Tina Hesman Saey Some snippets of RNA can be a real pain. A microRNA called miR-30c-5p contributes to nerve pain in rats and people, a new study finds. A different microRNA, miR-711, interacts with a well-known itch-inducing protein to cause itching, a second study concludes. Together, the research highlights the important role that the small pieces of genetic material can play in nerve cell function, and may help researchers understand the causes of chronic nerve pain and itch. MicroRNAs help regulate gene activity and protein production. The small molecules play a big role in controlling cancer (SN: 8/28/10, p. 18) and other aspects of health and disease (SN: 2/20/16, p. 18). Usually, microRNAs work by pairing up with bigger pieces of RNA called messenger RNAs, or mRNA. Messenger RNAs contain copies of genetic instructions that are read by cellular machinery to build proteins. When microRNAs glom onto the messengers, the mRNA can be degraded or the microRNAs can prevent the protein-building machinery from reading the instructions. Either way, the result is typically to dial down production of certain proteins. In the case of nerve pain, miR-30c-5p limits production of an important protein called TGF-beta that’s involved in controlling pain, María Hurlé, a pharmacologist at the University of Cantabria in Santander, Spain, and colleagues report August 8 in Science Translational Medicine. The researchers discovered the link in experiments with mice, rats and people. |© Society for Science & the Public 2000 - 2018.

Keyword: Pain & Touch
Link ID: 25329 - Posted: 08.14.2018

Mike Robinson To call gambling a “game of chance” evokes fun, random luck and a sense of collective engagement. These playful connotations may be part of why almost 80 percent of American adults gamble at some point in their lifetime. When I ask my psychology students why they think people gamble, the most frequent suggestions are for pleasure, money or the thrill. While these might be reasons why people gamble initially, psychologists don’t definitely know why, for some, gambling stops being an enjoyable diversion and becomes compulsive. What keeps people playing even when it stops being fun? Why stick with games people know are designed for them to lose? Are some people just more unlucky than the rest of us, or simply worse at calculating the odds? As an addiction researcher for the past 15 years, I look to the brain to understand the hooks that make gambling so compelling. I’ve found that many are intentionally hidden in how the games are designed. And these hooks work on casual casino-goers just as well as they do on problem gamblers. Uncertainty as its own reward in the brain One of the hallmarks of gambling is its uncertainty – whether it’s the size of a jackpot or the probability of winning at all. And reward uncertainty plays a crucial role in gambling’s attraction. Dopamine, the neurotransmitter the brain releases during enjoyable activities such as eating, sex and drugs, is also released during situations where the reward is uncertain. In fact dopamine release increases particularly during the moments leading up to a potential reward. © 2010–2018, The Conversation US, Inc.

Keyword: Drug Abuse; Attention
Link ID: 25328 - Posted: 08.14.2018

By Matt Neal Sir John Eccles is an icon of Australian science, but an attempt in later life to mix religion and science made him an outsider in the scientific community as it won him fans in the Catholic Church. In 1963, along with British biophysicists Sir Alan Hodgkin and Sir Andrew Huxley, he won the Nobel Prize for Physiology or Medicine for their groundbreaking work on synapses and the electrical properties of neurons. How Sir John revolutionised neuroscience: He shared the 1963 Nobel Prize for Physiology Or Medicine with Alan Lloyd Hodgkin and Andrew Fielding Huxley "for their discoveries concerning the ionic mechanisms involved in excitation and inhibition in the peripheral and central portions of the nerve cell membrane" Eccles' work showed that the transmission of information and impulses between neurons in the brain was both electrical and chemical in nature His experiments paved the way for treatments of nervous diseases as well as further research into the brain, heart and kidneys That same year, Eccles was named Australian of the Year. But, as University of Sydney Honorary Associate Professor John Carmody once wrote: "the nation appears to have forgotten [Eccles despite the fact] modern neuroscience is forever in his debt". Part of the reason for the decline in his regard could stem from his latter-career work, in which he controversially attempted to marry his scientific prowess with his religious beliefs, and went in search of the soul. © 2018 ABC

