Links for Keyword: Pain & Touch

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


Links 1 - 20 of 1024

By Cassandra Willyard Megan Hodge’s first bout of intense pain arrived when she was in her mid-20s. Hodge and her husband were getting ready to visit family for Thanksgiving. Though Hodge had been dealing with a variety of chronic health issues, her workout had gone well that morning and she finally felt like she was getting a handle on her health. Hodge began packing. As she reached into her closet to grab a sweater, her back gave out. The pain was excruciating, so intense that she felt light-headed and thought she might vomit. As the years passed, Hodge had more frequent and more severe bouts of back pain. Any small movement could be a trigger — grabbing a towel from the linen closet, picking up a toy off the floor, sneezing. In 2021, Hodge experienced a particularly bad flare-up. None of the strategies she had previously used to help her manage seemed to be working. She was afraid to make any movement. She felt hopeless. “I just could not regain footing, metaphorically and physically,” she says. “I truly felt frozen in my chronic pain and chronic health journey.” Hodge is far from alone. In the United States, chronic pain affects tens of millions of people — about 1 in 5 adults and nearly 1 in 3 people ages 65 and older. “The amount of suffering from arthritis and aging that I’ve seen in my pain clinic, it’s overwhelming to me as a pain doctor,” says Antje Barreveld, an anesthesiologist at Mass General Brigham’s Newton-Wellesley Hospital in Massachusetts. What’s more, the mainstay therapy for severe acute and chronic pain — prescription opioids — has helped fuel an epidemic that kills tens of thousands of people each year. “We have to have some better alternatives,” she says. So researchers have doubled down in their quest to find new pain treatments that aren’t as addictive as opioids. “The pain field has really made very rapid and tremendous progress in the last decade,” says D.P. Mohapatra, a former pain scientist who now oversees research at the National Institute of Neurological Disorders and Stroke in Bethesda, Md. © Society for Science & the Public 2000–2024.

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 4: Development of the Brain
Link ID: 29470 - Posted: 09.07.2024

By Marla Broadfoot When doctors ask Sara Gehrig to describe her pain, she often says it is indescribable. Stabbing, burning, aching—those words frequently fail to depict sensations that have persisted for so long they are now a part of her, like her bones and skin. “My pain is like an extra limb that comes along with me every day.” Gehrig, a former yoga instructor and personal trainer who lives in Wisconsin, is 44 years old. At the age of 17 she discovered she had spinal stenosis, a narrowing of the spinal cord that puts pressure on the nerves there. She experienced bursts of excruciating pain in her back and buttocks and running down her legs. That pain has spread over the years, despite attempts to fend it off with physical therapy, anti-inflammatory injections and multiple surgeries. Over-the-counter medications such as ibuprofen (Advil) provide little relief. And she is allergic to the most potent painkillers—prescription opioids—which can induce violent vomiting. Today her agony typically hovers at a 7 out of 10 on the standard numerical scale used to rate pain, where 0 is no pain and 10 is the most severe imaginable. Occasionally her pain flares to a 9 or 10. At one point, before her doctor convinced her to take antidepressants, Gehrig struggled with thoughts of suicide. “For many with chronic pain, it’s always in their back pocket,” she says. “It’s not that we want to die. We want the pain to go away.” Gehrig says she would be willing to try another type of painkiller, but only if she knew it was safe. She keeps up with the latest research, so she was interested to hear earlier this year that Vertex Pharmaceuticals was testing a new drug that works differently than opioids and other pain medications. That drug, a pill called VX-548, blocks pain signals before they can reach the brain. It gums up sodium channels in peripheral nerve cells, and obstructed channels make it hard for those cells to transmit pain sensations. Because the drug acts only on the peripheral nerves, it does not carry the potential for addiction associated with opioids—oxycodone (OxyContin) and similar drugs exert their effects on the brain and spinal cord and thus can trigger the brain’s reward centers and an addiction cycle.

