ByWarren Cornwall Bats use sound to hunt a dizzying array of prey. Some zero in on flowers to sip nectar, whereas others find cattle and suck their blood. Many nab insects midflight. One species of bat senses small fish beneath the water and snatches them as osprey do. Now, scientists have discovered an anatomical quirk in the ears of some bats that could help explain how they evolved so many hunting specialties. “For me this is a huge revelation,” says Zhe-Xi Luo, a University of Chicago evolutionary biologist who has studied the origins of mammalian hearing and supervised the new research. “This is totally distinct and unique from all other hearing mammals.” Most bats use their ears to “see” the world around them: After a bat chirps, its ears sense shapes and movement as sound waves bounce off objects, much as ships use sonar. Bats’ ears were long thought to be just a finely tuned version of the ears of nearly all mammals. Then, in 2015, Benjamin Sulser, a University of Chicago biology student on the hunt for a thesis project, took detailed 3D images of the inner ear of a bat skull. But he couldn’t find a feature common in virtually all mammals—a bony tube that encases the nerve cells and connects the ear to the brain. Thinking he’d made a mistake, he and Luo imaged the skulls of two more related species using a computed tomography scanner, with similar results. The researchers realized they might have stumbled across an answer to a mystery that had bedeviled bat biologists for 2 decades—and an explanation for why some families of bats had such a diverse echolocation arsenal. © 2022 American Association for the Advancement of Science.

Keyword: Hearing
Link ID: 28175 - Posted: 01.29.2022

By Meeri Kim Kellie Carr and her 13-year-old son, Daniel, sat in the waiting room of a pediatric neurology clinic for yet another doctor’s appointment in 2012. For years, she struggled to find out what was causing his weakened right side. It wasn’t an obvious deficit, by any means, and anyone not paying close attention would see a normal, healthy teenage boy. At that point, no one had any idea that Daniel had suffered a massive stroke as a newborn and lost large parts of his brain as a result. “It was the largest stroke I’d ever seen in a child who hadn’t died or suffered extreme physical and mental disability,” said Nico Dosenbach, the pediatric neurologist at Washington University School of Medicine in St. Louis who finally diagnosed him using a magnetic resonance imaging (MRI) scan. "If I saw the MRI first, I would have assumed this kid's probably in a wheelchair, has a feeding tube and might be on a ventilator," Dosenbach said. "Because normally, when a child is missing that much brain, it's bad." But Daniel — as an active, athletic young man who did fine in school — defied all logic. Before the discovery of the stroke, his mother had noticed some odd mannerisms, such as zipping up his coat or eating a burger using only his left hand. When engaged, his right hand often served as club-like support instead of a dexterous appendage with fingers. Daniel excelled as a left-handed pitcher in competitive baseball, but his coach found it unusual that he would always switch the glove to his left hand when catching the ball. Medical professionals tried to help — first his pediatrician, followed by an orthopedic doctor who sent him to physical therapy — but no one could figure out the root cause. They tried constraint-induced movement therapy, which forces patients to use the weaker arm by immobilizing the other in a cast, but Daniel soon rebelled and broke himself free. © 1996-2022 The Washington Post

Keyword: Development of the Brain; Stroke
Link ID: 28174 - Posted: 01.26.2022

John Crimaldi Brian H. Smith Elizabeth Hong Nathan Urban A dog raises its nose in the air before chasing after a scent. A mosquito zigzags back and forth before it lands on your arm for its next meal. What these behaviors have in common is that they help these animals “see” their world through their noses. While humans primarily use their vision to navigate their environment, the vast majority of organisms on Earth communicate and experience the world through olfaction – their sense of smell. We are members of Odor2Action, an international network of over 50 scientists and students using olfaction to study brain function in animals. Our goal is to understand a fundamental question in neuroscience: How do animal brains translate information from their environments to changes in their behaviors? Here, we trace the interconnections between smells and behaviors – looking at how behavior influences odor detection, how the brain processes sensory information from smells and how this information triggers new behaviors. When the odor of a flower is released into the air, it takes the shape of a wind-borne cloud of molecules called a plume. It encounters physical obstacles and temperature differences as it flows through space. These interactions create turbulence that splits the odor plume into thin threads that spread out as the scent moves away from its source. These filaments eventually reach an animal’s nose or an insect’s antenna. © 2010–2022, The Conversation US, Inc.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 28173 - Posted: 01.26.2022

