Chapter 11. Motor Control and Plasticity

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

Links 81 - 100 of 1285

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

Keyword: Movement Disorders; Aggression
Link ID: 18306 - Posted: 06.25.2013

By Amy Mathews Amos, My symptoms started in January 2008, with deep pain in my bladder and the sense that I had to urinate constantly. I was given a diagnosis of interstitial cystitis, a chronic bladder condition with no known cure. But in the following months, pain spread to my thighs, knees, hips, buttocks, abdomen and back. By the time my condition was properly diagnosed three years later, I had seen two urogynecologists, three orthopedists, six physical therapists, two manual therapists, a rheumatologist, a neurologist, a chiropractor and a homeopath. What was wrong? Something completely unexpected, given my symptoms: myofascial pain syndrome, a condition caused by muscle fibers that contract but don’t release. That constant contraction creates knots of taut muscle, or trigger points, that send pain throughout the body, even to parts that are perfectly healthy. Most doctors have never heard of myofascial pain syndrome and few know how to treat it. In my case, trigger points in my pelvic floor — the bowl of muscle on the bottom of the pelvis — referred pain to my bladder. Points along my thighs pulled on my knee joints, creating sharp pain when I walked. Points in my hips, buttocks and abdomen threw my pelvis and lower spine out of alignment, pushing even more pain up my back. The pain was so severe at times that I could sit for only brief periods. “Why didn’t anybody know this?” I asked my doctor, Timothy Taylor, soon after he correctly diagnosed the reason for my pain. “Because doctors don’t specialize in muscles,” he said. “It’s the forgotten organ.” © 1996-2013 The Washington Post

Keyword: Pain & Touch; Aggression
Link ID: 18292 - Posted: 06.20.2013

By E. Paul Zehr As an infant, the Man Of Steel escaped Krypton’s red sun in a rocket lovingly prepared for him by his parents. Kal-L (but more commonly known as Kal-El) arrived under our yellow sun in Smallville to eventually become Clark Kent. Since his debut in Action Comics #1 in June of 1938, Superman has accumulated a pretty long list of “super abilities”. For me, though, I really like the list of his abilities that come from the 1940s radio serials. This was back when Superman was described as “faster than a speeding bullet, more powerful than a locomotive, and able to leap tall buildings in a single bound”. These descriptions all have to do with super-strength when you get right down to it. And with this summer’s “Man of Steel” Superman re-boot, super-strength is the focus of this post. I have to admit I’ve always found the explanation for Superman’s powers to be, well, a bit dubious. He has his powers because of our yellow sun. That is, because he was from a red sun planet (Krypton) somehow the yellow sun of Earth unleashes some inner super power mechanism that gives Superman all his…super-ness. Of course it’s a bit pure escapist fun. But what if there actually was something to that, though? I don’t mean something to the “yellow sun / red sun” stuff. You can just check in with our “friendly neighborhood physics” professor Jim Kakalios and his bok “Physics of Superheroes” for the real deal on that one. I mean rather the unleashing of some inner mechanism bit. What if something inside the human body could be unleashed—like removing the shackles from Hercules—and allow for dramatically increased strength? © 2013 Scientific American

Keyword: Muscles; Aggression
Link ID: 18273 - Posted: 06.15.2013

by Trisha Gura A rare genetic disease may be going to the dogs. About six in 100,000 babies are born with centronuclear myopathy, which weakens skeletal muscles so severely that children have trouble eating and breathing and often die before age 18. Now, by discovering a very similar condition in canines, researchers have a means to diagnose the disease, unravel its molecular intricacies, and target new therapies. The story began when Jocelyn Laporte, a geneticist at the Institute of Genetics and Molecular and Cellular Biology in Strasbourg, France, uncovered the genetic roots of an odd form of centronuclear myopathy that showed up in a Turkish family. Three children, two of them fraternal twins, were born normal. Then, at the age of 3-and-a-half, they grew progressively and rapidly ill. (Most forms of the illness do not come on so suddenly.) The twins died by the age of 9. Their younger brother recently reached the same age but is very ill. Investigators traced the problem to a mutation in a gene called BIN1, which makes a protein that helps shape the muscle so that it can respond to nerve signals that initiate muscle contraction. To find out how mutations in this gene could lead to such dire consequences, other researchers tried to genetically engineer mice models. But deleting the BIN1 gene failed to recreate the disease in mice, so the researchers had to look elsewhere. Laporte's team joined with geneticist and veterinarian Laurent Tiret, at the Alfort School of Veterinary Medicine in Paris, to tap a network of vets in the United States, United Kingdom, Canada, Australia, and France. The idea was to track down and analyze dogs that had spontaneously acquired a similar condition. Because of their longer lifespans and larger size, the canines could model how the disease progresses and might respond to new therapies. © 2010 American Association for the Advancement of Science

