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By Jessica Hamzelou People who experience migraines that are made worse by light might be better off seeing the world in green. While white, blue, red and amber light all increase migraine pain, low-intensity green light seems to reduce it. The team behind the finding hope that specially developed sunglasses that screen out all wavelengths of light except green could help migraineurs. Many people experience sensitivity to light during a migraine. Photophobia, as it is known, can leave migraineurs resorting to sunglasses in well-lit rooms, or seeking the comfort of darkness. The reaction is thought to be due to the brain’s wiring. In a brain region called the thalamus, neurons that transmit sensory information from our retinas cross over with other neurons that signal pain. As a result, during migraine, light can worsen pain and pain can cause visual disturbance, says Rami Burstein at Harvard University. But not all colours of light have the same effect. Six years ago, Burstein and his colleagues studied migraine in sufferers who are blind, either due to the loss of an eye or retina, or because of retinal damage. They found that people who had some remaining retinal cells had worse migraines when they were in brightly lit environments, and that blue light seemed to have the strongest impact. The finding caused a flurry of excitement, and the promotion of sunglasses that filter out blue light. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 7: Vision: From Eye to Brain
Link ID: 22237 - Posted: 05.23.2016

By Adam Gopnik On a bitter, soul-shivering, damp, biting gray February day in Cleveland—that is to say, on a February day in Cleveland—a handless man is handling a nonexistent ball. Igor Spetic lost his right hand when his forearm was pulped in an industrial accident six years ago and had to be amputated. In an operation four years ago, a team of surgeons implanted a set of small translucent “interfaces” into the neural circuits of his upper arm. This afternoon, in a basement lab at a Veterans Administration hospital, the wires are hooked up directly to a prosthetic hand—plastic, flesh-colored, five-fingered, and articulated—that is affixed to what remains of his arm. The hand has more than a dozen pressure sensors within it, and their signals can be transformed by a computer into electric waves like those natural to the nervous system. The sensors in the prosthetic hand feed information from the world into the wires in Spetic’s arm. Since, from the brain’s point of view, his hand is still there, it needs only to be recalled to life. Now it is. With the “stimulation” turned on—the electronic feed coursing from the sensors—Spetic feels nineteen distinct sensations in his artificial hand. Above all, he can feel pressure as he would with a living hand. “We don’t appreciate how much of our behavior is governed by our intense sensitivity to pressure,” Dustin Tyler, the fresh-faced principal investigator on the Cleveland project, says, observing Spetic closely. “We think of hot and cold, or of textures, silk and cotton. But some of the most important sensing we do with our fingers is to register incredibly minute differences in pressure, of the kinds that are necessary to perform tasks, which we grasp in a microsecond from the feel of the outer shell of the thing. We know instantly, just by touching, whether to gently squeeze the toothpaste or crush the can.”

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 22215 - Posted: 05.14.2016

Nicola Davis People with a larger circle of friends are better able to tolerate pain, according to research into the pain thresholds and social networks of volunteers. The link is thought to be down a system in the brain that involves endorphins: potent pain-killing chemicals produced by the body that also trigger a sense of wellbeing. “At an equivalent dose, endorphins have been shown to be stronger than morphine,” said Katerina Johnson, a doctoral student at the University of Oxford, who co-authored the research. Writing in the journal Scientific Reports, Johnson and Robin Dunbar, professor of evolutionary psychology at the University of Oxford, sought to probe the theory that the brain’s endorphin system might have evolved to not only handle our response to physical discomfort, but influence our experience of pleasure from social interactions too. “Social behaviour and being attached to other individuals is really important for our survival - whether that is staying close to our parents, or our offspring or cooperating with others to find food or to help defend ourselves,” said Johnson. To test the link, the authors examined both the social networks and pain thresholds of 101 adults aged between 18 and 34. Each participant was asked to complete a questionnaire, designed to quiz them on friends they contacted once a week and those they got in touch with once a month. The personality of each participant was probed, looking at traits such as “agreeableness”; they were also asked to rate their fitness and stress levels. © 2016 Guardian News and Media Limited

