Chapter 5. The Sensorimotor System

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

Links 1 - 20 of 2549

Laura Sanders Pain is contagious, at least for mice. After encountering bedding where mice in pain had slept, other mice became more sensitive to pain themselves. The experiment, described online October 19 in Science Advances, shows that pain can move from one animal to another — no injury or illness required. The results “add to a growing body of research showing that animals communicate distress and are affected by the distress of others,” says neuroscientist Inbal Ben-Ami Bartal of the University of California, Berkeley. Neuroscientist Andrey Ryabinin and colleagues didn’t set out to study pain transfer. But the researchers noticed something curious during their experiments on mice who were undergoing alcohol withdrawal. Mice in the throes of withdrawal have a higher sensitivity to pokes on the foot. And surprisingly, so did these mice’s perfectly healthy cagemates. “We realized that there was some transfer of information about pain” from injured mouse to bystander, says Ryabinin, of Oregon Health & Sciences University in Portland. When mice suffered from alcohol withdrawal, morphine withdrawal or an inflaming injection, they become more sensitive to a poke in the paw with a thin fiber — a touchy reaction that signals a decreased pain tolerance. Mice that had been housed in the same cage with the mice in pain also grew more sensitive to the poke, Ryabinin and colleagues found. These bystander mice showed other signs of heightened pain sensitivity, such as quickly pulling their tails out of hot water and licking a paw after an irritating shot. |© Society for Science & the Public 2000 - 20

Keyword: Chemical Senses (Smell & Taste); Pain & Touch
Link ID: 22773 - Posted: 10.20.2016

Hannah Devlin Science correspondent Migraine sufferers have a different mix of gut bacteria that could make them more sensitive to certain foods, scientists have found. The study offers a potential explanation for why some people are more susceptible to debilitating headaches and why some foods appear to act as triggers for migraines. The research showed that migraine sufferers had higher levels of bacteria that are known to be involved in processing nitrates, which are typically found in processed meats, leafy vegetables and some wines. The latest findings raise the possibility that migraines could be triggered when nitrates in food are broken down more efficiently, causing vessels in the brain and scalp to dilate. Antonio Gonzalez, a programmer analyst at the University of California San Diego and the study’s first author, said: “There is this idea out there that certain foods trigger migraines - chocolate, wine and especially foods containing nitrates. We thought that perhaps there are connections between what people are eating, their microbiomes and their experiences with migraines.” When nitrates in food are broken down by bacteria in the mouth and gut they are eventually converted into nitric oxide in the blood stream, a chemical that dilates blood vessels and can aid cardiovascular health by boosting circulation. © 2016 Guardian News and Media Limited

Keyword: Pain & Touch; Obesity
Link ID: 22769 - Posted: 10.19.2016

Linda Geddes For the first time, a paralysed man has gained a limited sense of touch, thanks to an electric implant that stimulates his brain and allows him to feel pressure-like sensations in the fingers of a robotic arm. The advance raises the possibility of restoring limited sensation to various areas of the body, as well as giving people with spinal-cord injuries better control over prosthetic limbs. But restoring human-like feeling, such as sensations of heat or pain, will prove more challenging, the researchers say. Nathan Copeland had not been able to feel or move his legs and lower arms since a car accident snapped his neck and injured his spinal cord when he was 18. Now, some 12 years later, he can feel when a robotic arm has its fingers touched, because sensors on the fingers are linked to an implant in his brain. Brain implant restores paralysed man's sense of touch Rob Gaunt, a biomedical engineer at the University of Pittsburgh, performs a sensory test on a blindfolded Nathan Copeland. Nathan, who is paralysed, demonstrates his ability to feel by correctly identifying different fingers through a mind-controlled robotic arm. Video credit: UPMC/Pitt Health Sciences. “He says the sensations feel like they’re coming from his own hand,” says Robert Gaunt, a biomedical engineer at the University of Pittsburgh who led the study. © 2016 Macmillan Publishers Limited

