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By CATHERINE SAINT LOUIS Driven by a handful of reports of poliolike symptoms in children, federal health officials have asked the nation’s physicians to report cases of children with limb weakness or paralysis along with specific spinal-cord abnormalities on a magnetic resonance imaging test. As a respiratory illness known as enterovirus 68 is sickening thousands of children from coast to coast, officials are trying to figure out if the weakness could be linked to the virus. The emergence of several cases of limb weakness among children in Colorado put doctors on alert in recent months. The Centers for Disease Control and Prevention issued an advisory on Friday, and this week, other cases of unexplained muscle weakness or paralysis came to light in Michigan, Missouri and Massachusetts. The C.D.C. is investigating the cases of 10 children hospitalized at Children’s Hospital Colorado with unexplained arm or leg weakness since Aug. 9. Some of the children, who range in age from 1 to 18, also developed symptoms like facial drooping, double vision, or difficulty swallowing or talking. Four of them tested positive for enterovirus 68, also known as enterovirus D68, which has recently caused severe respiratory illness in children in 41 states and the District of Columbia. One tested positive for rhinovirus, which can cause the common cold. Two tested negative. Two patients’ specimens are still being processed; another was never tested. It is unclear whether the muscle weakness is connected to the viral outbreak. “It’s one possibility we are looking at, but certainly not the only possibility,” said Mark Pallansch, director of the C.D.C.’s division of viral diseases. © 2014 The New York Times Company
By Jocelyn Kaiser A virus that shuttles a therapeutic gene into cells has strengthened the muscles, improved the motor skills, and lengthened the lifespan of mice afflicted with two neuromuscular diseases. The approach could one day help people with a range of similar disorders, from muscular dystrophy to amyotrophic lateral sclerosis, or ALS. Many of these diseases involve defective neuromuscular junctions—the interface between neurons and muscle cells where brain signals tell muscles to contract. In one such disease, a form of familial limb-girdle myasthenia, people carry two defective copies of the gene called DOK7, which codes for a protein that’s needed to form such junctions. Their hip and shoulder muscles atrophy over many years, and some eventually have trouble breathing or end up in a wheelchair. Mice similarly missing a properly working Dok7 gene are severely underweight and die within a few weeks. In the new study, researchers led by molecular biologist Yuji Yamanashi of the University of Tokyo first injected young mice engineered to have defective Dok7 with a harmless virus carrying a good copy of the Dok7 gene, which is expressed only in muscle. Within about 7 weeks, the rodents recovered. Their muscle cells cranked out the DOK7 protein, and under a microscope their muscles had larger neuromuscular junctions than those of untreated mice with defective Dok7. What’s more, the mice grew to a healthy body weight and had essentially normal scores on tests of motor skills and muscle strength. © 2014 American Association for the Advancement of Science.
Ian Sample, science editor Scientists have prevented muscle wastage in mice with a form of muscular dystrophy by editing the faulty gene that causes the disease. The radical procedure could not be performed in humans, but researchers believe the work raises hopes for future gene-editing therapies to stop the disease from progressing in people. Duchenne muscular dystrophy is caused by mutations in a gene on the X chromosome and affects around one in 3,500 boys. Because girls have two X chromosomes they tend not to be affected, but can be carriers of the disease. The pivotal gene is used to make a protein called dystrophin which is crucial for muscle fibre strength. Without the protein, muscles in the body, including the heart and skeletal muscles, weaken and waste away. Most patients die by the age of 25 from breathing or heart problems. Researchers in the US used a powerful new gene-editing procedure called CRISPR to correct mutations in the dystrophin gene in mice that were destined to develop the disease. They extracted mouse embryos from their mothers and injected them with the CRISPR biological machinery, which found and corrected the faulty gene. After the injections, the mouse embryos were reimplanted in females and carried to term. Tests on the mice found that the therapy helped to restore levels of dystrophin, and that their skeletal muscle performed normally, even when only 17% of their cells contained corrected genes. The procedure could not be done in humans, but the proof-of-principle experiment demonstrates that correcting only a small proportion of cells could lead to a dramatic improvement for patients. © 2014 Guardian News and Media Limited