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 11: Emotions, Aggression, and Stress
Link ID: 22156 - Posted: 04.28.2016

Dr. Perri Klass First of all, nobody takes a small child on an airplane for the fun of it. I have been there and I know. Don’t get me wrong, I’m no airplane saint; you won’t generally catch me offering to hold someone else’s kid, or making friends around the seatback. I don’t usually admit to being a pediatrician, for fear of hearing a medical saga. But I have put in my time on airplanes with my own infants and toddlers and small children, and I certainly know how it feels. Probably the best thing that can be said for traveling with young children is that it teaches you to appreciate traveling without them, however puzzling the inflight announcements, however long the delays, however tightly spaced the seats. I did enough economy-class traveling with children while my own were young that my reflexive reaction to all flight cancellations, turbulence or the moment when the person in front of me reclines the seat very suddenly, knocking my laptop closed, is now: At least I don’t have a small child with me – thank heavens. Babies do not cry on airplanes for the fun of it either. Nor do they cry, by and large, to let you know that their parents are neglectful or callous. They cry for infant versions of the same reasons that adults snap at one another about reclining seats, or elbow each other with quiet savagery over the armrest. They cry because their ears hurt and they’re being made to stay in a certain position when they don’t want to or the air smells strange and the noises are loud, or their stomachs feel upset or the day has been too long and they still aren’t there yet or they’re just plain cranky. As are we all. Crying is an evolutionary strategy to summon adult aid; over millennia, crying has probably evolved to be hard to ignore. I don’t know if it’s any comfort, but when you’re the parent with the crying baby, it doesn’t particularly help to be an expert. “I remember one flight where my daughter screamed the whole way and kept trying to get out of her seatbelt,” said my old friend, Dr. Elizabeth Barnett, a professor of pediatrics at Boston University and a travel medicine specialist. “As a parent, you feel two things — you’re in distress because you’re trying to comfort your child and not succeeding, so you feel bad for your child, and you also feel guilty because you know your child is disturbing everybody else.” © 2016 The New York Times Company

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 13: Memory, Learning, and Development
Link ID: 22094 - Posted: 04.12.2016

By JOANNA KLEIN Misconception: Migraines are psychological manifestations of women’s inability to manage stress and emotions Actually: Neurologists are very clear that migraines are a real, debilitating medical condition related to temporary abnormal brain activity. The fact that they may be more common for some women during “that time of the month” has nothing to do with emotions. For centuries, doctors explained migraines as a woman’s problem caused by emotional disturbances like hysteria, depression or stress. “Bizarrely, the recommended cure was marriage!” said Dr. Anne MacGregor, the lead author of the British Association for the Study of Headache’s guidelines for diagnosing and managing migraines. While that prescription may be far behind us, the misconception that migraines are fueled by a woman’s inability to cope persists. “It was considered psychological, or that I was a nervous overachiever, so I would never tell people that I have them,” said Lorie Novak, an artist in her sixties who has suffered from migraines since she was 8. After reading Joan Didion’s 1968 essay “In Bed,” about the writer’s struggle with migraines, Ms. Novak decided to tackle the representation of these debilitating headaches. Starting in 2009, Ms. Novak photographed herself every time she got a migraine. Under the hashtag #notjustaheadache, hundreds of others on Twitter and Instagram have demonstrated their own frustration with a widespread lack of understanding of the reality of migraines. © 2016 The New York Times Company

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 11: Emotions, Aggression, and Stress
Link ID: 22078 - Posted: 04.07.2016