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 4: Development of the Brain
Link ID: 29445 - Posted: 08.21.2024

By Paula Span Mary Peart, 67, a retired nurse in Manchester-by-the-Sea, Mass., began taking gabapentin a year and a half ago to reduce the pain and fatigue of fibromyalgia. The drug helps her climb stairs, walk her dog and take art lessons, she said. With it, “I have a life,” she said. “If I forget to take a dose, my pain comes right back.” Jane Dausch has a neurological condition called transverse myelitis and uses gabapentin as needed when her legs and feet ache. “It seems to be effective at calming down nerve pain,” said Ms. Dausch, 67, a retired physical therapist in North Kingstown, R.I. Amy Thomas, who owns three bookstores in the San Francisco Bay Area, takes gabapentin for rheumatoid arthritis. Along with yoga and physical therapy, “it’s probably contributing to it being easier for me to move around,” Ms. Thomas, 67, said. All three are taking the non-opioid pain drug for off-label uses. The only conditions for which gabapentin has been approved for adult use by the Food and Drug Administration are epileptic seizures, in 1993, and postherpetic neuralgia, the nerve pain that can linger after a bout of shingles, in 2002. But that has not stopped patients and health care providers from turning to gabapentin (whose brand names include Neurontin) for a startling array of other conditions, including sciatica, neuropathy from diabetes, lower back pain and post-surgery pain. Also: Agitation from dementia. Insomnia. Migraines. Itching. Bipolar disorder. Alcohol dependence. Evidence of effectiveness for these conditions is all over the map. The drug appears to provide relief for some patients with diabetic neuropathy but not with some other kinds of neuropathic pain. Several small studies indicate that gabapentin can reduce the itching associated with kidney failure. But the data for its effectiveness against low back pain or a number of psychiatric disorders are limited and show no meaningful impact. “It’s crazy how many indications it’s used for,” said Dr. Michael Steinman, a geriatrician at the University of California, San Francisco, and a co-director of the U.S. Deprescribing Research Network. “It’s become a we-don’t-know-what-else-to-do drug.” © 2024 The New York Times Company

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 4: Development of the Brain
Link ID: 29438 - Posted: 08.19.2024

By Miryam Naddaf About one-third of people who suffer from migraines experience a phenomenon known as aura before the headache.Credit: Tunatura/Getty For one billion people worldwide, the symptoms can be debilitating: throbbing head pain, nausea, blurred vision and fatigue that can last for days. But how brain activity triggers these severest of headaches — migraines — has long puzzled scientists. A study1 in mice, published in Science on 4 July, now offers clues about the neurological events that spark migraines. It suggests that a brief brain ‘blackout’ — when neuronal activity shuts down — temporarily changes the content of the cerebrospinal fluid, the clear liquid that surrounds the brain and spinal cord. This altered fluid, researchers suggest, travels through a previously unknown gap in anatomy to nerves in the skull where it activates pain and inflammatory receptors, causing headaches. “This work is a shift in how we think the headaches originate,” says Gregory Dussor, a neuroscientist at the University of Texas at Dallas in Richardson. “A headache might just be a general warning sign for lots of things happening inside the brain that aren’t normal.” “Migraine is actually protective in that way. The pain is protective because it’s telling the person to rest and recover and sleep,” says study co-author Maiken Nedergaard, a neuroscientist at the University of Copenhagen. The brain itself has no pain receptors; the sensation of headaches comes from areas outside the brain that are in the peripheral nervous system. But how the brain, which is not directly linked to the peripheral nervous system, triggers nerves to cause headaches is poorly understood, making them difficult to treat. © 2024 Springer Nature Limited

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 29388 - Posted: 07.11.2024

By Rodrigo Pérez Ortega It starts with blind spots, flashing lights, and blurry vision—a warning of what’s to come. About an hour later, the dreadful headache kicks in. This pairing, a shining visual experience called an aura and then a headache, happens in about one-third of people who live with migraine. But researchers haven’t been able to figure out exactly how the two are linked at the molecular level. Now, a new study in mice, published today in Science, establishes a direct mechanism: molecules traveling in the fluid that bathes the brain. The finding could lead to new targets for much-needed migraine treatments. “It’s exciting,” says Rami Burstein, a translational neuroscientist at Harvard Medical School who was not involved in the new study. “It takes a very large step into understanding how something that happened in the brain can alter sensation or perception,” he says. It may also explain why the pain of migraine is experienced only in the head, he adds. Migraine, a debilitating neurological disorder, affects about 148 million people worldwide. Recently developed medications can help reduce headaches but are not effective for everyone. Although exact causes remain elusive, research has shown migraines most likely start with a pathological burst of neural activity. During an aura before a migraine, researchers have observed a seizurelike phenomenon called cortical spreading depression (CSD), in which a wave of abnormal neural firing slowly travels throughout the brain’s outer layer, or cortex. But because the brain itself contains no pain-sensing neurons, signals from the brain would have to somehow reach the peripheral nervous system—the nerves that communicate between the body parts and the brain—to cause a headache. In particular, they’d have to get to the two lumps of neurons below the brain called the trigeminal ganglia, which innervate the two sides of our face and head. Scientists knew that pain fibers from the trigeminal ganglion were nested in the meninges—the thin, delicate membranes that envelop and protect the brain.