Keyword: Consciousness
Link ID: 25327 - Posted: 08.14.2018

Laura Sanders To understand the human brain, take note of the rare, the strange and the downright spooky. That’s the premise of two new books, Unthinkable by science writer Helen Thomson and The Disordered Mind by neuroscientist Eric R. Kandel. Both books describe people with minds that don’t work the same way as everyone else’s. These are people who are convinced that they are dead, for instance; people whose mental illnesses lead to incredible art; people whose memories have been stolen by dementia; people who don’t forget anything. By scrutinizing these cases, the stories offer extreme examples of how the brain creates our realities. In the tradition of the late neurologist Oliver Sacks (SN: 10/14/17, p. 28), Thomson explores the experiences of nine people with unusual minds. She travels around the world to interview her subjects with compassion and curiosity. In England, she meets a man who, following a bathtub electrocution, became convinced that he was dead. (Every so often, he still feels “a little bit dead,” he tells Thomson.) In Los Angeles, she spends time with a 64-year-old man who can remember almost every day of his life in extreme detail. And in a frightening encounter in a hospital in the United Arab Emirates, she interviews a man with schizophrenia who transmogrifies into a growling tiger. By visiting them in their element, Thomson presents these people not as parlor tricks, but as fully rendered human beings. Kandel chooses the brain disorders themselves as his subjects. He explains the current neuroscientific understanding of autism, depression and schizophrenia, for example, by weaving together the history of the research and human examples. His chapter on dementia and memory is particularly compelling, given his own Nobel Prize–winning role in revealing how brains form memories (SN: 10/14/00, p. 247). |© Society for Science & the Public 2000 - 2018

Keyword: Miscellaneous
Link ID: 25326 - Posted: 08.14.2018

Philip Ball Carl Zimmer is a rarity among professional science writers in being influential among the scientists on whose work he writes and comments – to the extent that he has been appointed as professor adjunct in the department of molecular biophysics and biochemistry at Yale University. Zimmer has just published his 13th book, She Has Her Mother’s Laugh, a survey of “the power, perversions and potential of heredity”. What is the book’s main message about our attitudes to heredity? Heredity is central to our existence and how we define ourselves. But it’s not what we think it is. It’s not just genes, for example. We inherit culture too, and there may even be other channels of heredity. And the way genes enable heredity doesn’t fit our common notions. We tend to imagine that we inherit particular genes from our parents, grandparents and so on, and that these shape us in ways that are easy to understand and trace. But that’s not how heredity works. Each trait is typically influenced by hundreds or thousands of different genes, and the environment in which those genes are acting makes all the difference to how we turn out. You talk in the book about how some of these questions were brought home to you when your first daughter was born in 2001. What’s your personal journey into the story of heredity? In 2000 my wife was pregnant with our first child, and our doctor asked us to go to a genetics counsellor. I thought this was pointless. But the counsellor started asking me questions and I suddenly realised I had a really terrible grasp of my family history. I felt very ashamed and irresponsible, because here was this child who would be inheriting a lot of my genes. This was the first time heredity went from being something I learned about in class to one of the most important things in my existence. © 2018 Guardian News and Media Limited

Keyword: Genes & Behavior; Development of the Brain
Link ID: 25325 - Posted: 08.13.2018