Keyword: Robotics; Pain & Touch
Link ID: 22759 - Posted: 10.15.2016

By Elizabeth Pennisi Although it has a face—and body—that only a mother could love, the naked mole rat has a lot to offer biomedical science. It lives 10 times longer than a mouse, almost never gets cancer, and doesn’t feel pain from injury and inflammation. Now, researchers say they’ve figured out how the rodents keep this pain away. “It’s an amazing result,” says Harold Zakon, an evolutionary neurobiologist at the University of Texas, Austin, who was not involved with the work. “This study points us to important areas … that might be targeted to reduce this type of pain.” Naked mole rats are just plain weird. They live almost totally underground in colonies structured like honey bee hives, with hundreds of workers servicing a single queen and her few consorts. To survive, they dig kilometers of tunnels in search of large underground tubers for food. It’s such a tough life that—to conserve energy—this member of the rodent family gave up regulating its temperature, and they are able to thrive in a low-oxygen, high–carbon dioxide environment that would suffocate or be very painful to humans. “They might as well be from another planet,” says Thomas Park, a neuroscientist at the University of Illinois, Chicago. Gary Lewin, a neuroscientist at the Max Delbrück Center for Molecular Medicine in the Helmholtz Association in Berlin, began working with naked mole rats because a friend in Chicago was finding that the rodent's pain fibers were not the same as other mammals'. In 2008, the studies led to the finding that naked mole rats didn’t feel pain when they came into contact with acid and didn’t get more sensitive to heat or touch when injured, like we and other mammals do. Lewin was hooked and has been raising the rodents in his lab ever since. They are a little more challenging than rats or mice, he notes, because with just one female per colony producing young, he never really has quite enough individuals for his studies. © 2016 American Association for the Advancement of Science

Keyword: Pain & Touch; Evolution
Link ID: 22749 - Posted: 10.12.2016

Urine could potentially be used for a quick and simple way to test for CJD or "human mad cow disease", say scientists in the journal JAMA Neurology. The Medical Research Council team say their prototype test still needs honing before it could be used routinely. Currently there is no easy test available for this rare but fatal brain condition. Instead, doctors have to take a sample of spinal fluid or brain tissue, or wait for a post-mortem after death. What they look for is tell-tale deposits of abnormal proteins called prions, which cause the brain damage. Building on earlier US work, Dr Graham Jackson and colleagues, from University College London, have now found it is also possible to detect prions in urine. This might offer a way to diagnose CJD rapidly and earlier, they say, although there is no cure. Creutzfeldt-Jakob disease (CJD): CJD is a rare, but fatal degenerative brain disorder caused by abnormal proteins called prions that damage brain cells. There are several forms of the disease: sporadic, which occurs naturally in the human population, and accounts for 85% of all CJD cases variant CJD, linked to eating beef infected by bovine spongiform encephalopathy (BSE) iatrogenic infection, caused by contamination during medical or surgical treatment In the 1990s it became clear that a brain disease could be passed from cows to humans. The British government introduced a ban on beef on the bone. Since then, officials have kept a close check on how many people have become sick or died from CJD. © 2016 BBC

Keyword: Prions
Link ID: 22724 - Posted: 10.05.2016

By Carl Luepker For the past 35 years, a relentless neurological disorder has taken over my body, causing often painful muscle spasms that make it hard for me to walk and write and that cause my speech to be garbled enough that people often can’t understand me I can live with my bad luck in getting this condition, which showed up when I was 10; what’s harder to accept is that I have passed on this disorder, carried in my genes, to my 11-year-old son, Liam. As a parent, you hope that your child’s life will follow an upward trend, one of emotional and physical growth toward an adulthood of wide-open possibilities where they can explore the world, challenge themselves emotionally and physically, and perhaps play on a sports team. And you hope that you can pass down to your child at least some of what was passed down to you. Yet my generalized dystonia, as my progressive condition is called, was one thing I had hoped would end with me. Liam poses for a photograph just months before his diagnosis with dystonia. He “has just moved into middle school,” his father writes, where “he will have to both advocate for himself and educate his new teachers and peers about this genetic disorder.” When my wife and I started thinking of having kids, the statistics were fairly reassuring: There was a 1-in-2 chance that our child would inherit the gene that causes the disorder, but most people who have the gene don’t go on to manifest dystonia. We wanted a family and rolled the dice — twice. Our daughter does not have the gene. © 1996-2016 The Washington Post