By Jason DeParle WASHINGTON — A study that provided poor mothers with cash stipends for the first year of their children’s lives appears to have changed the babies’ brain activity in ways associated with stronger cognitive development, a finding with potential implications for safety net policy. The differences were modest — researchers likened them in statistical magnitude to moving to the 75th position in a line of 100 from the 81st — and it remains to be seen if changes in brain patterns will translate to higher skills, as other research offers reason to expect. Still, evidence that a single year of subsidies could alter something as profound as brain functioning highlights the role that money may play in child development and comes as President Biden is pushing for a much larger program of subsidies for families with children. “This is a big scientific finding,” said Martha J. Farah, a neuroscientist at the University of Pennsylvania, who conducted a review of the study for the Proceedings of the National Academy of Sciences, where it was published on Monday. “It’s proof that just giving the families more money, even a modest amount of more money, leads to better brain development.” Another researcher, Charles A. Nelson III of Harvard, reacted more cautiously, noting the full effect of the payments — $333 a month — would not be clear until the children took cognitive tests. While the brain patterns documented in the study are often associated with higher cognitive skills, he said, that is not always the case. © 2022 The New York Times Company

Keyword: Development of the Brain; Learning & Memory
Link ID: 28172 - Posted: 01.26.2022

In 2016, Science magazine ranked Randy L. Buckner among the top 10 most influential brain scientists of the modern era. He explains the road to discovering the default network, the pattern of brain activity triggered as we think about the past and the future. Q: Why don’t we begin with a brief description of what the default network is, how and when it was discovered, and why it’s important. Randy L. Buckner: In the 1990s, neuroscientists were just starting to do functional imaging studies. For the first time, we had brain scanners that could see the mind at work. We were like kids in a candy store in the sense that we no longer needed a scalpel to see the brain; the new technology allowed us to safely discern information out about what parts of the brain people used when given different tasks and different kinds of visual or auditory stimuli. I was a graduate student at the time at Washington University and one of my mentors, Marcus Raichle, was at the forefront of positron emission tomography (PET), an imaging technique that measures physiological changes in the brain and shows where blood flow is increasing due to brain activity. This is when many of us first became aware of the Dana Foundation, which was helping fund our work. I was a Dana fellow in those early days, and this was an exciting time in neuroscience. In early studies, we often asked participants to perform very simple tasks: read and say words, detect colors in pictures, or try to recognize whether a viewed word was on an earlier studied list. The imaging revealed the parts of the brain involved in their responses. But what jumped out at us was something unexpected: When people weren’t asked for a response or given a specific task, much of their brain still remained active. © 2022 The Dana Foundation.

Keyword: Brain imaging
Link ID: 28171 - Posted: 01.26.2022

Chloe Tenn Humans have a sugar sense. Animals and humans prefer sugar over artificial sweeteners in experiments, and that could be because a specific gut sensor cell triggers one of two separate neural pathways depending on which it detects, researchers suggest in a January 13 study in Nature Neuroscience. “It has been known for decades that animals prefer sugar to non-caloric sweeteners and that this preference relies on feedback from the gut,” Lisa Beutler, a Northwestern University endocrinologist who researches the connection between the gut and brain and was not affiliated with the new work, writes in an email to The Scientist. “This study is among the first to provide insight at the molecular level into how the gut knows the difference between sugar and non-caloric sweeteners, and how this drives preference.” The study builds on previous research from the lab of Duke University gut-brain neuroscientist Diego Bohórquez. In 2015, Bohórquez established that endocrine cells, which were previously thought to only communicate with the nervous system indirectly through hormone secretion, can in fact have direct contact with neurons, evidenced by a video. Then, in 2018, the Bohórquez Lab found that the gut has similar cells to those that allow for taste on the tongue and smell in the nose, and that these sensors also have direct contact with neurons. “If they are connected to neurons, they must be connected to the brain,” Bohórquez tells The Scientist. “When we ingest sugar, it stimulates cells in the gut, and these cells release glutamate and activate the vagus nerve,” Bohórquez explains of his prior research. The vagus nerve is a cranial nerve that plays a regulatory role in internal organ functions such as digestion. His team observed that these gut sensor cells, which the team dubbed “neuropods,” transmit the chemosensory information mere milliseconds after detecting sugar. © 1986–2022 The Scientist.

