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

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By Sandra G. Boodman At first the rash didn’t bother her, said Julia Omiatek, recalling the itchy red bumps that suddenly appeared one day on her palm, near the base of her first and third fingers. It was January 2013 — the dead of winter in Columbus, Ohio — so when the area reddened and cracked a few weeks later, she assumed her problem was simply dry skin and slathered on some cream. Omiatek, then 35, had little time to ponder the origin of her problem. An occupational therapist who works with adult patients, she was also raising two children younger than 3. A few weeks later when her lips swelled and the rash appeared on her face, she decided it was time to consult her dermatologist. Skin problems were nothing new; Omiatek was so allergic to nickel that her mother had had to sew cloth inside her onesies to prevent the metal snaps from touching her skin and causing a painful irritation. Over the years she had learned to avoid nickel and contend with occasional, inexplicable rashes that seemed to clear up when she used Elidel, a prescription cream that treats eczema. But this time the perpetually itchy rash didn’t go away, no matter what she did. Over the course of 11 months, she saw four doctors, three of whom said they didn’t know what was causing the stubborn eruption that eluded numerous tests. The fourth specialist took one look at her hand and figured it out. “The location was a tip-off,” said Matthew Zirwas, an assistant professor of dermatology at the Ohio State University Wexner Medical Center who specializes in treating unexplained rashes. Omiatek’s case was considerably less severe than that of many of the approximately 300 other patients he has treated for the same problem.

Keyword: Pain & Touch
Link ID: 19900 - Posted: 07.30.2014

By Janice Lynch Schuster I have never been one to visit a doctor regularly. Even though I had accumulated my share of problems by age 50— arthritic knees, poor hearing — I considered myself to be among the mostly well. But 19 months ago I developed a perplexing problem that forced me to become not only a regular patient but also one of the millions of Americans with chronic pain who struggle to find relief, in part through treatment with opioids. The trouble began with a terrible and persistent pain in my tongue. It alternately throbbed and burned, and it often hurt to eat or speak. The flesh looked red and irritated, and no amount of Orajel or Sensodyne relieved it. My doctor suggested I see my dentist; my dentist referred me to an oral surgeon. The surgeon thought the problem was caused by my being “tongue-tied,” a typically harmless condition in which the little piece of tissue under the tongue, called the frenulum, is too short. It seems I have always had this condition but had never noticed, because it hadn’t affected my ability to eat or speak. Now things had changed. The doctor recommended a frenectomy, a procedure to remove the frenulum and relieve tension on the tongue. “Just a snip,” he promised. It sounded trivial, and I was eager to be done with it. Although I make a living writing about health care, I didn’t even bother to do a Web search on the procedure. It never occurred to me that “a snip” might entail some risks. I trusted the oral surgeon.

Keyword: Pain & Touch
Link ID: 19871 - Posted: 07.23.2014

James Gorman All moving animals do their best to avoid running into things. And most living things follow a tried and true strategy — Watch where you’re going! Flying and swimming animals both have to cope with some complications that walkers, jumpers and gallopers don’t confront. Not only do they have to navigate in three dimensions, but they also cope with varying air and water flow. Beyond that, they often do so without the same references points and landmarks we have on the ground. Christine Scholtyssek of Lund University in Sweden, and colleagues decided to compare how two species in different mediums, air and water, which pose similar problems, reacted to apparent obstacles as they were moving. What they found, and reported in Biology Letters in May, was that the two species they examined — bumblebees and zebra fish — have very different strategies. It was known that the bees’ navigation depended on optic flow, which is something like the sensation of watching telephone poles speed past from a seat on a moving train. They tend to fly away from apparent obstacles as they approach them. The question was whether fish would do something similar. So, in order to give both animals the same test, Dr. Scholtyssek and her colleagues devised an apparatus that could contain air or water. When one wall had vertical stripes and the other horizontal, the bees, not surprisingly, flew away from the vertical stripes, which would have appeared as one emerging obstacle after another as the bees flew past. Horizontal stripes don’t change as a creature moves past, so they provide no reference for speed or progress. The fish, however, swam closer to the vertical stripes, which wasn’t expected. “It is surprising that although fish and bees have the same challenge, moving with or against streams, they do not use the same mechanisms,” Dr. Scholtyssek said. © 2014 The New York Times Company