Keyword: Movement Disorders; Genes & Behavior
Link ID: 22720 - Posted: 10.02.2016

By Jessica Boddy Activity trackers like Fitbits and Jawbones help fitness enthusiasts log the calories they burn, their heart rates, and even how many flights of stairs they climb in a day. Biologist Cory Williams of Northern Arizona University in Flagstaff is using similar technology to track the energy consumption of arctic ground squirrels in Alaska—insight that may reveal how the animals efficiently forage for food while avoiding being picked off by golden eagles. This week, Williams published a study in Royal Society Open Science that compared the activity levels of male and female squirrels. He found that although males spend a lot more time outside of their burrows, they’re pretty lazy, and sometimes just bask in the sun during warmer months. Females, on the other hand, have limited time to spare when caring for their young, and use it to run around and forage for themselves and their babies. In addition to previous work on arctic ground squirrel hibernation and seasonal differences in behavior, the finding is helping his team figure out why males tend to be more susceptible to being eaten. Williams sat down with Science to talk about creating a squirrel Fitbit, catching the animals in the wild, and how technology is improving ecological research. This interview has been edited for brevity and clarity. Q: What got you interested in studying arctic ground squirrels? A: It’s one of the only arctic animals that keeps a rigid schedule even when there’s no light/dark cycle for 6 week—meaning, they emerge from and return to their burrows the same time every day and they eat the same time each day, even though the sun stays in the sky for weeks and weeks. So I started to deploy the energy tracking technologies to better understand how the squirrels use energy through the seasons. © 2016 American Association for the Advancement of Science

Keyword: Sexual Behavior
Link ID: 22714 - Posted: 09.30.2016

By GRETCHEN REYNOLDS Before you skip another workout, you might think about your brain. A provocative new study finds that some of the benefits of exercise for brain health may evaporate if we take to the couch and stop being active, even just for a week or so. I have frequently written about how physical activity, especially endurance exercise like running, aids our brains and minds. Studies with animals and people show that working out can lead to the creation of new neurons, blood vessels and synapses and greater overall volume in areas of the brain related to memory and higher-level thinking. Presumably as a result, people and animals that exercise tend to have sturdier memories and cognitive skills than their sedentary counterparts. Exercise prompts these changes in large part by increasing blood flow to the brain, many exercise scientists believe. Blood carries fuel and oxygen to brain cells, along with other substances that help to jump-start desirable biochemical processes there, so more blood circulating in the brain is generally a good thing. Exercise is particularly important for brain health because it appears to ramp up blood flow through the skull not only during the actual activity, but throughout the rest of the day. In past neurological studies, when sedentary people began an exercise program, they soon developed augmented blood flow to their brains, even when they were resting and not running or otherwise moving. But whether those improvements in blood flow are permanent or how long they might last was not clear. So for the new study, which was published in August in Frontiers in Aging Neuroscience, researchers from the department of kinesiology at the University of Maryland in College Park decided to ask a group of exceedingly fit older men and women to stop exercising for awhile. © 2016 The New York Times Company

Keyword: Learning & Memory; Development of the Brain
Link ID: 22704 - Posted: 09.28.2016

Emma Yasinski Two often-overlooked medications might help millions of Americans who abuse alcohol to quit drinking or cut back. Public health officials, building on a push to treat people who abuse opioids with medications, want physicians to consider using medications to treat alcohol addiction. The drugs can be used in addition to or sometimes in place of peer-support programs, they say. "We want people to understand we think AA is wonderful, but there are other options," says George Koob, director of the National Institute of Alcohol Abuse and Alcoholism, a part of the federal National Institutes of Health. It is still rare for a person struggling with alcohol to hear that medication therapy exists. This partly reflects the tradition of treating addiction through 12-step programs. It's also a byproduct of limited promotion by the drugs' manufacturers and confusion among doctors about how to use them. A key study funded by the federal government reported last year that only 20 percent people who abuse alcohol will ever receive any form of treatment, which ranges from seeing a counselor or doctor to entering a specialized treatment program. The same is true for opioid addiction — about 80 percent of people dependent on opioids will never receive treatment. © 2016 npr

