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

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Victoria E Brings & Mark J Zylka A study finds that pain hypersensitivity in male and female mice is differentially dependent on microglia and T cells, and describes a sex-specific response to microglia-targeted pain treatments. This sex difference will be important to consider when developing treatments for pain and other neurological disorders involving microglia and immune cells. Animal studies1, 2 have spawned great interest in using microglial inhibitors such as minocycline to treat pain in humans. However, these studies were conducted largely on male rodents. Now, Sorge et al.3 have evaluated several microglial inhibitors in nerve-injured mice of both sexes. The study—led by Jeffrey Mogil, who has championed the testing of males and females in pain studies4—found that microglial inhibitors did reduce allodynia, a form of pain hypersensitivity to touch, in males. Surprisingly, however, these inhibitors were ineffective in female mice, despite a robust activation of spinal microglia (Fig. 1). The authors instead found that cells of the adaptive immune system promote pain hypersensitivity in females. Although focused on pain, these findings could have implications for other neurological disorders that disproportionately affect one sex, such as autism and neurodegeneration, and in which microglia and immune cells are implicated5, 6. Figure 1: Pain mechanisms differ in male and female mice. Pain mechanisms differ in male and female mice. Nerve injury activates microglial cells in the spinal cord of male and female mice, but microglial inhibitors only block allodynia in males. P2RX4 is upregulated in males only. Female mice have about twice as many T cells as males. Testosterone increases PPARα and decreases PPARγ gene expression in T cells. Compounds that activate PPARα inhibit mechanical pain hypersensitivity (allodynia) in males, whereas those that activate PPARγ inhibit allodynia in females. © 2015 Macmillan Publishers Limited

Keyword: Pain & Touch; Glia
Link ID: 21229 - Posted: 07.29.2015

By Annick Laurent Can you tell a pygmy blue whale from an Antarctic blue whale? If not, you aren’t alone. Marine biologists have had trouble distinguishing these enormous mammals with mottled skin patterns ever since they began studying them—and that has complicated efforts to figure out where they breed and how to best protect them. Now, researchers have caught a break thanks to a pygmy whale named Isabela. Researchers first photographed the whale and collected her DNA in 1998 in the waters off the Galapagos Islands. Then, in 2006, another team photographed and collected samples from a similar looking whale off Chile (both photos above). Now, in a study published online before print in Marine Mammal Science, scientists compared those samples and photographs, and discovered that they both belonged to the same whale. That means Isabela (named after the lead author’s daughter to represent hope for future preservation efforts) migrated a minimum of 5200 km, the longest recorded latitudinal migration made by any Southern Hemisphere blue whale on record. The findings suggest Chile's and the Galapagos’ blue whale aggregations are connected, meaning those feeding in the Gulf of Corcovado off Chile may be breeding in the Tropical Eastern Pacific. Knowing where this species migrates—including its feeding and breeding grounds—can help conservationists and governments better establish marine protected areas, the team says. © 2015 American Association for the Advancement of Science

Keyword: Animal Migration
Link ID: 21213 - Posted: 07.25.2015

By Sarah Schwartz Scientists think they have a new understanding of a potential long-lasting, targeted treatment for chronic pain. When injected into the spinal cord of a mouse with nerve damage, cells extracted from mouse bone marrow flock to injured cells and produce a pain-relieving protein, researchers report July 13 in the Journal of Clinical Investigation. The results may lead to better chronic pain treatments in humans. The specialized cells honed in on their ultimate destination by following chemical signals released by the injured nerve cells. There, the injected cells produced an anti-inflammatory protein, called transforming growth factor beta 1 (TGFB1), which provided long-term pain relief. Researchers had known that the marrow cells relieved pain, but didn’t know how, says study coauthor Ru-Rong Ji, a neurobiologist at Duke University Medical Center. “These cells make drugs at sites of injury,” says biologist Arnold Caplan of Case Western Reserve University in Cleveland. “They’re drugstores.” Ji and colleagues found that they could relieve chronic nerve pain in mice by injecting 250,000 cells or fewer into the narrow space under the spinal cord membrane. This site is protected by the blood-brain barrier, preventing immune attacks on the injected cells and allowing these cells to live longer, Ji says. Some clinical trials inject cells like these into the bloodstream, Caplan says, requiring the use of many more cells, many of which get stuck in the lungs and liver. © Society for Science & the Public 2000 - 2015