By Sandhya Somashekhar African Americans are routinely under-treated for their pain compared with whites, according to research. A study released Monday sheds some disturbing light on why that might be the case. Researchers at the University of Virginia quizzed white medical students and residents to see how many believed inaccurate and at times "fantastical" differences about the two races -- for example, that blacks have less sensitive nerve endings than whites or that black people's blood coagulates more quickly. They found that fully half thought at least one of the false statements presented was possibly, probably or definitely true. Moreover, those who held false beliefs often rated black patients' pain as lower than that of white patients and made less appropriate recommendations about how they should be treated. The study, published in the Proceedings of the National Academy of Sciences, could help illuminate one of the most vexing problems in pain treatment today: That whites are more likely than blacks to be prescribed strong pain medications for equivalent ailments. A 2000 study out of Emory University found that at a hospital emergency department in Atlanta, 74 percent of white patients with bone fractures received painkillers compared with 50 percent of black patients. Similarly, a paper last year found that black children with appendicitis were less likely to receive pain medication than their white counterparts. And a 2007 study found that physicians were more likely to underestimate the pain of black patients compared with other patients.

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 14: Attention and Consciousness
Link ID: 22074 - Posted: 04.06.2016

By Roni Caryn Rabin Sixty-five million Americans suffer from chronic lower back pain, and many feel they have tried it all: physical therapy, painkillers, shots. Now a new study reports many people may find relief with a form of meditation that harnesses the power of the mind to manage pain. The technique, called mindfulness-based stress reduction, involves a combination of meditation, body awareness and yoga, and focuses on increasing awareness and acceptance of one’s experiences, whether they involve physical discomfort or emotional pain. People with lower back pain who learned the meditation technique showed greater improvements in function compared to those who had cognitive behavioral therapy, which has been shown to help ease pain, or standard back care. Participants assigned to meditation or cognitive behavior therapy received eight weekly two-hour sessions of group training in the techniques. After six months, those learning meditation had an easier time doing things like getting up out of a chair, going up the stairs and putting on their socks, and were less irritable and less likely to stay at home or in bed because of pain. They were still doing better a year later. The findings come amid growing concerns about opioid painkillers and a surge of overdose deaths involving the drugs. At the beginning of the trial, 11 percent of the participants said they had used an opioid within the last week to treat their pain, and they were allowed to continue with their usual care throughout the trial. “This new study is exciting, because here’s a technique that doesn’t involve taking any pharmaceutical agents, and doesn’t involve the side effects of pharmaceutical agents,” said Dr. Madhav Goyal of Johns Hopkins University School of Medicine, who co-wrote an editorial accompanying the paper. © 2016 The New York Times Company

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 11: Emotions, Aggression, and Stress
Link ID: 22020 - Posted: 03.23.2016

Results from a new study, funded in part by the National Center for Complementary and Integrative Health, demonstrate that mindfulness meditation works on a different pain pathway in the brain than opioid pain relievers. The researchers noted that because opioid and non-opioid mechanisms of pain relief interact synergistically, the results of this study suggest that combining mindfulness-based and pharmacologic/nonpharmacologic pain-relieving approaches that rely on opioid signaling may be particularly effective in treating pain. Previous research has shown that mindfulness meditation helps relieve pain, but researchers have been unclear about how the practice induces pain relief — specifically, if meditation is associated with the release of naturally occurring opiates. Researchers recorded pain reports in 78 healthy adults during meditation or a non-meditation control in response to painful heat stimuli and intravenous administration of the opioid antagonist naloxone (a drug that blocks the transmission of opioid activity) or placebo saline. Participants were randomized to one of four treatment groups: 1) meditation plus naloxone; 2) control plus naloxone; 3) meditation plus saline; or 4) control plus saline. People in the control groups were instructed to “close your eyes and relax until the end of the experiment.” The researchers found that participants who meditated during saline administration had significantly lower pain intensity and unpleasantness ratings compared to those who did not meditate while receiving saline. Importantly, data from the meditation plus naloxone group showed that naloxone did not block meditation’s pain-relieving effects. No significant differences in reductions of pain intensity or pain unpleasantness were seen between the meditation plus naloxone and the meditation plus saline groups. Participants who meditated during naloxone administration also had significantly greater reductions in pain intensity and unpleasantness than the control groups.