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 29380 - Posted: 07.06.2024

By Claire Yuan Men and women experience pain differently, and until now, scientists didn’t know why. New research says it may be in part due to differences in male and female nerve cells. Pain-sensing nerve cells from male and female animal tissues responded differently to the same sensitizing substances, researchers report June 3 in Brain. The results suggest that at the cellular level, pain is produced differently between the sexes. The results might allow researchers “to come up with drugs that would be specific to treat female patients or male patients,” says Katherine Martucci, a neuroscientist who studies chronic pain at Duke University School of Medicine and was not involved in the study. “There’s no debate about it. They’re seeing these differences in the cells.” Some types of chronic and acute pain appear more often in one sex, but it’s unclear why. For instance, about 50 million adults in the United States suffer from chronic pain conditions, many of which are more common in women (SN: 5/22/23). Similar disparities exist for acute conditions. Such differences prompted pain researcher Frank Porreca of the University of Arizona Health Sciences in Tucson and colleagues to study nerve cells called nociceptors, which can act like alarm sensors for the body. The cells’ pain sensors, found in skin, organs and elsewhere in the body, can detect potentially dangerous stimuli and send signals to the brain, which then interprets the information as pain. In some cases, the nerve cells can become more sensitive to outside stimulation, registering even gentle sensations — like a shirt rubbing sunburned skin — as pain. © Society for Science & the Public 2000–2024.

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 8: Hormones and Sex
Link ID: 29366 - Posted: 06.24.2024

By Ingrid Wickelgren Ishmail Abdus-Saboor has been fascinated by the variety of the natural world since he was a boy growing up in Philadelphia. The nature walks he took under the tutelage of his third grade teacher, Mr. Moore, entranced him. “We got to interact and engage with wildlife and see animals in their native environment,” he recalled. Abdus-Saboor also brought a menagerie of creatures — cats, dogs, lizards, snakes and turtles — into his three-story home, and saved up his allowance to buy a magazine that taught him about turtles. When adults asked him what he wanted to be when he grew up, “I said I wanted to become a scientist,” he said. “I always raised eyebrows.” Abdus-Saboor did not stray from that goal. Today, he is an associate professor of biological sciences at the Mortimer B. Zuckerman Mind Brain Behavior Institute at Columbia University, where he studies how the brain determines whether a touch to the skin is painful or pleasurable. “Although this question is fundamental to the human experience, it remains puzzling to explain with satisfying molecular detail,” he said. Because the skin is our largest sensory organ and a major conduit to our environment, it may hold clues for treating conditions from chronic pain to depression. To find those clues, Abdus-Saboor probes the nervous system at every juncture along the skin-to-brain axis. He does not focus on skin alone or home in on only the brain as many others do. “We merge these two worlds,” he said. That approach, he added, requires mastering two sets of techniques, reading two sets of literature and attending two sets of scientific meetings. “It gives us a unique leg up,” he said. It has led to a landmark paper published last year in Cell that laid out the entire neural circuit for pleasurable touch. © 2024 Simons Foundation.

