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

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By Erin Garcia de Jesus A whiff of catnip can make mosquitoes buzz off, and now researchers know why. The active component of catnip (Nepeta cataria) repels insects by triggering a chemical receptor that spurs sensations such as pain or itch, researchers report March 4 in Current Biology. The sensor, dubbed TRPA1, is common in animals — from flatworms to people — and responds to environmental irritants such as cold, heat, wasabi and tear gas. When irritants come into contact with TRPA1, the reaction can make people cough or an insect flee. Catnip’s repellent effect on insects — and its euphoric effect on felines — has been documented for millennia. Studies have shown that catnip may be as effective as the widely used synthetic repellent diethyl-m-toluamide, or DEET (SN: 9/5/01). But it was unknown how the plant repelled insects. So researchers exposed mosquitoes and fruit flies to catnip and monitored the insects’ behavior. Fruit flies were less likely to lay eggs on the side of a petri dish that was treated with catnip or its active component, nepetalactone. Mosquitoes were also less likely to take blood from a human hand coated with catnip. Insects that had been genetically modified to lack TRPA1, however, had no aversion to the plant. That behavior — coupled with experiments in lab-grown cells that show catnip activates TRPA1 — suggests that insect TRPA1 senses catnip as an irritant. Puzzling out how the plant deters insects could help researchers design potent repellents that may be easier to obtain in developing countries hit hard by mosquito-borne diseases. “Oil extracted from the plant or the plant itself could be a great starting point,” says study coauthor Marco Gallio, a neuroscientist at Northwestern University in Evanston, Ill. © Society for Science & the Public 2000–2021

Keyword: Pain & Touch; Evolution
Link ID: 27719 - Posted: 03.06.2021

Linda Geddes Four scientists who discovered a key mechanism that causes migraines, paving the way for new preventive treatments, have won the largest prize for neuroscience in the world, sharing £1.1m. The Lundbeck Foundation in Denmark announced on Thursday that the British researcher Peter Goadsby, Michael Moskowitz of the US, Lars Edvinsson of Sweden and Jes Olesen of Denmark had won the Brain prize. Speaking at a press briefing ahead of the announcement, Goadsby, a professor of neurology at King’s College London, said: “I’m excited that migraine research is getting this award and that migraine – this disabling problem that is a brain disorder – is being recognised in an appropriate way.” Formally known as the Grete Lundbeck European brain research prize, the annual award recognises highly original and influential advances in any area of brain research. The award ceremony will take place in Copenhagen on 25 October, where the prize will be presented by Crown Prince Frederik of Denmark. The prize-winning research revolves around unpicking the neural basis of migraine, a crippling neurological condition characterised by episodes of throbbing head pain, as well as nausea, vomiting, dizziness, extreme sensitivity to sound, light, touch and smell. It affects about one in seven people globally and is about three times more common in women than men. In the UK, it is estimated that migraines result in the loss of 25m work or school days each year at an economic cost of £2.3bn. © 2021 Guardian News & Media Limited

Keyword: Pain & Touch
Link ID: 27717 - Posted: 03.06.2021

By Cara Giaimo Platypuses do it. Opossums do it. Even three species of North American flying squirrel do it. Tasmanian devils, echidnas and wombats may also do it, although the evidence is not quite so robust. And, breaking news: Two species of rabbit-size rodents called springhares do it. That is, they glow under black light, that perplexing quirk of certain mammals that is baffling biologists and delighting animal lovers all over the world. Springhares, which hop around the savannas of southern and eastern Africa, weren’t on anyone’s fluorescence bingo card. Like the other glowing mammals, they are nocturnal. But unlike the other creatures, they are Old World placental mammals, an evolutionary group not previously represented. Their glow, a unique pinkish-orange the authors call “funky and vivid,” forms surprisingly variable patterns, generally concentrated on the head, legs, rear and tail. Fluorescence is a material property rather than a biological one. Certain pigments can absorb ultraviolet light and re-emit it as a vibrant, visible color. These pigments have been found in amphibians and some birds, and are added to things like white T-shirts and party supplies. But mammals, it seems, don’t tend to have these pigments. A group of researchers, many associated with Northland College in Ashland, Wis., has been chasing down exceptions for the past few years — ever since one member, the biologist Jonathan Martin, happened to wave a UV flashlight at a flying squirrel in his backyard. It glowed eraser pink. © 2021 The New York Times Company