Keyword: Pain & Touch
Link ID: 21167 - Posted: 07.14.2015

By Esther Hsieh Strap on a headset, immerse yourself in an alternate reality and cure your pain—that's the idea of a recent study in Psychological Science. Most people think of pain as something that happens in the body—I twist my head too far, and my neck sends a “pain signal” to the brain to indicate that the twisting hurts. In reality, pain is simply the brain telling us we are in danger. Although certain nerve endings throughout the body can indeed detect bodily harm, their signals are only one factor that the brain uses to determine if we should experience pain. Many cases of chronic pain are thought to be the result of obsolete brain associations between movement and pain. To explore the mind's influence over pain, Daniel Harvie, a Ph.D. candidate at the University of South Australia, and his colleagues asked 24 participants who suffer from chronic neck pain to sit in a chair while wearing virtual-reality glasses and turn their head. The displays were manipulated to make the participants think that they were turning their head more or less than they actually were. Subjects could swivel their head 6 percent more than usual if the virtual reality made them think they were turning less, and they could rotate 7 percent less than usual when they thought they were turning more. The findings suggest that virtual-reality therapy has the potential to retrain the brain to understand that once painful movements are now safe, extinguishing the association with danger. © 2015 Scientific American

Keyword: Pain & Touch
Link ID: 21155 - Posted: 07.11.2015

By JAMES GORMAN Call it the case of the homing lizards. It’s a small mystery. No one of any species is murdered. But the central question is one that has prompted plenty of scientific research: How do animals find their way home? The lizards in this case are anoles — abundant, mostly small reptiles that thrive in the Caribbean. The species is Anolis gundlachi. The lead detective is Manuel Leal, a biologist at the University of Missouri. He has been studying the behavior of anoles for more than 20 years. For about three years, Dr. Leal has been trying to understand how the anole finds its way back to its own territory after being carried into the rain forest. And as he told an audience in June at the annual meeting of the Animal Behavior Society in Anchorage, the case is far from closed. First, a bit of background. Anoles are particularly abundant in the dense vegetation of the rain forests in Puerto Rico, where Dr. Leal studies them. Each species is tied to a very specific environment. For instance, many live on tree trunks, but only a particular part of the trunk. Trunk-ground anoles live only in the space from the ground up to six feet or so. Trunk-crown anoles live above them, up to the crown of the tree. Twig anoles live way up high. Several years ago, Dr. Leal was studying competition between two species. If he removed all of the trunk-ground anoles, he wondered, would the trunk-crown lizards extend their territory farther down the tree? He ran into a problem, however. He would take the trunk-ground lizards far from their home territory to make room for their upstairs neighbors, and then release them. But in a reptilian version of the children’s song, “The Cat Came Back,” the lizards wouldn’t stay away. “Lizards kept showing up in the territory that had just been scoured for lizards,” he said. Dr. Leal wondered whether new anoles were appearing in empty territory or the old ones were returning. But how could a lizard that had never left home find its way back through 25 yards or so of dense rain forest? © 2015 The New York Times Company