By Jane E. Brody Attention all you happy high school graduates about to go off to college, as well as the many others returning for another year of higher education. Grandsons Stefan and Tomas, that includes you. Whatever you may think can get in the way of a successful college experience, chances are you won’t think of one of the most important factors: how long and how well you sleep. And not just on weekends, but every day, Monday through Sunday. Studies have shown that sleep quantity and sleep quality equal or outrank such popular campus concerns as alcohol and drug use in predicting student grades and a student’s chances of graduating. Although in one survey 60 percent of students said they wanted information from their colleges on how to manage sleep problems, few institutions of higher learning do anything to counter the devastating effects of sleep deprivation on academic success and physical and emotional well-being. Some, in fact, do just the opposite, for example, providing 24-hour library hours that encourage students to pull all-nighters. (I did that only once, to study for an exam in freshman year, and fell asleep in the middle of the test. Lesson well learned!) An all-nighter may help if all you have to do is memorize a list, but if you have to do something complex with the information, you’ll do worse by staying up all night, J. Roxanne Prichard, an expert on college sleep issues, told me. After being awake 16 hours in a row, brain function starts to decline, and after 20 hours awake, you perform as if legally drunk, she said. Many college-bound kids start out with dreadful sleep habits that are likely to get worse once the rigorous demands of college courses and competing social and athletic activities kick in. © 2018 The New York Times Company

Keyword: Sleep; Learning & Memory
Link ID: 25324 - Posted: 08.13.2018

By Jessica Wright, Boosting levels of the chemical messenger serotonin makes mice that model autism more social, according to a study published in Nature. The study suggests the approach may do the same in people with autism. It also offers an explanation for why antidepressants do not ease autism traits: They may increase serotonin levels too slowly to be effective. The researchers used a technique that rapidly increases serotonin levels in the nucleus accumbens, a brain region that mediates social reward. “Somehow, the release of serotonin in the nucleus accumbens really plays an important role in enhancing sociability,” says lead researcher Robert Malenka, professor of psychiatry and behavioral sciences at Stanford University in California. “The simple hypothesis is it makes the social interaction more reinforcing.” Decades of research have suggested a connection between serotonin and autism. About 10 years ago, this led researchers to test antidepressants, which increase serotonin levels by blocking its reabsorption into neurons, as a treatment for autism. However, in several trials, antidepressants such as fluoxetine (Prozac) proved ineffective at easing the condition’s features. The new study suggests that a drug that rapidly activates serotonin receptors would be a more effective way of treating the condition. © 2018 Scientific American

Keyword: Autism
Link ID: 25323 - Posted: 08.13.2018

Michaeleen Doucleff My back hurts when I sit down. It's been going on for 10 years. It really doesn't matter where I am — at work, at a restaurant, even on our couch at home. My lower back screams, "Stop sitting!" To try to reduce the pain, I bought a kneeling chair at work. Then I got a standing desk. Then I went back to a regular chair because standing became painful. I've seen physical therapists, orthopedic surgeons and pain specialists. I've mastered Pilates, increased flexibility and strengthened muscles. At one point, my abs were so strong my husband nicknamed them "the plate." All these treatments helped a bit, at first. But the pain never really went away. So a few years ago, I decided to accept reality: Sitting down is — and will always be — painful for me. Then back in November, I walked into the studio of Jenn Sherer in Palo Alto, Calif. She is part of a growing movement on the West Coast to teach people to move and sit and stand as they did in the past — and as they still do in other parts of the world. I was interviewing Sherer for a story about bending. But she could tell I was in pain. So I told her my story. Her response left me speechless: "Sitting is a place where you can find heaven in your joints and in your back," she says. "It's not sitting that's causing the pain, it's how you're sitting. "Do you want me to show you how?" © 2018 npr

Keyword: Pain & Touch
Link ID: 25322 - Posted: 08.13.2018

Ann Robinson Imagine a neurological condition that affects one in 20 under-18s. It starts early, causes significant distress and pain to the child, damages families and limits the chances of leading a fulfilled life as an adult. One in 20 children are affected but only half of these will get a diagnosis and a fifth will receive treatment. If those stats related to a familiar and well-understood illness, such as asthma, there would be little debate about the need to improve intervention rates. But this is attention deficit hyperactivity disorder (ADHD), and the outcry is muted. If anything, we hear warnings that too many children are being labelled this way, and too many given prescriptions. In the United States, ADHD is diagnosed at more than twice the incidence in Britain. The true prevalence is likely to be the same on both sides of the Atlantic. So what’s the story? Is the US too gung-ho, or is the UK dragging its heels? Are American doctors too quick to medicate children, or British doctors too slow? Emily Simonoff, co-author of a new meta-analysis in the journal the Lancet Psychiatry, says the problem in the UK is “predominantly about undermedication and underdiagnosis”. Her study examined a range of drug treatments compared to placebo, and it shows that methylphenidate (better known by under the brand name Ritalin) works best for children and amphetamines for adults. © 2018 Guardian News and Media Limited