Keyword: Chemical Senses (Smell & Taste); Obesity
Link ID: 28170 - Posted: 01.26.2022

ByMichael Price When it comes to killing and eating other creatures, chimpanzees—our closest relatives—have nothing on us. Animal flesh makes up much more of the average human’s diet than a chimp’s. Many scientists have long suggested our blood lust ramped up about 2 million years ago, based on the number of butchery marks found at ancient archaeological sites. The spike in calories from meat, the story goes, allowed one of our early ancestors, Homo erectus, to grow bigger bodies and brains. But a new study argues the evidence behind this hypothesis is statistically flawed because it fails to account for the fact that researchers have focused most of their time and attention on later sites. As a result of this unequal “sampling effort” over time at different sites, the authors say, it’s impossible to know how big a role meat eating played in human evolution. Even before the study, many experts suspected the link between carnivory and bigger brains and bodies in early humans might be complex, says Rachel Carmody, an evolutionary biologist at Harvard University who wasn’t involved in the work. The new results, though, “take the important step of demonstrating empirically that controlling for sampling effort actually changes the interpretation.” To conduct the study, W. Andrew Barr, a paleoanthropologist at George Washington University, and colleagues reviewed previously reported data on the appearance of butchery marks at nine archaeological hotbeds of early human activity across eastern Africa spanning 2.6 million to 1.2 million years ago. As expected, the scientist found an increase in the number of cutmarks on animal bones beginning about 2 million years ago. However, the researchers noticed that archaeologists tended to find more cutmarks at the sites that have received the most research attention. In other words, the more time and effort researchers poured into a site, the more likely they were to discover evidence of meat eating. © 2022 American Association for the Advancement of Science.

Keyword: Evolution
Link ID: 28169 - Posted: 01.26.2022

By Christina Caron For the entirety of my adult life I have tried to avoid driving. I could claim all sorts of noble reasons for this: concern about the environment, a desire to save money, the health benefits gained from walking or biking. But the main reason is that I’m anxious. What if I did something stupid and accidentally pressed the gas pedal instead of the brake? What if a small child suddenly darted into the middle of the road? What if another driver was distracted or full of rage? By 2020 I had managed to avoid driving for eight years, even though I’d gotten my license in high school. Then came the pandemic. After more than a year of hunkering down in our Manhattan neighborhood, my little family of three was yearning for new surroundings. So, I booked lodging in the Adirondacks, about a three-hour drive from New York City, and — for the first time in my life — signed up for formal driving lessons. On that first day, I arrived queasy and full of impending doom, muscles tensed and brain on high alert. But my instructor assured me that we would not meet our demise — we wouldn’t be driving fast enough for that, he explained — and then he told me something that nobody ever had: “The fear never leaves you.” You have to learn to harness it, he said. Have just enough fear to stay alert and be aware of your surroundings, but not so much that it is making you overly hesitant. The idea that I didn’t need to completely erase my anxiety was freeing. Having some anxiety — especially when faced with a stressful situation — isn’t necessarily bad and can actually be helpful, experts say. Anxiety is an uncomfortable emotion, often fueled by uncertainty. It can create intense, excessive and persistent worry and fear, not just about stressful events but also about everyday situations. There are usually physical symptoms too, like fast heart rate, muscle tension, rapid breathing, sweating and fatigue. Too much anxiety can be debilitating. But a normal amount is meant to help keep us safe, experts say. © 2022 The New York Times Company

Keyword: Emotions; Evolution
Link ID: 28168 - Posted: 01.22.2022

Sung Han & Shijia Liu You’re startled by a threatening sound, and your breath quickens. You smash your elbow and pant in pain. Why does your breathing rate increase dramatically when you’re hurting or anxious? As neurobiologists studying how the brain responds to environmental threats and the neural circuitry of emotion, we were curious about the answer to this question ourselves. In our recently published study, we discovered that one particular circuit of the brain in mice underlies this tight connection between pain, anxiety and breathing. And this discovery may eventually help us develop safer pain killers for humans. One of the most common symptoms of both pain and anxiety disorders is shortness of breath, or hyperventilation. On the other hand, slow, deep breathing can reduce pain and distress. The simplest way to explain this, we reasoned, is the existence of a common pathway in the brain that regulates breathing, pain and anxiety simultaneously. So we searched for brain regions previously reported to regulate breathing, pain and emotion. A small area in the brainstem called the lateral parabrachial nucleus caught our attention. Not only is it part of the breathing regulation center of the brain, it also mediates pain and negative emotions like fear and anxiety. Searching through a public database of gene expression patterns, or how genetic material is translated into proteins that let cells function, in the mouse brain, we serendipitously found that one type of opioid receptor called the µ-opioid receptor is highly expressed in parabrachial neurons. © 2010–2022, The Conversation US, Inc.