Keyword: Drug Abuse
Link ID: 22698 - Posted: 09.27.2016

James Gorman When the leader of a flock goes the wrong way, what will the flock do? With human beings, nobody can be sure. But with homing pigeons, the answer is that they find their way home anyway. Either the lead pigeon recognizes that it has no clue and falls back into the flock, letting birds that know where they are going take over, or the flock collectively decides that the direction that it is taking just doesn’t feel right, and it doesn’t follow. Several European scientists report these findings in a stirring report in Biology Letters titled, “Misinformed Leaders Lose Influence Over Pigeon Flocks.” Isobel Watts, a doctoral student in zoology at Oxford, conducted the study with her advisers, Theresa Burt de Perera and Dora Biro, and with the participation of Mate Nagy, a statistical physicist from Hungary, who is affiliated with several institutions, including Oxford and the Hungarian Academy of Sciences. Dr. Biro, who studies social behavior in primates as well as pigeons, said that the common questions that ran through her work were “about group living and what types of challenges and opportunities it brings.” She and her colleagues at Oxford have pioneered a method of studying flock behavior that uses very-fine-resolution GPS units, which the birds wear in pigeon-size backpacks. The devices record a detailed position for each bird a number of times a second. Researchers in Budapest and Oxford developed software to analyze small movements and responses of every bird in a flock. With this method, the scientists can identify which pigeons are leading the way. They can build a picture of how each bird responds to changes in the flight of other birds. © 2016 The New York Times Company

Keyword: Animal Migration; Attention
Link ID: 22696 - Posted: 09.26.2016

By Alison F. Takemura Bodies like to keep their pH close to 7.4, whether that means hyperventilating to make the blood alkaline, or burning energy, shifting to anaerobic metabolism, and producing lactate to make the blood acidic. The lungs and kidneys can regulate pH changes systemically, but they may not act quickly on a local scale. Because even small pH changes can dramatically affect the nervous system, a study led by Sten Grillner of Karolinska Institute in Sweden looked for a mechanism for pH homeostasis in the spinal cord. Using the lamprey as a model system, the researchers observed that a type of spinal canal neuron, called CSF-c, fired more rapidly when they bathed it with high pH (7.7) or low pH (7.1) media. They could suspend the elevated activity by blocking two ion channels: PKD2L1 channels, which stimulate neurons in alkaline conditions, or ASIC3 channels, which, the team showed previously, do the same in acidic states. As the neurons fired, they released the hormone somatostatin, which inhibited the lamprey’s locomotor network. These results suggest that, whichever direction pH deviates, “the response of the system is just to reduce activity as much as possible,” Grillner says. The pH-regulating role of CSF-c neurons is likely conserved among animals, the authors suspect, given the presence of these neurons across vertebrate taxa. © 1986-2016 The Scientist

Keyword: Movement Disorders
Link ID: 22688 - Posted: 09.24.2016

By Michael Price A soft brush that feels like prickly thorns. A vibrating tuning fork that produces no vibration. Not being able to tell which direction body joints are moving without looking at them. Those are some of the bizarre sensations reported by a 9-year-old girl and 19-year-old woman in a new study. The duo, researchers say, shares an extremely rare genetic mutation that may shed light on a so-called “sixth sense” in humans: proprioception, or the body’s awareness of where it is in space. The new work may even explain why some of us are klutzier than others. The patients’ affliction doesn’t have a name. It was discovered by one of the study’s lead authors, pediatric neurologist Carsten Bönnemann at the National Institutes of Health (NIH) in Bethesda, Maryland, who specializes in diagnosing unknown genetic illnesses in young people. He noticed that the girl and the woman shared a suite of physical symptoms, including hips, fingers, and feet that bent at unusual angles. They also had scoliosis, an unusual curvature of the spine. And, significantly, they had difficulty walking, showed an extreme lack of coordination, and couldn’t physically feel objects against their skin. Bönnemann screened their genomes and looked for mutations that they might have in common. One in particular stood out: a catastrophic mutation in PIEZO2, a gene that has been linked to the body’s sense of touch and its ability to perform coordinated movements. At about the same time, in a “very lucky accident,” Bönnemann attended a lecture by Alexander Chesler, a neurologist also at NIH, on PIEZO2. Bönnemann invited Chesler to help study his newly identified patients. © 2016 American Association for the Advancement of Science.

