By Nicholas Bakalar Being overweight may be linked to an increased risk for dementia. British researchers used data on 6,582 men and women, age 50 and older, who were cognitively healthy at the start of the study. The analysis, in the International Journal of Epidemiology, tracked the population for an average of 11 years, recording incidents of physician-diagnosed dementia. Almost 7 percent of the group developed dementia. Compared with people of normal weight (body mass index between 18.5 and 24.9), overweight people with a B.M.I. of 25 to 29.9 were 27 percent more likely to develop dementia, and the obese, with a B.M.I. of 30 or higher, were 31 percent more likely to become demented. The researchers also found that women with central obesity — a waist size larger than 34.6 inches — were 39 percent more likely to develop dementia than those with normal waist size. Fat around the middle was not associated with a higher dementia risk in men. The study controlled for age, sex, APOE4 (a gene known to increase the risk of Alzheimer’s disease, the most common form of dementia), education, marital status, smoking and other known dementia risks. The lead author, Yixuan Ma, a student at University College London, said that this observational study does not prove cause and effect. “Being overweight is just a risk,” she said. “It doesn’t mean that an overweight person will necessarily get dementia. But for many reasons, it’s good to maintain a normal weight and engage in vigorous physical activity over a lifetime.” © 2020 The New York Times Company

Keyword: Alzheimers; Obesity
Link ID: 27449 - Posted: 09.05.2020

By Moises Velasquez-Manoff Jack Gallant never set out to create a mind-reading machine. His focus was more prosaic. A computational neuroscientist at the University of California, Berkeley, Dr. Gallant worked for years to improve our understanding of how brains encode information — what regions become active, for example, when a person sees a plane or an apple or a dog — and how that activity represents the object being viewed. By the late 2000s, scientists could determine what kind of thing a person might be looking at from the way the brain lit up — a human face, say, or a cat. But Dr. Gallant and his colleagues went further. They figured out how to use machine learning to decipher not just the class of thing, but which exact image a subject was viewing. (Which photo of a cat, out of three options, for instance.) One day, Dr. Gallant and his postdocs got to talking. In the same way that you can turn a speaker into a microphone by hooking it up backward, they wondered if they could reverse engineer the algorithm they’d developed so they could visualize, solely from brain activity, what a person was seeing. The first phase of the project was to train the AI. For hours, Dr. Gallant and his colleagues showed volunteers in fMRI machines movie clips. By matching patterns of brain activation prompted by the moving images, the AI built a model of how the volunteers’ visual cortex, which parses information from the eyes, worked. Then came the next phase: translation. As they showed the volunteers movie clips, they asked the model what, given everything it now knew about their brains, it thought they might be looking at. The experiment focused just on a subsection of the visual cortex. It didn’t capture what was happening elsewhere in the brain — how a person might feel about what she was seeing, for example, or what she might be fantasizing about as she watched. The endeavor was, in Dr. Gallant’s words, a primitive proof of concept. And yet the results, published in 2011, are remarkable. The reconstructed images move with a dreamlike fluidity. In their imperfection, they evoke expressionist art. (And a few reconstructed images seem downright wrong.) But where they succeed, they represent an astonishing achievement: a machine translating patterns of brain activity into a moving image understandable by other people — a machine that can read the brain. © 2020 The New York Times Company

