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

Follow us on Facebook and Twitter, or subscribe to our mailing list, to receive news updates. Learn more.


Links 41 - 60 of 867

By Katherine Harmon A bite from the black mamba snake (Dendroaspis polylepis) can kill an adult human within 20 minutes. But mixed in with that toxic venom is a new natural class of compound that could be used to help develop new painkillers. Named “mambalgins,” these peptides block acute and inflammatory pain in mice as well as morphine does, according to a new study. Researchers, led by Sylvie Diochot, of the Institute of Molecular and Cellular Pharmacology at Nice University, Sophia Antipolis in France, purified the peptides from the venom and profiled the compounds’ structure. They then were able to test the mambalgins in strains of mice with various genetic tweaks to their pain pathways. Diochot and her colleagues determined that the mambalgins work by blocking an as-yet untargeted set of neurological ion channels associated with pain signals. The findings were published online October 3 in Nature (Scientific American is part of Nature Publishing Group). As a bonus, mambalgins did not have the risky side effect of respiratory depression that morphine does. And the mice developed less tolerance to them over time than is typical with morphine. Experimenting with the newfound compounds should also help researchers learn more about the mechanisms that drive pain. As the researchers noted in their paper, “It is essential to understand pain better to develop new analgesics. The black mamba peptides discovered here have the potential to address both of these aims.” © 2012 Scientific American,

Keyword: Pain & Touch; Aggression
Link ID: 17333 - Posted: 10.04.2012

By PAUL CHRISTOPHER, M.D. “I’m addicted to painkillers,” J., a thickset construction worker, told me on a recent afternoon in the emergency room, his wife at his side. Two years before, after months of pain, stiffness and swelling in his hands and neck, his primary physician had diagnosed rheumatoid arthritis and had prescribed three medications: two to slow the disease and one, oxycodone, for pain. Bolstered by the painkiller, J. had felt more limber and energetic than he had in years. “I could finally keep up with the other guys,” he told me. He worked harder, and his pain worsened. His primary physician increased the oxycodone dose. Soon, J. was looking forward more to the buzz than to the relief the pills brought. He went to see two other physicians who, unaware that he was double-dipping, prescribed similar medications. When a co-worker offered to sell him painkillers directly, J.’s use spiraled out of control. By the time I saw him, he was taking dozens of pills a day, often crushing and snorting them to speed the onset of his high. With remarkable candor, he described how the drugs had marred every facet of his life — from days of missed work to increasing debt, deteriorating health and marital strain. But when I listed the treatment options that might help, J. shook his head, looked from me to his wife, and got up. “I’m all set,” he said, holding up his hands. Then he walked out of the room. Despair fell on his wife’s face. “Please,” she said, grabbing my arm, “you can’t let him leave.” Copyright 2012 The New York Times Company

Keyword: Drug Abuse; Aggression
Link ID: 17327 - Posted: 10.03.2012

By Sandra G. Boodman, The 80th birthday party for Josephine van Es marked two milestones, only one of which was apparent at the time. Held in November 2004 at her daughter’s house in Rehoboth Beach, Del., the event was a celebration of her longevity, good health and loving family. It also marked one of the last times van Es can remember feeling well and not beset by the pain that developed soon afterward and has left the inside of her mouth feeling perpetually scalded and with a constant metallic taste. “It’s awful,” said van Es, 87, who says the burning is worse than the taste, which she likens to “sucking on a penny.” Her daughter Karen van Es says that her mother’s problem has taken a toll on both their lives. For nearly eight years, she has taken time from her job at a Northern Virginia veterinary clinic to ferry her mother, who lives independently in a condominium in Lewes, Del., to doctors in Delaware, Philadelphia and Washington. She also has contacted specialists in Florida and Canada hoping one would propose an effective remedy for an ailment that took more than a year to diagnose and has so far eluded treatment. “She tells me, ‘I just feel rotten all the time,’ ” said Karen van Es, 63, an only child who speaks to her mother every day and sees her often. “My mother has lost confidence as a result of this,” Karen van Es said, adding that she often feels helpless and frustrated about not being able to do more. © 1996-2012 The Washington Post