Keyword: ADHD; Drug Abuse
Link ID: 25321 - Posted: 08.13.2018

by Antonia Noori Farzan It’s been well-documented that a decreased sex drive can be one of the side effects of antidepressants like Prozac. But the amount of these drugs that end up in sewage plants may also have an impact on the mating habits of wild birds, a new study from the University of York shows. Researchers found that female starlings that had been exposed to small doses of fluoxetine, the generic name for Prozac, became less attractive to male starlings, which sung to them less often and treated them more aggressively. Kathryn Arnold, one of the study’s authors and a senior lecturer in ecology at the University of York, described it as “the first evidence that low concentrations of an antidepressant can disrupt the courtship of songbirds.” That’s problematic because birds that are slow to find a mate may not get the chance to breed, she wrote. “We’re definitely not saying that it’s bad to take antidepressants, but certainly there is a greater need for new technologies to clean out sewage,” Arnold told The Washington Post. Birds like to graze at sewage treatment plants, which are teeming with worms, flies and maggots, she explained. But because antidepressants often make their way through the human body and into sewage plants without fully breaking down, those insects are frequently laced with prescription drugs. © 1996-2018 The Washington Post

Keyword: Depression; Sexual Behavior
Link ID: 25320 - Posted: 08.13.2018

There is a new study on the effect treating teens for depression has on their parents. It suggests just treating teens has benefits for parents. LULU GARCIA-NAVARRO, HOST: There are estimates that 13 percent of adolescents in the United States experience at least one episode of major depression. That depression can be treated in teens. And new research suggests that it helps not just them but also their parents. NPR's Rhitu Chatterjee reports. RHITU CHATTERJEE, BYLINE: We tend to think of depression as affecting individuals, but Myrna Weissman says... MYRNA WEISSMAN: Depression is a family affair. CHATTERJEE: Weissman is a professor of psychiatry at the College of Physicians and Surgeons at Columbia University. And she's studied depression in families for years. WEISSMAN: We know that there's high rates of depression in the offspring of depressed mothers. CHATTERJEE: Weissman's previous work has shown that when mothers are treated for depression, their children feel better, as well. That led another researcher, Kelsey Howard, to wonder, could the opposite be true? KELSEY HOWARD: So if kids get better, do parents then feel better? And we found that to be true, as well. CHATTERJEE: Howard is a graduate student at the department of Psychiatry and Behavioral Sciences at Northwestern University. To answer her question, she and her graduate adviser analyzed data from a previous study that followed more than 300 teenagers getting treatment for depression either through counseling or pills or both. Before and during the course of the study, the researchers had also surveyed one parent of each teenager for symptoms of depression. When Howard looked at that data, she found that... © 2018 npr

Keyword: Depression; Development of the Brain
Link ID: 25319 - Posted: 08.13.2018