Keyword: Vision; Brain imaging
Link ID: 27448 - Posted: 09.02.2020

Katherine May Sunday morning. I walk down to the beach with the dog straining at her lead. I’m already on high alert. It’s the moment in the week when people are most likely to be wandering along the seafront, feeling chatty. I’m mentally priming myself, sorting through the categories I might encounter: parents from the schoolyard (hopefully with their children), people I’ve worked with (increasingly hopeless), neighbours from the surrounding streets (no chance). I should have gone to the woods today. It’s too risky. I cross the road and hear, “Katherine! Hello!” I wonder if I can get away with pretending I didn’t notice. I’m wearing earbuds, which is usually a good precaution, but this woman is determined. She crosses the road diagonally, waving. “How the hell are you?” she says. Straight hair, mousy blonde. No glasses, no tattoos. Jeans, a grey sweatshirt. For God’s sake, why are these people so studiedly ordinary? I fidget with my phone, trying to buy time. Her face is plain. I don’t mean plain as in “ugly”. I mean plain as in vanilla: bland, unremarkable. There’s nothing here that I might have stored in words. Her nose is straight. Her eyes are blue. Her teeth are orderly. And she knows me. “Hi!” I say, as warmly as possible. “How are you?” This can sometimes elicit clues. Not today. One of the many side-effects of being face-blind is that you become uncomfortably aware of the ordinariness of most interactions. We have stopped in the street to say absolutely nothing to each other. And only one of us knows the context. The dog lunges to her feet and pulls in the direction of the sea. “Looks like she’s desperate to get going!” I say, laughing, “So sorry! Lovely to see you!” And I’m off at a gallop before this woman, whoever the hell she is, can think about joining me. I didn’t always know I was face-blind. I grew up thinking that I just didn’t remember people. This, as a friend once told me, seemed a lot like arrogance – an aloof lack of interest in others. But that’s not how it felt on the inside. © 2020 Guardian News & Media Limited

Keyword: Attention
Link ID: 27447 - Posted: 09.02.2020

By Elizabeth Preston We’re all getting used to face masks, either wearing them or figuring out who we’re looking at. They can even trip up those of us who are experts in faces. “Actually, I just had an experience today,” said Marlene Behrmann, a cognitive neuroscientist at Carnegie Mellon University who has spent decades studying the science of facial recognition. She went to meet a colleague outside the hospital where they collaborate, and didn’t realize the person was sitting right in front of her, wearing a mask. In fairness, “She’s cut her hair very short,” Dr. Behrmann said. Scientists have some ideas about why masks make recognizing others’ faces difficult, based on studying the brains of average people, as well as people who struggle to recognize anyone at all. But even when everyone around us is incognito, we still have ways to find each other. “We use face recognition in every aspect of our social interaction,” said Erez Freud, a psychologist with the Centre for Vision Research at York University in Toronto. In the faces of others, we find clues about their personality, gender and emotions. “This is something very fundamental to our perception. And suddenly, faces do not look the same,” Dr. Freud said. That’s why Dr. Freud and co-authors decided to study how masks impair people’s facial recognition skills. They recruited nearly 500 adults to complete a common face memory task online. Participants viewed unfamiliar faces and then tried to recognize them under increasingly difficult conditions. Half the participants saw faces with surgical-style masks covering their mouths and noses. People scored substantially worse on the test when faces were masked. The authors posted their findings, which have not yet completed peer review, online last month. © 2020 The New York Times Company

Keyword: Attention
Link ID: 27446 - Posted: 09.02.2020

By Jenny Marder In May, a 15-year-old boy set up a socially distanced visit with a friend. They met on opposite sides of a sidewalk — a full six feet apart — and talked. But when the teenager returned home, he brought with him a new set of Covid-19 fears, according to John Duffy, the boy’s therapist and a child psychologist in Chicago. How could he be sure six feet was a safe distance?, the teenager wanted to know. He began washing his hands more frequently. He stopped touching countertops. And he hasn’t wanted to see friends since. The pandemic has understandably intensified our need for good hygiene and safety precautions. But for some children and teens, these precautions have crossed the line from careful to compulsive. And for parents, it can sometimes be hard to distinguish between a reasonable reaction to a very real threat and something more concerning. There’s little data available yet on the toll the pandemic has taken on the mental health of children. But Eric Storch, an expert on obsessive-compulsive disorder and a professor at the Baylor College of Medicine, said calls to the university’s O.C.D. program have jumped significantly, by about 25 percent, since March. He attributed it in part to telemedicine improving access, and in part to worsening mental health concerns. Dr. Duffy said the number of his patients experiencing O.C.D.-like symptoms has tripled during this time. About 500,000 children and teens in the United States have obsessive-compulsive disorder, according to the International OCD Foundation. Obsessive-compulsive disorder has two main components. Obsessions take the form of uncontrollable thoughts, urges, feelings or uncomfortable sensations. Compulsions are behaviors repeated over and over. These can include excessive handwashing, showering or sanitizing, but also checking things, putting things in order, tapping, touching, seeking reassurance or asking the same question repeatedly. © 2020 The New York Times Company

