By GRETCHEN REYNOLDS Intense treadmill exercise can be safe for people who have recently been given diagnoses of Parkinson’s disease and may substantially slow the progression of their condition, according to an important new study of adults in the early stages of the disease. But the same study’s results also indicate that gentler exercise, while safe for people with Parkinson’s, does not seem to delay the disease’s advance. As most of us know, Parkinson’s disease is a progressive neurological disorder that involves problems with motor control. Symptoms like weakness, stiffness, loss of balance and falls can make exercise difficult and potentially hazardous. Though Parkinson’s is currently incurable, its symptoms can be eased for a time with various drugs. But most of those drugs lose their effectiveness in people over time. So some researchers have begun searching for other treatment options, particularly for use in the beginning stages of the disease. If people with early Parkinson’s could brake the disease’s advance and delay their need to start medications, the researchers have reasoned, they might change the arc of their disease, delaying its most severe effects. That possibility recently led a consortium of researchers from Northwestern University, the University of Colorado’s Anschutz Medical Campus in Aurora and other institutions to look at exercise as a treatment. There were precedents. Animal studies already had shown that exercise reduced symptoms and slowed physical decline in a rodent version of Parkinson’s. But rodents are not people. © 2017 The New York Times Company

Keyword: Parkinsons
Link ID: 24423 - Posted: 12.14.2017

By Jessica Hamzelou An Italian family that is barely able to sense pain has had the genetic root of their shared disorder uncovered. Understanding this gene may lead to new painkiller drugs. The affected family members include a 78-year-old woman, her two middle-aged daughters, and their three children. All of them fail to sense pain in the way most of us do, and don’t notice when they are being injured. When they were assessed, the family members were found to have bone fractures in their arms and legs that they hadn’t realised were there. “Sometimes they feel pain in the initial break but it goes away very quickly,” says James Cox, of University College London. “For example, Letizia broke her shoulder while skiing, but then kept skiing for the rest of the day and drove home. She didn’t get it checked out until the next day.” To find the cause of their lack of pain sensitivity, Cox and his colleagues performed a series of tests on the family members. The team found that all six individuals had normal numbers of nerves in their skin, but that they all had a mutation in a gene called ZFHX2. When the team deleted this gene entirely in mice, they found that the animals were not as good at sensing when painful pressure was applied to their tails, but they were hypersensitive to heat sensations. This suggests the gene may play a role in controlling whether stimuli are painful or not. © Copyright New Scientist Ltd.

Keyword: Pain & Touch; Genes & Behavior
Link ID: 24422 - Posted: 12.14.2017

Tina Hesman Saey PHILADELPHIA — Flat brains growing on microscope slides may have revealed a new wrinkle in the story of how the brain folds. Cells inside the brains contract, while cells on the outside grow and push outward, researchers at the Weizmann Institute of Science in Rehovot, Israel, discovered from working with the lab-grown brains, or organoids. This push and pull results in folds in the organoids similar to those found in full-size brains. Orly Reiner reported the results December 5 at the joint meeting of the American Society for Cell Biology and the European Molecular Biology Organization. Reiner and her colleagues sandwiched human brain stem cells between a glass microscope slide and a porous membrane. The apparatus allowed the cells access to nutrients and oxygen while giving the researchers a peek at how the organoids grew. The cells formed layered sheets that closed up at the edges, making the organoids resemble pita bread, Reiner said. Wrinkles began to form in the outer layers of the organoids about six days after the mini brains started growing. These brain organoids may help explain why people with lissencephaly — a rare brain malformation in which the ridges and folds are missing — have smooth brains. The researchers used the CRISPR/Cas9 gene-editing system to make a mutation in the LIS1 gene. People with lissencephaly often have mutations in that gene. Cells carrying the mutation didn’t contract or move normally, the team found. |© Society for Science & the Public 2000 - 2017.