Keyword: Animal Migration
Link ID: 19778 - Posted: 07.01.2014

By Lori Aratani The placebo effect — the idea that a treatment works because a patient believes it does — has long been a footnote to the work of finding ways to counteract disease. Some physicians have dismissed placebos as mere hokum, a trick of the mind. But researchers have found that in some people, placebos elicit similar responses in the brain to actual drug treatments. In one experiment, researchers using a PET scanner found that the brain activity in test subjects who received placebos and reported less pain mirrored that of those who received actual treatment for their pain. As Erik Vance writes in “Why Nothing Works,” published in the July/August 2014 issue of Discover magazine, the work suggests we possess an “inner pharmacy” of some sort that, if harnessed correctly, could be used as a complement to traditional treatments. But as Vance’s overview of recent research on the topic shows, it’s complicated. A placebo’s impact is not universal. Certain individuals — and certain conditions (pain and depression, for example) — seem to respond better than others to placebos. Researchers think that something in a person’s physiological makeup makes him more sensitive to placebos, while others feel little or no impact. There are ethical considerations, too, since it’s considered wrong to mislead volunteers participating in a study. But there are ways to navigate this thicket. In one small study, researchers gave placebos to a group of people with irritable bowel syndrome — after telling them that the pills were just placebos; a second group received no treatment. Surprisingly, many more of those who received the placebos reported improvements in their symptoms than did people in the no-treatment group.

Keyword: Pain & Touch; Aggression
Link ID: 19777 - Posted: 07.01.2014

Migraines have been diagnosed in about eight per cent of Canadians, a quarter or more of whom say the severe headaches impact day-to-day life such as getting a good night’s sleep or driving, Statistics Canada says. The federal agency on Wednesday released its first report on the prevalence of migraine, saying an estimated 2.7 million Canadians, or 8.3 per cent, reported they had been diagnosed with the severe headaches in 2010-2011. Chronic migraines are frequent, severe, pulsating headaches accompanied by nausea, vomiting, and sensitivity to light and sound. "I think the key finding that was quite interesting was the impact of migraine," said report author Pamela Ramage-Morin, a senior analyst in Ottawa. "For three-quarters to say that it had an impact on their getting a good night sleep, over half said it prevented them from driving on some occasions, even people feeling left out of things because of their condition. There's some social isolation that could be occurring. It may be limiting on people's education and employment opportunities. That can have a long-term effect." The sleep findings are important given lack of sleep can impact other aspects of life, Ramage-Morin said, noting how the effects can extend beyond the individual to the larger community. For both men and women surveyed, migraines were most common at ages 30 to 49, a group represents 12 per cent of the population and the prime working years. © CBC 2014

Keyword: Pain & Touch
Link ID: 19745 - Posted: 06.19.2014

Haroon Siddique The forehead and fingertips are the most sensitive parts to pain, according to the first map created by scientists of how the ability to feel pain varies across the human body. It is hoped that the study, in which volunteers had pain inflicted without touching them, could help the estimated 10 million people in the UK who suffer from chronic pain by allowing physicians to use lasers to monitor nerve damage across the body. This would offer a quantitative way to monitor the progression or regression of a condition. Lead author Dr Flavia Mancini, of the UCL Institute of Cognitive Neuroscience, said: "Acuity for touch has been known for more than a century, and tested daily in neurology to assess the state of sensory nerves on the body. It is striking that until now nobody had done the same for pain." In the study, a pair of lasers were used to cause brief sensation of pinprick pain to 26 blindfolded healthy volunteers on various parts of their body without any touch, in order to define our ability to identify where it hurts, known as "spatial acuity". Sometimes only one laser would be activated, and sometimes both. The participants were asked whether they felt one sting or two, at varying distances between the two beams and researchers recorded the minimum distance between the beams at which people were able to accurately say whether it was one sting or two. © 2014 Guardian News and Media Limited

