by Peter Hess Dysfunction in a brain circuit that regulates movement may contribute to some of the motor learning difficulties associated with autism, according to a new mouse study. The mice lack one copy of a chromosomal region called 16p11.2. Up to about one-third of people with this deletion have autism, and some have speech and motor problems. Most autistic people have motor difficulties and show delays in developmental milestones such as standing and walking. The 16p mice, too, are slow to learn new motor tasks, such as balancing on a spinning rod. The explanation seems to be a shortage of the neurotransmitter noradrenaline in the motor cortex, which helps coordinate and execute movements. The dearth originates in the locus coeruleus, a part of the brainstem that serves as the brain’s main source of the chemical. “Noradrenaline is known to be involved in modulating the excitability of neurons,” says lead researcher Simon Chen, assistant professor of cellular and molecular medicine at the University of Ottawa in Ontario, Canada. “When there’s low noradrenaline in the motor cortex and the mouse is learning a movement, it takes them longer for the neural circuits to consolidate neurons that are important to control movement.” The learning process is similar for people, Chen says. When learning how to walk, for instance, a child loses her footing and falls many times. But once in a while, she will take a few more steps than she did in the previous attempt, and the brain remembers the movement that made that possible. © 2021 Simons Foundation

Keyword: Autism; Learning & Memory
Link ID: 27769 - Posted: 04.14.2021

By Charles Choi Even after ancient humans took their first steps out of Africa, they still unexpectedly may have possessed brains more like those of great apes than modern humans, a new study suggests. For decades, scientists had thought modern humanlike organization of brain structures evolved soon after the human lineage Homo arose roughly 2.8 million years ago (SN: 3/4/15). But an analysis of fossilized human skulls that retain imprints of the brains they once held now suggests such brain development occurred much later. Modernlike brains may have emerged in an evolutionary sprint starting about 1.7 million years ago, researchers report in the April 9 Science. What sets modern humans apart most from our closest living relatives, the great apes, is most likely our brain. To learn more about how the modern human brain evolved, the researchers analyzed replicas of the brain’s convoluted outer surface, re-created from the oldest known fossils to preserve the inner surfaces of early human skulls. The 1.77-million to 1.85-million-year-old fossils are from the Dmanisi archaeological site in the modern-day nation of Georgia and were compared with bones from Africa and Southeast Asia ranging from roughly 2 million to 70,000 years old. The scientists focused on the brain’s frontal lobes, which are linked with complex mental tasks such as toolmaking and language. Early Homo from Dmanisi and Africa still apparently retained a great ape–like organization of the frontal lobe 1.8 million years ago, “a million or so years later than previously thought,” says paleoanthropologist Philipp Gunz at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who did not take part in this study. © Society for Science & the Public 2000–2021.

Keyword: Evolution
Link ID: 27768 - Posted: 04.10.2021

By Nikk Ogasa Honey bees can’t speak, of course, but scientists have found that the insects combine teamwork and odor chemicals to relay the queen’s location to the rest of the colony, revealing an extraordinary means of long distance, mass communication. The research is “really nice, and really careful,” says Gordon Berman, a biologist at Emory University who was not involved in the study. It shows once again, he says, that insects are capable of “exquisite and complex behaviors.” Honey bees communicate with chemicals called pheromones, which they sense through their antennae. Like a monarch pressing a button, the queen emits pheromones to summon worker bees to fulfill her needs. But her pheromones only travel so far. Busy worker bees, however, roam around, and they, too, can call to each other by releasing a pheromone called Nasanov, through a gesticulation known as “scenting; they raise their abdomens to expose their pheromone glands and fan their wings to direct the smelly chemicals backward (seen in the video above, and close-up in the video below). Scientists have long known individual bees scented, but just how these individual signals work together to gather tens of thousands of bees around a queen, such as when the colony leaves the hive to swarm, has remained a mystery. © 2021 American Association for the Advancement of Science.