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 22006 - Posted: 03.19.2016

The CDC recommends non-opioid therapy, including exercise and over-the-counter pain medications, as the preferred treatment for chronic pain. It says opioids should only be prescribed — at the lowest effective dosage possible — when the benefits from pain reduction and bodily function outweigh the risks. In 2014, American doctors wrote nearly 200 million prescriptions for opioid painkillers, while deaths linked to the drugs climbed to roughly 19,000 — the highest number on record. The number of Canadians who die every year from opioids is not readily known — the Canadian Centre on Substance Abuse does not track the statistics — but Toronto physician Nav Persaud told CBC News in 2014 that more than 1,000 Canadians die from painkillers every year. A 2012 study says one in eight deaths among young adults age 25 to 34 in Ontario and one out of every 170 deaths in the province as a whole are opioid overdoses. One in four people who entered a withdrawal management program at St. Joseph's Healthcare in Hamilton, Ont., were opioid patients in 2012, up from one in ten in 2002. Other studies have cast doubt on the effectiveness of opioids on chronic pain, raising questions on whether its limited long-term effects are worth the harmful risks. "The science is clear," CDC director Tom Frieden said Tuesday. "For the vast majority of patients, the known and often fatal risks [of opioids] far outweigh the proven and transient benefits." ©2016 CBC/Radio-Canada.

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 21992 - Posted: 03.16.2016

By Sandra G. Boodman Kim Pace was afraid he was dying. In six months he had lost more than 30 pounds because a terrible stabbing sensation on the left side of his face made eating or drinking too painful. Brushing his teeth was out of the question and even the slightest touch triggered waves of agony and a shocklike pain he imagined was comparable to electrocution. Painkillers, even morphine, brought little relief. Unable to work and on medical leave from his job as a financial consultant for a bank, Pace, then 59, had spent the first half of 2012 bouncing among specialists in his home state of Pennsylvania, searching for help from doctors who disagreed about the nature of his illness. Some thought his searing pain might be the side effect of a drug he was taking. Others suspected migraines, a dental problem, mental illness, or an attempt to obtain painkillers. Even after a junior doctor made what turned out to be the correct diagnosis, there was disagreement among specialists about its accuracy or how to treat Pace. His wife, Carol, a nurse, said she suspects that the couple’s persistence and propensity to ask questions led her husband to be branded “a difficult case” — the kind of patient whom some doctors avoid. And on top of that, a serious but entirely unrelated disorder further muddied the diagnostic picture. So on July 17, 2012, when Pace told his wife he thought he was dying, she fired off an emotional plea for help to the office of a prominent specialist in Baltimore. “I looked at Kim and it hit me: He was going to die,” she said. “He was losing weight and his color was ashen” and doctors were “blowing him off. I thought, ‘Okay, that’s it,’ and the nurse in me took over.”

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Link ID: 21986 - Posted: 03.15.2016

Rare ‘allergy’ to vibrations tied to faulty gene By Kelly Servick If you have the rare condition known as vibratory urticaria, you may be wary of handling lawnmowers and electric mixers. Rubbing or vibration against your skin—even from drying off with a towel—can cause you to break out in hives, make your face flush, give you headaches, or produce the sensation of a metallic taste. The condition, which runs in families, is so rare that the researchers who work on it have only tracked down a few cases over years of searching. But a genetic study on three such unique families has revealed a potential mechanism for the strange symptoms. Research published online today in the New England Journal of Medicine describes a mutation in a gene called ADGRE2, found in 22 people with vibratory urticaria, but not in 14 of their unaffected relatives. The gene codes for a receptor protein that was found on the surface of mast cells—immune cells in the skin that dump out inflammatory molecules such as histamines that increase blood flow to an area and can cause hives. The researchers observed that shaking mast cells in a dish breaks apart two subunits of this receptor protein, which prompts histamine release. In people with the newly discovered mutation, the receptor is more prone to breakage, which causes this protective immune response at the site of physical trauma to run amok. © 2016 American Association for the Advancement of Science.