Keyword: Development of the Brain
Link ID: 24421 - Posted: 12.14.2017

Eating is prompted, in part, by brain regions that help to maintain the body’s energy levels. But hunger pangs are not the only motivation for a trip to the snack bar. In an effort to understand how the brain’s emotional and cognitive machinery influences appetite, Yunlei Yang and his colleagues at the State University of New York Upstate Medical University in Syracuse examined the medial septal complex, a group of brain cells that has a role in emotion. Some of the complex’s cells produce a signalling chemical called glutamate. When the scientists turned on these glutamate-producing cells in mice, the animals ate less than half as much as control mice. That makes the region a good starting point for studies of emotionally triggered eating, the team says. Proc. Natl Acad. Sci. USA (2017)

Keyword: Obesity; Emotions
Link ID: 24420 - Posted: 12.14.2017

Hannah Devlin Science correspondent A landmark trial for Huntington’s disease has announced positive results, suggesting that an experimental drug could become the first to slow the progression of the devastating genetic illness. The results have been hailed as “enormously significant” because it is the first time any drug has been shown to suppress the effects of the Huntington’s mutation that causes irreversible damage to the brain. Current treatments only help with symptoms, rather than slowing the disease’s progression. Prof Sarah Tabrizi, director of University College London’s Huntington’s Disease Centre who led the phase 1 trial, said the results were “beyond what I’d ever hoped ... The results of this trial are of ground-breaking importance for Huntington’s disease patients and families,” she said. The results have also caused ripples of excitement across the scientific world because the drug, which is a synthetic strand of DNA, could potentially be adapted to target other incurable brain disorders such as Alzheimer’s and Parkinson’s. The Swiss pharmaceutical giant Roche has paid a $45m licence fee to take the drug forward to clinical use. Huntington’s is an incurable degenerative disease caused by a single gene defect that is passed down through families. The first symptoms, which typically appear in middle age, include mood swings, anger and depression. Later patients develop uncontrolled jerky movements, dementia and ultimately paralysis. Some people die within a decade of diagnosis. © 2017 Guardian News and Media Limited

Keyword: Huntingtons; Genes & Behavior
Link ID: 24419 - Posted: 12.11.2017

Hannah Devlin Huntington’s has blighted Peter Allen’s family for generations. He watched his mother, Stephanie, slowly die from the disease and before that his grandmother, Olive, fell victim to the same illness. At 51 years old, Peter is the first of his generation to show signs of the illness, but his sister, Sandy, and brother, Frank, know they are also carrying the gene. The onset of Huntington’s is insidious. Psychological changes typically come first – tiredness, mood swings, apathy and anger. Four years ago, Peter was formally diagnosed as symptomatic when he began suffering anxiety and panic attacks so severe he would become convinced that he couldn’t swallow. In retrospect, the depression he suffered in his thirties may have been an earlier manifestation of changes happening his brain. In person, Peter is articulate, funny and exudes affection for his wife and siblings, but there are small signs of the changes that are underway. Every now and then he pauses to search for the right word. A loss of dexterity means he can no longer write or sign his name, his balance is unsteady and, when tired, his speech becomes slurred. “You know that you’re gradually lessening,” he says. A lack of awareness about the disease and its symptoms means people sometimes assume he is drunk. “I’ve been asked to leave pubs before I’ve even had a drink,” he says. “I don’t go to those pubs any more.” Peter took redundancy from his marketing job at Network Rail in 2015 and has not returned to full-time work, although he is retraining to become a garden designer. Anti-depressant drugs have helped bring the psychological symptoms under control. In future, he will be offered other drugs to stiffen his muscles, which helps reduce involuntary movements. But no current treatments can slow the relentless progression of the disease, the loss of memory, motor control and eventually the ability to think. © 2017 Guardian News and Media Limited