Keyword: Muscles; Aggression
Link ID: 18272 - Posted: 06.15.2013

by Alyssa Danigelis Next time you happen across an enormous cockroach, check to see whether it’s got a backpack on. Then look for the person controlling its movements with a phone. The RoboRoach has arrived. The RoboRoach is a system created by University of Michigan grads who have backgrounds in neuroscience, Greg Gage and Tim Marzullo. They came up with the cyborg roach idea as part of an effort to show students what real brain spiking activity looks like using off-the-shelf electronics. Essentially the RoboRoach involves taking a real live cockroach, putting it under anesthesia and placing wires in its antenna. Then the cockroach is outfitted with a special lightweight little backpack Gage and Marzullo developed that sends pulses to the antenna, causing the neurons to fire and the roach to think there’s a wall on one side. So it turns. The backpack connects to a phone via Bluetooth, enabling a human user to steer the cockroach through an app. Why? Why would anyone do this? ”We want to create neural interfaces that the general public can use,” the scientists say in a video. “Typically, to understand how these hardware devices and biological interfaces work, you’d have to go to graduate school in a neuro-engineering lab.” They added that the product is a learning tool, not a toy, and through it they hope to start a neuro-revolution. Currently the duo’s Backyard Brains startup is raising money through a Kickstarter campaign to develop more fine-tuned prototypes, make them more affordable, and extend battery life. The startup says it will make the RoboRoach hardware by hand in an Ann Arbor hacker space. © 2013 Discovery Communications, LLC

Keyword: Robotics
Link ID: 18264 - Posted: 06.12.2013

By Melissa Hogenboom Science reporter, BBC News Activity observed in the brain when using a "mind machine" is similar to how the brain learns new motor skills, scientists have found. Participants' neural activity was recorded by using sensors implanted in their brain, which were linked to a computer that translated electrical impulses into actions. The researchers believe people will be able to perform increasingly complex tasks just by thinking them. The study is published in PNAS journal. The subjects in the study moved from thinking about a task to automatically processing a task, in a similar way to how other motor movements are learnt - like playing the piano or learning to ride a bicycle. This was shown by the areas of neurons that were active in the brain, which changed as subjects became more adept at a mental task. Scientists analysed the results of a mind control task on a brain-computer interface (BCI) of seven participants with epilepsy. They were asked to play a computer game where they had to manipulate a ball to move across a screen - using only their mind. Recent studies using BCIs have shown that our minds can control various objects, like a robotic arm, "but there is still a lot of mystery in the way we learn to control them", said Jeremiah Wander from the University of Washington in Seattle, US, who led the study. BBC © 2013

Keyword: Robotics
Link ID: 18255 - Posted: 06.11.2013

Devin Powell A model helicopter can now be steered through an obstacle course by thought alone, researchers report today in the Journal of Neural Engineering. The aircraft's pilot operates it remotely using a cap of electrodes to detect brainwaves that are translated into commands.1 Ultimately, the developers of the mind-controlled copter hope to adapt their technology for directing artificial robotic limbs and other medical devices. Today's best neural prosthetics require electrodes to be implanted in the body and are thus reserved for quadriplegics and others with disabilities severe enough justify invasive surgery. "We want to develop something non-invasive that can benefit lots of people, not just a limited number of patients," says Bin He, a biomedical engineer at the University of Minnesota in Minneapolis, whose new results build on his previous work with a virtual thought-controlled helicopter.2 But He's mechanical whirlybird isn't the first vehicle to be flown by the brain. In 2010 a team at the University of Illinois at Urbana-Champaign reported an unmanned aircraft that flies a fixed altitude but adjusts its heading to the left or right in response to a user's thoughts.3 The new chopper goes a step further. It can be guided up and down, as well as left or right, and it offers more precise control. To move it in a particular direction, a user imagines clenching his or her hands — the left one to go left, for instance, or both to go up. That mental image alters brain activity in the motor cortex. Changes in the strength and frequency of signals recorded by electrodes on the scalp using electroencephalography (EEG), and deciphered by a computer program, reveal the pilot's intent. © 2013 Nature Publishing Group