Keyword: Chemical Senses (Smell & Taste); Aggression
Link ID: 17305 - Posted: 09.26.2012

By PAULINE W. CHEN, M.D. Recounting her father’s struggle with cancer was difficult for the young woman, even several years after his death. He’d endured first surgery and then chemotherapy and radiation, she told me, and the cancer had gone into remission. He was thrilled, but the aggressive treatment left him with chronic, debilitating pain. Once active, he struggled to get around in his own home. “It wasn’t the cancer that got him,” the daughter said. “It was the pain.” Her father had turned to all of his doctors, with little relief. His surgeon had looked at his operative wounds, pronounced them well healed, then stated that they were in no way responsible for his disability. Both his cancer doctor and his radiation doctor congratulated him on being in remission but then declined to prescribe pain medications since they were no longer treating him and couldn’t provide ongoing follow-up and dosing guidance. His primary care doctor listened intently to his descriptions of his limitations, but then prescribed only small amounts of pain meds that offered fleeting relief at best. “I’ll never forget what my father had to go through,” she said, weeping. “I wouldn’t wish this on anyone.” I wish I could have reassured her that her father’s case was unusual. Sadly, according to a new study in The Journal of Clinical Oncology, a significant percentage of cancer patients continue to suffer from pain as her father did. Copyright 2012 The New York Times Company

Keyword: Pain & Touch; Aggression
Link ID: 17300 - Posted: 09.26.2012

By James Gallagher Health and science reporter, BBC News Up to a million people in the UK have "completely preventable" severe headaches caused by taking too many painkillers, doctors have said. They said some were trapped in a "vicious cycle" of taking pain relief, which then caused even more headaches. The warning came as part of the National Institute for Health and Clinical Excellence's (NICE) first guidelines for treating headaches. It is also recommending acupuncture in some circumstances. "Medication overuse headaches" feel the same as other common headaches or migraines. There is no definitive UK data on the incidence of the condition, but studies in other countries suggest 1-2% of people are affected, while the World Health Organization says figures closer to 5% have been reported. While painkillers would be many people's instant response, they could be making sufferers feel even worse. Prof Martin Underwood, from Warwick Medical School, who led the NICE panel, said: "This can end up getting into a vicious cycle where your headache gets worse, so you take more painkillers, so your headache gets worse and this just becomes worse and worse and worse. BBC © 2012

Keyword: Pain & Touch
Link ID: 17277 - Posted: 09.19.2012

In May, my six-year-old daughter, Julia, smashed into our front door handle and got a deep, bloody gash in her forehead. We rushed her, head wrapped like a tiny mummy, to the medical center at MIT, where we generally go for pediatric care. Julia wept while the nurse cleaned and examined her lacerated skin. After a short exam, she sent us to the emergency department at Children’s Hospital Boston for stitches. “How bad is that, generally?” I asked, having never experienced suturing either for myself or my cautious, risk-averse, older daughter. “It can be traumatic,” the nurse said. Julia cried, “I don’t want stitches.” It’s a large needle, but Julia is too busy coloring to notice. So I braced myself for the worst: an endless wait and nerve-wracking bustle; screaming, germ-laden children and brusque, end-of-shift staff. But more than anything, I dreaded the inevitable pain in store for my small child with the deep cut. (I know, kids get banged up on the path to adulthood and some pain is unavoidable. Still, when bloody heads are involved, I tend to overreact.) Indeed, I was in full Mama Bear mode when into our exam room strode Dr. Baruch Krauss, the attending physician that evening. Copyright Trustees of Boston University

Keyword: Pain & Touch; Aggression
Link ID: 17276 - Posted: 09.19.2012

By Jorge Cham and Dwayne Godwin [Graphic novel format.] Dwayne Godwin is a neuroscientist at the Wake Forest University School of Medicine. Jorge Cham draws the comic strip Piled Higher and Deeper at www.phdcomics.com. © 2012 Scientific American,