Keyword: Pain & Touch
Link ID: 19708 - Posted: 06.07.2014

Jessica Morrison Bees, like birds and butterflies, use the Sun as a compass for navigation, whereas mammals typically find their way by remembering familiar landmarks on a continuous mental map. However, the latest research suggests that bees also use this type of map, despite their much smaller brain size. The work adds a new dimension to complex bee-navigation abilities that have long captivated researchers. “The surprise comes for many people that such a tiny little brain is able to form such a rich memory described as a cognitive map,” says co-author Randolf Menzel, a neurobiologist at the Free University of Berlin. The research by Menzel and his team, published today in the Proceedings of the National Academy of Sciences1, demonstrates that bees can find their way back to their hives without relying solely on the Sun. Instead, they seem to use a 'cognitive map' that is made up of memorized landscape snapshots that direct them home. The cognitive map used by mammals is thought to originate in the brain’s hippocampus. Humans employ such maps on a daily basis; for example, even in a windowless office, many people can point towards their home, orienting themselves in space based on knowledge of their location relative to the outside world. “They can point to their home generally even though they can’t see it, even along a path through a wall that they haven’t travelled,” explains Fred Dyer, a behavioural biologist at Michigan State University in East Lansing, who was not involved in the research. The study authors argue that bees can do something similar, albeit on a much more rudimentary level. © 2014 Nature Publishing Group

Keyword: Animal Migration
Link ID: 19684 - Posted: 06.03.2014

|By Bret Stetka Skepticism around fibromyalgia stemmed in part from an elusive organic explanation. Symptoms appeared to arise out of nowhere, which didn't make any sense to empirically minded physicians. “I, too, have been assigned months of futility, long and weary nights of misery. When I go to bed, I think,`When will it be morning?' But the night drags on, and I toss till dawn...Depression haunts my days. My weary nights are filled with pain as though something were relentlessly gnawing at my bones.” Job suffered badly. And his Old Testament woes are considered by many to be one of the earliest descriptions of fibromyalgia, a painful, puzzling disorder that still has experts bickering and patients frustrated, bereft of relief. The Bible isn't exactly a paragon of medical accuracy, but Job’s ailment does sound an awful lot like the modern interpretation of fibromyalgia. The classic diffuse pain, aches and discomfort aren’t the half of it; depression, fatigue, stiffness, sleep loss and generally just feeling really bad are common too. Fibromyalgia patients — 2 percent to 8 percent of the population — have also endured decades of dismissals that it's all in their head — a psychosomatic conjuring, a failure of constitution. Skepticism around fibromyalgia stemmed in part from an elusive organic explanation. Symptoms appeared to arise out of nowhere, which didn't make any sense to empirically minded physicians. But over the past two decades, research has brought clinicians closer to deciphering this mysterious pain state, once thought muscular in nature, now known to be neurologic. Based on this recent work a new article in the Journal of the American Medical Association by chronic pain expert Dr. Daniel Clauw brings us up to speed on the understanding, diagnosis and management of fibromyalgia circa 2014. And the outlook for patients is rosier than you might expect given the condition’s perplexing reputation. © 2014 Scientific American

Keyword: Stress; Aggression
Link ID: 19667 - Posted: 05.28.2014

By C. CLAIBORNE RAY Q. WHY WOULD A PAIN MEDICATION LOSE ITS EFFICACY AFTER WORKING WELL FOR SEVERAL YEARS? A. The mechanism is complex, said Dr. Shakil Ahmed, a pain medicine specialist at NewYork-Presbyterian Hospital/Weill Cornell Medical Center. “It is due to a phenomenon called tolerance,” in which there is a decrease in response over time to repeated exposures of the body to pain medication, he said. “This might be due to alteration in the way the body disposes of the medication,” Dr. Ahmed suggested. Or it could occur because drug interactions or bodily changes add a substance that induces an enzyme responsible for disposing of the drug. Another explanation is that long-term administration of pain medications results in a reduction of the number of target drug receptors or a drop in their responsiveness, and in desensitization to the pain medication in question. There is also an increase in the function of other nervous system receptors, called NMDA receptors , which may lead to the development of the tolerance, Dr. Ahmed said. Dr. Ahmed’s practice and research include several alternatives to conventional drug treatment for pain, including spinal cord stimulation, use of radio frequency to interrupt the nerve pathways of pain, delivery of pain medication with a pump directly to the space around the spinal cord, and non-invasive laser therapy. © 2014 The New York Times Company

