Chapter 11. Motor Control and Plasticity
Follow us on Facebook and Twitter, or subscribe to our mailing list, to receive news updates. Learn more.
by Penny Sarchet Simon Sponberg of Georgia Institute of Technology in Atlanta and his team have figured out the secret to the moths' night vision by testing them with robotic artificial flowers (see above). By varying the speed of a fake flower's horizontal motion and changing brightness levels, the team tested moths' abilities under different conditions. It has been theorised that the moth brain slows down, allowing their visual system to collect light for longer, a bit like lengthening a camera's exposure. But the strategy might also introduce blur, making it hard to detect fast movement. If the moths were using this brain-slowing tactic, they would be expected to react to fast flower movements more slowly in darker conditions. The team found that there was indeed a lag. It helped them see motion in the dark while still allowing them to keep up with flowers swaying at normal speeds. The size of the lags matched the expected behaviour of a slowed nervous system, providing evidence that moths could be slowing down the action of neurons in their visual system. Previously, placing hawkmoths in a virtual obstacle courseMovie Camera revealed that they vary their navigation strategies depending on visibility conditions. Journal reference: Science, DOI: 10.1126/science.aaa3042 © Copyright Reed Business Information Ltd
Link ID: 21041 - Posted: 06.13.2015
By Sandra G. Boodman The test had become something of an annual ritual. Every year beginning when he turned 45, Thomas Clark Semmes, an IT consultant for the federal government, would visit his internist for a physical. In a standard test of the sensory system that is often part of a physical, the Baltimore doctor would prick the soles of Semmes’s feet with a pin. “He’d look at me and say, ‘Tell me when you feel it,’ and I’d say ‘I will when I can,’ ” Semmes, now 56, recalled of the pinprick test. Because he never felt anything, he said nothing. “It never really concerned me very much,” he recalled. His doctor would then dutifully jot something in his chart, never exploring it further. But in 2013, nearly a decade after that first test, a quick evaluation by a podiatrist revealed the reason for his unfeeling feet and provided an explanation for an anatomical oddity in one of Semmes’s close relatives. In retrospect, Semmes wishes he had asked his internist about the lack of sensation, but he assumed it wasn’t important — otherwise, the doctor would have said something. And as Semmes would later learn, not knowing what was wrong had cost him valuable time. “I definitely wish I’d been diagnosed sooner,” he said. “There are things that could have been done to lessen the impact.” Before 2013, Semmes never had much reason to think about his feet. He knew he had hammertoes — toes that bend downward at the middle joint as a result of heredity or trauma — as well as extremely high arches, but neither condition was painful or limiting. At least, he thought, he did not have bird legs like his father, whose limbs were so storklike that they were a running family joke. “I had big, muscular legs,” Semmes said.
Fergus Walsh Medical correspondent Scientists in Austria have created an artificial leg which allows the amputee to feel lifelike sensations from their foot. The recipient, Wolfang Rangger, who lost his right leg in 2007, said: "It feels like I have a foot again. It's like a second lease of life." Prof Hubert Egger of the University of Linz, said sensors fitted to the sole of the artificial foot, stimulated nerves at the base of the stump. He added it was the first time that a leg amputee had been fitted with a sensory-enhanced prosthesis. How it works Surgeons first rewired nerve endings in the patient's stump to place them close to the skin surface. Six sensors were fitted to the base of the foot, to measure the pressure of heel, toe and foot movement. These signals were relayed to a micro-controller which relayed them to stimulators inside the shaft where it touched the base of the stump. These vibrated, stimulating the nerve endings under the skin, which relayed the signals to the brain. Prof Egger said: "The sensors tell the brain there is a foot and the wearer has the impression that it rolls off the ground when he walks." Wolfgang Ranger, a former teacher, who lost his leg after a blood clot caused by a stroke, has been testing the device for six months, both in the lab and at home. He says it has given him a new lease of life He said: "I no longer slip on ice and I can tell whether I walk on gravel, concrete, grass or sand. I can even feel small stones." © 2015 BBC.