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 21862 - Posted: 02.06.2016

Laura Sanders Pain can sear memories into the brain, a new study finds. A full year after viewing a picture of a random, neutral object, people could remember it better if they had been feeling painful heat when they first saw it. “The results are fun, they are interesting and they are provocative,” says neuroscientist A. Vania Apkarian of Northwestern University in Chicago. The findings “speak to the idea that pain really engages memory.” Neuroscientists G. Elliott Wimmer and Christian Büchel of University Medical Center Hamburg-Eppendorf in Germany reported the results in a paper online at BioRxiv.org first posted December 24 and revised January 6. The findings are under review at a journal, and Wimmer declined to comment on the study until it is accepted for publication. Wimmer and Büchel recruited 31 brave souls who agreed to feel pain delivered by a heat-delivering thermode on their left forearms. Each person’s pain sensitivity was used to calibrate the amount of heat they received in the experiment, which was either not painful (a 2 on an 8-point scale) or the highest a person could endure multiple times (a full 8). While undergoing a functional MRI scan, participants looked at a series of pictures of unremarkable household objects, such as a camera, sometimes feeling pain and sometimes not. Right after seeing the images, the people took a pop quiz in which they answered whether an object was familiar. Pain didn’t influence memory right away. Right after their ordeal, participants remembered about three-quarters of the previously seen objects, regardless of whether pain was present, the researchers found. © Society for Science & the Public 2000 - 2015.

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 13: Memory, Learning, and Development
Link ID: 21776 - Posted: 01.12.2016

Pete Etchells Autonomous Sensory Meridian Response, or ASMR, is a curious phenomenon. Those who experience it often characterise it as a tingling sensation in the back of the head or neck, or another part of the body, in response to some sort of sensory stimulus. That stimulus could be anything, but over the past few years, a subculture has developed around YouTube videos, and their growing popularity was the focus of a video posted on the Guardian this last week. It’s well worth a watch, but I couldn’t help but feel it would have been a bit more interesting if there had been some scientific background in it. The trouble is, there isn’t actually much research on ASMR out there. To date, only one research paper has been published on the phenomenon. In March last year, Emma Barratt, a graduate student at Swansea University, and Dr Nick Davis, then a lecturer at the same institution, published the results of a survey of some 500 ASMR enthusiasts. “ASMR is interesting to me as a psychologist because it’s a bit ‘weird’” says Davis, now at Manchester Metropolitan University. “The sensations people describe are quite hard to describe, and that’s odd because people are usually quite good at describing bodily sensation. So we wanted to know if everybody’s ASMR experience is the same, and of people tend to be triggered by the same sorts of things.” The study asked a range of questions about where, when and why people watch ASMR videos, whether there was any consistency in ASMR-triggering content, as well as whether individuals felt it had any effect on their mood. There was a remarkable consistency across participants in terms of triggering content – whispering worked for the majority of people, followed by videos involving some sort of personal attention, crisp sounds, and slow movements. For the most part, participants reported that they watched ASMR videos for relaxation purposes, or to help them sleep or deal with stress. © 2016 Guardian News and Media Limited