Dr. Mark Saleh Bell's palsy is a neurological condition frequently seen in emergency rooms and medical offices. Symptoms consist of weakness involving all muscles on one side of the face. About 40,000 cases occur annually in the United States. Men and women are equally affected, and though it can occur at any age, people in their 40s are especially vulnerable. The facial weakness that occurs in Bell's palsy prevents the eye of the affected side from blinking properly and causes the mouth to droop. Because the eyelid doesn't close sufficiently, the eye can dry and become irritated. Bell's palsy symptoms progress fairly rapidly, with weakness usually occurring within three days. If the progression of weakness is more gradual and extends beyond a week, Bell's palsy may not be the problem, and other potential causes should be investigated. Those with certain medical conditions, such as diabetes or pregnancy, are at greater risk of developing Bell's palsy, and those who have had one episode have an 8 percent chance of recurrence. Bell's palsy is thought to occur when the seventh cranial (facial) nerve becomes inflamed. The nerve controls the muscles involved in facial expression and is responsible for other functions, including taste perception, eye tearing and salivation. The cause of the inflammation is unknown, although the herpes simplex virus and autoimmune inflammation are possible causes. © 2014 Hearst Communications, Inc.
Related chapters from BP7e: Chapter 11: Motor Control and Plasticity; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 11: Emotions, Aggression, and Stress
Link ID: 19637 - Posted: 05.20.2014
by Clare Wilson A genetic tweak can make light work of some nervous disorders. Using flashes of light to stimulate modified neurons can restore movement to paralysed muscles. A study demonstrating this, carried out in mice, lays the path for using such "optogenetic" approaches to treat nerve disorders ranging from spinal cord injury to epilepsy and motor neuron disease. Optogenetics has been hailed as one of the most significant recent developments in neuroscience. It involves genetically modifying neurons so they produce a light-sensitive protein, which makes them "fire", sending an electrical signal, when exposed to light. So far optogenetics has mainly been used to explore how the brain works, but some groups are exploring using it as therapy. One stumbling block has been fears about irreversibly genetically manipulating the brain. In the latest study, a team led by Linda Greensmith of University College London altered mouse stem cells in the lab before transplanting them into nerves in the leg – this means they would be easier to remove if something went wrong. "It's a very exciting approach that has a lot of potential," says Ziv Williams of Harvard Medical School in Boston. Greensmith's team inserted an algal gene that codes for a light-responsive protein into mouse embryonic stem cells. They then added signalling molecules to make the stem cells develop into motor neurons, the cells that carry signals to and from the spinal cord to the rest of the body. They implanted these into the sciatic nerve – which runs from the spinal cord to the lower limbs – of mice whose original nerves had been cut. © Copyright Reed Business Information Ltd.
Walking backward may seem a simple task, but researchers don’t know how the mind controls this behavior. A study published online today in Science provides the first glimpse of the brain circuit responsible—at least in fruit flies. Geneticists created 3500 strains of the insects, each with a temperature-controlled switch that turned random networks of neurons on when the flies entered an incubator. One mutant batch of fruit flies started strolling in reverse when exposed to warmth (video, right panel), which the team dubbed “moonwalkers,” in honor of Michael Jackson’s famous dance. Two neurons were responsible for the behavior. One lived in the brain and extended its connections to the end of the ventral nerve cord—the fly’s version of a spine, which runs along its belly. The other neuron had the opposite orientation—it started at the bottom of the nerve cord and sent its messaging cables—or axons—into the brain. The neuron in the brain acted like a reverse gear in a car; when turned on, it triggered reverse walking. The researchers say this neuron is possibly a command center that responds to environmental cues, such as, “Hey! I see a wall in front of me.” The second neuron functioned as the brakes for forward motion, but it couldn’t compel the fly to moonwalk. It may serve as a fail-safe that reflexively prevents moving ahead, such as when the fly accidentally steps onto a very cold floor. Using the two neurons as a starting point, the team will trace their links to sensory neurons for touch, sight, and smell, which feed into and control the moonwalking network. No word yet on the neurons responsible for the Macarena. © 2014 American Association for the Advancement of Science