by Helen Thomson Imagine a world where you think of something and it happens. For instance, what if the moment you realise you want a cup of tea, the kettle starts boiling? That reality is on the cards, now that a brain implant has been developed that can decode a person's intentions. It has already allowed a man paralysed from the neck down to control a robotic arm with unprecedented fluidity. But the implications go far beyond prosthetics. By placing an implant in the area of the brain responsible for intentions, scientists are investigating whether brain activity can give away future decisions – before a person is even aware of making them. Such a result may even alter our understanding of free will. Fluid movement "These are exciting times," says Pedro Lopes, who works at the human-computer interaction lab at Hasso Plattner Institute in Potsdam, Germany. "These developments give us a glimpse of an exciting future where devices will understand our intentions as a means of adapting to our plans." The implant was designed for Erik Sorto, who was left unable to move his limbs after a spinal cord injury 12 years ago. The idea was to give him the ability to move a stand-alone robotic arm by recording the activity in his posterior parietal cortex – a part of the brain used in planning movements. "We thought this would allow us to decode brain activity associated with the overall goal of a movement – for example, 'I want to pick up that cup'," Richard Andersen at the California Institute of Technology in Pasadena told delegates at the NeuroGaming Conference in San Francisco earlier this month. © Copyright Reed Business Information Ltd
by Andy Coghlan A man in his mid-50s with Parkinson's disease had fetal brain cells injected into his brain last week. He is the first person in nearly 20 years to be treated this way – and could recover full control of his movements in roughly five years. "It seemed to go fine," says Roger Barker of the University of Cambridge, who is leading the international team that is reviving the procedure. The treatment was pioneered 28 years ago in Sweden, but two trials in the US reported no significant benefit within the first two years following the injections, and the procedure was abandoned in favour of deep brain stimulation treatments. What these trials overlooked is that it takes several years for fetal cells to "bed in" and connect properly to the recipient's brain. Many Swedish and North American recipients improved dramatically, around three years or more after the implants – long after the trials had finished. "In the best cases, patients who had the treatment pretty much went back to normal," says Barker. After the fetal cells were wired up properly in their brains, they started producing the brain signalling chemical dopamine – low levels of this cause the classic Parkinson's symptom of uncontrolled movements. In fact, the cells produced so much dopamine that many patients could stop taking their Parkinson's drugs. "The prospect of not having to take medications for Parkinson's is fantastic," says James Beck of the Parkinson's Disease Foundation in the US. © Copyright Reed Business Information Ltd
by Helen Thomson A brain implant that can decode what someone wants to do has allowed a man paralysed from the neck down to control a robotic arm with unprecedented fluidity – and enjoy a beer at his own pace. Erik Sorto was left unable to move any of his limbs after an accident severed his spinal cord 12 years ago. People with similar injuries have previously controlled prosthetic limbs using implants placed in their motor cortex – an area of the brain responsible for the mechanics of movement. This is far from ideal because it results in delayed, jerky motions as the person thinks about all the individual aspects of the movement. When reaching for a drink, for example, they would have to think about moving their arm forward, then left, then opening their hand, then closing their hand around the cup and so on. Richard Andersen at the California Institute of Technology in Pasadena and his colleagues hoped they could achieve a more fluid movement by placing an implant in the posterior parietal cortex – a part of the brain involved in planning motor movements. "We thought this would allow us to decode brain activity associated with the overall goal of a movement – for example, 'I want to pick up that cup', rather than the individual components," said Anderson at the NeuroGaming Conference in San Francisco, California, where he presented the work this month. © Copyright Reed Business Information Ltd.
