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Allison Whitten Every time you reach for your coffee mug, a neuroscientific mystery takes shape. Moments before you voluntarily extend your arm, thousands of neurons in the motor regions of your brain erupt in a pattern of electrical activity that travels to the spinal cord and then to the muscles that power the reach. But just prior to this massively synchronized activity, the motor regions in your brain are relatively quiet. For self-driven movements like reaching for your coffee, the “go” signal that tells the neurons precisely when to act — instead of the moment just before or after — has yet to be found. In a recent paper in eLife, a group of neuroscientists led by John Assad at Harvard Medical School finally reveals a key piece of the signal. It comes in the form of the brain chemical known as dopamine, whose slow ramping up in a region lodged deep below the cortex closely predicted the moment that mice would begin a movement — seconds into the future. Dopamine is commonly known as one of the brain’s neurotransmitters, the fast-acting chemical messengers that are shuttled between neurons. But in the new work, dopamine is acting as a neuromodulator. It’s a term for chemical messengers that slightly alter neurons to cause longer-lasting effects, including making a neuron more or less likely to electrically communicate with other neurons. This neuromodulatory tuning mechanism is perfect for helping to coordinate the activity of large populations of neurons, as dopamine is likely doing to help the motor system decide precisely when to make a movement. The new paper is one of the latest results to expand our knowledge of the crucial and varied roles that neuromodulators play in the brain. With recent advances in technology, neuroscientists can now view neuromodulators at work in networks that traverse the entire brain. The new findings are overturning some long-held views about these modulators adrift in the brain, and they’re revealing exactly how these molecules allow the brain to flexibly change its internal state amid ever-changing environments. All Rights Reserved © 2022

Related chapters from BN: 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: Development of the Brain
Link ID: 28251 - Posted: 03.23.2022

By Lisa Sanders, M.D. “OK, I give up,” said the 74-year-old man. “I’ll go to the hospital.” His wife of 46 years gave an inner sigh of relief. Her husband was stubborn, a seventh-​generation Mainer, not given to complaining. But a few weeks earlier, she noticed that he was parking his tractor next to the back porch so he could get on it without pulling himself up. Then he needed help getting out of his big chair. Now he could barely walk. It happened so suddenly it scared her. She eased the car right next to the porch. He needed both hands on the railing to get down, grunting with each step. His legs moved awkwardly, as if they had somehow forgotten what to do. At the LincolnHealth-Miles Campus Hospital in nearby Damariscotta, it was clear to the E.R. doctors that the patient wasn’t weak but ataxic, lacking not strength but coordination. Virtually every movement the body makes requires several muscles working together — a collaboration that occurs in the cerebellum. The uncertain and awkward way the patient moved made doctors at LincolnHealth worry that something — maybe a stroke, maybe a tumor — had injured that part of the brain. But two CT scans and an M.R.I. were unrevealing. When his doctors weren’t sure what to do next, the patient decided it was time to go home. His wife was supportive but worried. How could she help him get around? He was a big guy and outweighed her by 50 pounds. And they still needed to figure out what was wrong with him. Couldn’t they try another hospital? Maybe, he said, but first he wanted to go home. So that’s where she took him. Once there, it took only a day for the man to recognize, again, that he couldn’t just tough it out at home. There was another hospital, a larger one a couple of towns over in Brunswick: Mid Coast Hospital. His wife was happy to take him there. Those few steps he took from porch to car, supported by his wife, were the last he would take for weeks. © 2022 The New York Times Company

Related chapters from BN: 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: 28204 - Posted: 02.16.2022

