Chapter 5. The Sensorimotor System
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by Hal Hodson Video: Bionic arm trumps flesh after elective amputation Bionic hands are go. Three men with serious nerve damage had their hands amputated and replaced by prosthetic ones that they can control with their minds. The procedure, dubbed "bionic reconstruction", was carried out by Oskar Aszmann at the Medical University of Vienna, Austria. The men had all suffered accidents which damaged the brachial plexus – the bundle of nerve fibres that runs from the spine to the hand. Despite attempted repairs to those nerves, the arm and hand remained paralysed. "But still there are some nerve fibres present," says Aszmann. "The injury is so massive that there are only a few. This is just not enough to make the hand alive. They will never drive a hand, but they might drive a prosthetic hand." This approach works because the prosthetic hands come with their own power source. Aszmann's patients plug their hands in to charge every night. Relying on electricity from the grid to power the hand means all the muscles and nerves need do is send the right signals to a prosthetic. Before the operation, Aszmann's patients had to prepare their bodies and brains. First he transplanted leg muscle into their arms to boost the signal from the remaining nerve fibres. Three months later, after the nerves had grown into the new muscle, the men started training their brains. © Copyright Reed Business Information Ltd.
Link ID: 20617 - Posted: 02.26.2015
Sara Reardon Annie is lying down when she answers the phone; she is trying to recover from a rare trip out of the house. Moving around for an extended period leaves the 56-year-old exhausted and with excruciating pain shooting up her back to her shoulders. “It's really awful,” she says. “You never get comfortable.” In 2011, Annie, whose name has been changed at the request of her lawyer, slipped and fell on a wet floor in a restaurant, injuring her back and head. The pain has never eased, and forced her to leave her job in retail. Annie sued the restaurant, which has denied liability, for several hundred thousand dollars to cover medical bills and lost income. To bolster her case that she is in pain and not just malingering, Annie's lawyer suggested that she enlist the services of Millennium Magnetic Technologies (MMT), a Connecticut-based neuroimaging company that has a centre in Birmingham, Alabama, where Annie lives. MMT says that it can detect pain's signature using functional magnetic resonance imaging (fMRI), which measures and maps blood flow in the brain as a proxy for neural activity. The scan is not cheap — about US$4,500 — but Steven Levy, MMT's chief executive, says that it is a worthwhile investment: the company has had ten or so customers since it began offering the service in 2013, and all have settled out of court, he says. If the scans are admitted to Annie's trial, which is expected to take place early this year, it could establish a legal precedent in Alabama. Most personal-injury cases settle out of court, so it is impossible to document how often brain scans for pain are being used in civil law. But the practice seems to be getting more common, at least in the United States, where health care is not covered by the government and personal-injury cases are frequent. Several companies have cropped up, and at least one university has offered the service. © 2015 Nature Publishing Group
By Michelle Roberts Health editor, BBC News online Scientists have proposed a new idea for detecting brain conditions including Alzheimer's - a skin test. Their work, which is at an early stage, found the same abnormal proteins that accumulate in the brain in such disorders can also be found in skin. Early diagnosis is key to preventing the loss of brain tissue in dementia, which can go undetected for years. But experts said even more advanced tests, including ones of spinal fluid, were still not ready for clinic. If they were, then doctors could treatment at the earliest stages, before irreversible brain damage or mental decline has taken place. Brain biomarker Investigators have been hunting for suitable biomarkers in the body - molecules in blood or exhaled breath, for example, that can be measured to accurately and reliably signal if a disease or disorder is present. Dr Ildefonso Rodriguez-Leyva and colleagues from the University of San Luis Potosi, Mexico, believe skin is a good candidate for uncovering hidden brain disorders. Skin has the same origin as brain tissue in the developing embryo and might, therefore, be a good window to what's going on in the mind in later life - at least at a molecular level - they reasoned. Post-mortem studies of people with Parkinson's also reveal that the same protein deposits which occur in the brain with this condition also accumulate in the skin. To test if the same was true in life as after death, the researchers recruited 65 volunteers - 12 who were healthy controls and the remaining 53 who had either Parkinson's disease, Alzheimer's or another type of dementia. They took a small skin biopsy from behind the ear of each volunteer to test in their laboratory for any telltale signs of disease. Specifically, they looked for the presence of two proteins - tau and alpha-synuclein. © 2015 BBC.