Keyword: Animal Migration
Link ID: 21141 - Posted: 07.07.2015

Moheb Costandi Different immune cells regulate pain sensitization in male and female mice, according to research published on 29 June in Nature Neuroscience1. The surprising biological divide may explain why some clinical trials of pain drugs have failed, and highlights shortcomings in the way that many researchers design their experiments. The immune system has important roles in chronic pain, with cells called microglia being key players. Microglia express a protein called brain-derived neurotrophic factor (BDNF) to signal to spinal-cord neurons. When injury or inflammation occurs, this signal sensitizes the body to pain, so that even light touch hurts. Robert Sorge, a psychologist at the University of Alabama in Birmingham, and his colleagues induced persistent pain and inflammation in healthy male and female mice by severing two of the three sciatic nerve branches in their hind paws. Seven days later, they injected the animals with one of three drugs that inhibit microglial function. They found that all three drugs reversed pain sensitization in the male animals, as had been previously reported. But the treatments had no effect on the females, even though the animals had displayed equivalent levels of pain. The researchers also genetically engineered mice in which the BDNF gene could be deleted in microglia at any time during the animals' lives. At first, these animals exhibited normal responses to a nerve injury. Killing the microglia one week later extinguished that hypersensitivity in the male animals, but not in the females. This confirmed that in males, hypersensitivity to pain depends on BDNF signals from microglia, but that in females it is mediated by some other mechanism. © 2015 Nature Publishing Group,

Keyword: Pain & Touch; Sexual Behavior
Link ID: 21113 - Posted: 06.30.2015

By Megan Cartwright Don’t pet the platypus. I know it’s tempting: Given the chance, I’d want to stroke their thick brown fur, tickle those big webbed feet, and pat that funny duck bill. And why not? What harm could come from this cute, egg-laying mammal from eastern Australia? Plenty. As someone who doesn’t enjoy “long lasting excruciating pain that cannot be relieved with conventional painkillers,” I’d really regret petting a platypus. Especially a male platypus, in late winter, when there’s only one thing on his mind and, even worse, something nasty on his feet. When British biologist Sir Everard Home got ahold of some platypus specimens in 1801, he told his fellow nerds at the Royal Society how the male specimen had a half-inch long “strong crooked spur” on the heel of each rear foot. The female, however, was spur-free. Home suggested that it “is probably by means of these spurs or hooks, that the female is kept from withdrawing herself in the act of copulation.” A very reasonable suggestion. But a wrong one. To be fair to Home, he could only study dead platypuses. If Home could have spent a year hanging out with living platypuses in their river homes, he would’ve seen that this “shy, semi-aquatic, mainly nocturnal” mammal is mostly interested in hunting on the river bottom for delicious insect larvae, crayfish, and shrimp. In other words, the platypus is usually an eater, not a lover. © 2014 The Slate Group

Keyword: Neurotoxins; Pain & Touch
Link ID: 21090 - Posted: 06.25.2015

Patricia Neighmond We all know that listening to music can soothe emotional pain, but Taylor Swift, Jay-Z and Alicia Keys can also ease physical pain, according to a study of children and teenagers who had major surgery. The analgesic effects of music are well known, but most of the studies have been done with adults and most of the music has been classical. Now a recent study finds that children who choose their own music or audiobook to listen to after major surgery experience less pain. The catalyst for the research was a very personal experience. Sunitha Suresh was a college student when her grandmother had major surgery and was put in intensive care with three other patients. This meant her family couldn't always be with her. So they decided to put her favorite south Indian classical Carnatic music on an iPod, so she could listen around the clock. It was very calming, Sunitha says. "She knew that someone who loved her had left that music for her and she was in a familiar place." This may be the most efficient way to get in shape, but it may also be the least fun. Suresh could see the music relaxed her grandmother and made her feel less anxious, but she wondered if she also felt less pain. That would make sense, because anxiety can make people more vulnerable to pain. At the time Suresh was majoring in biomedical engineering with a minor in music cognition at Northwestern University where her father, Santhanam Suresh, is a professor of anesthesiology and pediatrics. © 2015 NPR