By Lisa Sanders, M.D. The mother stood in the baggage-claim area of the Buffalo Niagara International Airport, waiting for her 37-year-old son, who had just flown in from North Carolina. The carousel was nearly empty by the time she caught sight of him. She was shocked by how sick he looked. His face was pale and thin, his hair and clothes rumpled as if he felt too awful to care. Most surprising of all: He was being rolled toward her in a wheelchair. “I had some trouble with the stairs,” he explained. He thanked the attendant and then struggled to get to his feet. He didn’t make it. Before he got more than a few inches off the seat, his arms and then his legs began to shake and wobble, and he fell heavily back into the chair. His mother collected his bag and pushed him out to where her husband was waiting in the car. On the drive home, the young man struggled to explain what was going on. He had always considered himself to be pretty strong and healthy, but these past few weeks had been rough. It started in his legs. He felt wobbly. When he walked, his hips, legs and especially his feet felt as if they might not be able to hold him up. He saw his physician assistant about it — he worried that it was caused by the cholesterol-lowering medication he had started taking — but the P.A. assured him it wasn’t. He was running a few times a week, but he had to stop because his legs were done well before the run was. And he didn’t feel as sharp as he used to be. His brain seemed foggy and slow. Then this morning he had trouble climbing the stairs to the plane. That was scary. The guy behind him helped by holding up his backpack, but his feet felt like dead weights. He had to use his arms to help get his body up high enough to take each step. Once on the plane, he supported himself on the headrests to get to his assigned seat. They offered the wheelchair when he arrived in Buffalo, and he gratefully accepted. His mother tentatively asked if he thought he should see a doctor. She knew he hated it when she tried to tell him what to do. He had flown up to see a football game with her ex-husband, his father, and a hockey game with his stepbrother. If he didn’t feel any better after that, he conceded, it would be time to see a doctor. © 2022 The New York Times Company

Related chapters from BN: Chapter 17: Learning and Memory; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 4: Development of the Brain
Link ID: 28150 - Posted: 01.12.2022

Leyland Cecco A whistleblower in the Canadian province of New Brunswick has warned that a progressive neurological illness that has baffled experts for more than two years appears to be affecting a growing number of young people and causing swift cognitive decline among some of the afflicted. Speaking to the Guardian, an employee with Vitalité Health Network, one of the province’s two health authorities, said that suspected cases are growing in number and that young adults with no prior health triggers are developing a catalog of troubling symptoms, including rapid weight loss, insomnia, hallucinations, difficulty thinking and limited mobility. The official number of cases under investigation, 48, remains unchanged since it was first announced in early spring 2021. But multiple sources say the cluster could now be as many as 150 people, with a backlog of cases involving young people still requiring further assessment. “I’m truly concerned about these cases because they seem to evolve so fast,” said the source. “I’m worried for them and we owe them some kind of explanation.” At the same time, at least nine cases have been recorded in which two people in close contact – but without genetic links – have developed symptoms, suggesting that environmental factors may be involved. One suspected case involved a man who was developing symptoms of dementia and ataxia. His wife, who was his caregiver, suddenly began losing sleep and experiencing muscle wasting, dementia and hallucinations. Now her condition is worse than his. A woman in her 30s was described as non-verbal, is feeding with a tube and drools excessively. Her caregiver, a nursing student in her 20s, also recently started showing symptoms of neurological decline. © 2021 Guardian News & Media Limited

Related chapters from BN: Chapter 11: Motor Control and Plasticity; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 10: Biological Rhythms and Sleep
Link ID: 28140 - Posted: 01.05.2022

Riluzole, a drug approved to treat amyotrophic lateral sclerosis (ALS), a disease affecting nerve cells controlling movement, could slow the gradual loss of a particular brain cell that occurs in Niemann-Pick disease type C1 (NPC1), a rare genetic disorder affecting children and adolescents, suggests a study in mice by scientists at the National Institutes of Health. The study was conducted by Forbes D. Porter, M.D., Ph.D., of NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), and colleagues in the National Human Genome Research Institute and National Institute of Arthritis and Musculoskeletal and Skin Disease. It appears in Molecular Genetics and Metabolism. The study was supported in part by a grant from the Ara Parseghian Medical Research Foundation. NPC1 results from an impaired ability to move cholesterol through cells, leading to difficulty controlling movements, liver and lung disease, impaired swallowing, intellectual decline and death. Much of the movement difficulties in NPC1 result from gradual loss of brain cells known as Purkinje neurons. The researchers found that mice with a form of NPC1 have a diminished ability to lower levels of glutamate — a brain chemical that stimulates neurons — after it has bound to a neuron’s surface. High levels of glutamate can be toxic to cells. The researchers believe the buildup of glutamate contributes to the brain cell loss seen in the disease. Riluzole blocks the release of glutamate and hence delays the progression of ALS in people.