Keyword: Emotions; Drug Abuse
Link ID: 28167 - Posted: 01.22.2022

Chloe Tenn Whether they’re predicting the outcomes of sports games or opening jars, the intelligence of octopuses and their cephalopod kin has fascinated avid sports fans and scientists alike (not that the two groups are mutually exclusive). However, insights into the animals’ brains have been limited, as structural data has come from low-tech methods such as dissection. Wen-Sung Chung, a University of Queensland Brain Institute neurobiologist who focuses on marine species, explains that octopuses have “probably the biggest centralized brain in invertebrates,” with multiple layers and lobes. Some species have more than 500 million neurons, he adds—compared to around 70 million in lab mice—making cephalopods especially intriguing as models for neuroscience. Chung and his colleagues decided to bring cephalopod neuroscience into the 21st century: using cutting-edge MRI, they probed the brains of four cephalopod species. They were especially interested in exploring whether cephalopod brain structures reflect the environments they live in. Indeed, the team reports numerous structural differences between species that live on reefs and those that dwell in deeper waters in a November 18 Current Biology paper. Giovanna Ponte, an evolutionary marine biologist at Stazione Zoologica Anton Dohrn Napoli in Italy who was not involved with the work, tells The Scientist that while this isn’t the first study to look for neurological correlates underlying ecological differences in cephalopods, it offers a new technological approach to investigating these animals’ brain morphology and diversity, and most importantly, “is the first time that there is . . . a comparative approach between different species.” © 1986–2022 The Scientist.

Keyword: Evolution; Brain imaging
Link ID: 28166 - Posted: 01.22.2022

by Lauren Schenkman Autism is thought to arise during prenatal development, when the brain is spinning its web of excitatory and inhibitory neurons, the main signal-generating cell types in the cerebral cortex. Though this wiring process remains mysterious, one thing seemed certain after two decades of studies in mice: Although both neuron types arise from radial glia, excitatory neurons crop up in the developing cortex, whereas inhibitory neurons, also known as interneurons, originate outside of the cortex and then later migrate into it. Not so in the human brain, according to a study published in December in Nature. A team of researchers led by Tomasz Nowakowski, assistant professor of anatomy at the University of California, San Francisco, used a new viral barcoding method to trace the descendants of radial glial cells from the developing human cortex and found that these progenitor cells can give rise to both excitatory neurons and interneurons. “This is really a paradigm-shifting finding,” Nowakowski says. “It sets up a new framework for studying, understanding and interpreting experimental models of autism mutations.” Nowakowski spoke with Spectrum about the discovery’s implications for studying the origins of autism in the developing brain. Spectrum: Why did you investigate this topic? Tomasz Nowakowski: My lab and I are interested in understanding the early neurodevelopmental events that give rise to the incredible complexity of the human cerebral cortex. We know especially little about the early stages of human development, primarily because a lot of our knowledge comes from mouse models. As we’ve begun to realize over the past decade, the processes that underlie development of the brain in humans and mice can be quite different. © 2022 Simons Foundation