Keyword: OCD - Obsessive Compulsive Disorder; Stress
Link ID: 27445 - Posted: 09.02.2020

Researchers say mother bats use baby talk to communicate with their pups. Experts say that it helps bats learn the language. MARY LOUISE KELLY, HOST: You know how scientists are always curious? Well, one scientist started wondering if bats do something that humans do. AHANA AURORA FERNANDEZ: When we humans talk to a baby, we automatically change our voices. Hello, my baby. You are so cute. My voice goes up. SACHA PFEIFFER, HOST: That's Ahana Aurora Fernandez. She's in Berlin but did her bat study in Panama. And she found that, as many humans do, mommy bats talk to baby bats in a similar way. There's a word for this way of talking. It's motherese (ph). Experts say that in humans - and, apparently, also in bats - it helps with language learning. KELLY: Ahana Fernandez sent us recordings she made to illustrate her findings. They are slowed down so we can better hear the differences between adult bats talking to each other and the motherese used on bat pups. First, here's two adult bats talking to each other. KELLY: OK, and now here's a mother bat with her pup. PFEIFFER: It took patience for Ahana Hernandez to record bat conversation. She sat in the jungle in a chair for hour after hour, waiting for bat conversations to happen. She even brought along books to pass the time. Scientific research is not always riveting. KELLY: No. All told, Ahana Fernandez and her colleagues conducted their research for these last five years, and they found something else along the way. Baby bats babble. FERNANDEZ: They use sort of a vocal practice behavior which is reminiscent of babbling in infants. KELLY: Bat baby talk. PFEIFFER: Her team's report was published this month, and it shows that in the first three months of life, these bat pups experiment with their speech. FERNANDEZ: They learn a part of their adult vocal repertoire through vocal imitation as we humans do. © 2020 npr

Keyword: Animal Communication; Language
Link ID: 27444 - Posted: 09.02.2020

Rory Cellan-Jones He is the most charismatic figure in technology with some amazing achievements to his name, from making electric cars desirable to developing rockets that can return to earth and be reused. But dare to suggest that anything Elon Musk does is not groundbreaking or visionary and you can expect a backlash from the great man and his army of passionate fans. That is what happened when a British academic criticised Musk's demo on Friday of his Neuralink project - and the retaliation he faced was largely my fault. Neuralink is a hugely ambitious plan to link the human brain to a computer. It might eventually allow people with conditions such as Parkinson's disease to control their physical movements or manipulate machines via the power of thought. There are plenty of scientists already at work in this field. But Musk has far greater ambitions than most, talking of developing "superhuman cognition" - enhancing the human brain in part to combat the threat he sees from artificial intelligence. Friday night's demo involved a pig called Gertrude fitted with what the tech tycoon described as a "Fitbit in your skull". A tiny device recorded the animal's neural activity and sent it wirelessly to a screen. A series of beeps happened every time her snout was touched, indicating activity in the part of her brain seeking out food. "I think this is incredibly profound", commented Musk. Some neuroscience experts were not quite as impressed. The UK's Science Media Centre, which does a good job of trying to make complex scientific stories accessible, put out a press release quoting Prof Andrew Jackson, professor of neural interfaces at Newcastle University. "I don't think there was anything revolutionary in the presentation," he said. "But they are working through the engineering challenges of placing multiple electrodes into the brain. "In terms of their technology, 1,024 channels is not that impressive these days, but the electronics to relay them wirelessly is state-of-the-art, and the robotic implantation is nice. "The biggest challenge is what you do with all this brain data. The demonstrations were actually quite underwhelming in this regard, and didn't show anything that hasn't been done before." He went on to question why Neuralink's work was not being published in peer-reviewed papers. I took his words and his summary of the demo - "this is solid engineering but mediocre neuroscience" - and posted a tweet. © 2020 BBC.