Keyword: Robotics
Link ID: 18231 - Posted: 06.05.2013

by Helen Thomson TWO years ago, Antonio Melillo was in a car crash that completely severed his spinal cord. He has not been able to move or feel his legs since. And yet here I am, in a lab at the Santa Lucia Foundation hospital in Rome, Italy, watching him walk. Melillo is one of the first people with lower limb paralysis to try out MindWalker – the world's first exoskeleton that aims to enable paralysed and locked-in people to walk using only their mind. Five people have been involved in the clinical trial of MindWalker over the past eight weeks. The trial culminates this week with a review by the European Commission, which funded the work. It's the end of a three-year development period for the project, which has three main elements. There is the exoskeleton itself, a contraption that holds a person's body weight and moves their legs when instructed. People learn how to use it in the second element: a virtual-reality environment. And then there's the mind-reading component. Over in the corner of the lab, Thomas Hoellinger of the Free University of Brussels (ULB) in Belgium is wearing an EEG cap, which measures electrical activity at various points across his scalp. There are several ways he can use it to control the exoskeleton through thought alone – at the moment, the most promising involves wearing a pair of glasses with flickering diodes attached to each lens. © Copyright Reed Business Information Ltd.

Keyword: Robotics
Link ID: 18227 - Posted: 06.04.2013

Linda Carroll TODAY contributor Each day brings Jenn McNary another dose of hope and heartache as she watches one son get healthier while the other becomes sicker. Both of McNary's sons were born with Duchene muscular dystrophy. Max, 11, is receiving an experimental therapy that appears to be making him better, while 14-year-old Austin is slowly dying. Austin was too sick to be included in the clinical trials for a promising new drug called Eteplirsen. “He can’t get into a chair, out of his wheelchair, into his bed and onto the toilet,” McNary told NBC’s Janet Shamlian. Max, however, was exactly what researchers were looking for. He was put on Eteplirsen, and now he's back to running around, climbing stairs and even playing soccer. “It’s a miracle,” McNary said. “It really is a miracle drug. This is something that nobody ever expected and he looks like an almost normal 11-year-old.” Eteplirsen is designed to partially repair one of the common genetic mutations that causes DMD. Even a partial repair may enough to improve life for boys struck by the condition, which results from a defect in the dystrophin gene. That gene resides on the X chromosome, which is why only boys end up with DMD. Boys get one X and one Y chromosome. Girls get two copies of the X chromosome — one from their mother and one from their father — so even if they inherit a defective copy from their mom, they get a healthy one from their dad. Although they won’t suffer symptoms, girls wind up with a 50 percent chance of being carriers for DMD.

Keyword: Muscles; Aggression
Link ID: 18196 - Posted: 05.28.2013

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

Keyword: Movement Disorders; Aggression
Link ID: 18171 - Posted: 05.20.2013

By David Brown, A team of researchers said Wednesday that it had produced embryonic stem cells — a possible source of disease-fighting spare parts — from a cloned human embryo. Scientists at the Oregon Health and Science University accomplished in humans what has been done over the past 15 years in sheep, mice, cattle and several other species. The achievement is likely to, at least temporarily, reawaken worries about “reproductive cloning” — the production of one-parent duplicate humans. But few experts think that production of stem cells through cloning is likely to be medically useful soon, or possibly ever. “An outstanding issue of whether it would work in humans has been resolved,” said Rudolf Jaenisch, a biologist at MIT’s Whitehead Institute in Cambridge, Mass., who added that he thinks the feat “has no clinical relevance.” “I think part of the significance is technical and part of the significance is historical,” said John Gearhart, head of the Institute for Regenerative Medicine at the University of Pennsylvania. “Many labs attempted it, and no one had ever been able to achieve it.” A far less controversial way to get stem cells is now available. It involves reprogramming mature cells (often ones taken from the skin) so that they return to what amounts to a second childhood from which they can grow into a new and different adulthood. Learning how to make and manipulate those “induced pluripotent stem” (IPS) cells is one of biology’s hottest fields. © 1996-2013 The Washington Post