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 4: Development of the Brain
Link ID: 29262 - Posted: 04.20.2024

By Joanne Silberner A hug, a handshake, a therapeutic massage. A newborn lying on a mother’s bare chest. Physical touch can buoy well-being and lessen pain, depression and anxiety, according to a large new analysis of published research released on Monday in the journal Nature Human Behaviour. Researchers from Germany and the Netherlands systematically reviewed years of research on touch, strokes, hugs and rubs. They also combined data from 137 studies, which included nearly 13,000 adults, children and infants. Each study compared individuals who had been physically touched in some way over the course of an experiment — or had touched an object like a fuzzy stuffed toy — to similar individuals who had not. For example, one study showed that daily 20-minute gentle massages for six weeks in older people with dementia decreased aggressiveness and reduced the levels of a stress marker in the blood. Another found that massages boosted the mood of breast cancer patients. One study even showed that healthy young adults who caressed a robotic baby seal were happier, and felt less pain from a mild heat stimulus, than those who read an article about an astronomer. Positive effects were particularly noticeable in premature babies, who “massively improve” with skin-to-skin contact, said Frédéric Michon, a researcher at the Netherlands Institute for Neuroscience and one of the study’s authors. “There have been a lot of claims that touch is good, touch is healthy, touch is something that we all need,” said Rebecca Boehme, a neuroscientist at Linkoping University in Sweden, who reviewed the study for the journal. “But actually, nobody had looked at it from this broad, bird’s eye perspective.” © 2024 The New York Times Company

Related chapters from BN: Chapter 15: Emotions, Aggression, and Stress; Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 5: The Sensorimotor System
Link ID: 29252 - Posted: 04.11.2024

By Alejandra Manjarrez People wear gloves when making a snowman for a reason: Handling cold stuff can hurt. A new mouse study reveals what may be a key player in this response: a protein already known to enable sensory neurons in worms to detect cold. New evidence published this week in Nature Neuroscience confirms that this protein has the same function in mammals. “The paper is exciting,” says Theanne Griffith, a neuroscientist at the University of California, Davis who was not involved in the research. She notes that the protein, called GluK2, is found in the brain and has “traditionally been thought to play a major role in learning and memory.” The new work shows that elsewhere in the body, it has an unsuspected and “completely divergent role.” We perceive touch, pain, and temperature thanks to a system of nerves that extends throughout our bodies. Researchers have identified skin sensors that detect hot and warm stimuli. Cold sensors, though, have proved more challenging to find. Researchers have proposed various candidates but found limited and contradictory evidence for their function. An ion channel named TRPM8 is the exception. Famous for detecting the “cool” sensation of menthol, it also detects cold temperatures and helped earn its discoverers the Nobel Prize in Physiology or Medicine in 2021. “Nobody questions that TRPM8 is a cold sensor,” says sensory neurobiologist Félix Viana of the Institute for Neuroscience in Alicante, Spain. But it could not be the whole story. It works most efficiently at temperatures above roughly 10°C, and mice lacking the gene for TRPM8 can still detect very cold temperatures. A few years ago, University of Michigan neuroscientists Shawn Xu and Bo Duan and their colleagues found another candidate: a protein on certain sensory neurons in the tiny roundworm Caenorhabditis elegans that causes the animals to avoid temperatures between 17°C and 18°C, which are colder than their preferred temperatures. Preliminary data from that study hinted that the equivalent protein in mammals, GluK2, also allowed mice to sense cold.

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 29190 - Posted: 03.16.2024

By Regina G. Barber, Anil Oza, Ailsa Chang, Rachel Carlson Neuroscientist Nathan Sawtell has spent a lot of time studying a funky looking electric fish characterized by its long nose. The Gnathonemus petersii, or elephantnose fish, can send and decipher weak electric signals, which Sawtell hopes will help neuroscientists better understand how the brain pieces together information about the outside world. But as Sawtell studied these electric critters, he noticed a pattern he couldn't explain: the fish tend to organize themselves in a particular orientation. "There would be a group of subordinates in a particular configuration at one end of the tank, and then a dominant fish at the other end. The dominant fish would swim in and break up the group, and they would scatter. A few seconds later, the group would coalesce and it would stay there for hours at a time in this stationary configuration," Sawtell, who runs a lab at Columbia University's Zuckerman Institute says. Initially Sawtell and his team couldn't put together why the fish were always hanging out in this configuration. "What could they really be talking to each other about all of this time?" A new study released this week in Nature by Sawtell and colleagues at Columbia University could have one potential answer: the fish are creating an electrical network that is larger than any field an individual fish can muster alone. In this collective field, the whole school of fish get instantaneous information on changes in the water around them, like approaching predators. Rather than being confused by the flurry of electric signals from other fish, "these fish were clever enough to exploit the pulses of group members to sense their environment," Sawtell says. © 2024 npr