Keyword: Autism; Development of the Brain
Link ID: 28165 - Posted: 01.22.2022

Rupert Neate The billionaire entrepreneur Elon Musk’s brain chip startup is preparing to launch clinical trials in humans. Musk, who co-founded Neuralink in 2016, has promised that the technology “will enable someone with paralysis to use a smartphone with their mind faster than someone using thumbs”. The Silicon Valley company, which has already successfully implanted artificial intelligence microchips in the brains of a macaque monkey named Pager and a pig named Gertrude, is now recruiting for a “clinical trial director” to run tests of the technology in humans. “As the clinical trial director, you’ll work closely with some of the most innovative doctors and top engineers, as well as working with Neuralink’s first clinical trial participants,” the advert for the role in Fremont, California, says. “You will lead and help build the team responsible for enabling Neuralink’s clinical research activities and developing the regulatory interactions that come with a fast-paced and ever-evolving environment.” Musk, the world’s richest person with an estimated $256bn fortune, said last month he was cautiously optimistic that the implants could allow tetraplegic people to walk. “We hope to have this in our first humans, which will be people that have severe spinal cord injuries like tetraplegics, quadriplegics, next year, pending FDA [Food and Drug Administration] approval,” he told the Wall Street Journal’s CEO Council summit. “I think we have a chance with Neuralink to restore full-body functionality to someone who has a spinal cord injury. Neuralink’s working well in monkeys, and we’re actually doing just a lot of testing and just confirming that it’s very safe and reliable and the Neuralink device can be removed safely.” © 2022 Guardian News & Media Limited

Keyword: Brain imaging; Robotics
Link ID: 28164 - Posted: 01.22.2022

Veronique Greenwood In the moment between reading a phone number and punching it into your phone, you may find that the digits have mysteriously gone astray — even if you’ve seared the first ones into your memory, the last ones may still blur unaccountably. Was the 6 before the 8 or after it? Are you sure? Maintaining such scraps of information long enough to act on them draws on an ability called visual working memory. For years, scientists have debated whether working memory has space for only a few items at a time, or if it just has limited room for detail: Perhaps our mind’s capacity is spread across either a few crystal-clear recollections or a multitude of more dubious fragments. The uncertainty in working memory may be linked to a surprising way that the brain monitors and uses ambiguity, according to a recent paper in Neuron from neuroscience researchers at New York University. Using machine learning to analyze brain scans of people engaged in a memory task, they found that signals encoded an estimate of what people thought they saw — and the statistical distribution of the noise in the signals encoded the uncertainty of the memory. The uncertainty of your perceptions may be part of what your brain is representing in its recollections. And this sense of the uncertainties may help the brain make better decisions about how to use its memories. The findings suggests that “the brain is using that noise,” said Clayton Curtis, a professor of psychology and neuroscience at NYU and an author of the new paper. All Rights Reserved © 2022

Keyword: Learning & Memory
Link ID: 28163 - Posted: 01.19.2022

Nicola Davis It’s a cold winter’s day, and I’m standing in a room watching my dog stare fixedly at two flower pots. I’m about to get an answer to a burning question: is my puppy a clever girl? Dogs have been our companions for millennia, domesticated sometime between 15,000 and 30,000 years ago. And the bond endures: according to the latest figures from the Pet Food Manufacturers Association 33% of households in the UK have a dog. But as well as fulfilling roles from Covid detection to lovable family rogue, scientists investigating how dogs think, express themselves and communicate with humans say dogs can also teach us about ourselves. And so I am here at the dog cognition centre at the University of Portsmouth with Calisto, the flat-coated retriever, and a pocket full of frankfurter sausage to find out how. We begin with a task superficially reminiscent of the cup and ballgame favoured by small-time conmen. Amy West, a PhD student at the centre, places two flower pots a few metres in front of Calisto, and appears to pop something under each. However, only one actually contains a tasty morsel. West points at the pot under which the sausage lurks, and I drop Calisto’s lead. The puppy makes a beeline for the correct pot. But according to Dr Juliane Kaminski, reader in comparative psychology at the University of Portsmouth, this was not unexpected. “A chimpanzee is our closest living relative – they ignore gestures like these coming from humans entirely,” she says. “But dogs don’t.” © 2022 Guardian News & Media Limited