Related chapters from BN: Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 28083 - Posted: 11.20.2021

By Gina Kolata CAMBRIDGE, Mass. — When Sharif Tabebordbar was born in 1986, his father, Jafar, was 32 and already had symptoms of a muscle wasting disease. The mysterious illness would come to define Sharif’s life. Jafar Tabebordbar could walk when he was in his 30s but stumbled and often lost his balance. Then he lost his ability to drive. When he was 50, he could use his hands. Now he has to support one hand with another. No one could answer the question plaguing Sharif and his younger brother, Shayan: What was this disease? And would they develop it the way their father had? As he grew up and watched his father gradually decline, Sharif vowed to solve the mystery and find a cure. His quest led him to a doctorate in developmental and regenerative biology, the most competitive ranks of academic medical research, and a discovery, published in September in the journal Cell, that could transform gene therapy — medicine that corrects genetic defects — for nearly all muscle wasting diseases. That includes muscular dystrophies that affect about 100,000 people in the United States, according to the Muscular Dystrophy Association. Scientists often use a disabled virus called an adeno-associated virus, or AAV, to deliver gene therapy to cells. But damaged muscle cells like the ones that afflict Dr. Tabebordbar’s father are difficult to treat. Forty percent of the body is made of muscle. To get the virus to those muscle cells, researchers must deliver enormous doses of medication. Most of the viruses end up in the liver, damaging it and sometimes killing patients. Trials have been halted, researchers stymied. Dr. Tabebordbar managed to develop viruses that go directly to muscles — very few end up in the liver. His discovery could allow treatment with a fraction of the dosage, and without the disabling side effects. Dr. Jeffrey Chamberlain, who studies therapies for muscular diseases at the University of Washington and is not involved in Dr. Tabebordbar’s research, said the new method, “could take it to the next level,” adding that the same method also could allow researchers to accurately target almost any tissue, including brain cells, which are only beginning to be considered as gene therapy targets. © 2021 The New York Times Company

Related chapters from BN: Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 28066 - Posted: 11.06.2021

By Emily Anthes Johnson & Johnson’s beleaguered Covid-19 vaccine may be associated with a small increased risk of Guillain–Barré syndrome, a rare but potentially serious neurological condition, federal officials said on Monday. The Food and Drug Administration has added a warning about the potential side effect to its fact sheets about the vaccine. The risk appears to be very small. So far, there have been 100 reports of the syndrome in people who had received the Johnson & Johnson vaccine. Nearly 13 million doses of the vaccine have been administered in the United States. Here are answers to some common questions about the syndrome and its connection to vaccination. What is Guillain-Barré syndrome? Guillain-Barré is a rare condition in which the body’s immune system attacks nerve cells. It can cause muscle weakness and paralysis. Although the symptoms often pass within weeks, in some cases, the condition can cause permanent nerve damage. In the United States, there are typically 3,000 to 6,000 cases of the syndrome per year, according to the Centers for Disease Control and Prevention. It is most common in adults over 50. The precise cause of the syndrome is unknown, but in many cases the condition follows another illness or infection, such as the flu. It has also been reported in people with Covid-19. This is not the first vaccine that has been linked to Guillain-Barré, although the risk appears to be tiny. A large swine flu vaccination campaign in 1976 led to a small uptick in the incidence of syndrome; the vaccine caused roughly one extra case of Guillain-Barré for every 100,000 people vaccinated. The seasonal flu shot is associated with roughly one to two additional cases for every million vaccines administered. © 2021 The New York Times Company