Keyword: Pain & Touch
Link ID: 21080 - Posted: 06.22.2015

Bill Chappell In what researchers say is a first, they've discovered the neuron in worms that detects Earth's magnetic field. Animals have been known to sense the magnetic field; a new study identifies the microscopic, antenna-shaped sensor that helps worms orient themselves underground. The sensory neuron that the worm C. elegans uses to migrate up or down through the soil could be similar to what many other animals use, according to the team of scientists and engineers at The University of Texas at Austin. The team's work was published Wednesday by eLife. In contrast to previous breakthroughs — such as a 2012 study on how pigeons' brains use information about magnetic fields, and another from the same year on olfactory cells in trout — the new work identifies the sensory neuron that detects magnetic fields. "We also found the first hint at a novel sensory mechanism for detecting the magnetic field," says Jon Pierce-Shimomura, an assistant professor of neuroscience who worked on the study. "Now researchers can check to see if this is used in other animals too." The list of animals that could be studied for their use of magnetic fields is long — and it seems to grow each year. In early 2014, for instance, a study found that dogs who need to relieve themselves of waste prefer to align themselves on a north-south axis when the magnetic conditions are right. Pierce-Shimomura says his team was surprised to make a new breakthrough in magnetism by looking at worms, which aren't known for their sophisticated migrations. © 2015 NPR

Keyword: Pain & Touch
Link ID: 21072 - Posted: 06.18.2015

By Andrea Alfano There are many types of touch. A cold splash of water, the tug of a strong breeze or the heat and heft of your coffee mug will each play on your skin in a different way. Within your skin is an array of touch sensors, each associated with nerve fibers that connect to the central nervous system. These sensors comprise specialized nerve endings and skin cells. Along with the fibers, they translate our physical interactions with the world into electrical signals that our brain can process. They help to bridge the gap between the physical act of touching and the cognitive awareness of tactile sensation. Even a simple stroke across the forearm engages several distinct nerve fibers. Three types—A-beta, A-delta and C fibers—have subtypes that are specialized for sensing particular types of touch; other subtypes carry information related to pain. The integration of information from these fibers is what allows us to gain such rich sensory experiences through our skin, but it has also made it more challenging for researchers to understand the fibers’ individual roles. Although these fibers do not act in isolation, the examples that follow highlight the primary nerve fibers engaged by different types of touch. © 2015 Scientific American

Keyword: Pain & Touch
Link ID: 21066 - Posted: 06.18.2015

by Laura Sanders The motor homunculus is a funny-looking fellow with a hulking thumb, delicate toes and a tongue that wags below his head. His body parts and proportions stem from decades-old experiments that mapped brain areas to the body parts they control. Now, a new study suggests that the motor homunculus’ neck was in the wrong place. Hyder Jinnah of Emory University in Atlanta and colleagues used fMRI to scan the brains of volunteers as they activated their head-turning neck muscles. (Pads held participants’ heads still, so the muscles fired but heads didn’t move.) This head turn was accompanied by activity in part of the brain that controls movement. The exact spot seems to be between the brain areas that control the shoulder and the trunk — not between the areas responsible for moving the thumb and the top of the head as earlier motor homunculi had suggested, the team reports in the June 17 Journal of Neuroscience. © Society for Science & the Public 2000 - 2015.

Keyword: Pain & Touch
Link ID: 21060 - Posted: 06.17.2015

Joe Palca Scientists found a molecule crucial to perceiving the sensation of itching. It affects how the brain responds to serotonin, and may explain why anti-depressants that boost serotonin make some itch. JOE PALCA, BYLINE: How do you go about discovering what makes us itch? Well, if you're Diana Bautista at the University of California, Berkeley, you ask what molecules are involved. DIANA BAUTISTA: We say OK, what are the possible molecular players out there that might be contributing to itch or touch? PALCA: Bautista says it turns out itch and touch, and even pain, all seem to be related - at least in the way our brains makes sense of these sensations. But how to tell which molecules are key players? Bautista says basically you try everything you can. BAUTISTA: We test a lot of candidates. And if we're really lucky, one of our candidates - we can prove that it plays a really important role. PALCA: And now she thinks she's found one. Working with colleagues at the Buck Institute for Research on Aging, she's found a molecule that's made by a gene called HTR7. When there's less of this molecule, animals with itchy skin conditions, like eczema, do less scratching. When there's more of it, itching gets worse. The way this molecule works is kind of interesting. It changes how sensitive brain cells are to a chemical called serotonin. Now, serotonin is a chemical that's related to depression. So Bautista's research might explain why certain antidepressant drugs that boost serotonin have a peculiar side effect. For some people, the drugs make them itch. Bautista says the new research is certainly not the end of the story when it comes to understanding itch. © 2015 NPR