By JON PALFREMAN EUGENE, Ore. — FOUR years ago, I was told I had Parkinson’s disease, a condition that affects about one million Americans. The disease is relentlessly progressive; often starting with a tremor in one limb on one side of the body, it spreads. The patient’s muscles become more rigid, frequently leading to a stooped posture, and movements slow down and get smaller and less fluid. As the disease advances — usually over a number of years — the patient becomes more and more disabled, experiencing symptoms from constipation to sleep disorders to cognitive impairment. Can Parkinson’s be slowed, stopped or even reversed? Can the disease be prevented before it starts, like polio and smallpox? More than at any time in history, success seems possible. Having sequenced the human genome, biomedical researchers have now set their sights on the ultimate frontier — the human brain. The formidable puzzle is to figure out how a three-pound lump of mostly fatty matter enables us to perform a seemingly endless number of tasks, like walking, seeing, hearing, smelling, tasting, touching, thinking, loving, hating, speaking and writing ... and why those awesome abilities break down with neurological disease. Many scientists view Parkinson’s as a so-called pathfinder. If they can figure out what causes Parkinson’s, it may open the door to understanding a host of other neurodegenerative diseases — and to making sense of an organ of incredible complexity. In Parkinson’s, the circuitry in a tiny region of the brain called the basal ganglia becomes dysfunctional. Along with the cerebellum, the basal ganglia normally acts as a kind of adviser that helps people learn adaptive skills by classic conditioning — rewarding good results with dopamine bursts and punishing errors by withholding the chemical. Babies rely on the basal ganglia to learn how to deploy their muscles to reach, grab, babble and crawl, and later to accomplish many complex tasks without thinking. For example, when a tennis player practices a stroke over and over again, the basal ganglia circuitry both rewards and “learns” the correct sequence of activities to produce, say, a good backhand drive automatically. © 2015 The New York Times Company
Link ID: 20606 - Posted: 02.24.2015
By Sandra G. Boodman Catherine Cutter’s voice was her livelihood. A professor of food science at Penn State University, the microbiologist routinely lectured to large classes about food safety in the meat and poultry industries. But in 2008, after Cutter’s strong alto voice deteriorated into a raspy whisper, she feared her academic career might be over.How could she teach if her students could barely hear her? The classroom wasn’t the only area of Cutter’s life affected by her voicelessness. The mother of two teenagers, Cutter, now 52, recalls that she “couldn’t yell — or even talk” to her kids and would have to knock on a wall or countertop to get their attention. Social situations became increasingly difficult as well, and going to a restaurant was a chore. Using the drive-through at her bank or dry cleaner was out of the question because she couldn’t be heard. “I just retreated,” said Cutter, who sought assistance from nearly two dozen specialists for her baffling condition. The remedies doctors prescribed — when they worked at all — resulted in improvement that was temporary at best. For two years Cutter searched in vain for help. It arrived in the form of a neurosurgeon she consulted for a second opinion about potentially risky surgery to correct a different condition. He suggested a disorder that had never been mentioned, a diagnosis that proved to be correct — and correctable. Until then, “everyone had been looking in the wrong place,” Cutter said.