Related chapters from BN: 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: 27909 - Posted: 07.14.2021

by Rachel Zamzow Most mornings, Huda Zoghbi, 67, climbs a glass-encased, curling staircase to reach her lab on the top and 13th floor of the Jan and Dan Duncan Neurological Research Institute in Houston, Texas. The twisting glass tower, which she designed with a team of architects, echoes the double helix of DNA — a structure that has been central to her career-long quest to uncover genes underlying neurological conditions. As the institute’s director — and as a scientist— she is known for going beyond the standard job description. Genetics researchers often cast a wide net and sequence thousands of genes at a time. But in her prolific career, Zoghbi has focused on a handful of genes, methodically building up an understanding of their function one careful step at a time. Thanks to that approach, Zoghbi has made a number of landmark discoveries, including identifying the genetic roots of Rett syndrome, an autism-related condition that primarily affects girls, as well as the genetic mutations that spur spinocerebellar ataxia, a degenerative motor condition. She has authored more than 350 journal articles. Her accomplishments have earned her almost every major biology and neuroscience research award, including the prestigious Breakthrough Prize in 2017 and the Brain Prize in 2020. “She’s clearly the international leader in the field,” said the late Stephen Warren, professor of human genetics at Emory University in Atlanta, Georgia. Zoghbi never set out to lead a large research center, she says — her heart is in the lab. That said, she has excelled at it: Since the institute’s inception in 2010, it has grown to host more than 200 scientists and fostered more than 70 new disease gene discoveries. © 2021 Simons Foundation

Related chapters from BN: 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 and Learning
Link ID: 27874 - Posted: 06.26.2021

By Charles Q. Choi Precise control of the tongue is often vital in life, from the way frogs capture flies to human speech (SN: 1/31/17). But much remains unknown about how the brain controls the tongue, given how its quick motions are difficult to track. Now, experiments show that the brain circuits in mice that help the tongue lick water may be the same ones that help primates reach out to grasp objects, scientists report online May 19 in Nature. Using high-speed video, neuroscientist Tejapratap Bollu and colleagues recorded the sides and bottoms of mouse tongues as the rodents drank from a waterspout. With the help of artificial intelligence to develop 3-D simulations of the appendages, the researchers discovered that successful licks required previously unknown corrective movements, too fast to be seen in standard video. These adjustments came after the tongue missed unseen or distant droplets, or when the spout was unexpectedly retracted a millimeter or more. Inhibiting a brain region that controls the body’s voluntary motions impaired these corrections, suggesting this brain area was behind these movements. These newfound corrective motions are similar to ones that primates use when reaching out with their limbs for uncertain targets, the researchers say. Those primate adjustments are also controlled by similar brain circuits as those used by the mice. “This to me shows that mammalian brains use similar principles to control the tongue and the limb,” says Bollu, now at the Salk Institute for Biological Studies in La Jolla, Calif. “Everything we know about reaching in the primates can also be used to understand how the brain controls [tongue] movements.” © Society for Science & the Public 2000–2021.

Related chapters from BN: Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 27828 - Posted: 05.27.2021

By Lisa Sanders, M.D. “I can’t move my legs,” the 26-year-old man told his younger brother, who towered above him as he lay sprawled on the floor. He’d been on his computer for hours, he explained, and when he tried to stand up, he couldn’t. His legs looked normal, felt normal, yet they wouldn’t move. At first, he figured his legs must have fallen asleep. He pulled himself up, leaning on his desk, and slowly straightened until he was standing. He could feel the weight on his feet and knees. He let go of the desk and commanded his legs to move. Instead, they buckled, and he landed on the floor with a thud. His brother awkwardly pulled him onto the bed. Then they waited. Surely this weird paralysis would disappear just as suddenly as it came. An hour passed, then two. I’m calling an ambulance, the younger brother announced finally. Reluctantly, the elder agreed. He was embarrassed to be this helpless but worried enough to want help. When the E.M.T.s arrived, they were as confused as the brothers. The medics asked what the young man had been up to. Nothing bad, he assured them. For the past few weeks he had been getting back into shape. He changed his diet, cut out the junk and was drinking a protein concoction that was supposed to help him build muscle. And he was working out hard every day. He’d lost more than 20 pounds, he added proudly. © 2021 The New York Times Company