Keyword: Movement Disorders; Genes & Behavior
Link ID: 22683 - Posted: 09.22.2016

Nicola Davis Tyrannosaur, Breaking the Waves and Schindler’s List might make you reach for the tissues, but psychologists say they have found a reason why traumatic films are so appealing. Researchers at Oxford University say that watching traumatic films boosts feelings of group bonding, as well as increasing pain tolerance by upping levels of feel-good, pain-killing chemicals produced in the brain. “The argument here is that actually, maybe the emotional wringing you get from tragedy triggers the endorphin system,” said Robin Dunbar, a co-author of the study and professor of evolutionary psychology at the University of Oxford. Previous research has found that laughing together, dancing together and working in a team can increase social bonding and heighten pain tolerance through an endorphin boost. “All of those things, including singing and dancing and jogging and laughter, all produce an endorphin kick for the same reason - they are putting the musculature of the body under stress,” said Dunbar. Being harrowed, he adds, could have a similar effect. “It has turned out that the same areas in the brain that deal with physical pain also handle psychological pain,” said Dunbar. Writing in the journal Royal Society Open Science, Dunbar and colleagues describe how they set out to unpick whether our love of storytelling, a device used to share knowledge and cultivate a sense of identity within a group, is underpinned by an endorphin-related bonding mechanism. © 2016 Guardian News and Media Limited

Keyword: Emotions; Pain & Touch
Link ID: 22677 - Posted: 09.21.2016

By SABRINA TAVERNISE WASHINGTON — The Food and Drug Administration approved the first drug to treat patients with the most common childhood form of muscular dystrophy, a vivid example of the growing power that patients and their advocates wield over the federal government’s evaluation of drugs. The agency’s approval went against the recommendation of its experts. The main clinical trial of the drug was small, involving only 12 boys with the disease known as Duchenne muscular dystrophy, and did not have an adequate control group of boys who had the disease but did not take the drug. A group of independent experts convened by the agency this spring said there was not enough evidence that it was effective. But the vote was close. Large and impassioned groups of patients, including boys in wheelchairs, and their advocates, weighed in. The muscular dystrophy community is well organized and has lobbied for years to win approval for the drug, getting members of Congress to write letters to the agency. A decision on the drug had been delayed for months. The approval was so controversial that F.D.A. employees fought over it, a dispute that was taken to the agency’s commissioner, Dr. Robert M. Califf, who ultimately decided that it would stand. The approval delighted the drug’s advocates and sent the share price of the drug’s maker, Sarepta Therapeutics, soaring. But it was taken as a deeply troubling sign among drug policy experts who believe the F.D.A. has been far too influenced by patient advocates and drug companies, and has allowed the delicate balance in drug approvals to tilt toward speedy decisions based on preliminary data and away from more conclusive evidence of effectiveness and safety. © 2016 The New York Times Company

Keyword: Movement Disorders; Muscles
Link ID: 22671 - Posted: 09.20.2016

Carrie Arnold Could a protein that originated in a virus explain why men are more muscular than women? Viruses are notorious for their ability to cause disease, but they also shape human biology in less obvious ways. Retroviruses, which insert their genetic material into our genomes to copy themselves, have left behind genes that help to steer our immune systems and mold the development of embryos and the placenta. Now researchers report in PLOS Genetics that syncytin, a viral protein that enables placenta formation, also helps to increase muscle mass in male mice1. These results could partially explain a lingering mystery in biology: why the males of many mammalian species tend to be more muscular than females. “As soon as I read it, my mind started racing with the potential implications,” says evolutionary virologist Aris Katzourakis of the University of Oxford, UK. About 8% of the 3 billion pairs of As, Ts, Gs and Cs that make up our DNA are viral detritus. Many of those viral hand-me-downs have degraded into useless junk — but not all, as a series of discoveries over the past 15 years has revealed. In 2000, scientists discovered that syncytin, a protein that enables the formation of the placenta, actually originated as a viral protein that humans subsequently ‘borrowed’2. That original viral protein enables the retrovirus to fuse with host cells, depositing its entire genome into the safe harbour of the cytoplasm. Syncytin has changed little from this ancestral protein form; it directs certain placental cells to fuse with cells in the mother’s uterus, forming the outer layer of the placenta. © 2016 Macmillan Publishers Limited