Keyword: Movement Disorders
Link ID: 20605 - Posted: 02.24.2015
By Emily Underwood SAN JOSE, CALIFORNIA—If you've ever had a migraine, you know it's no ordinary headache: In addition to throbbing waves of excruciating pain, symptoms often include nausea, visual disturbances, and acute sensitivity to sounds, smells, and light. Although there's no cure for the debilitating headaches, which affect roughly 10% of people worldwide, researchers are starting to untangle their cause and find more effective treatments. Here today at the annual meeting of AAAS (which publishes Science), Science sat down with Teshamae Monteith, a clinical neurologist at the University of Miami Health System in Florida, today to discuss the latest advances in the field. Q: How is our understanding of migraine evolving? A: It's more complicated than we thought. In the past, researchers thought of migraine as a blood vessel disorder, in part because some patients can feel a temple pulsation during a migraine attack. Now, migraine is considered a sensory perceptual disorder, because so many of the sensory systems—light, sound, smell, hearing—are altered. During an attack, patients have concentration impairments, appetite changes, mood changes, and sleeping is off. What fascinates me is that patients are often bothered by manifestations of migraine, such as increased sensitivity to light, in between attacks, suggesting that they may be wired differently, or their neurobiology may be altered. About two-thirds of patients with acute migraine attacks have allodynia, a condition that makes people so sensitive to certain stimuli that even steam from a shower can be incredibly painful. One way to view it is that migraineurs at baseline are at a different threshold for sensory stimuli. © 2015 American Association for the Advancement of Science.
Keyword: Pain & Touch
Link ID: 20585 - Posted: 02.16.2015
By Siri Carpenter “I don’t look like I have a disability, do I?” Jonas Moore asks me. I shake my head. No, I say — he does not. Bundled up in a puffy green coat in a drafty Starbucks, Moore, 35 and sandy-haired, doesn’t stand out in the crowd seeking refuge from the Wisconsin cold. His handshake is firm and his blue eyes meet mine as we talk. He comes across as intelligent and thoughtful, if perhaps a bit reserved. His disability — autism — is invisible. That’s part of the problem, says Moore. Like most people with autism spectrum disorders, he finds relationships challenging. In the past, he has been quick to anger and has had what he calls “meltdowns.” Those who don’t know he has autism can easily misinterpret his actions. “People think that when I do misbehave I’m somehow intentionally trying to be a jerk,” Moore says. “That’s just not the case.” His difficulty managing emotions has gotten him into some trouble, and he’s had a hard time holding onto jobs — an outcome he might have avoided, he says, if his coworkers and bosses had better understood his intentions. Over time, things have gotten better. Moore has held the same job for five years, vacuuming commercial buildings on a night cleaning crew. He attributes his success to getting the right amount of medication and therapy, to time maturing him and to the fact that he now works mostly alone. Moore is fortunate. His parents help support him financially. He has access to good mental health care. And with the help of the state’s division of vocational rehabilitation, he has found a job that suits him. Many adults with autism are not so lucky. © Society for Science & the Public 2000 - 2015.
Link ID: 20574 - Posted: 02.13.2015
|By Stephani Sutherland More than half a billion people carry a genetic mutation that incapacitates the enzyme responsible for clearing alcohol from the body. The deficiency is responsible for an alcohol flush reaction, colloquially known as the “Asian glow” because the vast majority of carriers are descendants of the Han Chinese. Now research published last September in Science Translational Medicine suggests that the mutation might also compromise carriers' pain tolerance. The finding points to a new target for pharmaceutical pain relief and implies that drinking alcohol might exacerbate inflammatory conditions such as arthritis. When people consume alcohol, the body breaks it down into several by-products, including chemicals called aldehydes. These compounds are noxious if they remain in the system too long, causing flushing, nausea, dizziness and other symptoms of the alcohol flush reaction. In most people, aldehydes are immediately broken down by the enzyme aldehyde dehydrogenase (ALDH2), but in those with the genetic mutation, the enzyme is incapacitated. Researchers led by Daria Mochly-Rosen of Stanford University genetically modified some mice to carry the mutation seen in humans that disables ALDH2. When they injected those mice and normal mice in the paw with an inflammatory compound that turned it red and swollen, mice carrying the mutation showed increased sensitivity to a poke compared with those with functioning ALDH2. When the researchers treated all the rodents with a novel drug called Alda-1 that boosts ALDH2 activity, the pain symptoms were reduced regardless of whether they carried the gene mutation. © 2015 Scientific American
By Gary Stix Everyone knows that ALS is a very bad disease, an awareness underscored by the recent Ice Bucket Challenge. The death of neurons that results in paralysis can be caused by specific genetic mutations. But in most cases, single genes are not the culprit. So researchers have looked for other risk factors that might play a role. Studies have tagged cigarette smoking as a definite danger. Alcohol, another plausible suspect, has yielded equivocal results in previous investigations. To get a better read on ethanol (some earlier studies were small), researchers from Sweden’s Lund University looked at giant medical registries from that country, compiled at various times between 1973 and 2010. They found that individuals who were classified as problem drinkers were a little more than half as likely to be diagnosed with ALS as those who didn’t have “alcohol use disorder.” More than 420,000 problem drinkers were registered during the period surveyed—and there were 7965 patients who received an ALS diagnosis. The study, just reported in The European Journal of Neurology, controlled for gender, education and place of birth, among other factors. But it was unable to tell why drinking might help. It did lead, though, to a number of intriguing speculations. The researchers cited studies in rats, done by other groups, that indicated that ingestion of alcohol decreased the number of brain cells called astrocytes that bore high levels of a certain protein linked to the pathology of ALS. © 2015 Scientific American