Related chapters from BN: Chapter 5: Hormones and the Brain; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 5: The Sensorimotor System
Link ID: 27813 - Posted: 05.12.2021

By Lisa Sanders, M.D. The voice on the phone was kind but firm: “You need to go to the emergency room. Now.” Her morning was going to be busy, replied the 68-year-old woman, and she didn’t feel well. Could she go later today or maybe tomorrow? No, said Dr. Benison Keung, her neurologist. She needed to go now; it was important. As she hung up the phone, tears blurred the woman’s already bad vision. She’d been worried for a while; now she was terrified. She was always healthy, until about four months earlier. It was a Saturday morning when she noticed that something seemed wrong with her right eye. She hurried to the bathroom mirror, where she saw that her right eyelid was drooping, covering the top half of the brown of her iris. On Monday morning, when she met her eye doctor, she was seeing double. Since then she’d had tests — so many tests — but received no answers. The woman walked to the bedroom where her 17-year-old granddaughter was still asleep. She woke her and asked for help getting dressed. Her hands were too weak for her to button her own clothes or tie her shoes. When she was completely dressed, she sent the girl to get her mother. She would need a ride to the hospital. She hadn’t been able to drive since she started seeing double. The events of the past few months had left the woman exhausted. First, she had seen her eye doctor. He took one look at her and told her that she had what’s called a third-nerve palsy. The muscles of the face and neck, he explained, are controlled by nerves that line up at the top of the spine. The nerve that controlled the eyelid, called the oculomotor nerve, was the third in this column. But he didn’t know what was affecting it or how to fix the problem. She needed to see a neuro-ophthalmologist, a doctor who specialized in the nerves that control the eyes. © 2021 The New York Times Company

Related chapters from BN: 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: 27720 - Posted: 03.06.2021

By Lisa Sanders, M.D. It started to drizzle just moments after the 24-year-old man crossed the finish line of the 2017 New York City Marathon. It was his first marathon, and he felt both elated and exhausted as the medal given for completing the brutal race was draped around his neck. A goody bag containing an energy drink was put in his left hand. It felt strangely heavy. His whole body ached and trembled with fatigue, but somehow that left arm felt even more tired. Unconcerned, he switched the bag to his right hand and went in search of his partner. Recovery took longer than he expected. It was a day and a half before his legs were strong enough for him to walk down stairs facing forward, rather than the sideways shuffle that his tired muscles insisted on. But by the end of the week he felt mostly normal. Only that left shoulder remained tired, sore and stiff. He went to a nearby walk-in clinic just south of City Hall. The nurse practitioner who examined him thought he had a rotator-cuff injury. She recommended a nonsteroidal anti-inflammatory like ibuprofen, physical therapy and time. The ibuprofen didn’t help much; neither did the physical therapy. That weekend he headed to the gym — his first workout since the race. He did his usual set of reps on his right biceps and triceps. But when he transferred the 25-pound dumbbell to his left hand, it seemed heavier. He struggled through two curls, but on the third the muscles in his arm turned wobbly. He grabbed the weight with his right hand and lowered it to the ground. By the time he got home, straightening his aching arm was excruciating, as if the muscles were too short to allow a full extension. That scared him. And it only got worse. The next day his whole arm was achy and tight. He couldn’t even work on his computer. Thinking back, the young runner questioned the assumption — shared by both him and the nurse practitioner — that the injury had occurred during the race. Now he suspected it started weeks earlier. © 2020 The New York Times Company

Related chapters from BN: 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: 27587 - Posted: 11.21.2020