Pamela Duncan and Nicola Davis More than four million people in England are long-term users of antidepressants, new figures obtained by the Guardian show. Data released under the Freedom of Information Act shows that more than 7.3 million people were prescribed antidepressants in 2017-18, 4.4 million of whom also received a prescription for such drugs in both of the two previous years. 1.6 million people prescribed antidepressants in the past year were “new” users, meaning they were not being prescribed such drugs in either 2015-16 or 2016-17. The figures also show the number of such “new” users of antidepressants is falling. Month-by-month figures show an overall decline from just over 179,000 “new” starters in April 2016 to just over 132,000 in March 2018. Experts say it is not clear what is behind the trend and that there could be a number of factors at play. Scott Weich, a professor of mental health at the University of Sheffield, said the tendency to prescribe antidepressants seems to have gone in phases over recent decades. “Professionals may be becoming slightly less certain about the benefits of antidepressants [for mild depression], and patients themselves may be declining medication,” he said. Weich noted other reasons might be that individuals are finding it increasingly difficult to access GP services to discuss mental health issues, or that the issues are not discussed due to time constraints or other pressures. On the other hand, he said, it could in part reflect the rise in so-called “talking therapies” like CBT. © 2018 Guardian News and Media Limited

Keyword: Depression
Link ID: 25318 - Posted: 08.11.2018

Public awareness of the debilitating impact of postpartum depression on new moms has grown over the years, but many people don't realize it can affect men too, mental health experts say. In a series of presentations at the American Psychological Association annual convention this week, a group of psychologists said about 10 per cent of new fathers experience symptoms of depression and anxiety in the weeks before, during or after their babies are born. "One of the main myths is men don't experience hormonal changes, therefore they can't get postpartum depression or anxiety," said Daniel Singley, one of the presenters and a psychologist based in San Diego, Calif. "In fact, plenty of research shows that men do get hormonal changes around the birth of children, and that hormonal changes is just one of a number of bio-psychosocial factors that cause postpartum mood issues," he said. The Canadian Mental Health Association acknowledges that men and women and even parents who adopt can suffer from the condition, noting on its website that "a mother or father with postpartum depression may not enjoy the baby and have frequent thoughts that they're a bad parent." Dealing with the issue of postpartum depression in men is important for the well-being of their children, Singley said, because fathers experiencing it are "much less likely" to be involved with their newborns — which, in turn, can negatively affect the babies' development. ©2018 CBC/Radio-Canada

Keyword: Depression
Link ID: 25317 - Posted: 08.11.2018

Laurel Hamers A Nobel Prize–winning discovery — that small double-stranded RNA molecules can silence genes by interrupting the translation of DNA’s instructions into proteins — is finally delivering on its medical promise. The first drug that takes advantage of this natural biological process, called RNA interference, was approved August 10 by the U.S. Food and Drug Administration. It targets a rare hereditary disease that causes misshapen proteins to build up in patients’ nerves, tissues and organs, causing loss of sensation, organ failure and even death. Heredity transthyretin amyloidosis, or ATTR, affects about 50,000 people worldwide. This drug will help the subset of those patients who have neurological impairments. Called patisiran, the drug uses specially designed pieces of RNA to silence a mutated gene that, when active in the liver, is responsible for patients’ symptoms. In a recent 18-month clinical trial, patients who received patisiran injections every three weeks showed a slight decrease in neurological symptoms, whereas patients on the placebo worsened overall. It’s not a cure — people still have the genetic mutation — but the treatment prevents the disease from progressing. This approval is “just the beginning,” says Craig Mello of the University of Massachusetts Medical School in Worcester, who co-discovered the process of RNA interference in roundworms (SN: 10/7/06, p. 229). Many more drugs using the same approach, for diseases ranging from hemophilia to HIV, are winding through clinical trials. |© Society for Science & the Public 2000 - 2018

Keyword: Genes & Behavior
Link ID: 25316 - Posted: 08.11.2018

Scientists say they have found how blue light from smartphones, laptops and other digital devices damages vision and can speed up blindness. Research by the University of Toledo in the US has revealed that prolonged exposure to blue light triggers poisonous molecules to be generated in the eye’s light-sensitive cells that can cause macular degeneration – an incurable condition that affects the middle part of vision. Blue light, which has a shorter wavelength and more energy compared with other colours, can gradually cause damage to the eyes. Dr Ajith Karunarathne, an assistant professor in the university’s department of chemistry and biochemistry, said: “We are being exposed to blue light continuously and the eye’s cornea and lens cannot block or reflect it. “It’s no secret that blue light harms our vision by damaging the eye’s retina. Our experiments explain how this happens, and we hope this leads to therapies that slow macular degeneration, such as a new kind of eye drop.” Macular degeneration, which affects around 2.4% of the adult population in the UK, is a common condition among those in their 50s and 60s that results in significant vision loss. It is caused by the death of photoreceptor, ie light-sensitive cells, in the retina. Age-related macular degeneration is the leading cause of blindness in the US and while it does not cause total blindness, it can make everyday activities such as reading and recognising faces difficult. © 2018 Guardian News and Media Limite