For years, some biomedical researchers have worried that a push for more bench-to-bedside studies has meant less support for basic research. Now, the chief of one of the National Institutes of Health’s (NIH’s) largest institutes has added her voice—and hard data—to the discussion. Story Landis describes what she calls a “sharp decrease” in basic research at her institute, a trend she finds worrisome. In a blog post last week, Landis, director of the $1.6 billion National Institute of Neurological Disorders and Stroke (NINDS), says her staff started out asking why, in the mid-2000s, NINDS funding declined for R01s, the investigator-initiated grants that are the mainstay of most labs. After examining the aims and abstracts of grants funded between 1997 and 2012, her staff found that the portion of NINDS competing grant funding that went to basic research has declined (from 87% to 71%) while applied research rose (from 13% to 29%). To dig deeper, the staffers divided the grants into four categories—basic/basic; basic/disease-focused; applied/translational; and applied/clinical. Here, the decline in basic/basic research was “striking”: It fell from 52% to 27% of new and competing grants, while basic/disease-focused has been rising (see graph). The same trend emerged when the analysts looked only at investigator-initiated grants, which are proposals based on a researcher’s own ideas, not a solicitation by NINDS for proposals in a specific area. The shift could reflect changes in science and “a natural progression of the field,” Landis writes. Or it could mean researchers “falsely believe” that NINDS is not interested in basic studies and they have a better shot at being funded if they propose disease-focused or applied studies. The tight NIH budget and new programs focused on translational research could be fostering this belief, she writes. When her staff compared applications submitted in 2008 and 2011, they found support for a shift to disease-focused proposals: There was a “striking” 21% decrease in the amount of funding requested for basic studies, even though those grants had a better chance of being funded. © 2014 American Association for the Advancement of Science.
Related chapters from BP7e: Chapter 11: Motor Control and Plasticity; Chapter 1: Biological Psychology: Scope and Outlook
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 1: An Introduction to Brain and Behavior
Link ID: 19440 - Posted: 04.02.2014
By James Gallagher Health and science reporter, BBC News US doctors are warning of an emerging polio-like disease in California where up to 20 people have been infected. A meeting of the American Academy of Neurology heard that some patients had developed paralysis in all four limbs, which had not improved with treatment. The US is polio-free, but related viruses can also attack the nervous system leading to paralysis. Doctors say they do not expect an epidemic of the polio-like virus and that the infection remains rare. Polio is a dangerous and feared childhood infection. The virus rapidly invades the nervous system and causes paralysis in one in 200 cases. It can be fatal if it stops the lungs from working. There have been 20 suspected cases of the new infection, mostly in children, in the past 18 months, A detailed analysis of five cases showed enterovirus-68 - which is related to poliovirus - could be to blame. In those cases all the children had been vaccinated against polio. Symptoms have ranged from restricted movement in one limb to severe weakness in both legs and arms. Dr Emanuelle Waubant, a neurologist at the University of California, San Francisco, told the BBC: "There has been no obvious increase in the pace of new cases so we don't think we're about to experience an epidemic, that's the good news. BBC © 2014
By Katherine Harmon Courage Unless you’ve eaten sannakji, the Korean specialty of semi-live octopus, you might never have had a squirming octopus arm in your mouth. But you’ve most likely had a very similar experience. In fact, you’re probably having one right now. Octopus arms might seem strange and mysterious, but they are remarkably similar to the human tongue. Known as muscular hydrostats, both of these appendages can easily bend, extend and change shape (remember that time you had to stretch out your tongue to lick that last bit of chocolate pudding from the bottom of the cup?). Researchers are hoping a new interdisciplinary project to look at movement in the octopus arm and the human tongue will shed light on how both of these complex structures are activated. This, in turn, could help scientists understand neurological diseases that affect speech, such as Parkinson’s. “The human tongue is a very different muscular system than the rest of the human body,” Khalil Iskarous, an assistant professor of linguistics at the University of Southern California who is helping to lead the research, said in a prepared statement. “Our bodies are vertebrate mechanisms that operate by muscle working on bone to move. The tongue is in a different muscular family, much like an invertebrate. It’s entirely muscle—it’s muscle moving muscle.” Both move by compressing fluid in one section of a muscle, creating movement in another part. But we know little about exactly how that movement is initiated and so finely controlled. © 2014 Scientific American