Keyword: Huntingtons; Genes & Behavior
Link ID: 24418 - Posted: 12.11.2017

/ By Rae Ellen Bichell In mid-October, Dr. David Bennett, a neurologist who directs the Alzheimer’s Disease Center at Rush University Medical Center in Chicago, stood in a St. Louis auditorium packed with nuns. His goal: To convince them — particularly the ones without brain disease — to donate their brains to science. “We are beginning to understand how little we actually know about the human brain.” Politicians, Bennett is fond of saying, can walk into a room and separate people from their money. “I can walk into a room and separate people from their brains.” To Bennett, making such acquisitions is, in some ways, more crucial than ever. Demand for brains for scientific research is rising across the board — driven in varying degrees by increased funding for research on brain disorders, rising incidence of age-related brain disease, big technological leaps in scientific tools used to analyze the brain, and a growing sense that sometimes, studying animals just isn’t good enough to understand and fix human disease. But more than this, scientists like Bennett are realizing that the brains they have traditionally studied (Bennett maintains 4,000 square feet of cabinets and freezers full of brain slices in Chicago), are too often riddled with the signs of end stage Alzheimer’s and other maladies that contribute to dementia. Far more rare are comparatively healthy brains that can allow scientists to more accurately identify what causes dementia — and what protects us from it. That deficiency now has Bennett and other scientists working hard to stock their shelves with a particularly precious resource: the brains of people like Sister Carleen Reck, who heard Bennett speak and thought his request for brain donations was a good idea, so she signed an anatomical gift act. Copyright 2017 Undark

Keyword: Alzheimers; Brain imaging
Link ID: 24417 - Posted: 12.11.2017

By PERRI KLASS, M.D. What does the child who can’t say goodbye to a parent without breaking down have in common with the child who is cripplingly terrified of dogs and the one who gets a bad stomach ache reliably on Monday morning? Anxieties and worries of all kinds are common in children, necessarily part of healthy development, but also, when they interfere with the child’s functioning, the most common pediatric mental health problems. From separation anxiety to social anxiety to school avoidance to phobias to generalized anxiety disorder, many children’s lives are at some point touched by anxiety that gets out of hand. “I often tell parents, anxiety and fears are totally a normal and healthy part of growing up,” said Dr. Sabrina Fernandez, an assistant professor of pediatrics at the University of California, San Francisco, who has written about strategies for primary care doctors to use in dealing with anxiety disorders. “I worry that it’s becoming something more when it interferes with the child’s ability to do their two jobs: to learn in school and to make friends.” Children whose lives are being seriously derailed by their anxieties often get psychotherapy or medication, or both. And a meta-analysis published in November in JAMA looked at the two best-studied treatments for anxiety disorders, cognitive behavioral therapy and psychotropic medication. The technique of a meta-analysis allows scientists to pull in a whole range of different studies, weight the results according to the size and rigor of the research, and then consider the wider array of data gleaned from multiple investigations. “We included panic disorder, social anxiety disorder, specific phobias, generalized anxiety disorder and separation anxiety,” said the lead author, Zhen Wang, an associate professor of health services research at the Mayo Clinic College of Medicine and Science (they did not include children with post-traumatic stress disorder or obsessive-compulsive disorder). The study looked at the effectiveness of treatments in reducing the symptoms of anxiety, and at ending the anxiety disorder state. And they also looked at any reports of adverse events associated with the treatments, from sleep disturbances to suicide. © 2017 The New York Times Company

Keyword: Development of the Brain; Stress
Link ID: 24416 - Posted: 12.11.2017

By Ferris Jabr Chickens are loquacious creatures, and Kevin Mitchell would know. He oversees the care of about a million of them on Wilcox Farms properties in Washington State and Oregon. Mitchell says the birds have “patterns of speech” that reveal a lot about their well-being. They are usually noisiest in the morning—a robust concert of clucks, chortles and caws. “When I hear that, I know they are pretty healthy and happy,” Mitchell says. In the evenings when they’re preparing to roost, the chickens are much more mellow, cooing softly. When a hen lays an egg she celebrates with a series of staccato clucks, like drumbeats, culminating in a loud “buck-caw!” If chickens detect an aerial predator—say, by spotting the shadow of a hawk or eagle—they produce a short, high-pitched shriek. And they have a distinct warning for terrestrial threats: The repetitive clucking most people associate with chickens is in fact a ground predator alarm call. One morning many years ago Mitchell entered a chicken house and found it oddly calm and quiet. Instead of making the usual ruckus, the birds were murmuring and shuffling lethargically. He soon discovered that an automated lighting system had failed and the lights had not switched off the night before; the chickens were sleep-deprived. If he had only been able to eavesdrop on the flock, he might have known much sooner that something was amiss. Over the past five years, engineers and poultry scientists at The University of Georgia and Georgia Institute of Technology have been collaborating to help farmers like Mitchell make better use of the information latent in chicken chatter. © 2017 Scientific American