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 29187 - Posted: 03.09.2024

By Simon Makin A new device makes it possible for a person with an amputation to sense temperature with a prosthetic hand. The technology is a step toward prosthetic limbs that restore a full range of senses, improving both their usefulness and acceptance by those who wear them. A team of researchers in Italy and Switzerland attached the device, called ”MiniTouch,” to the prosthetic hand of a 57-year-old man named Fabrizio, who has an above-the-wrist amputation. In tests, the man could identify cold, cool and hot bottles of liquid with perfect accuracy; tell the difference between plastic, glass and copper significantly better than chance; and sort steel blocks by temperature with around 75 percent accuracy, researchers report February 9 in Med. Thank you for being a subscriber to Science News! Interested in more ways to support STEM? Consider making a gift to our nonprofit publisher, Society for Science, an organization dedicated to expanding scientific literacy and ensuring that every young person can strive to become an engineer or scientist. “It’s important to incorporate these technologies in a way that prosthesis users can actually use to perform functional tasks,” says neuroengineer Luke Osborn of Johns Hopkins University Applied Physics Laboratory in Laurel, Md., who was not involved in the study. “Introducing new sensory feedback modalities could help give users more functionality they weren’t able to achieve before.” The device also improved Fabrizio’s ability to tell whether he was touching an artificial or human arm. His accuracy was 80 percent with the device turned on, compared with 60 percent with it off. “It’s not quite as good as with the intact hand, probably because we’re not giving [information about] skin textures,” says neuroengineer Solaiman Shokur of EPFL, the Swiss Federal Institute of Technology in Lausanne. © Society for Science & the Public 2000–2024.

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 29144 - Posted: 02.10.2024

By Sandra G. Boodman His plane was coming in for a landing at Philadelphia International Airport when Allen M. Weiss, a marketing professor at the University of Southern California, felt a spasm of pain pierce his left cheek near his nose. “It was really weird,” recalled Weiss, then director of Mindful USC, a group of meditation-based programs at the Los Angeles university. “My face froze up.” Within minutes the pain disappeared and the final leg of Weiss’s December 2015 trip home to California was uneventful. But over the next few months the sensation recurred in the same spot. At first the unpredictable pain was fairly mild and merely bothersome; later it became an excruciating daily torment. Several years after the pain first occurred Weiss, who had consulted dentists, oral pain experts and an otolaryngologist, was given a diagnosis that ended up being correct. But his complicated medical history, a radiology report that failed to describe an important finding and a cryptic warning by one of his doctors delayed effective treatment for three more years. “It was completely confusing,” Weiss said. In June 2023 he underwent surgery that has significantly reduced his pain and improved the quality of his life. N. Nicole Moayeri, the Santa Barbara, Calif., neurosurgeon who operated on Weiss, said a protracted search for a diagnosis and treatment is not unusual for those suffering from Weiss’s uncommon malady. “I commonly see people who’ve had multiple dental procedures for years” when the problem was not in their mouths, Moayeri said. “It’s really shocking to me that so many people suffer” with this for so long. After three months of intermittent pain following the flight, Weiss consulted his internist. For reasons that are unclear, the doctor told Weiss the cause was probably psychological, not physical, and that it wasn’t serious. He sent Weiss to an ear, nose and throat specialist whom he saw in March 2016. She performed an exam and ordered a CT scan that revealed a deviated septum, a typically painless condition estimated to affect up to 80 percent of the population in which the bone or cartilage that divides the nostrils is off-center. A moderate or severe deviation can contribute to the development of sinus infections, headaches and breathing problems. But Weiss had none of these. And a deviated septum didn’t explain the spasms of pain.