Keyword: Vision; Evolution
Link ID: 27697 - Posted: 02.19.2021

By Isobel Whitcomb It began with a pulled muscle. Each day after school, as the sun sank dusky purple over the hills of my hometown, I’d run with my track teammates. Even on our easy days, I’d bound ahead, leaving them behind. It wasn’t that I thought myself better than them—it’s that when I ran fast, and focused on nothing but the cold air burning my lungs and my feet pounding, my normally anxious thoughts turned to white noise. Until, one day, something popped in my leg. I stopped. I limped a little, and then tried running again: sharp, hot pain radiated down my thigh. Panic flooded me, as I imagined weeks without running: weeks without a predictable break from my own thoughts, weeks immersed in adolescent loneliness. I was 14. Pain was about to define a decade of my life. Advertisement First, I took a break from the sport—five months of stretching, icing, and waiting for the leg to heal. I returned to running, but soon after, I developed a throbbing pain in my back. The cycle repeated. Less than a year later, the pain showed up again, this time in my foot. My focus on healing my body became singular: I tried physical therapy and massage and acupuncture. I researched conditions that could lead to repeat injury. Maybe I had a rare soft-tissue disorder, I thought, or maybe early-onset rheumatoid arthritis. I let an osteopath stick a giant needle into my spinal ligaments, and inject me with sugar water, which is just as painful as it sounds. After a chiropractor recommended an anti-inflammatory diet, I subsisted on only meat and vegetables. I’d get a few good months—a joyful summer, a successful cross-country season. Then the pain would return again. As I prepared to leave home for college, my knees and ankles throbbed. For several months, my hip hurt so badly I dreaded even walking to the dining hall. Then, while scrambling to finish my senior thesis, neck spasms prevented me from leaving my bed for days. When I saw doctors, I hoped that they would discover something terribly wrong. They never did. “Have you tried psychotherapy?” one asked me. I had. I’d been in therapy for years. © 2021 The Slate Group LLC.

Keyword: Pain & Touch; Attention
Link ID: 27693 - Posted: 02.15.2021

By Mitch Leslie Spitting cobras protect themselves by shooting jets of venom into the eyes of their attackers. A new study suggests that over the course of several million years, all three groups of spitters independently tailored the chemistry of their toxins in the same way to cause pain to a would-be predator. The work provides a novel example of convergent evolution that “deepens our understanding of this unique system” for delivering venom, says Timothy Jackson, an evolutionary toxinologist at the University of Melbourne. Like other cobras, spitting cobras will bite attackers in self-defense. Spitting is their signature move, however, and the snakes are crack shots. They can direct a stream of venom into an attacker’s face from more than 2 meters away, aiming for the eyes. The behavior is such a formidable defense that it evolved independently three times: in Asian cobras, African cobras, and a cobra cousin called the rinkhals (Hemachatus haemachatus) that lives in southern Africa. Scientists previously found the venom of some other snakes evolved to better subdue their prey. By analyzing the venoms of 17 spitting and nonspitting species—and measuring their effects—venom biologist Nicholas Casewell of the Liverpool School of Tropical Medicine and colleagues tested whether the makeup of spitting cobra venom had also changed over time to become a more effective defense. © 2021 American Association for the Advancement of Science.