Keyword: Stem Cells; Aggression
Link ID: 18162 - Posted: 05.16.2013

Roberta Kwok Sitting motionless in her wheelchair, paralysed from the neck down by a stroke, Cathy Hutchinson seems to take no notice of the cable rising from the top of her head through her curly dark hair. Instead, she stares intently at a bottle sitting on the table in front of her, a straw protruding from the top. Her gaze never wavers as she mentally guides a robot arm beside her to reach across the table, close its grippers around the bottle, then slowly lift the vessel towards her mouth. Only when she finally manages to take a sip does her face relax into a luminous smile. This video of 58-year-old Hutchinson illustrates the strides being taken in brain-controlled prosthetics1. Over the past 15 years, researchers have shown that a rat can make a robotic arm push a lever2, a monkey can play a video game3 and a person with quadriplegia — Hutchinson — can sip from a bottle of coffee1, all by simply thinking about the action. Improvements in prosthetic limbs have been equally dramatic, with devices now able to move individual fingers and bend at more than two dozen joints. But Hutchinson's focused stare in that video also illustrates the one crucial feature still missing from prosthetics. Her eyes could tell her where the arm was, but she could not feel what it was doing. Nor could she sense when the grippers touched the bottle, or whether it was slipping out of their grasp. Without this type of sensory feedback, even the simplest actions can be slow and clumsy, as Igor Spetic of Madison, Ohio, knows well. Fitted with a prosthetic after his right hand was crushed in an industrial accident in 2010, Spetic describes breaking dishes, grabbing fruit too hard and bruising it and dropping a can when trying to pick it up at the local shop. Having a sense of touch would be “tremendous”, he says. “It'd be one step closer to having the hand back.” © 2013 Nature Publishing Group,

Keyword: Pain & Touch; Aggression
Link ID: 18138 - Posted: 05.09.2013

National Institutes of Health researchers used the popular anti-wrinkle agent Botox to discover a new and important role for a group of molecules that nerve cells use to quickly send messages. This novel role for the molecules, called SNARES, may be a missing piece that scientists have been searching for to fully understand how brain cells communicate under normal and disease conditions. "The results were very surprising,” said Ling-Gang Wu, Ph.D., a scientist at NIH’s National Institute of Neurological Disorders and Stroke. “Like many scientists we thought SNAREs were only involved in fusion." Every day almost 100 billion nerve cells throughout the body send thousands of messages through nearly 100 trillion communication points called synapses. Cell-to-cell communication at synapses controls thoughts, movements, and senses and could provide therapeutic targets for a number of neurological disorders, including epilepsy. Nerve cells use chemicals, called neurotransmitters, to rapidly send messages at synapses. Like pellets inside shotgun shells, neurotransmitters are stored inside spherical membranes, called synaptic vesicles. Messages are sent when a carrier shell fuses with the nerve cell’s own shell, called the plasma membrane, and releases the neurotransmitter “pellets” into the synapse. SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) are three proteins known to be critical for fusion between carrier shells and nerve cell membranes during neurotransmitter release.

Keyword: Muscles; Aggression
Link ID: 18115 - Posted: 05.04.2013

By PAULA SPAN It was supposed to be a short stay. In 2006, Roger Anderson was to undergo surgery to relieve a painfully compressed spinal disk. His wife, Karen, figured the staff at the hospital, in Portland, Ore., would understand how to care for someone with Parkinson’s disease. It can be difficult. Parkinson’s patients like Mr. Anderson, for example, must take medications at precise intervals to replace the brain chemical dopamine, which is diminished by the disease. “You don’t have much of a window,” Mrs. Anderson said. “If you have to wait an hour, you have tremendous problems.” Without these medications, people may “freeze” and be unable to move, or develop uncontrolled movements called dyskinesia, and are prone to falls. But the nurses at the Portland hospital didn’t seem to grasp those imperatives. “You’d have to wait half an hour or an hour, and that’s not how it works for Parkinson’s patients,” Mrs. Anderson said. Nor did hospital rules, at the time, permit her to simply give her husband the Sinemet pills on her own. Surgery and anesthesia, the disrupted medications, an incision that subsequently became infected — all contributed to a tailspin that lasted nearly three months. Mr. Anderson developed delirium, rotated between rehab centers and hospitals, took a fall, lost 60 pounds. “People were telling me, ‘He’s never going to come home,’” Mrs. Anderson said. He did recover, and at 69 is doing well, his wife said, though his disease has progressed. But his wasn’t an unusual story, neurologists say. © 2013 The New York Times Company