Keyword: Learning & Memory; Evolution
Link ID: 28162 - Posted: 01.19.2022

By Jane E. Brody Many people aren’t overly concerned when an octogenarian occasionally forgets the best route to a favorite store, can’t remember a friend’s name or dents the car while trying to parallel park on a crowded city street. Even healthy brains work less efficiently with age, and memory, sensory perceptions and physical abilities become less reliable. But what if the person is not in their 80s but in their 30s, 40s or 50s and forgets the way home from their own street corner? That’s far more concerning. While most of the 5.3 million Americans who are living with Alzheimer’s disease or other forms of dementia are over 65, some 200,000 are younger than 65 and develop serious memory and thinking problems far earlier in life than expected. “Young-onset dementia is a particularly disheartening diagnosis because it affects individuals in the prime years,” Dr. David S. Knopman, a neurologist at the Mayo Clinic in Rochester, Minn., wrote in a July 2021 editorial in JAMA Neurology. Many of the afflicted are in their 40s and 50s, midcareer, hardly ready to retire and perhaps still raising a family. Dementia in a younger adult is especially traumatic and challenging for families to acknowledge, and many practicing physicians fail to recognize it or even suspect it may be an underlying cause of symptoms. “Complaints about brain fog in young patients are very common and are mostly benign,” Dr. Knopman told me. “It’s hard to know when they’re not attributable to stress, depression or anxiety or the result of normal aging. Even neurologists infrequently see patients with young-onset dementia.” Yet recent studies indicate that the problem is far more common than most doctors realize. Worldwide, as many as 3.9 million people younger than 65 may be affected, a Dutch analysis of 74 studies indicated. The study, published in JAMA Neurology in September, found that for every 100,000 people aged 30 to 64, 119 had early dementia. © 2022 The New York Times Company

Keyword: Alzheimers; Genes & Behavior
Link ID: 28161 - Posted: 01.19.2022

By Erin Garcia de Jesús For many people, one of the fastest tip-offs that they have COVID-19 is the loss of taste or smell. Now researchers have pinpointed some genetic variants in people that may make it more likely that the coronavirus might rob them of these senses. A study of nearly 70,000 adults with COVID-19 found that individuals with certain genetic tweaks on chromosome 4 were 11 percent more likely to lose the ability to smell or taste than people without the changes, researchers report January 17 in Nature Genetics. The data come from people who’d had their DNA analyzed by genetic testing company 23andMe and self-reported a case of COVID-19. Two genes, UGT2A1 and UGT2A2, that help people smell reside in the region of chromosome 4 linked to sensory loss during infection, epidemiologist Janie Shelton of 23andMe and colleagues found. Both genes make enzymes that metabolize substances called odorants, which produce distinctive smells. Sign up for e-mail updates on the latest coronavirus news and research Studies suggest that loss of smell, a hallmark symptom of COVID-19, stems from infections taking hold in smell-supporting cells called sustentacular cells (SN: 6/12/20). It’s possible that the genetic variants near UGT2A1 and UGT2A2 could affect how the two genes are turned on or off to somehow mess with smell during an infection, Shelton says. © Society for Science & the Public 2000–2022.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 28160 - Posted: 01.19.2022

Sophie Fessl Mice raised in an enriched environment are better able to adapt and change than mice raised in standard cages, but why they show this higher brain plasticity has not been known. Now, a study published January 11 in Cell Reports finds that the environment could act indirectly: living in enriched environments changes the animals’ gut microbiota, which appears to modulate plasticity. The study “provides very interesting new insights into possible beneficial effects of environmental enrichment on the brain that might act via the gut,” writes Anthony Hannan, a neuroscientist at the Florey Institute of Neuroscience and Mental Health in Australia who was not involved in the study, in an email to The Scientist. “This new study has implications for how we might understand the beneficial effects of environmental enrichment, and its relevance to cognitive training and physical activity interventions in humans.” In previous studies, mice raised in what scientists call an enriched environment—one in which they have more opportunities to explore, interact with others, and receive sensory stimulation than they would in standard laboratory enclosures—have been better able to modify their neuronal circuits in response to external stimuli than mice raised in smaller, plainer cages. Paola Tognini, a neuroscientist at the University of Pisa and lead author of the new study, writes in an email to The Scientist that she “wondered if endogenous factors (signals coming from inside our body instead of the external world), such as the signals coming from the intestine, could also influence brain plasticity.” © 1986–2022 The Scientist.