Keyword: Pain & Touch; Evolution
Link ID: 27659 - Posted: 01.23.2021

By Jonathan Lambert One Volta’s electric eel — able to subdue small fish with an 860-volt jolt — is scary enough. Now imagine over 100 eels swirling about, unleashing coordinated electric attacks. Such a sight was assumed to be only the stuff of nightmares, at least for prey. Researchers have long thought that these eels, a type of knifefish, are solitary, nocturnal hunters that use their electric sense to find smaller fish as they sleep (SN: 12/4/14). But in a remote region of the Amazon, groups of over 100 electric eels (Electrophorus voltai) hunt together, corralling thousands of smaller fish together to concentrate, shock and devour the prey, researchers report January 14 in Ecology and Evolution. “This is hugely unexpected,” says Raimundo Nonato Mendes-Júnior, a biologist at the Chico Mendes Institute for Biodiversity Conservation in Brasilia, Brazil who wasn’t involved in the study. “It goes to show how very, very little we know about how electric eels behave in the wild.” Group hunting is quite rare in fishes, says Carlos David de Santana, an evolutionary biologist at the Smithsonian’s National Museum of Natural History in Washington, D.C. “I’d never even seen more than 12 electric eels together in the field,” he says. That’s why he was stunned in 2012 when his colleague Douglas Bastos, now a biologist at the National Institute of Amazonian Research in Manaus, Brazil, reported seeing more than 100 eels congregating and seemingly hunting together in a small lake in northern Brazil. © Society for Science & the Public 2000–2021.

Keyword: Evolution
Link ID: 27647 - Posted: 01.15.2021

By Krystnell A. Storr Can you tell the difference between high – and low –thread-count sheets just by touching them? Thank usherin, a protein found in a mysterious structure in your fingertips. Usherin also helps us see and hear, suggesting a deep molecular connection among our most important senses. “The work is surprising,” says Ellen Lumpkin, a neuroscientist at the University of California (UC), Berkeley, who was not involved in the study. The study, she says, points to a single protein being used over and over again in distinct ways to help us monitor the outside world. Scientists already had some hints that usherin is important for our sense of touch. A mutation in the gene that codes for it, USH2A, causes Usher syndrome—a rare, inherited disease that leads to blindness, deafness, and an inability to feel faint vibrations in the fingertips. To further explore usherin’s role in touch, researchers recruited 13 patients with a form of Usher syndrome that specifically affects touch. The team—led by Gary Lewin, a neuroscientist at the Max Delbrück Center for Molecular Medicine—measured how well each person sensed pain, temperature changes, and tiny vibrations at 10 and 125 hertz (Hz), mimicking the sensation of moving a fingertip across a rough surface. The scientists then compared the patients’ results against those of 65 healthy volunteers. People with Usher syndrome did just as well as their counterparts at sensing temperature changes and mild pain, the team found. But they were four times less likely to pick up on the 125-Hz vibrations and 1.5 times less likely to detect the 10-Hz vibrations. © 2020 American Association for the Advancement of Science.

Keyword: Pain & Touch
Link ID: 27623 - Posted: 12.12.2020

By Veronique Greenwood The ibis and the kiwi are dogged diggers, probing in sand and soil for worms and other buried prey. Sandpipers, too, can be seen along the shore excavating small creatures with their beaks. It was long thought that these birds were using trial and error to find their prey. But then scientists discovered something far more peculiar: Their beaks are threaded with cells that can detect vibrations traveling through the ground. Some birds can feel the movements of their distant quarry directly, while others pick up on waves bouncing off buried shells — echolocating like a dolphin or a bat, in essence, through the earth. There’s one more odd detail in this story of birds’ unusual senses: Ostriches and emus, birds that most definitely do not hunt this way, have beaks with a similar interior structure. They are honeycombed with pits for these cells, though the cells themselves are missing. Now, scientists in a study published Wednesday in Proceedings of the Royal Society B report that prehistoric bird ancestors dating nearly as far back as the dinosaurs most likely were capable of sensing vibrations with their beaks. The birds that use this remote sensing today are not closely related to one another, said Carla du Toit, a graduate student at the University of Cape Town in South Africa and an author of the paper. That made her and her co-authors curious about when exactly this ability evolved, and whether ostriches, which are close relatives of kiwis, had an ancestor that used this sensory ability. “We had a look to see if we could find fossils of early birds from that group,” Ms. du Toit said. “And we’re very lucky.” There are very well-preserved fossils of birds called lithornithids dating from just after the event that drove nonavian dinosaurs to extinction. © 2020 The New York Times Company