Keyword: Muscles; Sexual Behavior
Link ID: 22650 - Posted: 09.13.2016

By Karen Weintraub Researchers have long believed that problems with mitochondria—the power plants of cells—underlie some cases of Parkinson’s disease. Now a new study details those problems, and suggests that they may form a common thread linking previously unexplained cases of the disease with those caused by different genetic anomalies or toxins. Finding a common mechanism behind different suspected causes of Parkinson’s suggests that there might also be a common means to measure, treat or cure it, says Marco Baptista, research director at the nonprofit Michael J. Fox Foundation, a leading center for study and advocacy in the fight against Parkinson’s. The study, published Thursday in Cell Stem Cell, did identify a possible way to reverse the damage of Parkinson’s—but only in individual cells and fruit flies. Finding a treatment that does the same thing in people will be challenging, Baptista says. Roughly one million Americans have Parkinson’s disease, which is characterized by motor problems and can cause other symptoms including cognitive and gastrointestinal difficulties. About 1 to 2 percent of cases are linked to mutations in the LRRK2 gene, with far fewer associated with genes known as PINK1 and Parkin. Exposure to environmental factors such as toxic chemicals can also lead to Parkinson’s, although most cases have no obvious cause. In the new paper Xinnan Wang, an assistant professor of neurosurgery at Stanford University, and her colleagues show that mitochondria are underpowered in several types of Parkinson’s and that these mitochondria also release toxic chemicals. Looking at fly models of the disease as well as cells taken from patients, the researchers found that they could correct these problems and reverse neurodegeneration if they reduced levels of a protein involved in mitochondrial activity. © 2016 Scientific American

Keyword: Parkinsons
Link ID: 22642 - Posted: 09.10.2016

By Abby Olena Mammalian prions are notoriously difficult as structural biology subjects, given their insolubility and tendency to aggregate. Researchers have now overcome these challenges to figure out the preliminary structure of a shortened form of infectious prion (PrPSc), which they report today (September 8) in PLOS Pathogens. “For the first time, we have a structure of an infectious mammalian prion,” said Giuseppe Legname of Scuola Internazionale Superiore di Studi Avanzati in Trieste, Italy, who was not involved in this study. “It’s a very important paper,” he added. “What we have done is to obtain a very simple, very preliminary idea of what the structure of these mammalian prions are,” said study coauthor Jesús Requena of the University of Santiago de Compostela in Spain. Requena and colleagues generated a shortened form of PrPSc by injecting a laboratory strain of prions into transgenic mice that express a truncated form of normal cellular prion protein (PrPC), which lacks the attachment of a membrane anchor present in full-length PrPSc. In nature, PrPC transforms into full-length PrPSc, which causes Creutzfeldt-Jakob disease in humans, scrapie in sheep, and mad cow disease. The absence of the membrane anchor in shortened PrPSc from the transgenic mice allowed the researchers to isolate a fairly homogeneous population of PrPSc. They confirmed that this population was infectious by inoculating wild-type mice, which then developed symptoms of prion disease. © 1986-2016 The Scientist

Keyword: Prions
Link ID: 22638 - Posted: 09.10.2016

By JACK HEALY CINCINNATI — On the day he almost died, John Hatmaker bought a packet of Oreos and some ruby-red Swedish Fish at the corner store for his 5-year-old son. He was walking home when he spotted a man who used to sell him heroin. Mr. Hatmaker, 29, had overdosed seven times in the four years he had been addicted to pain pills and heroin. But he hoped he was past all that. He had planned to spend that Saturday afternoon, Aug. 27, showing his son the motorcycles and enjoying the music at a prayer rally for Hope Over Heroin in this region stricken by soaring rates of drug overdoses and opioid deaths. But first, he decided as he palmed a sample folded into a square of paper, he would snort this. As he crumpled to the sidewalk, Mr. Hatmaker became one of more than 200 people to overdose in the Cincinnati area in the past two weeks, leaving three people dead in what the officials here called an unprecedented spike. Similar increases in overdoses have rippled recently through Indiana, Kentucky and West Virginia, overwhelming ambulance crews and emergency rooms and stunning some antidrug advocates. Addiction specialists said the sharp increases in overdoses were a grim symptom of America’s heroin epidemic, and of the growing prevalence of powerful synthetic opiates like fentanyl. The synthetics are often mixed into batches of heroin, or sprinkled into mixtures of caffeine, antihistamines and other fillers. In Cincinnati, some medical and law enforcement officials said they believed the overdoses were largely caused by a synthetic drug called carfentanil, an animal tranquilizer used on livestock and elephants with no practical uses for humans. Fentanyl can be 50 times stronger than heroin, and carfentanil is as much as 100 times more potent than fentanyl. Experts said an amount smaller than a snowflake could kill a person. © 2016 The New York Times Company