Lenny Bernstein The Centers for Disease Control and Prevention warned parents and caregivers Tuesday to watch out for an uncommon, polio-like condition that mostly strikes children, usually between August and November. Acute flaccid myelitis, which may be caused by any of several viruses, is marked by a sudden weakness or paralysis of the limbs. Since surveillance began in 2014, prevalence of the ­syndrome has spiked in even-numbered years, often afflicting children about 5 years old. The disease is very rare, but a quick response is critical once the weakness sets in; the disease can progress over hours or days and lead to permanent paralysis or respiratory failure, according to a report issued Tuesday by the CDC. Among 238 cases in 2018 reviewed by the CDC, 98 percent of patients were hospitalized, 54 percent required intensive care, and 23 percent were placed on ventilators to help them breathe. Most patients were hospitalized within a day of experiencing weakness, but about 10 percent were not hospitalized until four or more days later, possibly because of failure to recognize the syndrome, the report said. Limb weakness, difficulty walking and limb pain are often preceded by fever or respiratory illness, usually by about six days, the CDC said. Hundreds of U.S. children have been affected, and many do not fully recover. A number of viruses — including West Nile virus, adenovirus and non-polio enteroviruses — are known to produce the symptoms in a small number of people who become infected by those pathogens. But enterovirus, particularly one dubbed EV-D68, appears to be the most common cause, the CDC said. The National Institute of Allergy and Infectious Diseases is working on a vaccine for EV-D68. © 1996-2020 The Washington Post

Related chapters from BN: 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: 27403 - Posted: 08.06.2020

Kayt Sukel A 44-year-old male patient, with no history of cardiovascular disease, arrived at an emergency room in New York City after experiencing difficulty speaking and moving the right side of his body. The on-call physician quickly determined he had suffered a stroke—a condition that normally affects people who are decades older. In Italy, a 23-year-old man sought care for a complete facial palsy and feelings of “pins and needles” in his legs. Doctors discovered axonal sensory-motor damage suggesting Guillain Barré Syndrome, a rare autoimmune neurological disorder where the immune system, sometimes following an infection, mistakes some of the body’s own peripheral nerve cells as foreign invaders and attacks them. A 58-year-old woman in Detroit was rushed to the hospital with severe cognitive impairment, unable to remember anything beyond her own name. MRI scans showed widespread inflammation across the patient’s brain, leading doctors to diagnose a rare but dangerous neurological condition called acute necrotizing hemorrhagic encephalopathy. At first glance, it may seem that these patients have little in common. Yet all three were also suffering from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease, better known as Covid-19. While most individuals infected with this new virus exhibit fever, cough, and respiratory symptoms, doctors across the globe are also documenting patients presenting with a handful of neurological manifestations—leading clinicians and researchers to wonder if Covid-19 also has the ability to invade the human nervous system. “As more people are being tested and diagnosed with this virus, physicians are starting to see more uncommon symptoms and complications, including neurological ones,” says Diane Griffin, M.D., Ph.D., a researcher at Johns Hopkins University’s Bloomberg School of Public Health. “But as Covid-19 is a new virus, we aren’t yet sure why these things are happening. Is the virus getting into the brain directly? Is it affecting the brain through other means? These are important questions to answer.” © 2020 The Dana Foundation

Related chapters from BN: 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: 27370 - Posted: 07.16.2020