Keyword: Pain & Touch
Link ID: 19666 - Posted: 05.28.2014

Pain is a symptom of many disorders; chronic pain can present as a disease in of itself. The economic cost of pain is estimated to be hundreds of billions of dollars annually in lost wages and productivity. “This database will provide the public and the research community with an important tool to learn more about the breadth and details of pain research supported across the federal government. They can search for individual research projects or sets of projects grouped by themes uniquely relevant to pain,” said Linda Porter, Ph.D., Policy Advisor for Pain at the National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institutes of Health (NIH). “It also can be helpful in identifying potential collaborators by searching for topic areas of interest or for investigators.” Users of the database easily can search over 1,200 research projects in a multi-tiered system. In Tier 1, grants are organized as basic, translational (research that can be applied to diseases), or clinical research projects. In Tier 2, grants are sorted among 29 scientific topic areas related to pain, such as biobehavioral and psychosocial mechanisms, chronic overlapping conditions, and neurobiological mechanisms. The Tier 2 categories are also organized into nine research themes: pain mechanisms, basic to clinical, disparities, training and education, tools and instruments, risk factors and causes, surveillance and human trials, overlapping conditions, and use of services, treatments, and interventions.

Keyword: Pain & Touch; Aggression
Link ID: 19665 - Posted: 05.28.2014

By Sandra G. Boodman, Cheron Wicker sank to her knees and began weeping, the contents of her purse and the bags of groceries she had dropped littering the floor of her suburban Maryland kitchen. As the searing pain in her index finger left her unable to reach the counter with the bags, Wicker felt an overwhelming sense of despair. Looking up, her gaze fell on a rack of kitchen knives. An idea that would have been unthinkable months earlier flickered through her mind. That morning in the fall of 2012 when she briefly considered cutting off her finger was the lowest point in her seven-year ordeal, recalled Wicker, a former public affairs official at the U.S. Maritime Administration. The Columbia resident had repeatedly consulted pain specialists and orthopedic surgeons, as well as her internist and endocrinologist; all were mystified by the persistence of her constant, excruciating pain. Wicker had even undergone two operations to replace the herniated disks in her neck that were believed to be the cause of the pain. She had taken all sorts of painkillers and become dependent on the sleeping pill Ambien to buy her a few hours of relief each night. She was increasingly convinced that she must be crazy; madness seemed to be the only reason that nothing had worked. The real reason, she would learn weeks later when she saw a new doctor, was simple: The pain in her fingertip was caused by something inside it, not by a pinched nerve in her neck. In December 2012, after a third surgery, her pain vanished. “I had to convince her that I knew what I was doing,” recalled Baltimore orthopedic surgeon Raymond Pensy, who diagnosed Wicker’s unusual disorder minutes after meeting her. “She was at her wit’s end.” © 1996-2014 The Washington Post

Keyword: Pain & Touch
Link ID: 19660 - Posted: 05.26.2014

Jasmin Fox-Skelly Scientists have found a way to beat back the hands of time and fight the ravages of old age, at least in mice. A new study finds that mice bred without a specific pain sensor, or receptor, live longer and are less likely to develop diseases such as diabetes in old age. What’s more, exposure to a molecule found in chili peppers and other spicy foods may confer the same benefits as losing this pain receptor—meaning that humans could potentially benefit, too. When you touch something hot or get a nasty paper cut, pain receptors in your skin are activated, causing neurons to relay a message to your brain: “Ouch!” Although pain protects your body from damage, it also causes harm. People who experience chronic pain, for example, are more likely to have shorter lifespans, but the reason for this has remained unclear. To investigate further, researchers from the University of California (UC), Berkeley, bred mice without a pain receptor called TRPV1. Found in the skin, nerves, and joints, it’s known to be activated by the spicy compound found in chili peppers, known as capsaicin. (When you feel like your mouth is burning after eating a jalapeño, that’s TRPV1 at work.) Surprisingly, the mice without TRPV1 lived on average 14% longer than their normal counterparts, the team reports today in Cell. (Meanwhile, calorie restriction—another popular way of lengthening mouse lifespans—can make them live up to 40% longer.) When the TRPV1-less mice got old, they still showed signs of fast, youthful metabolisms. Their bodies continued to quickly clear sugar from the blood—a trait called glucose tolerance that usually declines with age—and they burned more calories during exercise than regular elderly mice. © 2014 American Association for the Advancement of Science