Keyword: Brain imaging
Link ID: 27443 - Posted: 09.02.2020

By Jane E. Brody Orthostatic hypotension — to many people those are unfamiliar words for a relatively common but often unrecognized medical problem that can have devastating consequences, especially for older adults. It refers to a brief but precipitous drop in blood pressure that causes lightheadedness or dizziness when standing up after lying down or sitting, and sometimes even after standing, for a prolonged period. The problem is likely to be familiar to people of all ages who may have been confined to bed for a long time by an injury, illness or surgery. It also often occurs during pregnancy. But middle-aged and older adults are most frequently affected. A significant number of falls and fractures, particularly among the elderly, are likely to result from orthostatic hypotension — literally, low blood pressure upon standing. Many an older person has fallen and broken a hip when getting out of bed in the morning or during the night to use the bathroom, precipitating a decline in health and loss of independence as a result of this blood pressure failure. Orthostatic hypotension is also a risk factor for strokes and heart attacks and even motor vehicle accidents. It can be an early warning sign of a serious underlying cardiovascular or neurological disorder, like a heart valve problem, the course of which might be altered if detected soon enough. But as one team of specialists noted, although orthostatic hypotension is a “highly prevalent” disorder, it is “frequently unrecognized until late in the clinical course.” Under normal circumstances, when we stand up, gravity temporarily causes blood to pool in the lower half of the body; then, within 20 or 30 seconds, receptors in the heart and carotid arteries in the neck trigger a compensating mechanism called the baroreflex that raises the heart rate and constricts blood vessels to increase blood pressure and provide the brain with an adequate supply of blood. © 2020 The New York Times Company

Keyword: Stress
Link ID: 27442 - Posted: 09.02.2020

By Esther Landhuis A researcher slips stickers under some colored cups on a lazy Susan, then gives the tray a whirl. When the spinning stops, a preschooler must find the hidden stickers. Most children remember where the stickers are, but a few have to check every single cup. The game tests working memory, which is among the set of mental skills known as executive function that can be impaired in children who faced trauma early in life. Adversity wreaks havoc, and from there, “you have a system that responds differently,” says Megan Gunnar, a developmental psychobiologist at the University of Minnesota in Minneapolis who has spent two decades studying the impact of early-life adversity in adopted children. The focus of this work is extreme adversity, such as being orphaned, rather than everyday challenges, which might teach beneficial resilience. A childhood characterized by hardship, negligence or abuse can also alter the neuroendocrine system that regulates how the body responds to stress. Problems in the stress response can set kids on a path toward behavior struggles along with increased risk for depression, diabetes and a host of other health problems. But recent studies offer hints that such a difficult future may not be inevitable. As Gunnar and others have shown, impaired stress responses can return to normal during puberty, raising the possibility that imbalances created by early trauma can be erased. The research is prompting a new view of puberty as an opportunity — a chance for people who had a shaky start to reset their physiological responses to stress. © Society for Science & the Public 2000–2020.