Keyword: Vision
Link ID: 25315 - Posted: 08.10.2018

By Victoria Gill Science correspondent, BBC News Our primate cousins have surprised and impressed scientists in recent years, with revelations about monkeys' tool-using abilities and chimps' development of complex sign language. But researchers are still probing the question: why are we humans the only apes that can talk? That puzzle has now led to an insight into how different non-human primates' brains are "wired" for vocal ability. A new study has compared different primate species' brains. It revealed that primates with wider "vocal repertoires" had more of their brain dedicated to controlling their vocal apparatus. That suggests that our own speaking skills may have evolved as our brains gradually rewired to control that apparatus, rather than purely because we're smarter than non-human apes. Humans and other primates have very similar vocal anatomy - in terms of their tongues and larynx. That's the physical machinery in the throat which allows us to turn air into sound. So, as lead researcher Dr Jacob Dunn from Anglia Ruskin University in Cambridge explained, it remains a mystery that only human primates can actually talk. "That's likely due to differences in the brain," Dr Dunn told BBC News, "but there haven't been comparative studies across species." So how do our primate brains differ? That comparison is exactly what Dr Dunn and his colleague Prof Jeroen Smaers set out to do. They ranked 34 different primate species based on their vocal abilities - the number of distinct calls they are known to make in the wild. They then examined the brain of each species, using information from existing, preserved brains that had been kept for research. © 2018 BBC

Keyword: Language; Evolution
Link ID: 25314 - Posted: 08.10.2018

By Gretchen Reynolds Don’t skip drinking during exercise in hot weather, a new study reminds us. This advice might seem obvious. But apparently some athletes, especially in team sports, have begun to eschew fluids during hot weather workouts, in hopes that the privation might somehow make them stronger. But the new study finds that it is likely only to make them more physically stressed. And very, very thirsty. Working out in the heat is inherently difficult, as any of us who exercise outside in summer knows. When ambient temperatures are high, we generate internal heat more quickly than if the weather is cool. To remove this heat and maintain a safe body temperature, our hearts pump warm blood toward the skin’s surface, where heat can dissipate, and we sweat copiously, providing evaporative heat loss. These reactions become more pronounced and effective with practice, a process known as heat acclimation (also referred to as acclimatization). During heat acclimation, which can require several weeks of sultry exercise, we begin to sweat earlier and in greater volume. This and other changes help our hearts to labor less, so that, in general, the effort of being physically active in high temperatures starts to feel less wearing. A run on a sizzling summer day in August should feel easier than a similar run on an equally hot evening in June, if we have been running outside in the meantime, because our bodies will have acclimated to the heat. But athletes being athletes, some of them and their coaches began to wonder in recent years whether, if heat acclimation taxes the body and makes it stronger, would exacerbating the physical difficulties of acclimation lead to greater adaptations, in approved Machiavellian style? © 2018 The New York Times Company