Keyword: Pain & Touch; Evolution
Link ID: 27605 - Posted: 12.05.2020

Linda Geddes Many of the side-effects attributed to statins could be down to the “nocebo effect”, which occurs when someone expects to experience negative symptoms – even if the drug is a placebo – a study suggests. Statins are one of the most widely prescribed drugs in the UK, taken by nearly eight million people to reduce their risk of cardiovascular disease by lowering cholesterol levels. Yet, despite their effectiveness, up to a fifth of people stop taking them because of side-effects, such as fatigue, muscle aches, joint pain and nausea. Clinical studies have suggested, however, the incidence of side-effects is far lower. Researchers led by Frances Wood and Dr James Howard at Imperial College London recruited 60 patients who had been on statins, but stopped taking them owing to adverse effects. They were persuaded to resume treatment, and given four bottles containing atorvastatin, four bottles containing identical-looking placebo pills and four empty bottles, to be taken in a randomly prescribed order over the course of a year – including four months taking no pills. Each day, they recorded any side-effects on a smartphone, ranking their intensity from zero to 100. The researchers found 90% of symptoms experienced by the patients were present when they took placebo tablets. Also, 24 patients stopped taking tablets for at least one month of the trial, citing intolerable side-effects – amounting to 71 stoppages in total. Of these, 31 occurred during placebo months and 40 were during statin months. The results were published in the New England Journal of Medicine. © 2020 Guardian News & Media Limited

Keyword: Pain & Touch; Attention
Link ID: 27582 - Posted: 11.16.2020

By Carolyn Wilke Fish fins aren’t just for swimming. They’re feelers, too. The fins of round gobies can detect textures with a sensitivity similar to that of the pads on monkeys’ fingers, researchers report November 3 in the Journal of Experimental Biology. Compared with landlubbers, little is known about aquatic animals’ sense of touch. And for fish, “we used to only think of fins as motor structures,” says Adam Hardy, a neuroscientist at the University of Chicago. “But it’s really becoming increasingly clear that fins play important sensory roles.” Studying those sensory roles can hint at ways to mimic nature for robotics and provide a window into the evolution of touch. The newfound parallels between primates and fish suggest that limbs that sense physical forces emerged early, before splits in the vertebrate evolutionary tree led to animals with fins, arms and legs, says Melina Hale, a neurobiologist and biomechanist also at the University of Chicago. “These capabilities arose incredibly early and maybe set the stage for what we can do with our hands now and what fish can do with their fins in terms of touch.” Hardy and Hale measured the activity of nerves in the fins of bottom-dwelling round gobies (Neogobius melanostomus) to get a sense of what fish learn about texture from their fins. In the wild, round gobies brush against the bottom surface and rest there on their large pectoral fins. “They’re really well suited to testing these sorts of questions,” Hardy says. Working with fins from six euthanized gobies, the researchers recorded electrical spikes from their nerves as a bumpy plastic ring attached to a motor rolled lightly above each fin. A salt solution keeps the nerves functioning as they would if the nerves were in a live fish, Hardy says. © Society for Science & the Public 2000–2020