Keyword: Pain & Touch
Link ID: 17264 - Posted: 09.17.2012

Daniel Cressey Rabbits are the latest focus of work seeking to measure animal discomfort by assessing facial expressions. Researchers working with animals often find it difficult to scientifically assess when their study subjects are in pain. Traditional methods rely on after-the-fact measurements involving weight loss or food and water consumption, or on subjective judgements such as how an animal moves. In an attempt to make pain assessment more scientific, geneticist Jeffrey Mogil at McGill University in Montreal, Canada, and his colleagues developed the 'mouse grimace scale', which was published in Nature Methods1 in May 2010 (see 'Mice pull pained expressions'). The scale relies on the scoring of five ‘action units’ — such as narrowing of the eyes and bulging of the cheeks — between zero (not present) and two (obviously present), with the combined score indicating total pain. The scale rapidly caught on among veterinarians to assess post-operative pain. “I’m surprised how quickly it was adopted as a practical thing to use in real-time for animal care,” says Mogil. Matthew Leach, who researches animal welfare at Newcastle University, UK, and led the work in rabbits, has been working on facial expressions of pain in various animals since the original mouse grimace scale came out. "The only way you can alleviate pain is to be able to identify it, and to understand how much pain an animal is in," he says. "There is a broad interest in grimace scales,” he notes, adding that compared with traditional models, “I would argue it’s potentially better and faster in many circumstances”. © 2012 Nature Publishing Group

Keyword: Pain & Touch
Link ID: 17238 - Posted: 09.10.2012

by Colin Barras ON THE face of it, the placebo effect makes no sense. Someone suffering from a low-level infection will recover just as nicely whether they take an active drug or a simple sugar pill. This suggests people are able to heal themselves unaided - so why wait for a sugar pill to prompt recovery? New evidence from a computer model offers a possible evolutionary explanation, and suggests that the immune system has an on-off switch controlled by the mind. It all starts with the observation that something similar to the placebo effect occurs in many animals, says Peter Trimmer, a biologist at the University of Bristol, UK. For instance, Siberian hamsters do little to fight an infection if the lights above their lab cage mimic the short days and long nights of winter. But changing the lighting pattern to give the impression of summer causes them to mount a full immune response. Likewise, those people who think they are taking a drug but are really receiving a placebo can have a response which is twice that of those who receive no pills (Annals of Family Medicine, doi.org/cckm8b). In Siberian hamsters and people, intervention creates a mental cue that kick-starts the immune response. There is a simple explanation, says Trimmer: the immune system is costly to run - so costly that a strong and sustained response could dangerously drain an animal's energy reserves. In other words, as long as the infection is not lethal, it pays to wait for a sign that fighting it will not endanger the animal in other ways. © Copyright Reed Business Information Ltd.

Keyword: Pain & Touch; Aggression
Link ID: 17231 - Posted: 09.07.2012

By SEAN B. CARROLL Early one evening a few years ago, I took a short hike with my wife, Jamie, in the Cockscomb Basin Wildlife Sanctuary in Belize. The large, lush reserve is known for its healthy population of jaguars, so, following closely behind our guide, we kept our eyes peeled for the elusive cats. We saw a few tracks and some claw marks on trees, but elected to leave the jungle before nightfall. We were very near the end of the trail when we were surprised by a large snake, about six feet long, crossing directly in front of us. Belize has lots of snakes, more than 50 species. Some can get pretty large, like the boa constrictor, which is impressive but harmless. This one was not harmless. Even in the darkening jungle, the triangular pattern on its back allowed me to identify it quickly as a fer-de-lance, the most dangerous snake in Belize. Excited, and comfortable that I was well out of striking range, I reached into my backpack for my video camera and flipped on its “night shot” feature. I now saw the magnificent snake clearly on my LCD screen. As I tried to creep in for a closer shot, however, I felt something holding me back. It was Jamie. She had a grip on my backpack and was concerned that my enthusiasm for snakes had overtaken my judgment. She was not convinced that we were out of range, nor that the snake would not move quickly toward us. I used the zoom and filmed from where I stood. For me to film the snake in the dark, I had to rely on Sony’s innovation and engineering. The camera’s infrared LED source generated light with a longer wavelength than the human eye can detect; those photons then bounced off the snake and were detected by the camera’s infrared sensors and converted into an image. © 2012 The New York Times Company