Sherry H-Y. Chou Aarti Sarwal Neha S. Dangayach The patient in the case report (let’s call him Tom) was 54 and in good health. For two days in May, he felt unwell and was too weak to get out of bed. When his family finally brought him to the hospital, doctors found that he had a fever and signs of a severe infection, or sepsis. He tested positive for SARS-CoV-2, the virus that causes COVID-19 infection. In addition to symptoms of COVID-19, he was also too weak to move his legs. When a neurologist examined him, Tom was diagnosed with Guillain-Barre Syndrome, an autoimmune disease that causes abnormal sensation and weakness due to delays in sending signals through the nerves. Usually reversible, in severe cases it can cause prolonged paralysis involving breathing muscles, require ventilator support and sometimes leave permanent neurological deficits. Early recognition by expert neurologists is key to proper treatment. We are neurologists specializing in intensive care and leading studies related to neurological complications from COVID-19. Given the occurrence of Guillain-Barre Syndrome in prior pandemics with other corona viruses like SARS and MERS, we are investigating a possible link between Guillain-Barre Syndrome and COVID-19 and tracking published reports to see if there is any link between Guillain-Barre Syndrome and COVID-19. Some patients may not seek timely medical care for neurological symptoms like prolonged headache, vision loss and new muscle weakness due to fear of getting exposed to virus in the emergency setting. People need to know that medical facilities have taken full precautions to protect patients. Seeking timely medical evaluation for neurological symptoms can help treat many of these diseases. © 2010–2020, The Conversation US, Inc.

Related chapters from BN: 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: 27353 - Posted: 07.08.2020

By Gretchen Reynolds When we start to lift weights, our muscles do not strengthen and change at first, but our nervous systems do, according to a fascinating new study in animals of the cellular effects of resistance training. The study, which involved monkeys performing the equivalent of multiple one-armed pull-ups, suggests that strength training is more physiologically intricate than most of us might have imagined and that our conception of what constitutes strength might be too narrow. Those of us who join a gym — or, because of the current pandemic restrictions and concerns, take up body-weight training at home — may feel some initial disappointment when our muscles do not rapidly bulge with added bulk. In fact, certain people, including some women and most preadolescent children, add little obvious muscle mass, no matter how long they lift. But almost everyone who starts weight training soon becomes able to generate more muscular force, meaning they can push, pull and raise more weight than before, even though their muscles may not look any larger and stronger. Scientists have known for some time that these early increases in strength must involve changes in the connections between the brain and muscles. The process appears to involve particular bundles of neurons and nerve fibers that carry commands from the brain’s motor cortex, which controls muscular contractions, to the spinal cord and, from there, to the muscles. If those commands become swifter and more forceful, the muscles on the receiving end should respond with mightier contractions. Functionally, they would be stronger. © 2020 The New York Times Company

Related chapters from BN: Chapter 11: Motor Control and Plasticity; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 13: Memory and Learning
Link ID: 27343 - Posted: 07.02.2020

As we open computers to connect with each other remotely, motor neurons in our spinal cord are opening synaptic pathways to connect with our muscles physically. We rarely think about these electrical signals passing back and forth between computers or our neurons and muscles, until those signals are lost. Kennedy’s disease, a neuromuscular degenerative disease, affects 1 in 40,000 men every year. Little progress has been made in understanding its biological basis since it was identified in the 1960s, but one promising lead may be a family of proteins known as neurotrophic factors. MSU scientists Cynthia Jordan, professor in the College of Natural Science Neuroscience Program, and Katherine Halievski, former Ph.D. student in Jordan’s Lab and lead author, published a benchmark study in the Journal of Physiology describing the key role of one of these proteins in Kennedy’s disease: Brain-Derived Neurotrophic Factor (BDNF). “There were stories that neurotrophic factors could slow down neurodegenerative diseases, but where they fell short was really understanding how they slow down the disease,” Jordan explained. “Where this paper and Katherine’s work stand alone is in using classic neuroscience techniques to understand how BDNF improved neuromuscular function at the cellular level.” Motor neurons are cells that carry signals from the brain to every muscle in the body — fast twitch muscles that perform quick, high impact movements such as jumping, and slow-twitch muscles that sustain long contractions such as standing. At each step in the pathway — from the neuron, along the synaptic pathway and to the muscle — BDNF supports the process, giving both neurons and muscles what they need to connect, survive and thrive. © Michigan State University

Related chapters from BN: Chapter 11: Motor Control and Plasticity; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 8: Hormones and Sex
Link ID: 27320 - Posted: 06.24.2020