Keyword: Miscellaneous
Link ID: 25313 - Posted: 08.10.2018

Leah Rosenbaum Pregnant women aren’t immune to the escalating opioid epidemic. Data on hospital deliveries in 28 U.S. states shows the rate of opioid use among pregnant women has quadrupled, from 1.5 per 1,000 women in 1999 to 6.5 per 1,000 women in 2014, the U.S. Centers for Disease Control and Prevention reports. The highest increases in opioid use among pregnant women were in Maine, New Mexico, Vermont and West Virginia, according to the CDC study, published online August 9 in Morbidity and Mortality Weekly Report. “This analysis is a stark reminder that the U.S. opioid crisis is taking a tremendous toll on families,” says coauthor Jean Ko, a CDC epidemiologist in Atlanta. In this first look at opioid use during pregnancy by state, Washington, D.C. had the lowest rate in 2014, at 0.7 per 1,000 women, and Vermont had the highest, at 48.6 per 1,000. However, the data from the U.S. Health and Human Services Department represents only the 28 states that record opioid use at childbirth during the studied time frame. “We knew the incidence was increasing” as the number of babies going through opioid withdrawal has also gone up, says Matthew Grossman, a pediatrician at Yale University. Overall, the number of U.S. deaths attributed to opioids has also been steadily rising (SN: 3/31/18, p. 18). In 2014, there were 14.7 opioid deaths per 100,000 people, up from 6.2 per 100,000 in 2000, according to the CDC. © Society for Science & the Public 2000 - 2018

Keyword: Drug Abuse
Link ID: 25312 - Posted: 08.10.2018

by Dr. Francis Collins Though our thoughts can wander one moment and race rapidly forward the next, the brain itself is often considered to be motionless inside the skull. But that’s actually not correct. When the heart beats, the pumping force reverberates throughout the body and gently pulsates the brain. What’s been tricky is capturing these pulsations with existing brain imaging technologies. Recently, NIH-funded researchers developed a video-based approach to magnetic resonance imaging (MRI) that can record these subtle movements [1]. Their method, called phase-based amplified MRI (aMRI), magnifies those tiny movements, making them more visible and quantifiable. The latest aMRI method, developed by a team including Itamar Terem at Stanford University, Palo Alto, CA, and Mehmet Kurt at Stevens Institute of Technology, Hoboken, NJ. It builds upon an earlier method developed by Samantha Holdsworth at New Zealand’s University of Auckland and Stanford’s Mahdi Salmani Rahimi [2]. In the video, a traditional series of brain scans captured using standard MRI (left) make the brain appear mostly motionless. But a second series of scans captured using the new technique (right) shows the brain pulsating with each and every heartbeat. As described in the journal Magnetic Resonance in Medicine, the team started by measuring the pulse of a healthy person. They synchronized the pulse with MRI images of the person’s brain, stitching the scans together to create a sequential video. Their new MRI approach then relies on a special algorithm developed by another group to magnify the subtle changes.

Keyword: Brain imaging
Link ID: 25311 - Posted: 08.10.2018

Tina Hesman Saey Scientists now know how long it takes for a cell to tell itself it’s time to die. Signals triggering a type of cell suicide called apoptosis move through a cell like a wave, traveling at a rate of 30 micrometers per minute, Stanford University systems biologists Xianrui Cheng and James Ferrell Jr. report in the Aug. 10 Science. These findings resolve a debate over whether these death signals spread by diffusion, with signaling molecules working their own way across a cell, or as self-regenerating trigger waves, like toppling dominoes. The apoptosis process starts with damage that causes the release of death signal chemicals. One example is cytochrome c leaking from damaged mitochondria, the cell’s power plant. Once cytochrome c concentrations get high enough, the chemicals signal proteins called caspases to go to work. Caspases trigger other proteins to poke holes in neighboring mitochondria, releasing more cytochrome c and moving the death wave across the cell. That chain reaction happens more quickly than diffusion can, Ferrell says. In an African clawed frog egg, a trigger wave takes about a half-hour to spread across the 1.2 millimeter cell, whereas diffusion would take five hours, he says. Like forest fires, trigger waves will keep going as long as there is fuel to feed them — in this case, the death signal chemicals and proteins, Ferrell says. He predicts that many other biological signals may move as trigger waves. |© Society for Science & the Public 2000 - 2018

Keyword: Apoptosis; Development of the Brain
Link ID: 25310 - Posted: 08.10.2018