Keyword: Pain & Touch
Link ID: 19652 - Posted: 05.23.2014

By MICHAEL BEHAR One morning in May 1998, Kevin Tracey converted a room in his lab at the Feinstein Institute for Medical Research in Manhasset, N.Y., into a makeshift operating theater and then prepped his patient — a rat — for surgery. A neurosurgeon, and also Feinstein Institute’s president, Tracey had spent more than a decade searching for a link between nerves and the immune system. His work led him to hypothesize that stimulating the vagus nerve with electricity would alleviate harmful inflammation. “The vagus nerve is behind the artery where you feel your pulse,” he told me recently, pressing his right index finger to his neck. The vagus nerve and its branches conduct nerve impulses — called action potentials — to every major organ. But communication between nerves and the immune system was considered impossible, according to the scientific consensus in 1998. Textbooks from the era taught, he said, “that the immune system was just cells floating around. Nerves don’t float anywhere. Nerves are fixed in tissues.” It would have been “inconceivable,” he added, to propose that nerves were directly interacting with immune cells. Nonetheless, Tracey was certain that an interface existed, and that his rat would prove it. After anesthetizing the animal, Tracey cut an incision in its neck, using a surgical microscope to find his way around his patient’s anatomy. With a hand-held nerve stimulator, he delivered several one-second electrical pulses to the rat’s exposed vagus nerve. He stitched the cut closed and gave the rat a bacterial toxin known to promote the production of tumor necrosis factor, or T.N.F., a protein that triggers inflammation in animals, including humans. “We let it sleep for an hour, then took blood tests,” he said. The bacterial toxin should have triggered rampant inflammation, but instead the production of tumor necrosis factor was blocked by 75 percent. “For me, it was a life-changing moment,” Tracey said. What he had demonstrated was that the nervous system was like a computer terminal through which you could deliver commands to stop a problem, like acute inflammation, before it starts, or repair a body after it gets sick. “All the information is coming and going as electrical signals,” Tracey said. For months, he’d been arguing with his staff, whose members considered this rat project of his harebrained. “Half of them were in the hallway betting against me,” Tracey said. © 2014 The New York Times Company

Keyword: Robotics
Link ID: 19649 - Posted: 05.23.2014

Four common chronic pain conditions share a genetic element, suggesting they could - at least in part - be inherited diseases, say UK researchers. The four include irritable bowel syndrome, musculoskeletal pain, pelvic pain and dry eye disease. The study of more than 8,000 sets of twins found the ailments were common in identical pairs sharing the same DNA. The King's College London team say the discovery could ultimately help with managing these debilitating diseases. While environmental factors probably still play a role in the four conditions, genes could account for as much as two-thirds of someone's chances of developing the disease, they believe. They told the journal Pain that more research is needed to pinpoint the precise genes involved. Chronic pain - pain which persists or recurs for months on end - is common and has many different causes, which can make it difficult to diagnose and treat. While the pain can be related to other medical conditions, it is thought to be caused by problems with the nervous system, sending pain signals to the brain despite no obvious tissue damage. Experts are keen to understand more about chronic pain to improve the quality of life of the millions of people who have to endure it. Some have suspected that some people may have a genetic predisposition to chronic pain since many sufferers share similar symptoms and often have more than one of the different types of chronic pain conditions. The team at King's College London decided to study identical and non-identical twins because these two groups provide an ideal comparison for investigating inherited genes - identical twins share the same DNA while non-identical twins do not. BBC © 2014