Keyword: Parkinsons
Link ID: 18054 - Posted: 04.22.2013

By GRETCHEN REYNOLDS If you give a rat a running wheel and it decides not to use it, are genes to blame? And if so, what does that tell us about why many people skip exercise? To examine those questions, scientists at the University of Missouri in Columbia recently interbred rats to create two very distinct groups of animals, one of which loves to run. Those in the other group turn up their collective little noses at exercise, slouching idly in their cages instead. Then the scientists closely scrutinized and compared the animals’ bodies, brains and DNA. For some time, exercise scientists have suspected that the motivation to exercise — or not — must have a genetic component. When researchers have compared physical activity patterns among family members, and particularly among twins, they have found that close relations tend to work out similarly, exercising about as much or as little as their parents or siblings do, even if they grew up in different environments. These findings suggest that the desire to be active or indolent is, to some extent, inherited. But to what extent someone’s motivation to exercise is affected by genes — and what specific genes may be involved — has been hard to determine. There are only so many human twins around for study purposes, after all. And even more daunting, it’s difficult to separate the role of upbringing from that of genetics in determining whether and why some people want to exercise and others don’t. So the University of Missouri researchers decided to create their own innately avid runners or couch potatoes, provide them with similar upbringings, and see what happened next. Copyright 2013 The New York Times Company

Keyword: Emotions; Aggression
Link ID: 18044 - Posted: 04.18.2013

Nearly half of those with Parkinson's face regular discrimination, such as having their symptoms mistaken for drunkenness, a survey suggests. The survey of more than 2,000 people was commissioned by charity Parkinson's UK. One person in 500 people is affected by the condition in Britain. Parkinson's sufferer Mark Worsfold was arrested during last year's Olympics because police thought he looked suspicious. He was detained during the cycling road race in Leatherhead, Surrey, reportedly because he was not smiling - the condition means his face can appear expressionless. Parkinson's is a progressive neurological condition that attacks the part of the brain that controls movement. The main symptoms of Parkinson's are tremors or shaking that cannot be controlled, and rigidity of the muscles, which can make movement difficult and painful. Speech, language and facial expressions can also be affected. Most people who get it are aged 50 or over but younger people can have it too. The survey found that one in five people living with Parkinson's had been mistaken for being drunk, while one in 10 had been verbally abused or experienced hostility in public because of their condition. Around 62% said they thought the public had a poor understanding of how the condition affects people. BBC © 2013

Keyword: Parkinsons
Link ID: 18035 - Posted: 04.15.2013

By GRETCHEN REYNOLDS Two new experiments, one involving people and the other animals, suggest that regular exercise can substantially improve memory, although different types of exercise seem to affect the brain quite differently. The news may offer consolation for the growing numbers of us who are entering age groups most at risk for cognitive decline. It was back in the 1990s that scientists at the Salk Institute for Biological Studies in La Jolla, Calif., first discovered that exercise bulks up the brain. In groundbreaking experiments, they showed that mice given access to running wheels produced far more cells in an area of the brain controlling memory creation than animals that didn’t run. The exercised animals then performed better on memory tests than their sedentary labmates. Since then, scientists have been working to understand precisely how, at a molecular level, exercise improves memory, as well as whether all types of exercise, including weight training, are beneficial. The new studies provide some additional and inspiring clarity on those issues, as well as, incidentally, on how you can get lab rats to weight train. For the human study, published in The Journal of Aging Research, scientists at the University of British Columbia recruited dozens of women ages 70 to 80 who had been found to have mild cognitive impairment, a condition that makes a person’s memory and thinking more muddled than would be expected at a given age. Mild cognitive impairment is also a recognized risk factor for increasing dementia. Seniors with the condition develop Alzheimer’s disease at much higher rates than those of the same age with sharper memories. Copyright 2013 The New York Times Company