Keyword: Animal Communication; Language
Link ID: 24415 - Posted: 12.11.2017

By Catherine Offord Mantis shrimps are not the easiest animals to work with, as neuroanatomist Nicholas Strausfeld knows firsthand. Not least, there’s the challenge of capturing the crustaceans in the wild. Also known as stomatopods, mantis shrimps live in burrows in shallow seawater and have earned the descriptive nickname “thumb splitters,” thanks to their tendency to use their sharp, powerful claws to slash at prey and pursuers. “At low tide, you wade around and you try and catch these things,” says Strausfeld, who has plenty of experience chasing after the purple-spotted mantis shrimp (Gonodactylus smithii) with a small handheld net in the tropical waters around Lizard Island, Australia. “They’re incredibly fast—it’s very difficult.” For Strausfeld and other neurobiologists, however, all the trouble is well worth it, as these feisty little marine predators are yielding unique insight into the evolution of the arthropods—the most species-rich animal phylum on the planet, containing around 85 percent of all described animal species. “We knew [these shrimps] were very interesting,” says neuroanatomist Gabriella Wolff, previously a PhD student in Strausfeld’s lab at the University of Arizona and now a research associate at the University of Washington in Seattle. In addition to a complex visual system that receives inputs from independently moving eyes, “mantis shrimps have very advanced behaviors that we haven’t necessarily seen in other crustaceans so far.” Research has also suggested they are sophisticated navigators, regularly finding their way home from distant feeding sites. Plus, they recognize other individual mantis shrimps, and remember whether their interactions were confrontational or not. © 1986-2017 The Scientist

Keyword: Learning & Memory; Evolution
Link ID: 24414 - Posted: 12.11.2017

By Andy Coghlan Two gene variants have been found to be more common in gay men, adding to mounting evidence that sexual orientation is at least partly biologically determined. How does this change what we already knew? Didn’t we already know there were “gay genes”? We have known for decades that sexual orientation is partly heritable in men, thanks to studies of families in which some people are straight and some people are gay. In 1993, genetic variations in a region on the X chromosome in men were linked to whether they were heterosexual or homosexual, and in 1995, a region on chromosome 8 was identified. Both findings were confirmed in a study of gay and straight brothers in 2014. However, these studies didn’t home in on any specific genes on this chromosome. What’s new about the latest study? For the first time, individual genes have been identified that may influence how sexual orientation develops in boys and men, both in the womb and during life. Alan Sanders at North Shore University, Illinois, and his team pinpointed these genes by comparing DNA from 1077 gay and 1231 straight men. They scanned the men’s entire genomes, looking for single-letter differences in their DNA sequences. This enabled them to home in on two genes whose variants seem to be linked to sexual orientation. © Copyright New Scientist Ltd.

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 24413 - Posted: 12.09.2017

By Ruth Williams Two studies in Science today—one that focuses on prenatal development in humans, the other on infancy to old age—provide insights into the extent of DNA sequence errors that the average human brain cell accumulates over a lifetime. Together, they reveal that mutations become more common as fetuses develop, and over a lifetime a person may rack up more than 2,000 mutations per cell. “I think these are both very powerful technical papers, and they demonstrate how single-cell sequencing . . . can reliably detect somatic changes in the genomes of human neurons,” says neuroscientist Fred Gage of the Salk Institute in La Jolla who was not involved in either study. “What’s cool about [the papers] is that they show two different ways that one can look at somatic mutations in single human neurons . . . and yet they get consistent results,” says neuroscientist Michael McConnell of the University of Virginia School of Medicine. Cells of the human body acquire mutations over time, whether because of errors introduced during DNA replication or damage incurred during transcription and other cellular processes. But, until recent technological developments enabled whole genome sequencing from the miniscule quantities of DNA found inside single cells or small clones of the same cell, investigating the nature and extent of such somatic mutations—and the resulting tissue mosaicism—was practically impossible. © 1986-2017 The Scientist