Keyword: Evolution; Aggression
Link ID: 17210 - Posted: 08.28.2012

By Stephani Sutherland Ice cream headache is a familiar summertime sensation, but the pain's source has been mysterious until now. A team led by Jorge Serrador of Harvard Medical School produced brain scans of “second-by-second changes” in blood flow while subjects sipped iced water through a straw pressed against the roof of the mouth, which caused the brain's major artery to widen. “Blood flow changes actually preceded the pain” that subjects reported, Serrador says. As the vessel narrowed again, the discomfort ebbed. He suspects that the influx of blood is meant to protect the brain from extreme cold and that increased pressure inside the skull could cause the pain. Serrador presented the results at Experimental Biology 2012 in April in San Diego. © 2012 Scientific American

Keyword: Pain & Touch
Link ID: 17205 - Posted: 08.27.2012

by Gilead Amit The bath of cells in avian eyes could prolong a delicate quantum state that helps to explain how some birds navigate using Earth's magnetic field. It is thought that light reacts with receptors in the birds' eyes to produce two molecules with unpaired electrons, whose spins are linked by a special state called quantum entanglement. If the relative alignment of the spins is affected by Earth's magnetic field, the electron pair can cause chemical changes that the bird can sense. In 2009, researchers at the University of Oxford calculated that such entanglement must last for at least 100 microseconds for the internal compass to work. But how the sensitive state of quantum entanglement could survive that long in the eye was a mystery. Calculations by Zachary Walters of the Max Planck Institute for the Physics of Complex Systems in Dresden, Germany, now show that interactions with cells in the bird's eye allow the electron pairs to stay entangled for longer through a dampening effect. Rather like the way a car with stiff shock absorbers takes longer to stop bouncing after going over a bump, the signal from the electron pair dies away more slowly under strong interactions with the cellular bath. Predicting exactly how long entanglement is sustained won't be possible until the mechanism is better understood, says Walters. But he believes there's a good chance his model could account for the 100 microseconds. © Copyright Reed Business Information Ltd

Keyword: Vision
Link ID: 17190 - Posted: 08.22.2012

By Scicurious Or not. I so want to like press releases. But I got this press release: “SCIENTISTS CAN NOW BLOCK HEROIN, MORPHINE ADDICTION” And I got the paper along with it. As I read the paper, my head slowly hit the desk. And hit it again, and again, as I compared the press release to the paper and prepared to write this post. I will have a lovely little round bruise now. But let’s get the big questions out of the way first: 1. Is this paper good? Oh yes! Really neat! Cool new mechanism! 2. Does it “block” heroin addiction? No. This press release hurts us precious. It hurts us. This paper has a lot of GREAT things about it, and there’s a lot of potential for the future with a new mechanism for drug action, especially in the area of pain relief (which sadly got short shrift in the press release). But no one has cured addiction yet. © 2012 Scientific American

Keyword: Drug Abuse; Aggression
Link ID: 17171 - Posted: 08.16.2012

by Catherine de Lange A potential new treatment to prevent morphine addiction is at hand. Researchers have identified an immune receptor involved in addiction to the drug, and found a way to block this receptor without affecting pain relief. The discovery offers hope that morphine can be used to relieve pain without running the risk of addiction. Opioid drugs such as morphine are known to target opioid receptors in the central nervous system, which block pain signals to the brain and flood it with the "feel-good" chemical dopamine. This reward response is what makes opioids so addictive. Morphine is a widely used pain killer, but its addictiveness means it has to be administered with caution, and often cannot be used for protracted periods of chronic pain. Mark Hutchinson from the University of Adelaide, Australia, and colleagues have now discovered that as well as working through the central nervous system, opioid drugs like heroin and morphine trigger an immune response, which seems to boost their addictive effects. Blocking this immune response in animals inhibits their addiction. Hutchinson's team previously observed that opioids bind to TLR-4 – immune system receptors in the cell membrane – which are responsible for identifying foreign bodies. However, the team did not know how this binding affected the body. © Copyright Reed Business Information Ltd.