Keyword: Pain & Touch; Aggression
Link ID: 19643 - Posted: 05.21.2014

By KATIE THOMAS Almost overnight, a powerful new painkiller has become a $100 million business and a hot Wall Street story. But nearly as quickly, questions are emerging about how the drug is being sold, and to whom. The drug, Subsys, is a form of fentanyl, a narcotic that is often used when painkillers like morphine fail to provide relief. The product was approved in 2012 for a relatively small number of people — cancer patients — but has since become an outsize moneymaker for the obscure company that makes it, Insys Therapeutics. In the last year, the company’s sales have soared and its share price has jumped nearly 270 percent. Behind that business success is an unusual marketing machine that may have pushed Subsys far beyond the use envisioned by the Food and Drug Administration. The F.D.A. approved Subsys only for cancer patients who are already using round-the-clock painkillers, and warned that it should be prescribed only by oncologists and pain specialists. But just 1 percent of prescriptions are written by oncologists, according to data provided by Symphony Health, which analyzes drug trends. About half of the prescriptions were written by pain specialists, and a wide range of doctors prescribed the rest, including general practice physicians, neurologists and even dentists and podiatrists. Interviews with several former Insys sales representatives suggest the company, based in Chandler, Ariz., has aggressively marketed the painkiller, including to physicians who did not treat many cancer patients and by paying its sales force higher commissions for selling higher doses of the drug. Under F.D.A. rules, manufacturers may market prescription drugs only for approved uses. But doctors may prescribe drugs as they see fit. Over the last decade, pharmaceutical companies have paid billions of dollars to settle claims that they encouraged doctors to use drugs for nonapproved treatments, or so-called off-label uses, to increase sales and profits. © 2014 The New York Times Compan

Keyword: Drug Abuse; Aggression
Link ID: 19612 - Posted: 05.15.2014

By BARRY MEIER Four years and a lifetime ago, a new war began for Sgt. Shane Savage. On Sept. 3, 2010, the armored truck he was commanding near Kandahar, Afghanistan, was blown apart by a roadside bomb. His head hit the ceiling so hard that his helmet cracked. His left foot was pinned against the dashboard, crushing 24 bones. Sergeant Savage came home eight days later, at age 27, with the signature injuries of the conflicts in Iraq and Afghanistan: severe concussion, post-traumatic stress and chronic pain. Doctors at Fort Hood in Killeen, Tex., did what doctors across the nation do for millions of ordinary Americans: They prescribed powerful narcotic painkillers. What followed was a familiar arc of abuse and dependence and despair. At one point, Sergeant Savage was so desperate that he went into the bathroom and began swallowing narcotic tablets. He would have died had his wife, Hilary, not burst through the door. Today Sergeant Savage has survived, even prevailed, through grit, his family and a radical experiment in managing pain without narcotics. When off-duty, he pulls on cowboy boots and plays with his children, does charity work and, as part of a therapy program, rides horses. The only medication he takes for pain is Celebrex, a non-narcotic drug. “You have to find alternative ways to get out and do stuff to stay active, to get your brain off the thought process of ‘I’m in pain,’ ” said Sergeant Savage, whose ears push out from under a Texas A&M baseball cap. The story of Sergeant Savage illuminates an effort by experts inside and outside the military to change how chronic, or long-term, pain is treated. By some estimates, tens of millions of Americans suffer from chronic pain, and the use of opioids — drugs like hydrocodone, methadone and oxycodone (the active ingredient in painkillers like OxyContin) — to treat such conditions has soared over the last decade. © 2014 The New York Times Company

Keyword: Pain & Touch; Aggression
Link ID: 19600 - Posted: 05.12.2014

Jessica Morrison Interference from electronics and AM radio signals can disrupt the internal magnetic compasses of migratory birds, researchers report today in Nature1. The work raises the possibility that cities have significant effects on bird migration patterns. Decades of experiments have shown that migratory birds can orient themselves on migration paths using internal compasses guided by Earth's magnetic field. But until now, there has been little evidence that electromagnetic radiation created by humans affects the process. Like most biologists studying magnetoreception, report co-author Henrik Mouritsen used to work at rural field sites far from cities teeming with electromagnetic noise. But in 2002, he moved to the University of Oldenburg, in a German city of around 160,000 people. As part of work to identify the part of the brain in which compass information is processed, he kept migratory European robins (Erithacus rubecula) inside wooden huts — a standard procedure that allows researchers to investigate magnetic navigation while being sure that the birds are not getting cues from the Sun or stars. But he found that on the city campus, the birds could not orient themselves in their proper migratory direction. “I tried all kinds of stuff to make it work, and I couldn’t make it work,” Mouritsen says, “until one day we screened the wooden hut with aluminium.” Mouritsen and his colleagues covered the huts with aluminium plates and electrically grounded them to cut out electromagnetic noise in frequencies ranging from 50 kilohertz to 5 megahertz — which includes the range used for AM radio transmissions. The shielding reduced the intensity of the noise by about two orders of magnitude. Under those conditions, the birds were able to orient themselves. © 2014 Nature Publishing Group,