Keyword: Drug Abuse; Pain & Touch
Link ID: 22637 - Posted: 09.07.2016

By The Scientist Staff Growing up, we learn that there are five senses: sight, smell, touch, taste, and hearing. For the past five years, The Scientist has taken deep dives into each of those senses, explorations that revealed diverse mechanisms of perception and the impressive range of these senses in humans and diverse other animals. But as any biologist knows, there are more than just five senses, and it’s difficult to put a number on how many others there are. Humans’ vestibular sense, for example, detects gravity and balance through special organs in the bony labyrinth of the inner ear. Receptors in our muscles and joints inform our sense of body position. (See “Proprioception: The Sense Within.”) And around the animal kingdom, numerous other sense organs aid the perception of their worlds. The comb jelly’s single statocyst sits at the animal’s uppermost tip, under a transparent dome of fused cilia. A mass of cells called lithocytes, each containing a large, membrane-bound concretion of minerals, forms a statolith, which sits atop four columns called balancers, each made up of 150–200 sensory cilia. As the organism tilts, the statolith falls towards the Earth’s core, bending the balancers. Each balancer is linked to two rows of the ctenophore’s eight comb plates, from which extend hundreds of thousands of cilia that beat together as a unit to propel the animal. As the balancers bend, they adjust the frequency of ciliary beating in their associated comb plates. “They’re the pacemakers for the beating of the locomotor cilia,” says Sidney Tamm, a researcher at the Marine Biological Laboratory in Woods Hole, Massachusetts, who has detailed the structure and function of the ctenophore statocyst (Biol Bull, 227:7-18, 2014; Biol Bull, 229:173-84, 2015). © 1986-2016 The Scientist

Keyword: Pain & Touch; Chemical Senses (Smell & Taste)
Link ID: 22629 - Posted: 09.05.2016

By CATHERINE SAINT LOUIS In seven countries that recently experienced Zika outbreaks, there were also sharp increases in the numbers of people suffering from a form of temporary paralysis, researchers reported Wednesday. The analysis, published online in The New England Journal of Medicine, adds to substantial evidence that Zika infections — even asymptomatic ones — may bring on a paralysis called Guillain-Barré syndrome. The syndrome can be caused by a number of other factors, including infection with other viruses. Researchers studying the Zika epidemic in French Polynesia had estimated that roughly 1 in 4,000 people infected with the virus could develop the syndrome. The Centers for Disease Control and Prevention has said that the Zika virus is “strongly associated” with Guillain-Barré, but has stopped short of declaring it a cause of the condition. The new data suggest a telling pattern: Each country in the study saw unusual increases in Guillain-Barré that coincided with peaks in Zika infections, the researchers concluded. “It’s pretty obvious that in all seven sites there is a clear relationship,” said Dr. Marcos A. Espinal, the study’s lead author and the director of communicable diseases at the Pan American Health Organization, which collected data on confirmed and suspected cases of Zika infection and on the incidence of Guillain-Barré. “Something is going on.” In Venezuela, officials expected roughly 70 cases of Guillain-Barré from December 2015 to the end of March 2016, as mosquitoes were spreading the virus. Instead, there were 684 cases. Similarly, during five months in which the Zika virus was circulating in Colombia, officials recorded 320 cases of Guillain-Barré when there should have been about 100. From September 2015 to March 2016, while Zika infections peaked in El Salvador, cases of Guillain-Barré doubled to 184 from 92. © 2016 The New York Times Company

Keyword: Movement Disorders
Link ID: 22618 - Posted: 09.01.2016