Link ID: 20972 - Posted: 05.23.2015
Scientists at Mayo Clinic, Jacksonville, Florida created a novel mouse that exhibits the symptoms and neurodegeneration associated with the most common genetic forms of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS, Lou Gehrig’s disease), both of which are caused by a mutation in the a gene called C9ORF72. The study was partially funded by the National Institutes of Health and published in the journal Science. More than 30,000 Americans live with ALS, which destroys nerves that control essential movements, including speaking, walking, breathing and swallowing. After Alzheimer’s disease, FTD is the most common form of early onset dementia. It is characterized by changes in personality, behavior and language due to loss of neurons in the brain’s frontal and temporal lobes. Patients with mutations in the chromosome 9 open reading frame 72 (C9ORF72) gene have all or some symptoms associated with both disorders. “Our mouse model exhibits the pathologies and symptoms of ALS and FTD seen in patients with theC9ORF72 mutation,” said the study’s lead author, Leonard Petrucelli, Ph.D., chair and Ralph and Ruth Abrams Professor of the Department of Neuroscience at Mayo Clinic, and a senior author of the study. “These mice could greatly improve our understanding of ALS and FTD and hasten the development of effective treatments.” To create the model, Ms. Jeannie Chew, a Mayo Graduate School student and member of Dr. Petrucelli’s team, injected the brains of newborn mice with a disease-causing version of the C9ORF72 gene. As the mice aged, they became hyperactive, anxious, and antisocial, in addition to having problems with movement that mirrored patient symptoms.
By Lisa Sanders, M.D On Thursday we challenged Well readers to solve the difficult case of twin sisters who, in the prime of youth, developed a weakness that forced them to use their arms to rise from a chair. Nearly 300 of you wrote in with thoughts on this difficult case. Many of you recognized that this was likely to be a genetic disorder, though I greatly admired the “House”-ian thinking that led to a host of possible reasons why two sisters, living in different states, might develop the same symptoms independent of their shared DNA. It took this patient, Katie Buryk, four years to get her answer, which was: Late onset Tay-Sachs disease Although several of you made this difficult diagnosis, the first to do so was George Bonadurer, a second year medical student at Mayo Medical School in Rochester, Minn. He says he recently read about this disease in a book of unusual cases that had come to the Mayo clinic for help. This is actually Mr. Bonadurer’s second win of this contest. Strong work! Tay-Sachs disease was first identified by two physicians, independently, in the 1880s. Dr. Warren Tay was an ophthalmologist in London. Dr. Bernard Sachs was a neurologist in New York City. Each described a disease in infants that caused profound weakness, blindness and, usually by age 4, death. Careful consideration of cases over the following decades showed that the disease was inherited and often seen in children of Ashkenazi descent. Studying the patterns of inheritance, it became clear that both parents had to have the abnormal gene and that each of their children would have a one in four chance of being born with the disease. The terrible manifestations of the disease derive from an inherited inability to make an essential protein in the brain. This protein acts to break down discarded components of the cells. Without this protein, these discarded cell parts accumulate, interrupting normal nerve and brain cell functioning. This mechanism and the missing protein was identified in 1969, allowing for the development of a test for carriers. Since the development of this test, the incidence of Tay-Sachs in the United States has dropped by 90 percent. © 2015 The New York Times Company
Andrew Griffin Companies are taking out a huge amount of patents related to reading brainwaves, according to analysis, with a range of different applications. Fewer than 400 neuro-technology related patents were filed between 2000-2009. But in 2010 alone that reached 800, and last year 1,600 were filed, according to research company SharpBrains. The patents are for a range of uses, not just for the healthcare technology that might be expected. The company with the most patents is market research firm Nielsen, which has 100. Microsoft also has 89 related patents. Other uses of the technology that have been patented include devices that can change the thoughts of feelings of those that they are used on. But there are still medical uses — some of those patents awarded include technology to measure brain lesions and improve vision. The volume and diversity of the patents shows that we are at the beginning of “the pervasive neurotechnology age”, the company’s CEO Alvaro Fernandez said. "Neurotech has gone well beyond medicine, with non-medical corporations, often under the radar, developing neurotechnologies to enhance work and life," said Fernandez.