By Nick Lavars Keeping ourselves upright is something most of us shouldn't need to think a whole lot about, given we've been doing it almost our entire lives. But when it comes to dealing with more precarious terrain, like walking on ice or some sort of tight rope, you might think some pretty significant concentration is required. But researchers have found that even in our moments of great instability, our subconsciousness is largely responsible for keeping us from landing on our backsides. This is due to what scientists are describing as a mini-brain, a newly mapped bunch of neurons in the spinal cord which processes sensory information and could lead to new treatment for ailing motor skills and balance. "How the brain creates a sensory percept and turns it into an action is one of the central questions in neuroscience," says Martin Goulding, senior author of the research paper and professor at the Salk Institute. "Our work is offering a really robust view of neural pathways and processes that underlie the control of movement and how the body senses its environment. We’re at the beginning of a real sea change in the field, which is tremendously exciting.” The work of Goulding and his team focuses on how the body processes light touch, in particular the sensors in our feet that detect changes in the surface underfoot and trigger a reaction from the body. "Our study opens what was essentially a black box, as up until now we didn’t know how these signals are encoded or processed in the spinal cord," says Goulding. "Moreover, it was unclear how this touch information was merged with other sensory information to control movement and posture."
Keyword: Movement Disorders
Link ID: 20561 - Posted: 02.07.2015
By Angelina Fanous After the height of the Ice Bucket Challenge last fall, I found myself at a dinner party where the conversation turned to A.L.S. — amyotrophic lateral sclerosis — the disease for which millions were dousing themselves to raise awareness and money. “Would you rather have A.L.S., Alzheimer’s, or Parkinson’s?” someone asked. All those diseases are devastating, but A.L.S. is unique in that it usually kills within two to three years of diagnosis. It was just a game to my friends, all of whom are in their 20s. Everyone chose A.L.S., agreeing that it would be the fastest and therefore easiest death. But I stayed silent. I hadn’t yet told my friends that I had been diagnosed with A.L.S. in July — two months after my 29th birthday. Had I been healthy, I might have answered A.L.S., too. But since my diagnosis, all I have wanted is more time. When I first noticed I couldn’t type with my left hand, the doctors narrowed down it down to two options: a treatable autoimmune disease or A.L.S. They initially began treating me for the autoimmune disease. About once a month, we shut down my immune system so it would stop attacking my central nervous system. But with no immune system I made regular visits to the E.R. “At least it’s not A.L.S.,” I consoled myself. When the treatment didn’t work and the weakness spread to my left leg and right hand, A.L.S. was the only remaining possibility. Still, I did that socially acceptable but also borderline insane thing where I sought second, third and fourth opinions. I voluntarily subjected myself to excruciating medical tests. I got shocked with electricity, had my spinal fluid drained, and underwent a surgery to remove a piece of my muscles and nerves, all in the hopes of finding a different diagnosis. All of the tests confirmed the diagnosis of A.L.S. © 2015 The New York Times Company
Keyword: ALS-Lou Gehrig's Disease
Link ID: 20556 - Posted: 02.05.2015
by Bethany Brookshire The windup before the pitch. The take-away before the golf swing. When you learn to pitch a softball, swing a golf club or shoot a basketball, you learn that preparation is important. You also learn about follow-through — the upswing of the golf club or the bend in the elbow after a softball pitch. It’s the preparation and the execution that get the ball across the plate, so why should we care about follow-through? In theory, once the ball has left your hands or sailed away from your club or racket, there’s no movement you could make that could affect what happens next. So while some follow-through might be important to diffuse the energy you just put into your shot, it shouldn’t really matter whether you swing your golf club up in an arc, whip it off to the side or club your opponent over the head with it. But follow-through is in fact quite important, and not just as an extension of the movements that preceded it. Consistent follow-through actually helps performance, reports neuroscientist Ian Howard and colleagues at the University of Plymouth in England. The finding gives coaches some science to back up their training, and helps scientists understand how the brain accesses motor memories. Howard has always been interested in how the brain learns movement tasks. “The first study we did looked at the preparation movement — you move backwards and then you move forwards [as in a golf swing],” he says. His lab found that the preparation before a particular motion had a strong effect on how our brains learn and recall motor movements. © Society for Science & the Public 2000 - 2015.