Keyword: Stress; Development of the Brain
Link ID: 27441 - Posted: 08.29.2020

by Jonathan Moens Conversations between an autistic and a typical person involve less smiling and more mismatched facial expressions than do interactions between two typical people, a new study suggests1. People engaged in conversation tend to unconsciously mimic each other’s behavior, which may help create and reinforce social bonds. But this synchrony can break down between autistic people and their neurotypical peers, research shows. And throughout an autistic person’s life, these disconnects can lead to fewer opportunities to meet people and maintain relationships. Previous studies have looked at autistic people’s facial expressions as they react to images of social scenes on a computer screen2. The new work, by contrast, is one of a growing number of experiments to capture how facial expressions unfold during ordinary conversation. Changes in facial expressions are easy to observe but notoriously hard to measure, says lead investigator John Herrington, assistant professor of psychiatry at the Children’s Hospital of Philadelphia in Pennsylvania. He and his colleagues devised a new method to quantify these changes over time in an automated and granular way using machine-learning techniques. Atypical facial expressions are in part a manifestation of difficulties with social coordination, Herrington says. So tracking alterations in facial expression may be a useful way to monitor whether interventions targeting these traits are effective. The new study included 20 autistic people and 16 typical controls, aged 9 to 16 years and matched for their scores on intelligence and verbal fluency. Each participant engaged in two 10-minute conversations — first with their mother and then with a research assistant — to plan a hypothetical two-week trip. © 2020 Simons Foundation

Keyword: Autism; Emotions
Link ID: 27440 - Posted: 08.29.2020

By Michelle Konstantinovsky Rosey has lived with bulimia for more than a decade. The 31-year-old resident of Melbourne, Australia, started therapy for her eating disorder six years ago. Although she says she had never considered herself “cured,” she had reached a point in her recovery that felt hopeful and manageable. Then along came the novel coronavirus. When mandatory COVID-19 lockdowns began in Australia in March, Rosey’s anxiety went into overdrive. “I’m single, I live alone, my family lives in another state, and I’m not able to see friends,” she says, adding that her need for control—something she has now lost in almost every area of her life—has played a major role in the resurgence of symptoms: “To have everything I knew and had control over, including how I managed my illness, ripped away has been one of the hardest things.” Rosey is living an experience that may be familiar to anyone dealing with an eating disorder while weathering the unexpected storms of 2020. Recent research indicates that pandemic-related stay-at-home orders have ramped up anorexia, bulimia and binge-eating disorder symptoms. A study published last month in the International Journal of Eating Disorders revealed that during the first few months of the pandemic, many individuals with anorexia reported restricting their eating more. Meanwhile others with bulimia and binge-eating disorder reported more bingeing urges and episodes. Respondents also noted increased anxiety and concern about COVID-19’s impact on their mental health. More than one third of the 1,021 participants (511 in the U.S. and 510 in the Netherlands) said their eating disorder had worsened—and they attributed this change to issues such as a lack of structure, a triggering environment, the absence of social support and an inability to obtain foods that fit their meal plans. © 2020 Scientific American,

Keyword: Anorexia & Bulimia; Stress
Link ID: 27439 - Posted: 08.29.2020

A collaborative study conducted by scientists from the National Institutes of Health, Department of Defense (DOD), and multiple academic institutions has identified blood biomarkers that could help to predict which athletes need additional time to recover from a sports related concussion. This collaboration, known as the Concussion Assessment, Research, and Education (CARE) consortium, is supported, in part, by DOD and the National Collegiate Athletic Association (NCAA). In this study, conducted at several sites across the U.S., 127 male and female collegiate athletes who had sustained a sports-related concussion were tested at several time points: shortly after injury, when their symptoms resolved, and one week after returning to play. Each athlete had also undergone preseason, baseline testing. Using an ultrasensitive assay that can detect minute amounts of protein, the researchers tested blood serum from these athletes and identified two blood proteins that were associated with the length of time needed by the athletes to return to play. Amounts of these two proteins, tau protein and glial fibrillary acidic protein (GFAP) were found to be significantly different in athletes who needed less or more than 14 days to return. While further research is needed, the results of this study are an important step towards the development of a test that could help predict which athletes need more time to recover from a concussion and resume activity. This study was published in JAMA Network Open.