Keyword: Pain & Touch; Aggression
Link ID: 17169 - Posted: 08.15.2012

by Carol Cruzan Morton Migraines are a battle of the sexes that women might prefer not winning. Each year, roughly three times more women than men—up to 18% of all women—suffer from the debilitating headaches, as tallied by epidemiological surveys in Europe and the United States. A new brain imaging study may explain the divide: The brains of women with migraines appear to be built differently than those of their male counterparts. To conduct the study, researchers headed by David Borsook, a neurologist and neurobiologist of Boston Children’s Hospital and Harvard Medical School, recruited 44 men and women, half of whom were migraine sufferers. The women who had migraines rated them as being as intense as the men did, but they tended to find them more unpleasant. Borsook says the distinction is analogous to the loudness of fingernails scratching on a chalkboard versus the torment of hearing the sound. The team then scanned the brains of the volunteers. The researchers gathered two kinds of data sets, one that captured brain shapes and features, and one that measured brain activity. Female migraine sufferers showed slightly thicker gray matter in two regions: one, the posterior insula, is well-known in pain processing; the other, the precuneus, has been recently linked to migraines but is more widely known as a fundamental brain hub that may house a person's consciousness or sense of self. The other volunteers, including the male migraine sufferers, did not show this thickening. All of the scans were done when people did not have a migraine. To figure out what those structural changes meant, lead author Nasim Maleki, a medical physicist at Boston Children's Hospital and Harvard Medical School, returned to the MRI scans of only those men and women with episodic migraines. © 2010 American Association for the Advancement of Science.

Keyword: Pain & Touch; Aggression
Link ID: 17160 - Posted: 08.14.2012

by Krystnell A. Storr Imagine feeling like you’re lifting a 50-kilogram weight just by pulling at thin air. That’s just one of the possible applications of new "smart fingertips" created by a team of nanoengineers. The electronic fingers mold to the shape of the hand, and so far the researchers have shown that they can transmit electric signals to the skin. The team hopes to one day incorporate the devices into a smart glove that creates virtual sensations, fooling the brain into feeling everything from texture to temperature. Scientists have already developed circuits that stimulate our sense of touch. Some are used in Braille readers that allow blind people to browse the Internet. The devices work by sending electric currents to receptors in the skin, which interpret them as real sensations. However, most of these circuits are built on flat, rigid surfaces that can’t bend, stretch, or fold, says Darren Lipomi, a nanoengineer at the University of California, San Diego, who was not involved in the new study. Hoping to create circuits with the flexibility of skin, materials scientist John Rogers of the University of Illinois, Urbana-Champaign, and colleagues cut up nanometer-sized strips of silicon; implanted thin, wavy strips of gold to conduct electricity; and mounted the entire circuit in a stretchable, spider web-type mesh of polymer as a support. They then embedded the circuit-polyimide structure onto a hollow tube of silicone that had been fashioned in the shape of a finger. Just like turning a sock inside out, the researchers flipped the structure so that the circuit, which was once on the outside of the tube, was on the inside where it could touch a finger placed against it. © 2010 American Association for the Advancement of Science

Keyword: Pain & Touch; Aggression
Link ID: 17152 - Posted: 08.13.2012

By ANAHAD O'CONNOR THE FACTS Certain regions of the human brain are dedicated to the various senses. The visual cortex handles vision, for example, while the auditory cortex processes sound. But what happens if one of the senses is lost? Do the neurons in the auditory cortex of a deaf person atrophy and go to waste, for instance, or are they put to work processing vision and other senses? In studies, scientists have shown that when one sense is lost, the corresponding brain region can be recruited for other tasks. Researchers learned this primarily by studying the blind. Brain imaging studies have found that blind subjects can locate sounds using both the auditory cortex and the occipital lobe, the brain’s visual processing center. But recently a similar phenomenon was discovered in the deaf. In a study financed by the National Institutes of Health and published in The Journal of Neuroscience, researchers recruited 13 deaf volunteers and a dozen volunteers with normal hearing and looked at what happened in their brains when touch and vision responses were stimulated. They found that both senses were processed in Heschl’s gyrus, where the auditory cortex is situated, suggesting that this part of the brain had been dedicated to other senses. Other studies have shown that structural changes in the auditory cortex are noticeable in the brains of deaf children from a very early age. THE BOTTOM LINE Losing one sense can cause the brain to become rewired. Copyright 2012 The New York Times Company