Roger Dobson Tapping your fingers on the table is usually a sign of boredom or irritation. But not all tappers are equal, it seems. Men drum their digits slightly faster than women and people in their twenties tap substantially faster than people twice their age. The results of the first study into finger-tapping speeds also found that smokers tap a little faster than non-smokers and fit people tap faster than those who avoid exercise. The research, carried out by scientists at two universities in Istanbul – Bogazici University and Fatih University – examined the tapping rates and “finger load capacities” of 148 people aged between 18 and 85. Each participant was asked to perform a one-minute tapping exercise on a keyboard at “maximum volitional tempo”. Researchers found that the index finger on the right hand of both men and women was the fastest digit, achieving a tapping rate of up to five beats a second among those in their twenties. The middle finger was almost as nifty as the index finger, but the little finger – the slowest digit in the bunch – was capable only of a sluggish 3.8 taps a second among people in the same age group. At first glance, the study might appear to be rather frivolous. But a deeper understanding of finger tapping could aid the design of computer keyboards and musical instruments. It may also aid researchers who use finger-tapping tests for medical assessment of neurological conditions such as Parkinson’s disease, schizophrenia and Alzheimer’s.
Scientists have raised hopes that they may be able to create a vaccine to block the progress of Parkinson’s disease. They believe new research provides evidence that an abnormal protein may trigger the condition. If the theory is correct, researchers say it might be possible to prime a person’s immune system – using a special vaccine – so it is ready to attack the rogue protein as it passes through the body. In this way, the protein would be prevented from destroying a person’s dopamine-manufacturing cells, where the disease inflicts its greatest damage. This new vision of Parkinson’s has been arousing excitement among researchers. “It has transformed the way we see Parkinson’s,” said Roger Barker, professor of clinical neurosciences at Cambridge University. Parkinson’s does not usually affect people until they are over 50. However, researchers have uncovered recent evidence that suggests it may be caused by an event occurring 10 to 20 years before its main symptoms – tremors, rigidity and slowness of movement – manifest themselves. “If you ask Parkinson’s patients if, in the past, they have experienced loss of sense of smell or suffer from disturbed sleep or have problems with their bowels, very often they reply they have,” said Barker, whose work is backed by the charity Parkinson’s UK, whose Parkinson Awareness week ends on Sunday. “Frequently these patients manifest symptoms several years before it becomes apparent they have the disease. We now believe there is a link.” © 2015 Guardian News and Media Limited
Link ID: 20855 - Posted: 04.28.2015
By Emily Dwass In the frightening world of brain tumors, “benign” is a good word to hear. But even a nonmalignant tumor can be dangerous — especially if, as in my case, it goes undetected, becoming a stealth invader. “Anecdotally, we often hear about women who were originally misdiagnosed — sometimes for years,” said Tom Halkin, a spokesman for the patient advocacy nonprofit National Brain Tumor Society. When I developed tingling in my limbs 12 years ago, two Los Angeles neurologists diagnosed Guillain-Barré syndrome, a disorder in which the immune system attacks the nervous system. The symptoms of numbness and weakness ebbed and flowed for three years. Then one day, I couldn’t slide my right foot into a flip-flop. This got me a ride in a magnetic resonance imaging machine, which revealed a brain mass the size of a tennis ball. It was a benign meningioma, a tumor that grows in the membranes surrounding the brain and spinal cord. After the diagnosis, I consulted with Los Angeles surgeons. “We’re going to cut your head open like a pumpkin,” one told me. I chose someone else, who had a stellar reputation, who was compassionate, and who did not compare my skull to a squash. “You’re cured,” he said as I awoke