrics found. Sixty percent of the children exposed to opioids were younger than 5, while teenagers accounted for 30 percent. Pediatric exposure to opioids increased by 86 percent from 2000 to 2009 but decreased overall for all ages under 20 from 2009 until 2015, the study found. Increasing awareness among people with prescription drugs, physicians putting more thought into prescribing opioids, and prescription drug monitoring programs implemented by many states and efforts by different organizations could have contributed to the decrease in exposure, said Marcel Casavant, study author, medical director of the Central Ohio Poison Center and chief toxicologist at Nationwide Children’s Hospital in Columbus. “We are not quite sure, and so it would be good to try to sort out of all the things that we are trying, which ones are the most effective and how can we spend more time doing that,” Casavant said. © 1996-2017 The Washington Post

Keyword: Pain & Touch; Drug Abuse
Link ID: 23377 - Posted: 03.20.2017

Doctors who limit the supply of opioids they prescribe to three days or less may help patients avoid the dangers of dependence and addiction, a new study suggests. Among patients without cancer, a single day's supply of a narcotic painkiller can result in 6 per cent of patients being on an opioid a year later, the researchers said. The odds of long-term opioid use increased most sharply in the first days of therapy, particularly after five days of taking the drugs. The rate of long-term opioid use increased to about 13 per cent for patients who first took the drugs for eight days or more, according to the report. "Awareness among prescribers, pharmacists and persons managing pharmacy benefits that authorization of a second opioid prescription doubles the risk for opioid use one year later might deter overprescribing of opioids," said senior researcher Martin Bradley. He is from the division of pharmaceutical evaluation and policy at the University of Arkansas for Medical Sciences. "The chances of long-term opioid use, use that lasts one year or more, start increasing with each additional day supplied, starting after the third day, and increase substantially after someone is prescribed five or more days, and especially after someone is prescribed one month of opioid therapy," Bradley said. The odds of chronic opioid use also increase when a second prescription is given or refilled, he noted. ©2017 CBC/Radio-Canada.

Keyword: Drug Abuse; Pain & Touch
Link ID: 23373 - Posted: 03.19.2017

By Linda Geddes A gentle touch can make all the difference. Premature babies – who miss out on the sensory experiences of late gestation – show different brain responses to gentle touch from babies that stay inside the uterus until term. This could affect later physical and emotional development, but regular skin-to-skin contact from parents and hospital staff seem to counteract it. Infants who are born early experience dramatic events at a time when babies that aren’t born until 40 weeks are still developing in the amniotic fluid. Premature babies are often separated from their parents for long periods, undergo painful procedures like operations and ventilation, and they experience bigger effects of gravity on the skin and muscles. “There is substantial evidence that pain exposure during early life can cause long-term alterations in infant brain development,” says Rebeccah Slater at the University of Oxford. But it has been less clear how gentle touches shape the brains of babies, mainly because the brain’s response to light touch is about a hundredth of that it has to pain, so it’s harder to study. Nathalie Maitre of the Nationwide Children’s Hospital in Columbus, Ohio, and her colleagues have gently stretched soft nets of 128 electrodes over the heads of 125 preterm and full-term babies, shortly before they were discharged from hospital. These were used to record how their brains responded to a gentle puff of air on the skin. © Copyright Reed Business Information Ltd.

Keyword: Development of the Brain; Pain & Touch
Link ID: 23371 - Posted: 03.17.2017

By Catherine Offord A few years ago, UK composer and technology reporter LJ Rich participated in a music technology competition as part of a project with the BBC. The 24-hour event brought together various musicians, and entailed staying awake into the wee hours trying to solve technical problems related to music. Late into the night, during a break from work, Rich thought of a way to keep people’s spirits up. “At about four in the morning, I remember playing different tastes to people on a piano in the room we were working in,” she says. For instance, “to great amusement, during breakfast I played people the taste of eggs.” It didn’t take long before Rich learned, for the first time, that food’s association with music was not as universally appreciated as she had assumed. “You realize everybody else doesn’t perceive the world that way,” she says. “For me, it was quite a surprise to find that people didn’t realize that certain foods had different keys.” Rich had long known she had absolute pitch—the ability to identify a musical note, such as B flat, without any reference. But that night, she learned she also has what’s known as synesthesia, a little-understood mode of perception that links senses such as taste and hearing in unusual ways, and is thought to be present in around 4 percent of the general population. It’s a difficult phenomenon to get to the bottom of. Like Rich, many synesthetes are unaware their perception is atypical; what’s more, detecting synesthesia usually relies on self-reported experiences—an obstacle for standardized testing. But a growing body of evidence suggests that Rich is far from being alone in possessing both absolute pitch and synesthesia. © 1986-2017 The Scientist

Keyword: Hearing
Link ID: 23353 - Posted: 03.14.2017

Susan Milius Catch sight of someone scratching and out of nowhere comes an itch, too. Now, it turns out mice suffer the same strange phenomenon. Tests with mice that watched itchy neighbors, or even just videos of scratching mice, provide the first clear evidence of contagious scratching spreading mouse-to-mouse, says neuroscientist Zhou-Feng Chen of Washington University School of Medicine in St. Louis. The quirk opens new possibilities for exploring the neuroscience behind the spread of contagious behaviors. For the ghostly itch, experiments trace scratching to a peptide nicknamed GRP and areas of the mouse brain better known for keeping the beat of circadian rhythms, Chen and colleagues found. They report the results in the March 10 Science. In discovering this, “there were lots of surprises,” Chen says. One was that mice, nocturnal animals that mostly sniff and whisker-brush their way through the dark, would be sensitive to the sight of another mouse scratching. Yet Chen had his own irresistible itch to test the “crazy idea,” he says. Researchers housed mice that didn’t scratch any more than normal within sight of mice that flicked and thumped their paws frequently at itchy skin. Videos recorded instances of normal mice looking at an itch-prone mouse mid-scratch and, shortly after, scratching themselves. In comparison, mice with not-very-itchy neighbors looked at those neighbors at about the same frequency but rarely scratched immediately afterward. |© Society for Science & the Public 2000 - 2017.

Keyword: Pain & Touch; Learning & Memory
Link ID: 23341 - Posted: 03.10.2017

By Colin Barras What a difference 1000 kilometres make. Neanderthals living in prehistoric Belgium enjoyed their meat – but the Neanderthals who lived in what is now northern Spain seem to have survived on an almost exclusively vegetarian diet. This is according to new DNA analysis that also suggests sick Neanderthals could self-medicate with naturally occurring painkillers and antibiotics, and that they shared mouth microbiomes with humans – perhaps exchanged by kissing. Neanderthals didn’t clean their teeth particularly well – which is lucky for scientific investigators. Over time, plaque built up into a hard substance called dental calculus, which still clings to the ancient teeth even after tens of thousands of years. Researchers have already identified tiny food fragments in ancient dental calculus to get an insight into the diets of prehistoric hominins. Now Laura Weyrich at the University of Adelaide, Australia, and her colleagues have shown that dental calculus also carries ancient DNA that can reveal both what Neanderthals ate and which bacteria lived in their mouths. The team focused on three Neanderthals – two 48,000-year-old specimens from a site called El Sidrón in Spain and a 39,000-year-old specimen from a site called Spy in Belgium. The results suggested that the Spy Neanderthal often dined on woolly rhinoceros, sheep and mushrooms – but no plants. The El Sidrón Neanderthals ate more meagre fare: moss, bark and mushrooms – and, apparently, no meat. © Copyright Reed Business Information Ltd.

Keyword: Evolution; Pain & Touch
Link ID: 23331 - Posted: 03.09.2017