Keyword: Pain & Touch; Aggression
Link ID: 17133 - Posted: 08.07.2012

By Jessica Gross An amiable joke can be much more effective than darker humor at improving mood, according to recent research from Stanford University. In the study, led by psychologist Andrea Samson and James Gross and published in February in Cognition & Emotion, 40 people in Switzerland and 37 people in the U.S. looked at photographs of upsetting things such as car accidents, corpses and dangerous animals. They were instructed to either say nothing about the images, use good-natured humor focusing on the absurdity of life or the human condition, or use mean-spirited humor. The experimenters offered examples of each type of response to help coach the subjects; given a picture of a snake with its prey, for instance, “Looks like someone's bitten off more than they can chew” exhibits positive humor, whereas “Nourishing my future handbag” has a negative spin. In both countries, those who made benevolent jokes about the images had more positive emotions and fewer negative emotions afterward than those who laughed mockingly at the pictures, although both groups who used humor fared better than those who simply looked silently. The upshot: when something upsets you, humor can help. The next time you try to laugh off a grim situation, reflect on whether your jokes skew negative (“My boss isn't just dumb; he has terrible body odor, too!”) or positive (“No matter what happens at work, I've got it better than a politician these days …”). You might find tweaking your comedic style could give more of a boost. © 2012 Scientific American,

Keyword: Pain & Touch; Aggression
Link ID: 17074 - Posted: 07.21.2012

People who are born deaf process the sense of touch differently than people who are born with normal hearing, according to research funding by the National Institutes of Health. The finding reveals how the early loss of a sense — in this case hearing — affects brain development. It adds to a growing list of discoveries that confirm the impact of experiences and outside influences in molding the developing brain. The study is published in the July 11 online issue of The Journal of Neuroscience. The researchers, Christina M. Karns, Ph.D., a postdoctoral research associate in the Brain Development Lab at the University of Oregon, Eugene, and her colleagues, show that deaf people use the auditory cortex to process touch stimuli and visual stimuli to a much greater degree than occurs in hearing people. The finding suggests that since the developing auditory cortex of profoundly deaf people is not exposed to sound stimuli, it adapts and takes on additional sensory processing tasks. "This research shows how the brain is capable of rewiring in dramatic ways," said James F. Battey, Jr., M.D., Ph.D., director of the NIDCD. "This will be of great interest to other researchers who are studying multisensory processing in the brain." Previous research, including studies performed by the lab director, Helen Neville Ph.D., has shown that people who are born deaf are better at processing peripheral vision and motion. Deaf people may process vision using many different brain regions, especially auditory areas, including the primary auditory cortex. However, no one has tackled whether vision and touch together are processed differently in deaf people, primarily because in experimental settings, it is more difficult to produce the kind of precise tactile stimuli needed to answer this question.

Keyword: Hearing; Aggression
Link ID: 17035 - Posted: 07.12.2012

by Sarah C. P. Williams After spending 3 years at sea and traveling up to 300 kilometers away from home, a rainbow trout can swim straight back to its original hatching ground, following freshwater streams inland and rarely heading in the wrong direction. This remarkable feat of navigation likely relies on many senses; the fish have superb eyesight and smell. But the trout also seem to rely on Earth's magnetic fields, which point them in the right direction. Now, for the first time in any animal, scientists have isolated magnetic cells in the fish that respond to these fields. The advance may help researchers get to the root of magnetic sensing in a variety of creatures, including birds. "We think this will really be a game changer," says Michael Winklhofer, an earth scientist at Ludwig Maximilians University Munich in Germany who led the new study. "To study magnetic sensory cells, you have to be able to get hold of them first, and that's what we've finally developed a way to do." Previous research has shown that many species of fish, as well as migratory birds, have the ability to detect differences in magnetic field strengths, which vary around the globe. Scientists think that the key to this ability is magnetite, the most magnetic of all minerals, which they've found embedded in bird and fish tissues. They've even narrowed down which tissues in these animals could contain magnetite by using dyes that bind to the mineral. But they've never been able to isolate individual cells that contain magnetite, and some of the staining methods have led to false positives and controversy in the field. © 2010 American Association for the Advancement of Science

Keyword: Animal Migration
Link ID: 17021 - Posted: 07.10.2012