in the operating room. Recovery took about six weeks and went smoothly, except for my right foot, which remains partly numb. I relearned to walk and to drive with my left foot, using adaptive equipment. Had my tumor been diagnosed earlier, I might have avoided a large craniotomy and permanent foot issues. “It’s critical to find these tumors when they are small, when radiosurgery is an option, rather than when they are very big or produce a lot of symptoms, at which point it’s not optimal to treat them without doing open surgery,” said Dr. Susan Pannullo, the director of neuro-oncology and neurosurgical radiosurgery at NewYork-Presbyterian Hospital and Weill Cornell Medical College. © 2015 The New York Times Company
Keyword: Movement Disorders
Link ID: 20854 - Posted: 04.28.2015
By Jerry Adler Smithsonian Magazine | In London, Benjamin Franklin once opened a bottle of fortified wine from Virginia and poured out, along with the refreshment, three drowned flies, two of which revived after a few hours and flew away. Ever the visionary, he wondered about the possibility of incarcerating himself in a wine barrel for future resurrection, “to see and observe the state of America a hundred years hence.” Alas, he wrote to a friend in 1773, “we live in an age too early . . . to see such an art brought in our time to its perfection.” If Franklin were alive today he would find a kindred spirit in Ken Hayworth, a neuroscientist who also wants to be around in 100 years but recognizes that, at 43, he’s not likely to make it on his own. Nor does he expect to get there preserved in alcohol or a freezer; despite the claims made by advocates of cryonics, he says, the ability to revivify a frozen body “isn’t really on the horizon.” So Hayworth is hoping for what he considers the next best thing. He wishes to upload his mind—his memories, skills and personality—to a computer that can be programmed to emulate the processes of his brain, making him, or a simulacrum, effectively immortal (as long as someone keeps the power on). Hayworth’s dream, which he is pursuing as president of the Brain Preservation Foundation, is one version of the “technological singularity.” It envisions a future of “substrate-independent minds,” in which human and machine consciousness will merge, transcending biological limits of time, space and memory. “This new substrate won’t be dependent on an oxygen atmosphere,” says Randal Koene, who works on the same problem at his organization, Carboncopies.org. “It can go on a journey of 1,000 years, it can process more information at a higher speed, it can see in the X-ray spectrum if we build it that way.”
By Brady Dennis In recent months, Pasadena-based Genervon has galvanized many patients with ALS by repeatedly touting the results of 12-week, 12-person trial involving the company's drug, GM604. The company asserted its early results were “statistically significant,” “very robust” and “dramatic.” It also has said it "submitted an accelerated approval application" to the FDA which, if approved, "would allow immediate access" to patients with ALS, also known as Lou Gehrig's disease. But the Wall Street Journal reported Monday that Genervon said in an email that it is “at the point of communicating with FDA about whether [the agency] would accept our formal application” for accelerated approval. In other words, the company has not yet submitted a New Drug Application, a step needed to officially set the FDA approval process in motion. The company's acknowledgement that it has not filed an NDA appears to contradict earlier press releases and statements made by the firm's owners, Winston and Dorothy Ko -- or at least to have sown confusion about the actual status of GM604. In one February press release, for example, the company said that in a meeting with the FDA, "three times during the one-hour meeting we requested that the FDA grant GM604 accelerated approval." Asking, however, is not the same as filing the necessary paperwork and the accompanying data required for the FDA to accept it as sufficient. The difference might seem to be a matter of semantics. But the real-world consequence is that, if Genervon has no application pending at the FDA, there is no imminent decision for the FDA to make about approving GM604.