Helen Shen To researchers who study how living things move, the octopus is an eight-legged marvel, managing its array of undulating appendages by means of a relatively simple nervous system. Some studies have suggested that each of the octopus’s tentacles has a 'mind' of its own, without rigid central coordination by the animal’s brain1. Now neuroscientist Guy Levy and his colleagues at the Hebrew University in Jerusalem report that the animals can rotate their bodies independently of their direction of movement, reorienting them while continuing to crawl in a straight line. And, unlike species that use their limbs to move forward or sideways relative to their body's orientation, octopuses tend to slither around in all directions. The team presented its findings on 10 November at the annual meeting of the Society for Neuroscience in San Diego, California. The new description of octopus movement is “not how one would imagine that would happen, but it seems to give a lot of control to the animal", says Gal Haspel, a neuroscientist at the New Jersey Institute of Technology in Newark. Haspel studies worm locomotion, and he was also surprised by the researchers’ report that the octopus pushes itself with worm-like contractions of its tentacles. Different combinations flex together to produce movement in different directions. Levy, who began the research as part of a project to design and control flexible, octopus-like robots, says that the work could also help to uncover basic biological principles of locomotion. Levy’s team deconstructed octopus movement using a transparent tank rigged with a system of mirrors and video cameras, in which they tested nine adult common octopuses (Octopus vulgaris). © 2013 Nature Publishing Group
Related chapters from BP7e: Chapter 11: Motor Control and Plasticity; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 18936 - Posted: 11.16.2013
by Ashley Yeager The compound that gives mold its musty smell can cause changes in fruit flies’ brains that mimic those of patients with Parkinson’s disease. Scientists do not know the exact cause of Parkinson’s disease, but studies have shown that exposure to human-made chemicals may be a risk factor for developing the movement disorder. Now researchers have found that the chemical 1-octen-3-ol, which mold naturally emits, kills flies’ brain cells that transmit dopamine, a compound involved in controlling movement. The mold molecule also reduces dopamine levels in the flies’ brains. In experiments with human cells, the mold chemical also blocked the cells from taking in dopamine, researchers report November 11 in the Proceedings of the National Academy of Sciences. The results offer insight into cases of movement problems that doctors have associated with fungi exposure, the scientists say. © Society for Science & the Public 2000 - 2013
Related chapters from BP7e: Chapter 11: Motor Control and Plasticity; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 18911 - Posted: 11.12.2013
By JAMES GORMAN SEATTLE — To hear Michael Dickinson tell it, there is nothing in the world quite as wonderful as a fruit fly. And it’s not because the fly is one of the most important laboratory animals in the history of biology, often used as a simple model for human genetics or neuroscience. “I don’t think they’re a simple model of anything,” he says. “If flies are a great model, they’re a great model for flies. “These animals, you know, they’re not like us,” he says, warming to his subject. “We don’t fly. We don’t have a compound eye. I don’t think we process sensory information the same way. The muscles that they use are just incredibly much more sophisticated and interesting than the muscles we use. “They can taste with their wings,” he adds, as his enthusiasm builds. “No one knows any reason why they have taste cells on their wing. Their bodies are just covered with sensors. This is one of the most studied organisms in the history of science, and we’re still fundamentally ignorant about many features of its basic biology. It’s like having an alien in your lab. “And,” he says, pausing, seeming puzzled that the world has not joined him in open-mouthed wonder for his favorite creature, “they can fly!” If he had to define his specialty, Dr. Dickinson, 50, who counts a MacArthur “genius” award among his honors, would call himself a neuroethologist. As such, he studies the basis of behavior in the brain at the University of Washington, in Seattle. In practice he is a polymath of sorts who has targeted the fruit fly, Drosophila melanogaster, and its flying behavior for studies that involve physics, mathematics, neurobiology, computer vision, muscle physiology and other disciplines. © 2013 The New York Times Company