Keyword: Development of the Brain; Epigenetics
Link ID: 24412 - Posted: 12.09.2017

Michael Ruffolo When we talk about female representation in science, we’re rarely talking about test subjects. We tend to want more women behind the microscope, not under it. Neuroscience is one of the most skewed fields when it comes to testing on female physiology. One review found single-sex brain studies using male animals outnumbered those using females 6.7 to one. Aarthi Gobinath, a neuroscientist at the University of British Columbia, calls this a “hidden gap” in her field. She says there’s reason to question the assumption that the brains of males and females are identical, particularly in unique states like pregnancy. This is particularly true for early animal testing, where new drugs for depression and anxiety are first developed. “This leads to the ultimate outcome of our research not even benefiting males and females equally,” Gobinath said. Gobinath wanted to tackle the issue of sex bias by trying to understand what depression looks like in female rat brains, specifically looking at postpartum depression. Her research suggests our standard depression treatments don’t apply to new moms. VICE caught up with Gobinath to ask about her new study, which could have wide-ranging implications for humans of all sexes and genders. VICE: What do you mean when you say there’s “sex bias” in brain research? Aarthi Gobinath: So when I say "sex," what I mean is genetic sex, meaning XX or XY chromosomes. [Sex bias] is a bias toward using male subjects in research and then concluding from that research that what was true in that experiment will be true for both sexes without necessarily addressing that maybe it won’t be true for the female physiology.

Keyword: Sexual Behavior
Link ID: 24411 - Posted: 12.09.2017

By SHEILA KAPLAN Chris Beekman, whose company sells the dietary supplement Opiate Detox Pro, does not understand what all the fuss is about. “If it works, it works,” Mr. Beekman, the owner of NutraCore Health Products, said in an interview. “If it doesn’t, it doesn’t.” His customers, addicts trying to shake a dependence on opioids, can always get their money back, he said. Opiate Detox Pro’s label says, “Opioid addiction ease,” and the company’s website claims, “Our ingredients are the most effective on the market for treating withdrawal symptoms.” Mr. Beekman said he did not have scientific evidence to prove that the product worked, and would not be conducting research to buttress the company’s claims. “It’s just not going to happen,” he said, citing what he called the prohibitive cost of scientific studies and clinical trials. Peter Lurie thinks that is an unacceptable position from someone who sells supplements that purport to treat addiction. Dr. Lurie, a former Food and Drug Administration official, runs the nonprofit Center for Science in the Public Interest, which on Friday urged the F.D.A. and the Federal Trade Commission to crack down on businesses that target addicts with products that make unproven health claims. The F.D.A. has already zeroed in on another supplement, kratom, a botanical substance that has been promoted as a safe substitute for opioids and an adjunct to opioid use. Last month, the agency issued a public health advisory for kratom, warning that the product carried “deadly risks,” and linked about three dozen deaths to it. Earlier, the agency had ordered that kratom imports be seized and told companies to take it out of supplements. In general, the agency can fine companies that make and distribute them, or take other enforcement actions. In the past few weeks, reacting to other agency warnings, Amazon has stopped making available some products claiming to assist in opioid withdrawal. © 2017 The New York Times Company

Keyword: Drug Abuse
Link ID: 24410 - Posted: 12.09.2017

Paula Span Jeannie Cox currently enjoys a flavor called Coffee & Cream when she vapes. She’s also fond of White Lotus, which tastes “kind of fruity.” She buys those nicotine-containing liquids, along with her other e-cigarette supplies, at Mountain Oak Vapors in Chattanooga, Tenn., where she lives. A retired secretary in her 70s, she’s often the oldest customer in the shop. Not that she cares. What matters is that after ignoring decades of doctors’ warnings and smoking two packs a day, she hasn’t lit up a conventional cigarette in four years and four months. “Not one cigarette,” she said. “Vaping took its place.” Like Ms. Cox, some smokers have been able to stop smoking by switching to e-cigarettes, and many are trying. A recent study by the Centers for Disease Control and Prevention found that more smokers now attempt to quit by using e-cigarettes as a partial or total substitute for cigarettes than by using nicotine gum or lozenges, prescription medications or several other more established methods. Her success is what researchers disdainfully call “anecdotal evidence,” however. There’s “no conclusive evidence” that e-cigarettes help people stop smoking long-term, said Brian King, deputy director of the C.D.C.’s Office of Smoking and Health. At the moment, therefore, neither the C.D.C., the Food and Drug Administration nor the United States Preventive Services Task Force has approved or recommended e-cigarettes for smoking cessation. In fact, the rise of e-cigarettes has generated contentious debate among public health officials and advocates. But while the proportion of Americans who smoke continues to decrease — down to 15.1 percent in 2015 — the decline has stalled among older adults. © 2017 The New York Times Company