Keyword: ALS-Lou Gehrig's Disease
Link ID: 20833 - Posted: 04.22.2015
Carl Zimmer In 1998, Dr. Philip A. Starr started putting electrodes in people’s brains. A neurosurgeon at the University of California, San Francisco, Dr. Starr was treating people with Parkinson’s disease, which slowly destroys essential bits of brain tissue, robbing people of control of their bodies. At first, drugs had given his patients some relief, but now they needed more help. After the surgery, Dr. Starr closed up his patients’ skulls and switched on the electrodes, releasing a steady buzz of electric pulses in their brains. For many patients, the effect was immediate. “We have people who, when they’re not taking their meds, can be frozen,” said Dr. Starr. “When we turn on the stimulator, they start walking.” First developed in the early 1990s, deep brain stimulation, or D.B.S., was approved by the Food and Drug Administration for treating Parkinson’s disease in 2002. Since its invention, about 100,000 people have received implants. While D.B.S. doesn’t halt Parkinson’s, it can turn back the clock a few years for many patients. Yet despite its clear effectiveness, scientists like Dr. Starr have struggled to understand what D.B.S. actually does to the brain. “We do D.B.S. because it works,” said Dr. Starr, “but we don’t really know how.” In a recent experiment, Dr. Starr and his colleagues believe they found a clue. D.B.S. may counter Parkinson’s disease by liberating the brain from a devastating electrical lock-step. The new research, published on Monday in Nature Neuroscience, may help scientists develop better treatments for Parkinson’s disease. It may also help researchers adapt D.B.S. for treatment of such brain disorders as depression and obsessive compulsive disorder. © 2015 The New York Times Company
Link ID: 20817 - Posted: 04.18.2015
by Jessica Hamzelou An exoskeleton that enables movement and provides tactile feedback has helped eight paralysed people regain sensation and move previously paralysed muscles "I FELT the ball!" yelled Juliano Pinto as he kicked off the Football World Cup in Brazil last year. Pinto, aged 29 at the time, lost the use of his lower body after a car accident in 2006. "It was the most moving moment," says Miguel Nicolelis at Duke University in North Carolina, head of the Walk Again Project, which developed the thought-controlled exoskeleton that enabled Pinto to make his kick. Since November 2013, Nicolelis and his team have been training Pinto and seven other people with similar injuries to use the exoskeleton – a robotic device that encases the limbs and converts brain signals into movement. The device also feeds sensory information to its wearer, which seems to have partially reawakened their nervous system. When Nicolelis reassessed his volunteers after a year of training, he found that all eight people had regained sensations and the ability to move muscles in their once-paralysed limbs. "Nobody expected it at all," says Nicolelis, who presented the results at the Brain Forum in Lausanne, Switzerland, on 31 March. "When we first saw the level of recovery, there was not a single person in the room with a dry eye." When a person's spinal cord is injured, the connection between body and brain can be damaged, leaving them unable to feel or move parts of their body. If a few spinal nerves remain, people can sometimes regain control over their limbs, although this can involve years of rehabilitation. © Copyright Reed Business Information Ltd.
Link ID: 20805 - Posted: 04.16.2015
by Hal Hodson For a few days last summer, a handful of students walked through a park behind the University of Hannover in Germany. Each walked solo, but followed the same route as the others: made the same turns, walked the same distance. This was odd, because none of them knew where they were going. Instead, their steps were steered from a phone 10 paces behind them, which sent signals via bluetooth to electrodes attached to their legsMovie Camera. These stimulated the students' muscles, guiding their steps without any conscious effort. Max Pfeiffer of the University of Hannover was the driver. His project directs electrical currentMovie Camera into the students' sartorius, the longest muscle in the human body, which runs from the inside of the knee to the top of the outer thigh. When it contracts, it pulls the leg out and away from the body. To steer his test subjects left, Pfeiffer would zap their left sartorius, opening their gait and guiding them in that direction. Pfeiffer hopes his system will free people's minds up for other things as they navigate the world, allowing them to focus on their conversation or enjoy their surroundings. Tourists could keep their eyes on the sights while being imperceptibly guided around the city. Acceptance may be the biggest problem, although it is possible that the rise of wearable computing might help. Pfeiffer says the electrode's current causes a tingling sensation that diminishes the more someone uses the system. Volunteers said they were comfortable with the system taking control of their leg muscles, but only if they felt they could take control back. © Copyright Reed Business Information Ltd
Link ID: 20761 - Posted: 04.06.2015
By Amy Ellis Nutt and Brady Dennis For people with amyotrophic lateral sclerosis, which attacks the body’s motor neurons and renders a person unable to move, swallow or breathe, the search for an effective treatment has been a crushing disappointment. The only drug available for the disease, approved two decades ago, typically extends life just a few months. Then in the fall, a small California biotech company named Genervon began extolling the benefits of GM604, its new ALS drug. In an early-stage trial with 12 patients, the results were “statistically significant,” “very robust” and “dramatic,” the company said in news releases. Such enthusiastic pronouncements are unusual for such a small trial. In February, Genervon took an even bolder step: It applied to the Food and Drug Administration for “accelerated approval,” which allows promising treatments for serious or life-threatening diseases to bypass costly, large-scale efficacy trials and go directly to market. ALS patients responded by pleading with the FDA, in emotional videos and e-mails, to grant broad access to the experimental drug. Online forums lit up, and a Change.org petition calling for rapid approval attracted more than a half-million signatures. “Why would anyone oppose it?” asked ALS patient David Huntley in a letter read aloud in the past week at a rally on Capitol Hill. Huntley, a former triathlete, can no longer speak or travel, so his wife, Linda Clark, flew from San Diego to speak for him.