Keyword: Pain & Touch; Evolution
Link ID: 27564 - Posted: 11.04.2020

By Lisa Sanders, M.D. The 61-year-old woman put on her reading glasses to try to decipher the tiny black squiggles on the back of the package of instant pudding. Was it two cups of milk? Or three? The glasses didn’t seem to help. The fuzzy, faded marks refused to become letters. The right side of her head throbbed — as it had for weeks. The constant aggravation of the headache made everything harder, and it certainly wasn’t helping her read this label. She rubbed her forehead, then brought her hand down to cover her right eye. The box disappeared into darkness. She could see only the upper-left corner of the instructions. Everything else was black. She quickly moved her hand to cover her left eye. The tiny letters sprang into focus. She moved back to the right: blackness. Over to the left: light and letters. That scared her. For the past few months, she’d had one of the worst headaches she had ever experienced in her lifetime of headaches. One that wouldn’t go away no matter how much ibuprofen she took. One that persisted through all the different medications she was given for her migraines. Was this terrible headache now affecting her vision? The neurologists she saw over the years always asked her about visual changes. She’d never had them, until now. “Should I take you to the hospital?” her husband asked anxiously when she told him about her nearly sightless left eye. “This could be serious.” She thought for a moment. No, tomorrow was Monday; her neurologist’s office would be open, and the doctor would see her right away. She was always reliable that way. The patient had bad headaches for most of her adult life. They were always on the right side. They were always throbbing. They could last for days, or weeks, or sometimes months. Loud noises were always bothersome. With really bad headaches, her eye would water and her nose would run, just on that side. Bending over was agony. For the past few weeks, her headache had been so severe that if she dropped something on the floor, she had to leave it there. When she bent down, the pounding was excruciating. © 2020 The New York Times Company

Keyword: Pain & Touch; Vision
Link ID: 27553 - Posted: 10.28.2020

By Perri Klass, M.D. In a new report on pediatric pain in the British medical journal The Lancet, a commission of experts, including scientists, doctors, psychologists, parents and patients, challenged those who take care of children to end what they described as the common undertreatment of pain in children, starting at birth. Isabel Jordan, of Squamish, British Columbia, took part as a parent partner, along with her son Zachary, 19, who has a genetic condition, and lives with chronic pain. “Pain matters with every child and at every intersection with the health care system,” she said. But for her son, “it didn’t matter with many providers, doctors, nurses, phlebotomists, and that made for worse outcomes.” “The professionals had a wealth of knowledge and experience, but what they lacked was the knowledge of what was really impacting patients in day-to-day life, they didn’t know how impactful poorly managed procedural pain was to patients,” especially children like her son who have ongoing medical issues, Ms. Jordan said. “He’s got a rare disease and has had a lifetime of chronic pain and also procedure pain.” Although we often pride ourselves, in pediatrics, on taking a kinder and gentler approach to our patients, pain experts feel that children’s pain is often taken for granted, and that simple and reliable strategies to mitigate it are disregarded; such as, for example, the 2015 World Health Organization recommendations that infants should be held by parents and perhaps breastfed during immunizations, and that distraction techniques should be used with older children. Christopher Eccleston, a professor of pain science and medical psychology at the University of Bath, where he directs the Centre for Pain Research, was the lead author on the report. He became interested in pediatric pain through working with adults with chronic pain, he said, and realizing that many of them had pain going back into adolescence, which had not been treated. © 2020 The New York Times Company