Keyword: Animal Communication; Evolution
Link ID: 27767 - Posted: 04.10.2021

by Angie Voyles Askham Sluggish fetal head growth toward the end of the second trimester foretells poor performance on tests of cognition, language and fine motor skills at age 2, according to a new international study. By the time a child shows developmental delays, which are common in autism, “a lot of other things have already happened” to put her on that track, says Hao Huang, associate professor of radiology at the University of Pennsylvania in Philadelphia, who was not involved in the study. If clinicians could predict such delays in advance, they could start behavioral interventions early, during the period when a child’s brain is most responsive to treatment, he says. The new study offers a step toward that goal, identifying a potential biomarker of atypical development in routine ultrasound scans taken at 20 to 25 weeks of gestation. Researchers analyzed the scans — performed more frequently than usual during 3,598 pregnancies at six international sites — to measure how fetal head circumference changed over time. “[Change in] head circumference is a very nice proxy of growth, particularly brain growth,” says study investigator José Villar, professor of perinatal medicine at the University of Oxford in the United Kingdom. Fetal head growth follows one of five paths, Villar and his colleagues found. Each path is associated with a different outcome on cognitive and behavioral tests when the child is 2 years old. © 2021 Simons Foundation

Keyword: Development of the Brain; Autism
Link ID: 27766 - Posted: 04.10.2021

Nicola Davis It is a trope used in films from King Kong to Tarzan – a male primate standing upright and beating its chest, sometimes with a yell and often with more than a dash of hubris. But it seems the pounding action is less about misplaced bravado than Hollywood would suggest: researchers studying adult male mountain gorillas say that while chest-beating might be done to show off, it also provides honest information. “We found it is definitely a real, reliable signal – males are conveying their true size,” said Edward Wright, co-author of the research from the Max Planck Institute for Evolutionary Anthropology in Germany. Advertisement Writing in the journal Scientific Reports, Wright and colleagues report how they studied chest-beating in six adult male mountain gorillas in the Volcanoes national park in Rwanda. The team used a camera setup involving two parallel green lasers a known distance apart to determine the breadth of each gorilla’s back from a photograph. They then recorded 36 chest-beating episodes among these six males between November 2015 and July 2016, and analysed the recordings. The results revealed that the duration of the chest-beating, number of beats and the rate of the beats during an episode were not associated with the size of the gorilla. However, the average peak frequency of the sound produced was – the larger the gorilla, the lower the frequency of the sound produced. © 2021 Guardian News & Media Limited

Keyword: Sexual Behavior; Evolution
Link ID: 27765 - Posted: 04.10.2021

By Meagan Cantwell In order to see the world as clearly as we do, we process vision from each eyeball on both sides of our brain—a capability known as bilateral visual projection. For a long time, researchers thought this feature developed after fish transitioned to land, more than 375 million years ago. But does this theory hold water today? In a new study, scientists injected fluorescent tracers into the eyes of 11 fish species to illuminate their visual systems. After examining their brains under a specialized 3D fluorescence microscope, they found ancient fish with genomes more similar to mammals can project vision on both the same and opposite side of their brain (see video, above). This suggests bilateral vision did not coincide with the transition from water to land, researchers report this week in Science. In the future, scientists plan to uncover the genes that drive same-sided visual projection to better understand how vision evolved. © 2021 American Association for the Advancement of Science.

Keyword: Vision; Evolution
Link ID: 27764 - Posted: 04.10.2021

By Alla Katsnelson New monthly payments in the pandemic relief package have the potential to lift millions of American children out of poverty. Some scientists believe the payments could change children’s lives even more fundamentally — via their brains. It’s well established that growing up in poverty correlates with disparities in educational achievement, health and employment. But an emerging branch of neuroscience asks how poverty affects the developing brain. Over the past 15 years, dozens of studies have found that children raised in meager circumstances have subtle brain differences compared with children from families of higher means. On average, the surface area of the brain’s outer layer of cells is smaller, especially in areas relating to language and impulse control, as is the volume of a structure called the hippocampus, which is responsible for learning and memory. These differences don’t reflect inherited or inborn traits, research suggests, but rather the circumstances in which the children grew up. Researchers have speculated that specific aspects of poverty — subpar nutrition, elevated stress levels, low-quality education — might influence brain and cognitive development. But almost all the work to date is correlational. And although those factors may be at play to various degrees for different families, poverty is their common root. A continuing study called Baby’s First Years, started in 2018, aims to determine whether reducing poverty can itself promote healthy brain development. © 2021 The New York Times Company