Lying in bed, unable to move a muscle, so-called locked-in patients have few ways to communicate with the outside world. But researchers have now found a way to use the widening and narrowing of the pupils to send a message, potentially helping these patients break the silence. Doctors use the constriction of pupils under bright light to test whether a patient’s brain stem is intact. But our pupils also show the opposite response—dilation—based on our thoughts and emotions, says Wolfgang Einhäuser, a neurophysicist at Philipps University of Marburg in Germany. Einhäuser had been struggling to interpret changes in pupil size during decision-making when he began to wonder about a different application. He contacted Steven Laureys, a member of the Coma Science Group at the University Hospital of Liège in Belgium, to explore how the pupil could be used to communicate a choice. Laureys works with locked-in patients, who have normal mental acuity but are paralyzed and unable to express thoughts to those around them. Many can control only the muscles that move their eyes; some, not even that. They can learn to communicate using EEG technology, in which electrodes on the scalp detect changes in brain activity. But applying the electrode cap is time-consuming, and the equipment is expensive, Einhäuser says. “If you imagine doing that every day, basically to communicate, that’s troublesome.” To find a different technique, Einhäuser, Laureys, and colleagues reached back in time. “The pieces have been there since the early ’60s,” Einhäuser says. A 1964 study showed that our pupils dilate when we perform mental arithmetic, like attempting to multiply 27 and 15 with no pencil and paper, and that harder tasks led to more dramatic dilation. The team set up a camera and a laptop to explore this automatic response. © 2012 American Association for the Advancement of Science.
Related chapters from BP7e: Chapter 11: Motor Control and Plasticity; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 14: Attention and Consciousness
Link ID: 18466 - Posted: 08.06.2013
Brendan Maher Hugh Rienhoff says that his nine-year-old daughter, Bea, is “a fire cracker”, “a tomboy” and “a very sassy, impudent girl”. But in a forthcoming research paper, he uses rather different terms, describing her hypertelorism (wide spacing between the eyes) and bifid uvula (a cleft in the tissue that hangs from the back of the palate). Both are probably features of a genetic syndrome that Rienhoff has obsessed over since soon after Bea’s birth in 2003. Unable to put on much muscle mass, Bea wears braces on her skinny legs to steady her on her curled feet. She is otherwise healthy, but Rienhoff has long worried that his daughter’s condition might come with serious heart problems. Rienhoff, a biotech entrepreneur in San Carlos, California, who had trained as a clinical geneticist in the 1980s, went from doctor to doctor looking for a diagnosis. He bought lab equipment so that he could study his daughter’s DNA himself — and in the process, he became a symbol for the do-it-yourself biology movement, and a trailblazer in using DNA technologies to diagnose a rare disease (see Nature 449, 773–776; 2007). “Talk about personal genomics,” says Gary Schroth, a research and development director at the genome-sequencing company Illumina in San Diego, California, who has helped Rienhoff in his search for clues. “It doesn’t get any more personal than trying to figure out what’s wrong with your own kid.” Now nearly a decade into his quest, Rienhoff has arrived at an answer. Through the partial-genome sequencing of his entire family, he and a group of collaborators have found a mutation in the gene that encodes transforming growth factor-β3 (TGF-β3). Genes in the TGF-β pathway control embryogenesis, cell differentiation and cell death, and mutations in several related genes have been associated with Marfan syndrome and Loeys–Dietz syndrome, both of which have symptomatic overlap with Bea’s condition. The mutation, which has not been connected to any disease before, seems to be responsible for Bea’s clinical features, according to a paper to be published in the American Journal of Medical Genetics. © 2013 Nature Publishing Group,
by Mara Hvistendahl and Martin Enserink A mysterious group of viruses known for their circular genome has been detected in patients with severe disease on two continents. In papers published independently this week, researchers report the discovery of agents called cycloviruses in Vietnam and in Malawi. The studies suggest that the viruses—one of which also widely circulates in animals in Vietnam—could be involved in brain inflammation and paraplegia, but further studies are needed to confirm a causative link. The discovery in Vietnam grew out of a frustrating lack of information about the causes of some central nervous system (CNS) infections such as encephalitis and meningitis, which can be fatal or leave lasting damage. "There are a lot of severe cases in the hospitals here, and very often we can't come to a diagnosis," says H. Rogier van Doorn, a clinical virologist with the Oxford University Clinical Research Unit in the Hospital for Tropical Diseases, Ho Chi Minh City. Extensive diagnostic tests turn up pathogens in only about half of patients with such infections, he says. Van Doorn and colleagues in Vietnam and at the University of Amsterdam's Academic Medical Center hoped that they might uncover new pathogens using a powerful new technique called next-generation sequencing. The group sequenced all the genetic material in cerebrospinal fluid (CSF) samples taken from more than 100 patients with undiagnosed CNS infections. One sample batch returned a promising lead: a viral sequence belonging to the Circoviridae family. © 2010 American Association for the Advancement of Science