Keyword: Pain & Touch
Link ID: 27548 - Posted: 10.26.2020

By Lisa Sanders, M.D. The pain woke the 52-year-old physician from a dead sleep. It was as if all the muscles in his right leg, from those in the buttock down his thigh to the very bottom of his calf, were on fire. He shifted slightly to see if he could find a more comfortable position. There was a jag of pain, and he almost cried out. He glanced at the clock: 4 a.m. In just three hours he would have to get up. He had a full day of patients to see. Massage didn’t help. He couldn’t get comfortable lying flat, so finally he moved to the living room, to a recliner. Only then, and only by lying completely still, did he manage to get the pain to abate. He drifted off, but never for long. The searing pain in his leg and buttock slowly eased, and by the time his alarm went off, he could stand and walk — though his muscles still ached and he had to baby his right leg, causing a limp. Between patients, he arranged to see his own doctor. He’d had pain off and on in his buttocks, one side or the other, for more than a year. The pain was in the middle of each cheek and was worse when he was sitting and at the end of the day. Walking to and from his car on the way home was brutal. And then, as mysteriously as it came, it would disappear — only to come back a week or two later. When he first told his doctor about his pain, the exam didn’t show much. He was a little tender at the bottom of the bones you sit on, called the ischia. His doctor thought it was ischial bursitis. Between the tips of the ischia and the largest muscles of the buttocks, there are little pads called bursae. Sometimes these pads become inflamed. The man’s doctor recommended stretching exercises for the muscles around the bursae. He did them regularly, though he wasn’t sure they helped. The pain he had that night, though, was different, and a whole lot worse. Again, his doctor couldn’t find much. Maybe it was a kind of nerve pain, like sciatica, the patient suggested. The doctor agreed and ordered an M.R.I. to look for a pinched nerve. The result was normal. © 2020 The New York Times Company

Keyword: Pain & Touch; Neuroimmunology
Link ID: 27474 - Posted: 09.16.2020

By Amanda Loudin Last summer while out on a bike ride, 35-year-old Andrew Bernstein of Boulder, Colo., was hit by a van that knocked him off the road and kept on going. A passing driver spotted Bernstein lying, unmoving, in a ditch and called 911. Bernstein’s injuries were life threatening. After multiple surgeries, 10 weeks recovering in the hospital and more than three weeks in inpatient rehab, Bernstein has spent the better part of every week since then working with a number of practitioners to help him progress to where he is today — in a wheelchair and walking with the assistance of a full-length leg brace and crutches. But almost all of that effort came to a complete halt when the coronavirus pandemic hit in March and all of his physical therapy facilities either closed or dramatically reduced their patient contact. “I typically worked with a variety of therapists nine or 10 times a week at four different facilities,” Andrew Bernstein says. He was given a home-based plan but “the disruptions to my therapies was challenging. It was frustrating to do without supervision, because my condition changes from one week to the next, something my therapists might notice even if I don’t.”“I typically worked with a variety of therapists nine or 10 times a week at four different facilities,” Andrew Bernstein says. He was given a home-based plan but “the disruptions to my therapies was challenging. It was frustrating to do without supervision, because my condition changes from one week to the next, something my therapists might notice even if I don’t.”

Keyword: Pain & Touch
Link ID: 27460 - Posted: 09.09.2020

Abby Carney Shortly after relocating to Texas from California three years ago, Cheryl Webster started hosting a game night at her home as a way of meeting new people. They stopped meeting due to Covid-19, and Webster has only heard from one person in the group in the months since they were able to play. Eventually, she decided to pick up the phone herself – but nobody called back. “I think that’s the hardest part about loneliness,” she said. “Is it my fault? Am I not a very nice person? Or is there something wrong with me?” End of the office: the quiet, grinding loneliness of working from home Read more Webster, 65, is a proactive doer who volunteers regularly and has even helped finance the education of several friends’ children. She sits on the board of the Austin housing authority and the chamber of commerce, and is sure the Christian business leaders’ group she meets with monthly would say flattering things about her. Though divorced and childless, Webster is not a Havisham spinster – putting herself “out there” comes naturally. And so she supposes many people in her life would be surprised to learn that she’s lonely. Despite following the advice of experts to ward off the feeling, her heart still aches. Advertisement Webster is not alone. A growing number of people share her affliction – so much so that some governments are incorporating loneliness into their health public policy. To help people like her, a number of scientists are researching medical solutions, such as pills and nasal sprays. But will treating loneliness like a disease, rather than an existential question, work to ease their pain? © 2020 Guardian News & Media Limited