Keyword: Pain & Touch
Link ID: 21042 - Posted: 06.13.2015

Fergus Walsh Medical correspondent Scientists in Austria have created an artificial leg which allows the amputee to feel lifelike sensations from their foot. The recipient, Wolfang Rangger, who lost his right leg in 2007, said: "It feels like I have a foot again. It's like a second lease of life." Prof Hubert Egger of the University of Linz, said sensors fitted to the sole of the artificial foot, stimulated nerves at the base of the stump. He added it was the first time that a leg amputee had been fitted with a sensory-enhanced prosthesis. How it works Surgeons first rewired nerve endings in the patient's stump to place them close to the skin surface. Six sensors were fitted to the base of the foot, to measure the pressure of heel, toe and foot movement. These signals were relayed to a micro-controller which relayed them to stimulators inside the shaft where it touched the base of the stump. These vibrated, stimulating the nerve endings under the skin, which relayed the signals to the brain. Prof Egger said: "The sensors tell the brain there is a foot and the wearer has the impression that it rolls off the ground when he walks." Wolfgang Ranger, a former teacher, who lost his leg after a blood clot caused by a stroke, has been testing the device for six months, both in the lab and at home. He says it has given him a new lease of life He said: "I no longer slip on ice and I can tell whether I walk on gravel, concrete, grass or sand. I can even feel small stones." © 2015 BBC.

Keyword: Pain & Touch; Robotics
Link ID: 21028 - Posted: 06.09.2015

Mo Costandi Being unable to feel pain may sound appealing, but it would be extremely hazardous to your health. Pain is, for most of us, a very unpleasant feeling, but it serves the important evolutionary purpose of alerting us to potentially life-threatening injuries. Without it, people are more prone to hurting themselves and so, because they can be completely oblivious to serious injuries, a life without pain is often cut short. Take 16-year-old Ashlyn Blocker from Patterson, Georgia, who has been completely unable to sense any kind of physical pain since the day she was born. As a newborn, she barely made a sound, and when her milk teeth started coming out, she nearly chewed off part of her tongue. Growing up, she burnt the skin off the palm of her hands on a pressure washer that her father had left running, and once ran around on a broken ankle for two whole days before her parents noticed the injury. She was once swarmed and bitten by hundreds of fire ants, has dipped her hands into boiling water, and injured herself in countless other ways, without ever feeling a thing. Ashlyn is one of a tiny number of people with congenital insensitivity to pain. The condition is so rare, in fact, that the doctor who diagnosed her in 2006 told her parents that she may be the only one in the world who has it. But later that year, a research team led by Geoffrey Woods of the University of Cambridge, identified three distinct mutations in the SCN9A gene, all of which cause the same condition in members of three large families in northern Pakistan, and in 2013, Ashlyn’s doctor Roland Staud and his colleagues reported that her condition is the result of two other mutations in the same gene. Now, Woods and his colleagues have discovered yet more mutations that cause congenital insensitivity to pain. © 2015 Guardian News and Media Limited