By Abdul-Kareem Ahmed “I use a spoon instead of a fork, so I spill less,” the patient said. “I eat sandwiches and hamburgers so I can use both hands to hold my food.” He was 73 and had suffered from essential tremor for the past decade. His hands would shake uncontrollably, more on the right than on the left, which would worsen if he tried using them. “I could still do crowns, but giving injections became impossible,” he said. His disease, gradual and grasping, had forced the Baltimore-area dentist into early retirement. The patient, who is not being named to protect his privacy, was going to undergo surgery to treat his tremor, which I was curious to observe. I headed to the MRI exam suite to meet him. Wearing a hospital gown, he sat at the edge of his bed, talking to the attending neurosurgeon. He was tall, and balder today than he usually was. As was required, he had shaved his head. Essential tremor is a neurological disease that can affect the torso, arms, neck, head or even voice. Medications are used to attenuate symptoms, but for many patients, these fail or are difficult to tolerate. “I don’t want to take medications forever,” he said. A particularity to this disease is social visibility. Like our patient, people with essential tremor tend to withdraw from society, feeling self-conscious about their inability to perform simple tasks. Dropping food, drinks or other objects is quickly noticed by others.

Related chapters from BN: Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 27087 - Posted: 03.03.2020

By Megan Schmidt Scientists say they’ve figured out what causes essential tremor, a common neurological disorder characterized by involuntary, rhythmic trembling that typically occurs in the hands. In a paper published in Science Translational Medicine this week, researchers at National Taiwan University and Columbia University Irving Medical Center discovered that people with essential tremor have abnormal connections among the neurons in their cerebellum, a region in the back of the brain that’s involved in the coordination of voluntary movement. Researchers say people with these abnormalities tend to generate overactive brain waves, or too much electrical activity, in this region of the brain, which is what fuels the tremors. In addition to pinpointing the roots of the disorder, the researchers say their work uncovered some new approaches that could potentially treat and diagnose essential tremor more effectively. Essential tremor is often mistaken for Parkinson’s disease, but there are some key distinctions that set these movement disorders apart. Parkinson’s, which is less common than essential tremor, is caused by the progressive loss of dopamine neurons in the midbrain, a small region of the brain that plays an important role in motor function. Essential tremor, as this new research reveals, is linked to abnormalities in the hindbrain — specifically, the cerebellum. © 2020 Kalmbach Media Co.

Related chapters from BN: Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 26994 - Posted: 01.25.2020

Catherine Offord A clinical trial of a gene therapy for Duchenne muscular dystrophy has been halted after a patient suffered serious side effects following treatment, Reuters reports today (November 12). After receiving Solid Biosciences’s experimental therapy, SGT-001, the patient experienced kidney injury and drops in red blood cell count, leading the US Food and Drug Administration (FDA) to place the study on hold. “We are encouraged that this patient is recovering,” Ilan Ganot, Solid Biosciences’s CEO, president, and cofounder, says in a statement. “In the coming weeks, we anticipate that we will have a better understanding of the biological activity and potential benefit of SGT-001. We look forward to sharing this additional data and working with the FDA to resolve the clinical hold and determining next steps for the program.” SGT-001 has been administered to six people so far, and involves the transfer of an engineered version of the dystrophin gene DMD, which is dysfunctional in people with Duchenne muscular dystrophy, using an adeno-associated virus (AAV) as a vector. Sarepta Therapeutics, Pfizer, and other biopharmaceutical companies are investigating similar approaches to treat the condition, although the choice of AAV varies. See “Positive Trial Results for Experimental DMD Gene Therapy” This isn’t the first time Solid Biosciences’s trial of SGT-001 has been put on hold. Early last year, the FDA halted the same study after a patient receiving a low dose of the therapy experienced a drop in red blood cell count and had to be hospitalized. The company was allowed to resume the trial last June after making changes to the study design. © 1986–2019 The Scientist

Related chapters from BN: Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 26816 - Posted: 11.14.2019