Keyword: Pain & Touch; Hormones & Behavior
Link ID: 27405 - Posted: 08.06.2020

By Abdul-Kareem Ahmed “He doesn’t look like himself,” his wife said. It was midnight, and I was consulting on a patient in the emergency room. He was 48 years old and complaining of a headache. Ten years ago my attending had partially removed a benign tumor growing in his cerebellum, part of the hindbrain that controls movement, coordination and speech. Our team had also placed a shunt in his brain. The brain is buoyed and bathed by cerebrospinal fluid. This clear fluid is made in large cavities, called ventricles, and is eventually absorbed by veins. The tumor’s inoperable remnant had blocked the fluid’s natural escape, causing it to build up, a condition known as hydrocephalus. A shunt is a thin rubber tube that is placed in the ventricles of the brain and tunneled under the skin, into the abdomen. It can have a programmable pressure valve, a gauge that sits under the scalp. His shunt had been siphoning excess fluid to his abdomen for years where it was absorbed, preventing life-threatening high pressure in the brain. Today, however, something was wrong, and I thought it was revealed on his new head CT. His ventricles were very large, suggesting high pressure. “I get a bad headache when I sit up,” he mumbled. “Sometimes I vomit. I feel better when I lie flat.” His wife, a strong and kindhearted woman, corroborated his complaint. “He’s also having memory problems, and he’s losing his balance when he walks,” she added. His symptoms were the opposite of what I expected. He was describing a low-pressure headache. He was relieved by lying down but worsened when sitting up.

Keyword: Pain & Touch
Link ID: 27397 - Posted: 08.03.2020

Ewen Callaway Despite their rough and tumble existence, Neanderthals had a biological predisposition to a heightened sense of pain, finds a first-of-its kind genome study published in Current Biology on 23 July1. Evolutionary geneticists found that the ancient human relatives carried three mutations in a gene encoding the protein NaV1.7, which conveys painful sensations to the spinal cord and brain. They also showed that in a sample of British people, those who had inherited the Neanderthal version of NaV1.7 tend to experience more pain than others. “It’s a first example, to me, about how we begin to perhaps get an idea about Neanderthal physiology by using present-day people as transgenic models,” says Svante Pääbo at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who led the work with Hugo Zeberg at the Karolinska Institute in Stockholm. Pain-sensing protein Researchers have access to only a few Neanderthal genomes, and most of those have been sequenced at a low resolution. This has made it hard to identify mutations that evolved after their lineage split from that of humans some 500,000–750,000 years ago. But in the past few years, Pääbo and his team have generated three high-quality Neanderthal genomes from DNA found in caves in Croatia and Russia. This allows them to confidently identify mutations that were probably common in Neanderthals, yet very rare in humans. Mutations in a gene called SCN9A — which encodes the NaV1.7 protein — stood out because all of the Neanderthals had three mutations that alter the shape of the protein. The mutated version of the gene was found on both sets of chromosomes in all three Neanderthals, hinting that it was common across their populations. © 2020 Springer Nature Limited

Keyword: Pain & Touch; Evolution
Link ID: 27382 - Posted: 07.25.2020

By Erik Stokstad Dogs are renowned for their world-class noses, but a new study suggests they may have an additional—albeit hidden—sensory talent: a magnetic compass. The sense appears to allow them to use Earth’s magnetic field to calculate shortcuts in unfamiliar terrain. The finding is a first in dogs, says Catherine Lohmann, a biologist at the University of North Carolina, Chapel Hill, who studies “magnetoreception” and navigation in turtles. She notes that dogs’ navigational abilities have been studied much less compared with migratory animals such as birds. “It’s an insight into how [dogs] build up their picture of space,” adds Richard Holland, a biologist at Bangor University who studies bird navigation. There were already hints that dogs—like many animals, and maybe even humans—can perceive Earth’s magnetic field. In 2013, Hynek Burda, a sensory ecologist at the Czech University of Life Sciences Prague who has worked on magnetic reception for 3 decades, and colleagues showed dogs tend to orient themselves north-south while urinating or defecating. Because this behavior is involved in marking and recognizing territory, Burda reasoned the alignment helps dogs figure out the location relative to other spots. But stationary alignment isn’t the same thing as navigation. In the new study, Burda’s graduate student, Kateřina Benediktová, initially put video cameras and GPS trackers on four dogs and took them on trips into the forest. The dogs would scamper off to chase the scent of an animal for 400 meters on average. The GPS tracks showed two types of behavior during their return trips to their owner (see map, below). In one, dubbed tracking, a dog would retrace its original route, presumably following the same scent. In the other behavior, called scouting, the dog would return along a completely new route, bushwhacking without any backtracking. Benediktová et al., eLife (2020) 10.7554 (CC BY) © 2020 American Association for the Advancement of Science.