Keyword: Brain Injury/Concussion
Link ID: 27438 - Posted: 08.29.2020

by Nicholette Zeliadt An experimental drug prevents seizures and death in a mouse model of Dravet syndrome, a severe form of epilepsy that is related to autism, researchers reported 18 October 2019. The drug works by silencing a DNA segment called a ‘poison exon’ and is expected to enter clinical trials next year. If it works, it offers hope for treating not just Dravet, but other forms of autism as well: Another team has identified a poison exon in SYNGAP1, an autism gene that also causes epilepsy. Poison exons seem to impede the production of certain crucial proteins; blocking these segments would restore normal levels of the proteins. “The beauty of the technology,” says Gemma Carvill, assistant professor of neurology and pharmacology at Northwestern University in Chicago, Illinois, “is that “any gene that has a poison exon is potentially a target.” Several teams presented unpublished work on poison exons in a standing-room-only session at the 2019 American Society of Human Genetics meeting in Houston, Texas. People with Dravet often have autism, and most die in childhood2. The syndrome typically stems from mutations in a gene called SCN1A, which encodes an essential sodium channel in neurons. Only about 25 percent of mice with mutations in SCN1A live beyond 30 days of age. The new drug consists of short strands of ‘antisense’ RNA that restore normal levels of the channel, said Lori Isom of the University of Michigan, who presented the work. And all but 1 of 33 mice that received a single injection of the drug at 2 days of age remained alive 88 days later. © 2020 Simons Foundation

Keyword: Epilepsy; Autism
Link ID: 27437 - Posted: 08.29.2020

By Carolyn Wilke Female hyenas may be out for cubs’ blood — even within their own clans. New research suggests that infanticide may be part of a strategy females use to maintain their social standing. “It’s not that these events are weird one-off things … this is actually a pretty significant source of mortality,” says Eli Strauss, a behavioral ecologist at the University of Nebraska–Lincoln. Strauss and his colleagues scoured three decades of data on spotted hyena populations in Kenya to study deaths of cubs less than a year old (SN: 4/23/02). Of 99 observed deaths, 21 could be attributed to infanticide, always by female killers. Starvation and lions also took many young cubs’ lives. The infanticide observations made the team wonder why hyenas kill within their own group. It “seems sort of counterintuitive if animals benefit from living socially,” Strauss says. Though hyenas spend much of their time alone, group living allows them to defend their turf against rival hyena clans and to gang up against threatening lions, he says. Hyena mothers give birth in an isolated den. But typically within a few weeks, they move their cubs to a communal den. Such dens shelter little ones from large predators that can’t enter the sanctuary’s small access holes, says Ally Brown, an environmental biology student at Michigan State University in East Lansing. But the communal den presents other risks — all the cases of infanticide occurred in its vicinity, documented by researchers who either found the dead cubs or observed the clans from cars that serve as mobile blinds (SN: 4/23/02). © Society for Science & the Public 2000–2020.

Keyword: Aggression; Sexual Behavior
Link ID: 27436 - Posted: 08.26.2020

By Apoorva Mandavilli The coronavirus may infect anyone, young or old, but older men are up to twice as likely to become severely sick and to die as women of the same age. Why? The first study to look at immune response by sex has turned up a clue: Men produce a weaker immune response to the virus than do women, the researchers concluded. The findings, published on Wednesday in Nature, suggest that men, particularly those over age 60, may need to depend more on vaccines to protect against the infection. “Natural infection is clearly failing” to spark adequate immune responses in men, said Akiko Iwasaki, an immunologist at Yale University who led the work. The results are consistent with what’s known about sex differences following various challenges to the immune system. Women mount faster and stronger immune responses, perhaps because their bodies are rigged to fight pathogens that threaten unborn or newborn children. But over time, an immune system in a constant state of high alert can be harmful. Most autoimmune diseases — characterized by an overly strong immune response — are much more prevalent in women than in men, for example. “We are looking at two sides of the same coin,” said Dr. Marcus Altfeld, an immunologist at the Heinrich Pette Institute and at the University Medical Center Hamburg-Eppendorf in Germany. The findings underscore the need for companies pursing coronavirus vaccines to parse their data by sex and may influence decisions about dosing, Dr. Altfeld and other experts said. © 2020 The New York Times Company