Keyword: Drug Abuse
Link ID: 24409 - Posted: 12.09.2017

Carl Zimmer When you drive toward an intersection, the sight of the light turning red will (or should) make you step on the brake. This action happens thanks to a chain of events inside your head. Your eyes relay signals to the visual centers in the back of your brain. After those signals get processed, they travel along a pathway to another region, the premotor cortex, where the brain plans movements. Now, imagine that you had a device implanted in your brain that could shortcut the pathway and “inject” information straight into your premotor cortex. That may sound like an outtake from “The Matrix.” But now two neuroscientists at the University of Rochester say they have managed to introduce information directly into the premotor cortex of monkeys. The researchers published the results of the experiment on Thursday in the journal Neuron. Although the research is preliminary, carried out in just two monkeys, the researchers speculated that further research might lead to brain implants for people with strokes. “You could potentially bypass the damaged areas and deliver stimulation to the premotor cortex,” said Kevin A. Mazurek, a co-author of the study. “That could be a way to bridge parts of the brain that can no longer communicate.” In order to study the premotor cortex, Dr. Mazurek and his co-author, Dr. Marc H. Schieber, trained two rhesus monkeys to play a game. The monkeys sat in front of a panel equipped with a button, a sphere-shaped knob, a cylindrical knob, and a T-shaped handle. Each object was ringed by LED lights. If the lights around an object switched on, the monkeys had to reach out their hand to it to get a reward — in this case, a refreshing squirt of water. © 2017 The New York Times Company

Keyword: Learning & Memory; Movement Disorders
Link ID: 24408 - Posted: 12.08.2017

By Mitch Leslie Scientists once had high hopes that inhibiting a hormone named ghrelin would be the key to preventing obesity. Ghrelin didn’t turn out to be a weight loss panacea. But now, the discovery of the first molecule naturally made by the body that blocks ghrelin’s effects may open up new avenues for treating other conditions, including diabetes and anorexia. The finding may also explain some of the benefits of bariatric surgery, which shrinks or reroutes the stomach to control weight. “It’s a very impressive piece of research,” says bariatric physician Carel le Roux of University College Dublin, who wasn’t connected to the study. “I think it will have significant clinical impact.” When researchers discovered ghrelin about 20 years ago, they dubbed it the “hunger hormone” because early results suggested it ramped up our appetite. But studies soon found that thwarting the molecule didn’t curtail food consumption or promote weight loss in mice. Still, the hormone induces a variety of other positive changes in our metabolism. For example, ghrelin may bolster muscle strength, spurring scientists to test whether drugs that mimic the hormone can counteract the muscle deterioration and weakness often suffered by cancer patients. The new study didn’t start as a hunt for ghrelin-blocking compounds. Instead, a team headed by researchers at NGM Biopharmaceuticals in South San Francisco, California, was investigating how bariatric surgery overhauls metabolism. The scientists operated on obese mice, performing a type of bariatric surgery called vertical sleeve gastrectomy that involves removing most of the stomach. They then examined which genes became more or less active after the procedure. As they report online today in Cell Metabolism, the rodents’ downsized stomachs produced 52 times more of a protein named LEAP2 than normal. © 2017 American Association for the Advancement of Science