Keyword: Animal Migration
Link ID: 27374 - Posted: 07.18.2020

by Angie Voyles Askham Toddlers with autism have unusually strong connections between sensory areas of the brain, according to a new study1. And the stronger the connections, the more pronounced a child’s autism traits tend to be. Overconnectivity in sensory areas may get in the way of an autistic child’s brain development, says lead investigator Inna Fishman, associate research professor at San Diego State University in California. “Their brain is busy with things it shouldn’t be busy with.” The findings add to a complicated field of research on brain connectivity and autism, which has shown weakened connectivity between some brain areas, strengthened connectivity between others, or no difference in connectivity at all. Previous brain-imaging studies have found that babies and toddlers with autism have altered connectivity in various brain areas and networks, including sensory areas. But most of these data come from ‘baby sibs’ — the younger siblings of autistic children, who are about 20 times more likely to have autism than the general population. “A lot of our early knowledge is from these high-risk samples of infant siblings,” says Benjamin Yerys, assistant professor of psychology in psychiatry at the University of Pennsylvania, who was not involved with the study. “If their behaviors and genetics are different, then all of this early brain work may also be different.” By contrast, the new work focused on autistic children who were newly diagnosed. “There are very, very few studies focused on this age, right around the time the diagnosis can be made,” says Christine Wu Nordahl, associate professor at the University of California, Davis MIND Institute. “I think that is the major strength of the study.” © 2020 Simons Foundation

Keyword: Autism
Link ID: 27345 - Posted: 07.06.2020

By William Schwalbe More than three years ago, I came down with a mysterious illness I thought might be a flu, but turned out to be something entirely different. My blizzard of symptoms began innocuously in November 2016 with terribly cold feet. So cold that even when I got under the covers with a hot water bottle between them, and they were warm to the touch, they still felt like painful ice-blocks. At other times, I had the equally unpleasant sensation that my feet and shins were burning or already burnt. A few weeks later, I started to experience intense throbbing pain in all my toes, as if someone had seconds before stomped on them with heavy boots, which made walking or standing difficult. Often my legs were so heavy that I could barely move them. Occasionally, my feet turned bright red. And every few hours came shooting pains, electric shocks that traveled up my legs. In my 55 years on earth, I’d never felt pain like that — except when a dentist drilled without Novocain. All the symptoms increased at night, so sleep became elusive. I wound up sticking my feet outside the covers because even a sheet brushing against them proved too painful to bear. Before long, the same panoply of pains had moved to my hands and then arms — and occasionally my face and stomach. Heat made the symptoms worse; cold and damp made them much worse. But often these pains flared for no discernible reason. Totally unrelated, or so I thought, were other things that began to go wrong with me over the next few months: I often found myself pouring with sweat from my forehead, but became unable to sweat on my legs and arms; I lost all the hair on my lower legs; I was increasingly faint and dizzy, with my heart racing whenever I changed position or had a shower; and I was experiencing a fatigue and bone-pain so profound that every few hours I needed to stop whatever I was doing and lie down on the floor. © 1996-2020 The Washington Post

Keyword: Pain & Touch
Link ID: 27334 - Posted: 06.29.2020