Keyword: Pain & Touch; Genes & Behavior
Link ID: 20981 - Posted: 05.26.2015

by Jessica Hamzelou Painful needle heading your way? A sharp intake of breath might be all that is needed to make that injection a little more bearable. When you are stressed, your blood pressure rises to fuel your brain or limbs should you need to fight or flee. But your body has a natural response for calming back down. Pressure sensors on blood vessels in your lungs can tell your brain to bring the pressure back down, and the signals from these sensors also make the brain dampen the nervous system, leaving you less sensitive to pain. This dampening mechanism might be why people with higher blood pressures appear to have higher pain thresholds. Gustavo Reyes del Paso at the University of Jaén in Spain wondered whether holding your breath – a stress-free way of raising blood pressure and triggering the pressure sensors – might also raise a person's pain threshold. To find out, he squashed the fingernails of 38 people for 5 seconds while they held their breath. Then he repeated the test while the volunteers breathed slowly. Both techniques were distracting, but the volunteers reported less pain when breath-holding than when slow breathing. Reyes del Paso thinks holding your breath might be a natural response to the expectation of pain. "Several of our volunteers told us they already do this when they are in pain," he says. But he doesn't think the trick will work for a stubbed toe or unexpected injury. You have to start before the pain kicks in, he says, for example, in anticipation of an injection. © Copyright Reed Business Information Ltd

Keyword: Pain & Touch
Link ID: 20930 - Posted: 05.14.2015

Patricia Neighmond Terri Bradford has suffered debilitating headache pain all her life. Some days the pain is so bad, she says, "By 11 o'clock in the morning, I'm on the couch in a darkened room with my head packed in ice." Over the years, Bradford, who is 50 years old and lives in Bedford, Mass., has searched desperately for pain relief. She's been to the doctor countless times for countless tests. "Everything I've had, I've had twice," she says. "I've had two spinal taps; I've had so many nerve blocks I've lost count." Bradford is not alone. It's estimated that every year 12 million Americans go to the doctor seeking help for headaches. Nearly one quarter of the population suffers from recurrent severe tension headaches or migraines. People who go to the doctor for headache pain are more likely to be sent for advanced testing and treatment, a study finds. That testing is expensive, it may not be necessary and could even be harmful, says lead researcher Dr. John Mafi of Beth Israel Deaconess Medical Center in Boston. Mafi looked at the rates of advanced imaging like CT scans and MRIs in people with headaches, as well as referrals to other doctors, presumably specialists. He found that from 1999 to 2010, the number of diagnostic tests rose from 6.7 percent of all doctor visits to 13.9 percent. At the same time, referrals to other doctors increased from 6.9 percent to 13.2 percent. So almost double what it was a decade ago. Mafi says this isn't because more people are suffering headaches. The headache rate has remained virtually the same over the past decade. But what has changed is supply and demand. Today there are a lot more advanced diagnostic machines than there were a decade ago, and more patients are asking to be tested. © 2015 NPR

Keyword: Parkinsons; Stress
Link ID: 20906 - Posted: 05.11.2015

by Helen Thomson Giving people the illusion of teleporting around a room has revealed how the brain constructs our sense of self. The findings may aid treatments for schizophrenia and asomatognosia – a rare condition characterised by a lack of awareness of a part of one's body. As we go about our daily lives, we experience our body as a physical entity with a specific location. For instance, when you sit at a desk you are aware of your body and its rough position with respect to objects around you. These experiences are thought to form a fundamental aspect of self-consciousness. Arvid Guterstam, a neuroscientist at the Karolinska Institute in Stockholm, Sweden, and his colleagues wondered how the brain produces these experiences. To find out, Guterstam's team had 15 people lie in an fMRI brain scanner while wearing a head-mounted display. This was connected to a camera on a dummy body lying elsewhere in the room, enabling the participants to see the room – and themselves inside the scanner - from the dummy's perspective. A member of the team then stroked the participant's body and the dummy's body at the same time. This induced the out-of-body experience of owning the dummy body and being at its location. The experiment was repeated with the dummy body positioned in different parts of the room, allowing the person to be perceptually teleported between the different locations, says Guterstam. All that was needed to break the illusion was to touch the participant's and the dummy's bodies at different times. © Copyright Reed Business Information Ltd.