Keyword: Sexual Behavior; Neuroimmunology
Link ID: 27435 - Posted: 08.26.2020

By Charlotte Hartley “I was at home and that scary red monster thing from that stupid Looney Tunes show was hanging around,” reads the dream diary of Izzy, a teenage girl. “There were lots of them trying to get in and I was scared to death.” Like many people, Izzy dreams about strange characters in unlikely situations. But according to a new study, in which researchers analyzed thousands of dreams with an automated tool, Izzy’s dream is probably just an expression of her adolescent anxieties—a funhouse reflection of her everyday experiences. The researchers say the tool, which identifies and quantifies the characters, interactions, and emotions of dreams, could help psychologists quickly identify potential stressors and mental health issues among their patients. Throughout history, people have tried to extract hidden meaning from dreams. Ancient Babylonians believed dreams contained prophecies, whereas ancient Egyptians revered them as messages from the gods. In the 1890s, Sigmund Freud assigned symbolic meanings to dream characters, objects, and scenarios—with an emphasis on sex and aggression. Today, however, most psychologists support the “continuity hypothesis,” which posits that dreams are a continuation of what happens in waking life. Indeed, numerous studies have shown that dreams often reflect day-to-day activities and can act as a sort of nocturnal therapist, helping people process experiences and prepare for real-life problems. “If we can understand our dreams better at scale, then maybe we can also tailor technologies that improve our waking life,” says Luca Maria Aiello, a computational social scientist at Nokia Bell Labs and co-author of the study. © 2020 American Association for the Advancement of Science

Keyword: Sleep
Link ID: 27434 - Posted: 08.26.2020

Georgina Ferry The lightning flick of the tongue that secures a frog its next meal depends on a rapid response to a small black object moving through its field of view. During the 1950s the British neuroscientist Horace Barlow established that neurons in the frog’s retina were tuned to produce just such a response, not only detecting but also predicting the future position of a passing fly. This discovery raised the curtain on decades of research by Barlow and others, establishing that individual neurons of the billions that make up the visual system contribute to the efficient processing of movement, colour, position and orientation of objects in the visual world. Barlow, who has died aged 98, combined three approaches to the question of how the brain enables us to see. He looked at how people perceive, for example measuring the smallest and faintest spot of light they could reliably detect; he studied the responses of single neurons in the retina and brain to different visual stimuli; and he developed theories to account for the relationship between what neurons are doing and the corresponding visual experience. All his work started from the principle – apparently obvious but not often stated – that a deep, mathematical understanding of what is involved in the psychological process of seeing is an essential basis for exploring how the physiological elements of the visual system serve that end. In a vivid analogy, he wrote: “A wing would be a most mystifying structure if one did not know that birds flew.” He is best known for demanding answers to the question of how such a complex system could work most efficiently. He was influenced by early computer scientists, and was a pioneer in seeing visual signals as information to be processed. His concept of “efficient coding” predicted that of all the information presented to the eye, the brain would transmit the minimum necessary, wasting no energy on redundant signals. © 2020 Guardian News & Media Limite

Keyword: Vision
Link ID: 27433 - Posted: 08.26.2020

Although the number of people with dementia continues to increase, the rate of growth has declined by 13 percent in each of the past three decades. The brain disorder currently affects nearly 50 million people worldwide and nearly 6 million in the United States. The new finding, reported by Harvard researchers in the journal Neurology, suggests that the number of people developing dementia in coming years may be less than expected. Nonetheless, that number — known as the prevalence of dementia — is expected to triple in the next 30 years, growing to more than 150 million people worldwide, due in large part to increases in life expectancy and population size. Dementia, which involves deterioration in memory, thinking and behavior beyond what is considered a normal part of aging, includes but is not limited to Alzheimer’s disease, which accounts for 60 to 70 percent of dementia cases. The researchers cited a “somewhat stronger” decline in the rate of growth — referred to as the incidence rate — among men than women (24 percent vs. 8 percent). They projected that, if the trend continues, it is possible that up to 60 million fewer people than expected would develop dementia worldwide by 2040. The researchers did not determine underlying causes of the decline in incidence, but they did note that improvements in lifestyle overall — as well as better control of blood pressure and cardiovascular issues — may have contributed to the decline. Their research was based on data from seven long-term studies, involving 49,202 people 65 and older from six countries in Europe and North America, including the United States. But the database included only people of European ancestry, and other research has found stable or increasing rates of dementia diagnoses in other ethnic and geographic regions. — Linda Searing