Keyword: Movement Disorders
Link ID: 20549 - Posted: 02.05.2015
By Lenny Bernstein Parkinson's Disease patients secretly treated with a placebo instead of their regular medication performed better when told they were receiving a more expensive version of the "drug," researchers reported Wednesday in an unprecedented study that involved real patients. The research shows that the well-documented "placebo effect" -- actual symptom relief brought about by a sham treatment or medication -- can be enhanced by adding information about cost, according to the lead author of the study. It is the first time that concept has been demonstrated using people with a real illness, in this case Parkinson's, a progressive neurological disease that has no cure, according to an expert not involved in the study. "The potentially large benefit of placebo, with or without price manipulations, is waiting to be untapped for patients with [Parkinson's Disease], as well as those with other neurologic and medical diseases," the authors wrote in a study published online Wednesday in the journal Neurology. But deceiving actual patients in a research study raised ethical questions about violating the trust involved in a doctor-patient relationship. Most studies in which researchers conceal their true aims or other information from subjects are conducted with healthy volunteers. This one was subjected to a lengthy review before it was allowed to proceed, and, in an editorial that accompanied the article, two other physicians wrote that "the authors do not mention whether there was any possible effect (reduction) on trust in doctors or on willingness to engage in future clinical research."
Ewen Callaway Since August 2014, more than 100 children and young adults in the United States have developed a mysterious paralysis. Many of them had fevers before losing strength in one or more limbs, and the cases coincided with a wider epidemic of a little-known respiratory pathogen. That virus, enterovirus D68 (EV-D68), is the leading candidate for the cause of the paralysis, which few children have recovered from. Yet researchers have not definitively linked the two, or determined how the virus could cause the children’s symptoms. A study published on 28 January in The Lancet1 that describes a cluster of cases from Denver, Colorado, strengthens the link, but falls short of providing a 'smoking gun'. Here is what we know about the virus — and what scientists are trying to find out. It belongs to the enterovirus family, which includes poliovirus and the pathogens that cause common colds; it is most similar to the rhinoviruses that cause respiratory infections. Although EV-D68 was first isolated in the 1960s, it is relatively uncommon among enteroviruses circulating worldwide. However, since August 2014, the virus has been linked to more than 1,000 respiratory infections in the United States, some of them severe, and France has seen cases, too. John Watson, a medical epidemiologist at the US Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, says that last year, EV-D68 was the predominant type of enterovirus circulating in the country. “That’s a first,” he says. Genome sequencing2 of viruses recovered from respiratory cases in St Louis, Missouri, shows that the EV-D68 strain circulating in the United States is most closely related to viruses that caused a pneumonia-like illness in three children in Thailand in 20113. What is the evidence that links EV-D68 to the cases of paralysis? © 2015 Nature Publishing Group
Keyword: Movement Disorders
Link ID: 20533 - Posted: 01.29.2015
The presence of a romantic partner during painful medical procedures could make women feel worse rather than better, researchers say. A small study found this increase in pain was most pronounced in women who tended to avoid closeness in their relationships. The authors say bringing a loved one along for support may not be the best strategy for every patient. The work appears in the journal Social Cognitive and Affective Neuroscience. Researchers from University College London, King's College London and the University of Hertfordshire say there has been very little scientific research into the effects of a partner's presence on someone's perception of pain, despite this being common medical advice. They recruited 39 heterosexual couples and asked them a series of questions to measure how much they sought or avoided closeness and emotional intimacy in relationships. Each female volunteer was then subjected to a series of painful laser pulses while her partner was in and then out of the room. The women were asked to score their level of pain. They also had their brain activity measured using a medical test called an EEG. The researchers found that certain women were more likely to score high levels of pain while their partner was in the room. These were women who said they preferred to avoid closeness, trusted themselves more than their partners and felt uncomfortable in their relationships. © 2015 BBC