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 21767 - Posted: 01.09.2016

By Emily Underwood As long as she can remember, 53-year-old Rosa Sundquist has tallied the number of days per month when her head explodes with pain. The migraines started in childhood and have gotten worse as she’s grown older. Since 2008, they have incapacitated her at least 15 days per month, year-round. Head-splitting pain isn’t the worst of Sundquist’s symptoms. Nausea, vomiting, and an intense sensitivity to light, sound, and smell make it impossible for her to work—she used to be an office manager—or often even to leave her light-proofed home in Dumfries, Virginia. On the rare occasions when she does go out to dinner or a movie with her husband and two college-aged children, she wears sunglasses and noise-canceling headphones. A short trip to the grocery store can turn into a full-blown attack “on a dime,” she says. Every 10 weeks, Sundquist gets 32 bee sting–like injections of the nerve-numbing botulism toxin into her face and neck. She also visits a neurologist in Philadelphia, Pennsylvania, who gives her a continuous intravenous infusion of the anesthetic lidocaine over 7 days. The lidocaine makes Sundquist hallucinate, but it can reduce her attacks, she says—she recently counted 20 migraine days per month instead of 30. Sundquist can also sometimes ward off an attack with triptans, the only drugs specifically designed to interrupt migraines after they start. Millions of others similarly dread the onset of a migraine, although many are not afflicted as severely as Sundquist. Worldwide, migraines strike roughly 12% of people at least once per year, with women roughly three times as likely as men to have an attack. © 2016 American Association for the Advancement of Science.

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 11: Emotions, Aggression, and Stress
Link ID: 21764 - Posted: 01.08.2016

By Stephani Sutherland A technique called optogenetics has transformed neuroscience during the past 10 years by allowing researchers to turn specific neurons on and off in experimental animals. By flipping these neural switches, it has provided clues about which brain pathways are involved in diseases like depression and obsessive-compulsive disorder. “Optogenetics is not just a flash in the pan,” says neuroscientist Robert Gereau of Washington University in Saint Louis. “It allows us to do experiments that were not doable before. This is a true game changer like few other techniques in science.” Since the first papers were published on optogenetics in the mid-aughts some researchers have mused about one day using optogenetics in patients, imagining the possibility of an off-switch for depression, for instance. The technique, however, would require that a patient submit to a set of highly invasive medical procedures: genetic engineering of neurons to insert molecular switches to activate or switch off cells, along with threading of an optical fiber into the brain to flip those switches. Spurred on by a set of technical advances, optogenetics pioneer Karl Deisseroth, together with other Stanford University researchers, has formed a company to pursue optogenetics trials in patients within the next several years—one of several start-ups that are now contemplating clinical trials of the technique. Circuit Therapeutics, founded in 2010, is moving forward with specific plans to treat neurological diseases. (It also partners with pharmaceutical companies to help them use optogenetics in animal research to develop novel drug targets for human diseases.) © 2016 Scientific America

Related chapters from BP7e: Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals; Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals; Chapter 5: The Sensorimotor System
Link ID: 21758 - Posted: 01.07.2016

A woman born incapable of feeling pain has been hurt for the first time – thanks to a drug normally prescribed for opioid overdoses. She was burned with a laser, and quite liked the experience. The breakthrough may lead to powerful new ways to treat painful conditions such as arthritis. Only a handful people around the world are born unable to feel pain. These individuals can often suffer a range of injuries when they are young. Babies with the condition tend to chew their fingers, toes and lips until they bleed, and toddlers can suffer an increased range of knocks, tumbles and encounters with sharp or hot objects. The disorder is caused by a rare genetic mutation that results in a lack of ion channels that transport sodium across sensory nerves. Without these channels, known as Nav1.7 channels, nerve cells are unable to communicate pain. Researchers quickly sought to make compounds that blocked Nav1.7 channels, thinking they might be able to block pain in people without the disorder. “It looked like a fantastic drug target,” says John Wood at University College London. “Pharma companies went bananas and made lots of drugs.” But while a few compounds saw some success, none brought about the total pain loss seen in people who lack the channel naturally. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Link ID: 21677 - Posted: 12.05.2015