Keyword: Obesity; Hormones & Behavior
Link ID: 24407 - Posted: 12.08.2017

By KAREN WEINTRAUB Q. For working parents, it’s difficult to find time to exercise during the week, and early morning is often the only time slot available. Is it better for my overall health to get eight hours of sleep per night during the week but not have time to exercise, or to get six and a half to seven hours of sleep per night and fit in a morning workout? A. “That’s a terrible choice,” said Dr. Charles Czeisler, a sleep expert at Brigham and Women’s Hospital and Harvard Medical School in Boston. Both sleep and exercise are key components of a healthy lifestyle and shouldn’t be pitted against each other, Dr. Czeisler said. Sleep is important for workouts, he noted, reducing the risk of injury and allowing muscles to recover from exercise. Lack of sleep weakens the immune system, making people more likely to become sick — which means missing workouts. Sacrificing sleep has also been tied to weight gain, cardiovascular disease and diabetes, among other health problems. Of course, regular exercise provides a lot of benefits, too, including sounder sleep. Dr. Czeisler also noted that going to bed late, particularly if you’re using electronic devices and sitting under bright lights before bedtime, shifts the body’s circadian rhythms later. But people still need around eight hours of sleep per night. So if you get up after six and a half hours to work out, “you’re essentially exercising during your biological night,” he said. Research from Northwestern University suggests that muscle cells also have circadian rhythms, and that they perform and recover much better during the biological daytime than the biological night. “So, getting up during your biological night to exercise is counterproductive,” Dr. Czeisler said. © 2017 The New York Times Company

Keyword: Sleep
Link ID: 24406 - Posted: 12.08.2017

Mariah Quintanilla When escaping from humans, narwhals don’t just freeze or flee. They do both. These deep-diving marine mammals have similar physiological responses to those of an animal frozen in fear: Their heart rate, breathing and metabolism slow, mimicking a “deer in the headlights” reaction. But narwhals (Monodon monoceros) take this freeze response to extremes. The animals decrease their heart rate to as slow as three beats per minute for more than 10 minutes, while pumping their tails as much as 25 strokes per minute during an escape dive, an international team of researchers reports in the Dec. 8 Science. “That was astounding to us because there are other marine mammals that can have heart rates that low but not typically for that long a period of time, and especially not while they’re swimming as hard as they can,” says Terrie Williams, a biologist at the University of California, Santa Cruz. So far, this costly escape has been observed only after a prolonged interaction with humans. Usually, narwhals will escape natural predators such as killer whales by stealthily slipping under ice sheets or huddling in spots too shallow for their pursuers, Williams says. But interactions with humans — something that will happen increasingly as melting sea ice opens up the Arctic — may be changing that calculus. Monitoring a female narwhal showed that her heart rate dropped precipitously low at times as she performed a series of dives after escaping a net (top graph). The red box shows periods of “cardiac freeze,” when her heart only beat a few times per minute. About two days later, the same narwhal was back to performing regular deep dives (bottom graph), in which her heart rate dropped to 10 to 20 beats per minute, an adaption that allows the sea mammals to conserve energy during stretches underwater. |© Society for Science & the Public 2000 - 2017.

Keyword: Stress
Link ID: 24405 - Posted: 12.08.2017

Nell Greenfieldboyce At least one young woman suffered eye damage as a result of unsafe viewing of the recent total solar eclipse, according to a report published Thursday, but it doesn't appear that many such injuries occurred. Doctors in New York say a woman in her 20s came in three days after looking at the Aug. 21 eclipse without protective glasses. She had peeked several times, for about six seconds, when the sun was only partially covered by the moon. The area between the yellow brackets in the top photo shows the damage to the center part of the retina. The middle image is a type of visual field test and the bottom image uses optical coherence tomography. Courtesy of New York Eye and Ear Infirmary of Mount Sinai Four hours later, she started experiencing blurred and distorted vision and saw a central black spot in her left eye. The doctors studied her eyes with several different imaging technologies, described in the journal JAMA Ophthalmology, and were able to observe the damage at the cellular level. "We were very surprised at how precisely concordant the imaged damage was with the crescent shape of the eclipse itself," noted Dr. Avnish Deobhakta, a retina surgeon at New York Eye and Ear Infirmary of Mount Sinai in New York, in an email to NPR. © 2017 npr

Keyword: Vision
Link ID: 24404 - Posted: 12.08.2017