Keyword: Pain & Touch
Link ID: 20502 - Posted: 01.21.2015
by Jessica Hamzelou YOU'RE not imagining the pain. But your brain might be behind it, nonetheless. For the first time, it is possible to distinguish between brain activity associated with pain from a physical cause, such as an injury, and that associated with pain linked to your state of mind. A fifth of the world's population is thought to experience some kind of chronic pain – that which has lasted longer than three months. If the pain has no clear cause, people can find themselves fobbed off by doctors who they feel don't believe them, or given ineffective or addictive painkillers. But a study led by Tor Wager at the University of Colorado, Boulder, now reveals that there are two patterns of brain activity related to pain. One day, brain scans could be used to work out your relative components of each, helping to guide treatment. "Pain has always been a bit of a puzzle," says Ben Seymour, a neuroscientist at the University of Cambridge. Hearing or vision, for example, can be traced from sensory organs to distinct brain regions, but pain is more complex, and incorporates thoughts and emotions. For example, studies have linked depression and anxiety to the development of pain conditions, and volunteers put in bad moods have a lower tolerance for pain. So does this mean we can think our way into or out of pain? To find out, Wager and his colleagues used fMRI to look at the brain activity of 33 healthy adults while they were feeling pain. First, the team watched the changing activity as they applied increasing heat to the volunteers' arms. As the heat became painful, a range of brain structures lit up. The pattern was common to all the volunteers, so Wager's team called it the neurologic pain signature. © Copyright Reed Business Information Ltd.
By SAM ROBERTS When he was just 5 years old, Thomas Graboys declared that he intended to become a doctor. As a young physician, he visited a nephew serving in the Peace Corps in Mauritania and remained for two months, treating dozens of patients a day. He skied and played tennis and joined fellow cardiologists as the drummer in a rock band called the Dysrhythmics. In Boston, he was famous as a member of the team that diagnosed the Celtics star Reggie Lewis’s heart defect before he died abruptly on a basketball court. In short, “he was a medical version of one of Tom Wolfe’s masters of the universe,” one reviewer concluded after Dr. Graboys (pronounced GRAY-boys) published his autobiography. But barely 60, after experiencing horrific nightmares, frequently flailing in bed, losing his memory, suffering tremors and finally collapsing on his wedding day, he acknowledged that he was suffering from Parkinson’s disease and the onset of dementia. He informed his patients that he had no choice but to close his practice. “My face is often expressionless, though I still look younger than my 63 years,” he recalled in the autobiography, “Life in the Balance: A Physician’s Memoir of Life, Love, and Loss With Parkinson’s Disease and Dementia,” which was published in 2008. “I am stooped,” he continued. “I shuffle when I walk, and my body trembles. My train of thought regularly runs off the rails. There is no sugarcoating Parkinson’s. There is no silver lining here. There is anger, pain, and frustration at being victimized by a disease that can to some extent be managed but cannot be cured.” After managing for more than a decade, Dr. Graboys died on Jan. 5 at his home in Chestnut Hill, Mass., his daughter, Penelope Graboys Blair, said. The cause was complications of Lewy Body Dementia, which was diagnosed after his Parkinson’s. He was 70. © 2015 The New York Times Company
Link ID: 20485 - Posted: 01.15.2015