The paralyzing syndrome Guillain-Barré syndrome isn't linked to receiving common vaccines, according to a U.S. study. Concerns about the association of Guillain-Barré syndrome with vaccines have "flourished" since there was a hint of an increased risk after the 1976 swine flu vaccine campaign. It hasn’t been clearly linked since then. The syndrome is an acute inflammatory disease that results in destruction of a nerve’s myelin sheath and some nerves, which in severe cases can progress to complete paralysis and even death. Researchers from the U.S. Centers for Disease Control and Prevention and Kaiser Permanente Vaccine Study Center in Oakland, Calif. looked back at cases of GBS over 13 years in the state that were confirmed by a neurologist who reviewed the medical records. In the 13-year study period 415 patients were confirmed with GBS only 25 had received a vaccine within six weeks before onset of the disease. "In summary, this study did not find any association between influenza vaccine or any other vaccine and development of GBS within six weeks following vaccination," Dr. Roger Baxter, co-director of the Kaiser Permanente Vaccine Study Center and his co-authors concluded in Monday's online issue of Clinical Infectious Diseases. © CBC 2013
Related chapters from BP7e: Chapter 11: Motor Control and Plasticity; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 11: Emotions, Aggression, and Stress
Link ID: 18306 - Posted: 06.25.2013
By ALLISON HERSH LONDON I’M in line at the supermarket holding three items close to my chest. But I might as well be juggling my Kleenex box, toothpaste tube and an orange. Because — as you’d surely notice if you were behind me in line — I‘m bent forward at a sharp angle, which makes holding things difficult. I know you don’t want to stare, but you do. Maybe you think you’re being considerate when you say, apropos of nothing, “You look like you’re in pain.” Well, thanks, I am — but I’ll resist replying the way I want (“You look like you’re having a bad hair day”). I’m sorry. I know you mean well. Anyway it’s my turn at the register which means I’m closer to being at home where I can lie down and wait for the spasms to subside. Besides, if I told you what my issue was, you would probably shrug and reply that you’d never heard of it. There aren’t any public service announcements about it or telethons. No Angelina Jolies to bravely inform the world. Just people like me, in supermarket checkout lines. And this, I realize, is at the core of a problem that extends beyond me and my condition and that affects the way all of us respond to illnesses, some of which are the subject of public attention — and resources — and some of which are not. I have dystonia, a neurological disorder. Some years ago, for reasons no one knows, the muscles in my back and neck began to spasm involuntarily; the spasms multiply quickly, fatigue the muscles and force the body into repetitive movements and awkward postures like mine. There is no cure, only treatment options like deep brain stimulation, which requires a surgery I underwent last year as a last resort. © 2013 The New York Times Company
Related chapters from BP7e: Chapter 11: Motor Control and Plasticity; Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 5: The Sensorimotor System
Link ID: 18171 - Posted: 05.20.2013
Voluntary movements involve the coordinated activation of two brain pathways that connect parts of deep brain structures called the basal ganglia, according to a study in mice by researchers at the National Institute on Alcohol Abuse and Alcoholism (NIAAA), part of the National Institutes of Health. The findings, which challenge the classical view of basal ganglia function, were published online in Nature on Jan. 23. “By improving our understanding of how the basal ganglia control movements, these findings could aid in the development of treatments for disorders in which these circuits are disrupted, such as Parkinson’s disease, Huntington’s disease and addiction,” says NIAAA Acting Director Kenneth R. Warren, Ph.D. The predominant model of basal ganglia function proposes that direct and indirect pathways originating in a brain region called the striatum have opposing effects on movement. Activity of neurons in the direct pathway is thought to promote movement, while activity in the indirect pathway is thought to inhibit movement. Newer models, however, suggest that co-activation of these pathways is necessary to synchronize basal ganglia circuits during movement. “Testing these models has been difficult due to the lack of methods to measure specific neurons in the direct and indirect pathways in freely moving animals,” explains first author Guohong Cui, Ph.D., of the NIAAA Laboratory for Integrated Neuroscience (LIN). To overcome these difficulties, Dr. Cui and colleagues devised a new approach for measuring the activity of neurons deep within the brain during complex behaviors. Their technique uses fiber optic probes implanted in the mouse brain striatum to measure light emissions from neurons engineered to glow when activated.