By David Noonan The 63-year-old chief executive couldn't do his job. He had been crippled by migraine headaches throughout his adult life and was in the middle of a new string of attacks. “I have but a little moment in the morning in which I can either read, write or think,” he wrote to a friend. After that, he had to shut himself up in a dark room until night. So President Thomas Jefferson, in the early spring of 1807, during his second term in office, was incapacitated every afternoon by the most common neurological disability in the world. The co-author of the Declaration of Independence never vanquished what he called his “periodical head-ach,” although his attacks appear to have lessened after 1808. Two centuries later 36 million American migraine sufferers grapple with the pain the president felt. Like Jefferson, who often treated himself with a concoction brewed from tree bark that contained quinine, they try different therapies, ranging from heart drugs to yoga to herbal remedies. Their quest goes on because modern medicine, repeatedly baffled in attempts to find the cause of migraine, has struggled to provide reliable relief. Now a new chapter in the long and often curious history of migraine is being written. Neurologists believe they have identified a hypersensitive nerve system that triggers the pain and are in the final stages of testing medicines that soothe its overly active cells. These are the first ever drugs specifically designed to prevent the crippling headaches before they start, and they could be approved by the U.S. Food and Drug Administration next year. If they deliver on the promise they have shown in studies conducted so far, which have involved around 1,300 patients, millions of headaches may never happen. © 2015 Scientific American

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 21662 - Posted: 11.28.2015

By Virginia Morell Plunge a live crab into a pot of boiling water, and it’s likely to try to scramble out. Is the crab’s behavior simply a reflex, or is it a sign of pain? Many scientists doubt that any invertebrate (or fish) feels pain because they lack the areas in the brain associated with human pain. Others argue this is an unfair comparison, noting that despite the major differences between vertebrate and invertebrate brains, their functions (such as seeing) are much the same. To get around this problem, researchers in 2014 argued that an animal could be classified as experiencing pain if, among other things, it changes its behavior in a way that indicates it’s trying to prevent further injury, such as through increased wariness, and if it shows a physiological change, such as elevated stress hormones. To find out whether crabs meet these criteria, scientists collected 40 European shore crabs (Carcinus maenas), shown in the photo above, in Northern Ireland. They placed the animals into individual tanks, and gave half 200-millisecond electrical shocks every 10 seconds for 2 minutes in their right and left legs. The other 20 crabs served as controls. Sixteen of the shocked crabs began walking in their tanks, and four tried to climb out. None of the control crabs attempted to clamber up the walls, but 14 walked, whereas six didn’t move at all. There was, however, one big physiological difference between the 16 shocked, walking crabs and the 14 control walkers, the scientists report in today’s issue of Biology Letters: Those that received electrical jolts had almost three times the amount of lactic acid in their haemolymph, a fluid that’s analogous to the blood of vertebrates—a clear sign of stress. Thus, crabs pass the bar scientists set for showing that an animal feels pain. © 2015 American Association for the Advancement of Science.

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 21623 - Posted: 11.11.2015

By Arlene Karidis Several years ago, Peggy Chenoweth began having excruciating cramping in her ankle. It felt severely sprained and as if her toe were twisting to the point where it was being ripped off her foot. “The pain is right here,” she told an orthopedic surgeon, “in my ankle and foot.” But the 41-year-old Gainesville, Va., resident no longer had that ankle and foot. Her leg had been amputated below the knee after a large piece of computer equipment fell off a cart, crushed her foot and caused nerve damage. Further, she insisted that since the amputation, she could feel her missing toes move. Chenoweth’s surgeon knew exactly what was going on: phantom pain. Lynn Webster, an anesthesiologist and past president of the American Academy of Pain Medicine, explains the phenomenon: “With ‘phantom pain,’ nerves that transmitted information from the brain to the now-missing body part continue to send impulses, which relay the message of pain.” It feels as if the removed part is still there and hurting, but pain is actually in the brain. The sensation ranges from annoying itching to red-hot burning. Physicians wrote about phantom pain as early as the 1860s, but U.S. research on this condition has increased recently, spurred by the surge of amputees returning from warfare in Iraq and Afghanistan and by increasing rates of diabetes. (Since 2003, nearly 1,650 service members have lost limbs, according to the Congressional Research Service. In 2010, about 73,000 amputations were performed on diabetics in the United States, according to the Centers for Disease Control and Prevention.)

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 21620 - Posted: 11.10.2015

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

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 21593 - Posted: 11.03.2015