Keyword: ALS-Lou Gehrig's Disease
Link ID: 20752 - Posted: 04.04.2015
Davide Castelvecchi Boots rigged with a simple spring-and-ratchet mechanism are the first devices that do not require power aids such as batteries to make walking more energy efficient. People walking in the boots expend 7% less energy than they do walking in normal shoes, the devices’ inventors report on 1 April in Nature1. That may not sound like much, but the mechanics of the human body have been shaped by millions of years of evolution, and some experts had doubted that there was room for further improvement in human locomotion, short of skating along on wheels. “It is the first paper of which I’m aware that demonstrates that a passive system can reduce energy expenditure during walking,” says Michael Goldfarb, a mechanical engineer at Vanderbilt University in Nashville, Tennessee, who develops exoskeletons for aiding people with disabilities. As early as the 1890s, inventors tried to boost the efficiency of walking by using devices such as rubber bands, says study co-author Gregory Sawicki, a biomedical engineer and locomotion physiologist at North Carolina State University in Raleigh. More recently, engineers have built unpowered exoskeletons that enable people to do tasks such as lifting heavier weights — but do not cut down the energy they expend. (Biomechanists still debate whether the running ‘blades’ made famous by South African sprinter Oscar Pistorius are more energetically efficient than human feet.2, 3) For their device, Sawicki and his colleagues built a mechanism that parallels human physiology. When a person swings a leg forward to walk, elastic energy is stored mostly in the Achilles tendon of their standing leg. That energy is released when the standing leg's foot pushes into the ground and the heel lifts off, propelling the body forwards. “There is basically a catapult in our ankle,” Sawicki says. © 2015 Nature Publishing Group
Link ID: 20750 - Posted: 04.02.2015
By Maggie Fox and Jane Derenowski A new strain of the polio-like EV-D68 may be causing the rare and mystifying cases of muscle weakness that's affected more than 100 kids across the United States, researchers reported Monday. They say they've found the strongest evidence yet that the virus caused the polio-like syndrome, but they also say it appears to be rare and might have to do with the genetic makeup of the patients. No other germ appears to be responsible, the team reports in the journal Lancet Infectious Diseases. But because most kids were tested many days after they first got sick, it may be impossible to ever know for sure. The body will have cleared the virus itself by then, said Dr. Charles Chiu of the University of California San Francisco, who helped conduct the study. "This is a virus that causes the common cold," Chiu told NBC News. "Parents don't bring their kids in until they are really sick. By that time, typically, the viral levels may be very, very low or undetectable." "Every single virus that we found in the children corresponded to new strain of the virus, called B-1." Enterovirus D68 (EV-D68) is one of about 100 different enteroviruses that infect people. They include polio but also a range of viruses that cause cold-like symptoms. Polio's the only one that is vaccinated against; before widespread vaccination it crippled 35,000 people a year in the United States.
Keyword: Movement Disorders
Link ID: 20739 - Posted: 03.31.2015