Keyword: Pain & Touch; Attention
Link ID: 20874 - Posted: 05.02.2015

by Jacob Aron Now that's an in-flight meal. To snatch a mealworm in mid-air, the bat in this video performs impressive aerial acrobatics aided by a unique cluster of touch sensors on its wings. Bats are known to use echolocation to identify their dinner, steering towards prey by listening for reflected sounds. It turns out that their sense of touch plays a key role as well. Ellen Lumpkin of Columbia University, New York, and her colleagues have discovered that bats have a special arrangement of hairs and touch-sensitive receptors across their wings that detect changes in airflow to help stabilise flight. The team also found that sensory neurons arranged in a pattern on bat wings (pictured) send signals to the lower spinal cord, which is unusual for a mammal. This part of the spinal cord usually receives messages from an animal's torso. The bizarre circuitry reflects the embryonic origins of bat wings, which form when their front limbs, torso and hind limbs fuse together. Journal reference: Cell Reports, DOI: 10.1016/j.celrep.2015.04.001 © Copyright Reed Business Information Ltd

Keyword: Pain & Touch
Link ID: 20872 - Posted: 05.02.2015

The brains of babies “light up” in a similar way to adults when exposed to the same painful stimulus, suggesting they feel pain much like adults do, researchers said on Tuesday. In the first of its kind study using magnetic resonance imaging (MRI), scientists from Britain’s Oxford University found that 18 of the 20 brain regions active in adults experiencing pain were also active in babies. Brain scans of the sleeping infants while they were subjected to mild pokes on the bottom of their feet with a special rod – creating a sensation “like being poked with a pencil” – also showed their brains had the same response to a slighter “poke” as adults did to a stimulus four times as strong, suggesting babies have a much lower pain threshold. “Obviously babies can’t tell us about their experience of pain and it is difficult to infer pain from visual observations,” said Rebeccah Slater, a doctor at Oxford’s paediatrics department who led the study. “In fact some people have argued that babies’ brains are not developed enough for them to really feel pain ... [yet] our study provides the first really strong evidence this is not the case.” Even as recently as the 1980s it was common practice for babies undergoing surgery to be given neuromuscular blocks but no pain relief medication. Last year, a review of neonatal pain management in intensive care found that although these babies experience an average of 11 painful procedures per day, 60% do not receive any kind of pain medication. © 2015 Guardian News and Media Limited

Keyword: Pain & Touch; Development of the Brain
Link ID: 20824 - Posted: 04.21.2015

Angus Chen A common pain medication might make you go from "so cute!" to "so what?" when you look at a photo of an adorable kitten. And it might make you less sensitive to horrifying things too. It's acetaminophen, the active ingredient in Tylenol. Researchers say the drug might be taking the edge off emotions – not just pain. "It seems to take off the highs of your daily highs and the lows off your daily lows," says Baldwin Way, a psychologist at Ohio State University and the principal investigator on the study, "It kind of flattens out the vicissitudes of your life." The idea that over-the-counter pain pills might affect emotions has been circulating since 2010, when two psychologists, Naomi Eisenberger and Nathan DeWall, led a study showing that acetaminophen seemed to be having both a psychological and a neurological effect on people. They asked volunteers to play a rigged game that simulated social rejection. Not only did the acetaminophen appear to be deflecting social anxieties, it also seemed to be dimming activity in the insula, a region of the brain involved in processing emotional pain. A brain that can let other thoughts bubble up despite being in pain might help its owner benefit from meditation or other cognitive therapies. "But [the insula] is a portion of the brain that seems to be involved in a lot of things," Way says. In older studies, scientists saw that people with damage in their insula didn't react as strongly to either negative or positive images. So Way and one of his students, Geoffrey Durso, figured that if acetaminophen is doing something to the insula, then it might be having a wider effect, too. © 2015 NPR

Keyword: Emotions; Pain & Touch
Link ID: 20807 - Posted: 04.16.2015