By Peter Holley "Lynchian," according to David Foster Wallace, "refers to a particular kind of irony where the very macabre and the very mundane combine in such a way as to reveal the former's perpetual containment within the latter." Perhaps no other word better describes the onetime fate of Martin Pistorius, a South African man who spent more than a decade trapped inside his own body involuntarily watching "Barney" reruns day after day. "I cannot even express to you how much I hated Barney," Martin told NPR during the first episode of a new program on human behavior, "Invisibilia." The rest of the world thought Pistorius was a vegetable, according to NPR. Doctors had told his family as much after he'd fallen into a mysterious coma as a healthy 12-year-old before emerging several years later completely paralyzed, unable to communicate with the outside world. The nightmarish condition, which can be caused by stroke or an overdose of medication, is known as "total locked-in syndrome," and it has no cure, according to the National Institute of Neurological Disorders and Stroke. In a first-person account for the Daily Mail, Pistorius described the period after he slipped into a coma: I was completely unresponsive. I was in a virtual coma but the doctors couldn’t diagnose what had caused it. When he finally did awaken in the early 1990s, around the age of 14 or 15, Pistorius emerged in a dreary fog as his mind gradually rebooted itself.
By Will Boggs MD NEW YORK (Reuters Health) - Patients with chronic pain show signs of glial activation in brain centers that modulate pain, according to results from a PET-MRI study. "Glia appears to be involved in the pathophysiology of chronic pain, and therefore we should consider developing therapeutic approaches targeting glia," Dr. Marco L. Loggia from Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, told Reuters Health by email. "Glial activation is accompanied by many cellular responses, which include the production and release of substances (such as so-called 'pro-inflammatory cytokines') that can sensitize the pain pathways in the central nervous system," he explained. "Thus, glial activation is not a mere reaction to a pain state but actively contributes to the establishment and/or maintenance of persistent pain." To test their hypothesis that patients with chronic pain demonstrate in vivo activation of brain glia, Dr. Loggia's team imaged the brains of 19 individuals diagnosed with chronic low back pain as well as 25 pain-free healthy volunteers using 11C-PBR28, a PET radioligand that binds to the translocator protein (TSPO), a protein upregulated in activated microglia and reactive astrocytes in animal models of pain. Each patient exhibited higher 11C-PBR28 uptakes than his/her age-, sex-, and TSPO genotype-matched control in the thalamus, and there were no brain regions for which the healthy controls showed statistically higher uptakes than the patients with chronic low back pain. © 2015 Scientific American
By CATHERINE SAINT LOUIS A nationwide outbreak of a respiratory virus last fall sent droves of children to emergency departments. The infections have now subsided, as researchers knew they would, but they have left behind a frightening mystery. Since August, 103 children in 34 states have had an unexplained, poliolike paralysis of an arm or leg. Each week, roughly three new cases of so-called acute flaccid myelitis are still reported to the Centers for Disease Control and Prevention. Is the virus, called enterovirus 68, really the culprit? Experts aren’t certain: Unexplained cases of paralysis in children happen every year, but they are usually scattered and unrelated. After unusual clusters of A.F.M. appeared this fall, enterovirus 68 became the leading suspect, and now teams of researchers are racing to figure out how it could have led to such damage. “It’s unsatisfying to have an illness and not know what caused it,” said Dr. Samuel Dominguez, an epidemiologist and an infectious disease specialist at Children’s Hospital Colorado, which has had the largest cluster of patients. For many families, the onset of persistent limb paralysis has been a bewildering experience. Roughly two thirds of the children with A.F.M. have reported some improvement, according to the C.D.C. About a third show none. Only one child has fully recovered. In August, Jack Wernick, a first grader in Kingsport, Tenn., developed a “crummy little cold,” said his father, Dan Wernick, who works for a paper company. It seemed ordinary, until Jack complained that his right arm was heavy, his face began drooping and pain started shooting down his right leg. © 2015 The New York Times Company
Keyword: Movement Disorders
Link ID: 20477 - Posted: 01.13.2015