Keyword: Learning & Memory
Link ID: 18015 - Posted: 04.10.2013

By KATIE HAFNER While undressing for bed one night in 2009, Susan Spencer-Wendel noticed that the muscles in her left palm had disappeared, leaving a scrawny pile of tendons and bones. Her right hand was fine. She let out a yelp and showed the hand to her husband, who told her to go to the doctor. She was 42. Ms. Spencer-Wendel then entered a protracted period of denial. Adopted as an infant in Florida, she traveled from her home in West Palm Beach to find blood relatives living in Cyprus, who confirmed that there was no family history of her worst fear: amyotrophic lateral sclerosis, or A.L.S., the relentless disease that lays waste to muscles while leaving the mind intact. In June 2011, a doctor in Miami gave her a definitive diagnosis of A.L.S., smiling “like he was inviting me to a birthday party,” she writes in “Until I Say Goodbye: My Year of Living With Joy.” Patients with A.L.S., which is also known as Lou Gehrig’s disease, typically live no more than four years after the onset of symptoms. There is no cure. Ms. Spencer-Wendel thought she had prepared herself fully — that she would burst off the starting block like a sprinter to greet her fate. Instead, when she heard the news, “I dropped my head for the start ... and began to cry.” Her heart-ripping book chronicles what she did immediately after her diagnosis: she decided to embrace life while death chased her down. Instead of letting the world close in on her, she resolved to travel as far and as wide for as long as she could. She went to the Yukon with her best friend, Budapest with her husband, and the Bahamas with her sister. © 2013 The New York Times Company

Keyword: ALS-Lou Gehrig's Disease
Link ID: 18007 - Posted: 04.09.2013

By John McCarthy Maybe this discovery is interesting because it sheds therapeutic light on the dreaded neurodegenerative diseases that killed Woody Guthrie and Lou Gehrig. Or maybe it’s fascination with healthy cells, and yet another unsuspected complexity in how they work. What’s discovered: a previously unknown energy source in nerve cells. It propels the molecular “motors” that drag neurotransmitters from the nucleus where they’re made. The “motors” are assemblies of molecules. They walk like clumsy robots, with a staggering gait, dragging a capsule of neurotransmitter “bullets” along microtubule “highways” between nucleus and synapses. They move by flinging their boot-like feet (lavender blobs, in the image) forward, a billionth of a meter at each step. (A superb animation of “motors” in action is XVIVO’s “Life of a Cell” (at ~1:15 of playing time)). When the cargo finally arrives at the synapses, neurotransmitters are loaded into compartments at the synapse’s interior face, like bullets into a magazine. They are ready to be “fired” across a synapse to signal an adjoining neuron. It’s this transport of neurotransmitter “bullets” that failed in Guthrie’s and Gehrig’s nerve cells. Their synapses had nothing to fire. What powers the flinging that moves those boots? Previously, the answer has been specialized molecules (acronym: ATP) spewed into the cell’s fluid interior by mitochondria. The boots, it was thought, powered each step by grabbing a floating ATP and blowing it up like a firecracker. © 2013 Scientific American

Keyword: Huntingtons
Link ID: 17978 - Posted: 04.02.2013

By Emily Burns Lots of people set themselves goals – like things to do by the time you’re 30. Maybe it’s to find your dream job, meet the love of your life, or travel the world! For sufferers of Cystic Fibrosis, it’s living to see your 30th birthday. Even with all of the advances in medicine and technology, the average life expectancy of someone with Cystic Fibrosis is 33 years. Cystic Fibrosis is an inherited disease that mostly affects the lungs, but also the pancreas, liver and intestines. The body fluids we need – like the mucus in our lungs and intestines – are much thicker than normal, making it extremely difficult to breathe and digest food. Constant physiotherapy, breathing exercises, diet supplements and antibiotics are needed just to get on with daily life. And all of this suffering is caused by one tiny change in our DNA, which then messes up how one single protein folds into the right shape. It’s otherwise known as a protein misfolding disease. There are over 2 million proteins in the human body, carrying out their individual tasks to keep us breathing, thinking – enabling us to live. But their production isn’t easy. It’s an incredibly intricate and specialised process that is constantly going on inside us. If it goes wrong, there are serious consequences to our health, with Cystic Fibrosis being a prime example.... While the primary causes Alzheimer’s and Parkinson’s is still not known, one of the theories suggests that cellular and ER stress results in the cell death that we see. They are known as amyloid diseases, as they’re caused by the accumulation of amyloids in cells. We usually think of amyloids as being associated with Alzheimer’s, so you might think that they were a particular type of protein, but that’s not quite it. Instead, amyloids are protein delinquents: any protein that can form a beta sheet can become an amyloid. When a mutated protein misfolds, the side chains of amino acids (that dictate the specific fold) are no longer so important: the main chain of the polypeptide now causes these amyloid fibres to stick together. These amyloid fibres are formed regardless of the original folded protein structure (meaning that they form the same fibrous shape for every protein) and can penetrate the cells, causing cell stress and death. © 2013 Scientific American

Keyword: Alzheimers; Aggression
Link ID: 17964 - Posted: 03.28.2013