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 29054 - Posted: 12.19.2023

Nell Greenfieldboyce If you've got itchy skin, it could be that a microbe making its home on your body has produced a little chemical that's directly acting on your skin's nerve cells and triggering the urge to scratch. That's the implication of some new research that shows how a certain bacteria, Staphylococcus aureus, can release an enzyme that generates an itchy feeling. What's more, a drug that interferes with this effect can stop the itch in laboratory mice, according to a new report in the journal Cell. "That's exciting because it's a drug that's already approved for another condition, but maybe it could be useful for treating itchy skin diseases like eczema," says Isaac Chiu, a scientist at Harvard Medical School who studies interactions between microbes and nerve cells. He notes that eczema or atopic dermatitis is actually pretty common, affecting about 20% of children and 10% of adults. In the past, says Chiu, research on itchy skin conditions has focused on the role of the immune response and inflammation in generating the itch sensation. People with eczema often take medications aimed at immune system molecules. But scientists have also long known that people with eczema frequently have skin that's colonized by Staphylococcus aureus, says Chiu, even though it's never been clear what role the bacteria might play in this condition. Chiu's previous lab work had made him realize that bacteria can directly act on nerve cells to cause pain. "So this made us ask: Could certain microbes like Staphylococcus aureus also particularly be in some way linked to itch?" says Chiu. "Is there a role for microbes in talking to itch neurons?" He and his colleagues first found that putting this bacteria on the skin of mice resulted in vigorous scratching by these animals, leading to damaged skin that spread beyond the original exposure site. © 2023 npr

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 29022 - Posted: 11.26.2023

By Veronique Greenwood When someone brushes a hand across your skin, it’s like a breeze blowing through a forest of countless small hairs. Nerves that surround your hair follicles detect that contact, and very far away in your brain, other cells fire. Some of the neurons responding to light contact might make you shiver and give you goose bumps. Some might tell you to move away. Or they might tell you to move closer. Scientists who study the sense of touch have explored which cells bear these messages, and they have made an intriguing discovery: Follicle cells triggered by hair movements release the neurotransmitters histamine and serotonin, chemical messengers linked to biological phenomena as varied as inflammation, muscle contraction and mood changes. The observation, reported in October in the journal Science Advances, lays the groundwork for tracing how gentle touch makes us feel the way it does. Studying hair follicles is challenging, because they begin to decay soon after being removed from the body, said Claire Higgins, a bioengineering professor at Imperial College London and an author of the study. So she and her colleagues went to a hair transplant clinic. There, they were able to look at freshly harvested follicles, which they gently prodded with a very small rod to simulate touch. The scientists knew from work done by other groups that the neurons in the skin surrounding hair follicles are capable of sensing movement. “When you brush your hair, you feel it because the sensory neurons are directly being stimulated,” Dr. Higgins said. But they were curious whether the cells of the follicle itself — the tube from which a hair sprouts — could be contributing to some of the feelings associated with more gentle touch. Not all of the follicle cells had movement sensors, but some did. The researchers identified these and watched them carefully as the rod touched them. “We found that when we stimulated our hair follicle cells, they actually released mood-regulating neurotransmitters serotonin and histamine,” Dr. Higgins said. © 2023 The New York Times Company

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 11: Emotions, Aggression, and Stress
Link ID: 28999 - Posted: 11.11.2023

Marlys Fassett Itching can be uncomfortable, but it’s a normal part of your skin’s immune response to external threats. When you’re itching from an encounter with poison ivy or mosquitoes, consider that your urge to scratch may have evolved to get you to swat away disease-carrying pests. However, for many people who suffer from chronic skin diseases like eczema, the sensation of itch can fuel a vicious cycle of scratching that interrupts sleep, reduces productivity and prevents them from enjoying daily life. This cycle is caused by sensory neurons and skin immune cells working together to promote itching and skin inflammation. But, paradoxically, some of the mechanisms behind this feedback loop also stop inflammation from getting worse. In our newly published research, my team of immunologists and neuroscientists and I discovered that a specific type of itch-sensing neuron can push back on the itch-scratch-inflammation cycle in the presence of a small protein. This protein, called interleukin-31, or IL-31, is typically involved in triggering itching. This negative feedback loop – like the vicious cycle – is only possible because the itch-sensing nerve endings in your skin are closely intertwined with the millions of cells that make up your skin’s immune system. The protein IL-31 is key to the connection between the nervous and immune systems. This molecule is produced by some immune cells, and like other members of this molecule family, it specializes in helping immune cells communicate with each other. © 2010–2023, The Conversation US, Inc.