Keyword: Animal Migration
Link ID: 19590 - Posted: 05.08.2014

by Susan Milius Sometimes called the unicorn of the sea, the male narwhal’s tusk is actually a tooth, and it grows directly through the whale’s upper lip instead of pushing the lip aside. It’s an exuberantly large version of a canine tooth that grows in a spiral; the only tooth known to do so. Otherwise narwhals are practically toothless, with only vestigial stubs that stop growing during development and rarely emerge into the mouth. This extreme anatomy has captivated dentist Martin Nweeia, who practices in Connecticut and teaches at Harvard University. For more than a decade, he has pioneered ways to study these difficult-to-reach Arctic whales, and he and his colleagues now describe in the April Anatomical Record that narwhals can detect changes in water salinity using only their tusks. The animals “don’t have a good sense of humor,” though, about being temporarily restrained for the testing, Nweeia says. © Society for Science & the Public 2000 - 2013

Keyword: Pain & Touch
Link ID: 19571 - Posted: 05.05.2014

By JAN HOFFMAN How well can computers interact with humans? Certainly computers play a mean game of chess, which requires strategy and logic, and “Jeopardy!,” in which they must process language to understand the clues read by Alex Trebek (and buzz in with the correct question). But in recent years, scientists have striven for an even more complex goal: programming computers to read human facial expressions. We all know what it’s like to experience pain that makes our faces twist into a grimace. But can you tell if someone else’s face of pain is real or feigned? The practical applications could be profound. Computers could supplement or even replace lie detectors. They could be installed at border crossings and airport security checks. They could serve as diagnostic aids for doctors. Researchers at the University of California, San Diego, have written software that not only detected whether a person’s face revealed genuine or faked pain, but did so far more accurately than human observers. While other scientists have already refined a computer’s ability to identify nuances of smiles and grimaces, this may be the first time a computer has triumphed over humans at reading their own species. “A particular success like this has been elusive,” said Matthew A. Turk, a professor of computer science at the University of California, Santa Barbara. “It’s one of several recent examples of how the field is now producing useful technologies rather than research that only stays in the lab. We’re affecting the real world.” People generally excel at using nonverbal cues, including facial expressions, to deceive others (hence the poker face). They are good at mimicking pain, instinctively knowing how to contort their features to convey physical discomfort. © 2014 The New York Times Company

Keyword: Emotions; Aggression
Link ID: 19546 - Posted: 04.29.2014

It takes a lot to deter a male from wanting sex. A new study has found that male mice keep trying to copulate even when they are in pain, whereas females engage in less sex. But when given drugs that target pleasure centers in the human brain, the females again became interested. The findings could shed light on the nature of libido across various animal species. To assess how pain influences sexual desire, researchers first identified pairs of mice that wanted to have sex. “What we found early on was not all mice will mate with each other,” says clinical psychologist Melissa Farmer, who led the study while earning her Ph.D. at McGill University in Montreal, Canada. The team set up the rodents on a series of “dates,” during which a male and female were paired together for 30 minutes. Couples that copulated for most of the session were deemed compatible and moved into a cage with separate rooms. A small doorway allowed a female mouse to freely cross over from her chamber, but the male—which is larger—could not. The scientists then induced pain in males or females by applying a small dose of inflammatory compounds to the cheek, tail, foot, or genitals. The sensation would primarily be soreness, like a bad sunburn, says Farmer, who now works at Northwestern University’s Feinberg School of Medicine in Chicago, Illinois. Female mice that were in pain, whether genital or nongenital, spent 50% less time with their male partners, implying a decrease in sexual motivation. Even when they did visit their paramours, females wouldn’t allow males to mount them with the same frequency, the team reports online today in The Journal of Neuroscience. © 2014 American Association for the Advancement of Science.

Keyword: Sexual Behavior; Aggression
Link ID: 19526 - Posted: 04.23.2014