By Sandra G. Boodman, For the first decade of his life, every doctor who saw Jack DeWitt inevitably zeroed in on the harrowing circumstances of his premature birth. Delivered by emergency Caesarean section in December 1999, doctors universally ascribed his developmental problems to his being born six weeks early, said his mother, Ruth DeWitt. “It always came back to that.” When Jack’s walking became odd at age 5, doctors chalked it up to a mild form of cerebral palsy that can occur in children born too soon. “We were okay with it,” his mother said, because mild cerebral palsy would not “affect the length of his life or his enjoyment of it.” Jack’s parents were also reassured by his ability to catch up; with help, he mastered various skills: jumping, walking and writing in cursive. But by age 10, when his ability to walk badly deteriorated, a reevaluation by his doctors resulted in a very different diagnosis and prognosis. “We had all those years of feeling that he was a normal, healthy kid with some challenges,” his mother recalled. Discovering what was really wrong has been a heavy blow, magnified by Jack’s perceptive awareness of its implications. Ruth DeWitt, who lives with her family in Howell, Mich., outside Ann Arbor, was in the hospital undergoing a test for preeclampsia, or pregnancy-induced hypertension, when she began hemorrhaging, a sign of placental abruption. The life-threatening condition occurs when the placenta prematurely detaches from a woman’s uterus. Rushed into surgery, Jack was born weighing 3 pounds, 9 ounces, and was transferred to the neonatal intensive care unit at the University of Michigan Medical Center. Small but strong, he needed oxygen but no ventilator, and he came home 15 days later. © 1996-2012 The Washington Post
Related chapters from BP7e: Chapter 11: Motor Control and Plasticity; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 13: Memory, Learning, and Development
Link ID: 17615 - Posted: 12.18.2012
By ANDREW POLLACK An experimental drug preserved and even improved the walking ability of boys with Duchenne muscular dystrophy in a clinical trial, raising hopes that the first effective treatment for the disease may be on the horizon. Boys with the disease who received the highest dose of the drug had a slightly improved ability to walk after 48 weeks of treatment, the drug’s developer, Sarepta Therapeutics, announced Wednesday. By contrast, the boys who received a placebo suffered a sharp decline in how well they could walk. The drug, called eteplirsen, also appeared to restore levels of the crucial protein that muscular dystrophy patients lack to about half of normal levels, Sarepta said. “I think this changes the entire playing field for muscular dystrophy,” said Dr. Jerry R. Mendell, director of the gene therapy and muscular dystrophy programs at Nationwide Children’s Hospital in Columbus, Ohio, and the lead investigator in the trial. There are many caveats. The trial had only 12 patients, with only four receiving the high dose and four the placebo, and the data has not been reviewed by experts. It is also unclear how long the effects of the drug would last or if safety issues would arise with longer treatment. Also, eteplirsen would be appropriate for only about 13 percent to 15 percent of Duchenne patients, those with the particular genetic mutation the drug is meant to counteract. However, a similar approach might work for some other mutations. © 2012 The New York Times Company