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 11: Emotions, Aggression, and Stress
Link ID: 28961 - Posted: 10.14.2023

Regina G. Barber Ever had an itch you can't scratch? Maybe it's out of reach, or your hands are full, or you don't want to damage your skin. It can be deeply frustrating. And even though the itch response, or what scientists refer to simply as "itch," has a purpose — it's one of our bodies' alert systems — it can also go very wrong. The importance of a regular itch Itch is evolution's way of drawing our attention to something on our skin that needs removing. This could be a stinging bug, a nesting parasite or an irritating plant (poison ivy, anyone?!). All these things urge us to scratch, which generally removes the threat and soothes the itch. "We know that itch can activate sensory neurons and the signal will be transmitted to the brain. When we scratch the skin, somehow other neural circuits will be activated. And these neural circuits will suppress the itch circuits and alleviate the itch sensation," says Qin Liu, a neuroscientist at the Washington University School of Medicine in St. Louis. Because the itch sensation has separate neural circuitry from temperature, pressure and pain, applying pressure or ice or scratching can relieve an itch. They're effective neural distractions. Oftentimes, when someone experiences hives or an insect bite, histamine is involved, a chemical released by our immune system that can contribute to itchiness. So relieving that itch only requires antihistamine medication. "But most other forms of itch, like atopic dermatitis, eczema, other conditions, they don't actually have a pathway for histamine as the itch mediator," says Kwatra. © 2023 npr

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 28929 - Posted: 09.27.2023

By Claudia López Lloreda When someone loses a hand or leg, they don’t just lose the ability to grab objects or walk—they lose the ability to touch and sense their surroundings. Prosthetics can restore some motor control, but they typically can’t restore sensation. Now, a preliminary studyposted to the preprint server bioRxiv this month—shows that by mimicking the activity of nerves, a device implanted in the remaining part of the leg helps amputees “feel” as they walk, allowing them to move faster and with greater confidence. “It's a really elegant study,” says Jacob George, neuroengineer at the University of Utah who was not involved with the research. Because the experiments go from a computational model to an animal model and then, finally humans, he says, “This work is really impactful, because it's one of the first studies that's done in a holistic way.” Patients with prosthetics often have a hard time adapting. One big issue is that they can’t accurately control the device because they can’t feel the pressure that they’re exerting on an object. Hand and arm amputees, for example, are more prone to drop or break things. As a result, some amputees refuse to use such prosthetics. In the past few years, researchers have been working on prosthetic limbs that provide more natural sensory feedback both to help control the device better and give them back a sense of agency over their robotic limb. In a critical study in 2019, George and his team showed that so-called biomimetic feedback, sensory information that aims to resemble the natural signals that occur with touch, allowed a patient who’d lost his hand to more precisely grip fragile objects such as eggs and grapes. But such studies have been limited to single patients. They’ve also left many questions unanswered about how exactly this feedback helps with motor control and improves the use of the prosthetic. So in the new work, researchers used a computer model that re-creates how nerves in the foot respond to different inputs, such as feeling pressure. The goal was to create natural patterns of neural activity that might occur when sensing something with the foot or walking. © 2023 American Association for the Advancement of Science.

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 5: The Sensorimotor System
Link ID: 28863 - Posted: 08.02.2023

By Charlotte Stoddart Charlotte Stoddart: Can a sugar pill make you feel better? What about the rituals surrounding a visit to the doctor? Can the care of a doctor or your trust in them reduce the amount of pain you feel? I’m Charlotte Stoddart and this is Knowable. This episode is all about the placebo effect. We’re going to look in detail at one key paper to learn how the placebo effect has been used in medicine and how it’s been understood and misunderstood. The paper is called “The Powerful Placebo.” It was written by Henry Beecher and published in JAMA, the Journal of the American Medical Association, in 1955. I chose this paper because it’s often referred to as a classic, and it’s still one of the most frequently cited papers on the placebo effect. I’ve enlisted the help of Ted Kaptchuk, who knows the paper well. Ted Kaptchuk: I enjoyed rereading it, actually. It’s a remarkable paper. I’ve read it probably 15 times in my life. Charlotte Stoddart: Ted is director of the Program in Placebo Studies at the Beth Israel Deaconess Medical Center in Boston and a professor of medicine at Harvard Medical School, where Henry Beecher also held a professorship. Beecher also worked at Massachusetts General Hospital. Charlotte Stoddart: During the Second World War, Beecher served in the US Army, and there’s a story about how that experience got him interested in the placebo effect. It goes like this: Beecher was working at a military hospital. One day, a badly injured soldier needed surgery, but the hospital had run out of morphine. So Beecher injected the soldier with saline solution instead. The soldier relaxed and Beecher carried out the operation without any real anesthetic. This, so the story goes, is when Beecher realized the power of the mind over the body. There are several different versions of this story, but Ted says it’s likely some version of it is true. © 2023 Annual Reviews