Keyword: Alzheimers
Link ID: 27432 - Posted: 08.26.2020

By Benedict Carey For a couple of minutes on Thursday, the sprawling, virtual Democratic National Convention seemed to hold its collective breath as 13-year-old Brayden Harrington of Concord, N.H., addressed the nation from his bedroom, occasionally stumbling on his words. “I’m a regular kid,” he said into a home camera, and a recent meeting with the candidate “made me feel confident about something that has bothered me my whole life.” Joe Biden and Mr. Harrington have had to manage stuttering, and the sight of the teenager openly balking on several words, including “stutter,” was a striking reminder of how the speech disorder can play havoc with sociability, relationships, even identity. Movies like “The King’s Speech,” and books like Philip Roth’s “American Pastoral,” explore how consequential managing the disorder can be, just as Mr. Biden’s own story does. How many people stutter? The basic numbers are known: About one in 10 children will exhibit some evidence of a stutter — it usually starts between ages 2 and 7 — and 90 percent of them will grow out of it before adulthood. Around 1 percent of the population carries the speech problem for much of their lives. For reasons not understood, boys are twice as likely to stutter, and nearly four times as likely to continue doing so into adulthood. And it is often anxiety that triggers bursts of verbal stumbling — which, in turn, create a flood of self-conscious stress. When Mr. Harrington got stuck for a couple of seconds on the “s” in “stutter,” he turned his head and his eyes fluttered — an embodiment of physical and mental effort — before saying, “It is really amazing that someone like me could get advice from” a presidential candidate. About half of children who stutter are related to someone else who does, but it is impossible to predict who will develop the speech disorder. There are no genes for stuttering; and scientists do not know what might happen after conception, during development, that predisposes children to struggle with speaking in this way. © 2020 The New York Times Company

Keyword: Language; Attention
Link ID: 27431 - Posted: 08.22.2020

by Angie Voyles Askham A new study pinpoints genes and cell types that may account for the atypical brain structure in people with genetic conditions related to autism1. The work offers insight into how the brain develops differently in people with these conditions and identifies new potential therapeutic targets, says Mallar Chakravarty, associate professor of psychiatry at McGill University in Montreal. Chakravarty has collaborated with the researchers previously but was not involved in the new work. The analysis considered people with six genetic conditions associated with atypical brain development, including syndromes associated with deletions in the chromosomal regions 11p13 and 22q11.2, both of which increase the likelihood of autism2. “We used known genetic conditions as a kind of foothold into the complex biology of neurodevelopmental disorders,” says lead researcher Armin Raznahan, chief of the Developmental Neurogenomics section at the U.S. National Institute of Mental Health intramural research program. Previous studies of mice with autism-linked genetic conditions have shown that brain structure changes tend to crop up in regions where the relevant genes are ordinarily expressed3. The same holds true for people, Raznahan and his colleagues found after comparing measurements from brain scans with existing data from postmortem brains. “It’s wildly creative,” Chakravarty says of the method. Raznahan and his colleagues used magnetic resonance imaging to scan the brains of 231 adolescents and adults with one of the six genetic conditions and 287 controls. Each of the six conditions results from a deletion or duplication of a chromosome or set of genes within a chromosome. © 2020 Simons Foundation

Keyword: Autism; Development of the Brain
Link ID: 27430 - Posted: 08.22.2020