Keyword: Learning & Memory; Obesity
Link ID: 28159 - Posted: 01.19.2022

By Amelia Nierenberg Most people think of melatonin as a natural nod-off aid, kind of like chamomile tea in pill form. Even the name of the popular dietary supplement sounds sleepy — that long “o” sound almost makes you yawn mid-word. But melatonin is also a hormone that our brains naturally produce, and hormones, even in minuscule amounts, can have potent effects throughout the body. “There are some clinical uses for it, but not the way that it’s marketed and used by the vast majority of the general public,” said Jennifer Martin, a psychologist and professor of medicine at the University of California, Los Angeles. Experts strongly urge people to consult their doctor or a sleep specialist before taking melatonin, in part because the supplement does not address many underlying health problems that may be disrupting sleep. Anxiety can cause insomnia, as can a host of other potentially serious ailments, such as sleep apnea, restless legs syndrome or mood disorders like depression, that may require medical treatment. Melatonin, however, is relatively inexpensive and readily available at local pharmacies in the United States (in other countries it typically requires a prescription), and many people will go out and buy it on their own. So what’s the best approach to taking melatonin? Here’s what experts had to say. During the day, the brain’s pea-sized pineal gland remains inactive. A few hours before our natural sleep time, as it starts to get dark outside and the light entering our retina fades, the gland switches on to flood the brain with melatonin. “Melatonin is sometimes called the ‘hormone of darkness’ or ‘vampire hormone,’” because it comes out at night, said Matthew Walker, a professor of neuroscience and psychology at the University of California, Berkeley, and the author of the book “Why We Sleep.” As levels of melatonin rise, levels of cortisol, the stress hormone, fall. Respiration slows. Soon, our eyelids begin to droop. Instead of a lights-out trigger, melatonin acts more like a dimmer switch, turning the day functions off and switching night functions on. So taking a melatonin supplement is sort of like taking a dose of sunset, tricking your body into feeling like it’s nighttime. It doesn’t put you to sleep as much as it tells the body that it’s time to sleep. © 2022 The New York Times Company

Keyword: Biological Rhythms; Sleep
Link ID: 28158 - Posted: 01.19.2022

By Linda Searing For people with early-stage Parkinson’s disease, four hours a week of moderate exercise may help slow the progression of the disease. Symptoms of Parkinson’s, which is a movement disorder, generally start gradually but worsen over time. FAQ: What to know about the omicron variant of the coronavirus But research published in the journal Neurology found that those who were regularly active for at least that amount of time — whether with traditional exercise or such physical activity as walking, gardening or dancing — had less decline in balance and walking ability, were better able to maintain daily activities and did better on cognitive tests five years later than those who exercised less. The researchers noted that the key to achieving these benefits was maintaining regular exercise over time, rather than how active people had been when their disease started. Parkinson’s, which is more common in men than women, usually begins about age 60 as nerve cells in the brain (neurons) become weak or damaged. Symptoms may include trembling or shaking (tremor), muscle stiffness (rigidity), slow movement (bradykinesia) and poor balance and coordination. As symptoms get worse, people may have trouble walking, talking or continuing to do routine daily activities. Although no cure exists for Parkinson’s, treatment — medication, surgery or electrical stimulation — can sometimes help ease some symptoms for a while. The researchers wrote, however, that “there is still no disease-modifying treatment to slow the disease’s progression.”

Keyword: Parkinsons
Link ID: 28157 - Posted: 01.19.2022

By Azeen Ghorayshi An upsurge in teenagers requesting hormones or surgeries to better align their bodies with their gender identities has ignited a debate among doctors over when to provide these treatments. An international group of experts focused on transgender health last month released a draft of new guidelines, the gold standard of the field that informs what insurers will reimburse for care. Many doctors and activists praised the 350-page document, which was updated for the first time in nearly a decade, for including transgender people in its drafting and for removing language requiring adults to have psychological assessments before getting access to hormone therapy. But the guidelines take a more cautious stance on teens. A new chapter dedicated to adolescents says that they must undergo mental health assessments and must have questioned their gender identity for “several years” before receiving drugs or surgeries. Experts in transgender health are divided on these adolescent recommendations, reflecting a fraught debate over how to weigh conflicting risks for young people, who typically can’t give full legal consent until they are 18 and who may be in emotional distress or more vulnerable to peer influence than adults are. Some of the drug regimens bring long-term risks, such as irreversible fertility loss. And in some cases, thought to be quite rare, transgender people later “detransition” to the gender they were assigned at birth. Given these risks, as well as the increasing number of adolescents seeking these treatments, some clinicians say that teens need more psychological assessment than adults do. “They absolutely have to be treated differently,” said Laura Edwards-Leeper, a child clinical psychologist in Beaverton, Ore., who works with transgender adolescents. Dr. Edwards-Leeper was one of seven authors of the new adolescent chapter, but the organization that publishes the guidelines, the World Professional Association for Transgender Health, did not authorize her to comment publicly on the draft’s proposed wording. © 2022 The New York Times Company

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 28156 - Posted: 01.15.2022