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 28832 - Posted: 06.28.2023

By Laura Sanders Scientists can see chronic pain in the brain with new clarity. Over months, electrodes implanted in the brains of four people picked up specific signs of their persistent pain. This detailed view of chronic pain, described May 22 in Nature Neuroscience, suggests new ways to curtail the devastating condition. The approach “provides a way into the brain to track pain,” says Katherine Martucci, a neuroscientist who studies chronic pain at Duke University School of Medicine. Chronic pain is incredibly common. In the United States from 2019 to 2020, more adults were diagnosed with chronic pain than with diabetes, depression or high blood pressure, researchers reported May 16 in JAMA Network Open. Chronic pain is also incredibly complex, an amalgam influenced by the body, brain, context, emotions and expectations, Martucci says. That complexity makes chronic pain seemingly invisible to an outsider, and very difficult to treat. One treatment approach is to stimulate the brain with electricity. As part of a clinical trial, researchers at the University of California, San Francisco implanted four electrode wires into the brains of four volunteers with chronic pain. These electrodes can both monitor and stimulate nerve cells in two brain areas: the orbitofrontal cortex, or OFC, and the anterior cingulate cortex, or ACC. The OFC isn’t known to be a key pain influencer in the brain, but this region has lots of neural connections to pain-related areas, including the ACC, which is thought to be involved in how people experience pain. But before researchers stimulated the brain, they needed to know how chronic pain was affecting it. For about 3 to 6 months, the implanted electrodes monitored brain signals of these people as they went about their lives. During that time, the participants rated their pain on standard scales two to eight times a day. © Society for Science & the Public 2000–2023.

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 2: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Link ID: 28795 - Posted: 05.23.2023

By Priyanka Runwal Researchers have for the first time recorded the brain’s firing patterns while a person is feeling chronic pain, paving the way for implanted devices to one day predict pain signals or even short-circuit them. Using a pacemaker-like device surgically placed inside the brain, scientists recorded from four patients who had felt unremitting nerve pain for more than a year. The devices recorded several times a day for up to six months, offering clues for where chronic pain resides in the brain. The study, published on Monday in the journal Nature Neuroscience, reported that the pain was associated with electrical fluctuations in the orbitofrontal cortex, an area involved in emotion regulation, self-evaluation and decision making. The research suggests that such patterns of brain activity could serve as biomarkers to guide diagnosis and treatment for millions of people with shooting or burning chronic pain linked to a damaged nervous system. “The study really advances a whole generation of research that has shown that the functioning of the brain is really important to processing and perceiving pain,” said Dr. Ajay Wasan, a pain medicine specialist at the University of Pittsburgh School of Medicine, who wasn’t involved in the study. About one in five American adults experience chronic pain, which is persistent or recurrent pain that lasts longer than three months. To measure pain, doctors typically rely on patients to rate their pain, using either a numerical scale or a visual one based on emojis. But self-reported pain measures are subjective and can vary throughout the day. And some patients, like children or people with disabilities, may struggle to accurately communicate or score their pain. “There’s a big movement in the pain field to develop more objective markers of pain that can be used alongside self-reports,” said Kenneth Weber, a neuroscientist at Stanford University, who was not involved in the study. In addition to advancing our understanding of what neural mechanisms underlie the pain, Dr. Weber added, such markers can help validate the pain experienced by some patients that is not fully appreciated — or is even outright ignored — by their doctors. © 2023 The New York Times Company

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 2: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Link ID: 28794 - Posted: 05.23.2023