Keyword: Development of the Brain; Learning & Memory
Link ID: 27763 - Posted: 04.08.2021

Diana Kwon Susan was still a child when she first suspected something might be wrong with her mother. A cup or plate would often crash to the floor by accident when her mother was serving dinner or washing up dishes. “She was, she would have said, ‘clumsy’, but she wasn’t really clumsy,” says Susan. “Her hands had beautiful, glamorous movements, which I now recognize as early HD.” Huntington’s disease (HD) is an inherited condition that causes widespread deterioration in the brain and disrupts thinking, behaviour, emotion and movement. The disease usually begins in midlife, with subtle changes such as mood swings and difficulty in staying focused. As it progresses, people develop dementia and an inability to speak or move. Susan, who requested that her last name be withheld to protect her privacy, vividly remembers the day she learnt that her mother had the disease. It was the spring of 1982, and her mother had been admitted to a hospital because of her extreme exhaustion, frequent falls and irregular movements. There was no genetic test for the condition at the time, so she underwent a series of assessments. Her neurologist gathered the entire family into a room to break the news. “He told us that our mother had Huntington’s disease,” recalls Susan. “And that there’s no treatment and it can be wiped out in a generation if you just don’t breed.” Those blunt words had a profound impact on the lives of Susan and her siblings: her brother decided never to get married, and her sister chose to be sterilized. For Susan, however, those options were out of reach: she was pregnant when she received the news. © 2021 Springer Nature Limited

Keyword: Genes & Behavior; Movement Disorders
Link ID: 27762 - Posted: 04.08.2021

By Joshua Kendall When adults claim to have suddenly recalled painful events from their childhood, are those memories likely to be accurate? This question is the basis of the “memory wars” that have roiled psychology for decades. And the validity of buried trauma turns up as a point of contention in court cases and in television and movie story lines. Warnings about the reliability of a forgotten traumatic event that is later recalled—known formally as a delayed memory—have been endorsed by leading mental health organizations such as the American Psychiatric Association (APA). The skepticism is based on a body of research showing that memory is unreliable and that simple manipulations in the lab can make people believe they had an experience that never happened. Some prominent cases of recovered memory of child abuse have turned out to be false, elicited by overzealous therapists. But psychotherapists who specialize in treating adult survivors of childhood trauma argue that laboratory experiments do not rule out the possibility that some delayed memories recalled by adults are factual. Trauma therapists assert that abuse experienced early in life can overwhelm the central nervous system, causing children to split off a painful memory from conscious awareness. They maintain that this psychological defense mechanism—known as dissociative amnesia—turns up routinely in the patients they encounter. © 2021 Scientific American

Keyword: Stress; Learning & Memory
Link ID: 27761 - Posted: 04.08.2021

By Rachel Schraer People diagnosed with Covid-19 in the previous six months were more likely to develop depression, dementia, psychosis and stroke, researchers have found. A third of those with a previous Covid infection went on to develop or have a relapse of a psychological or neurological condition. But those admitted to hospital or in intensive care had an even higher risk. The study authors pointed to both the effects of stress, and the virus having a direct impact on the brain. UK scientists looked at the electronic medical records of more than half a million patients in the US, and their chances of developing one of 14 common psychological or neurological conditions, including: Anxiety and mood disorders were the most common diagnosis among those with Covid, and these were more likely to be down to the stress of the experience of being very ill or taken to hospital, the researchers explained. Conditions like stroke and dementia were more likely to be down to the biological impacts of the virus itself, or of the body's reaction to infection in general. Covid-19 was not associated with an increased risk of Parkinson's or Guillain-Barré syndrome (a risk from flu). Cause and effect The study, published in the Lancet Psychiatry journal, was observational. So the researchers couldn't say whether Covid had caused any of the diagnoses - and some people would have had a stroke or depression in the next six months regardless. But by comparing a group of people who had had Covid-19 with two groups - with flu and with other respiratory infections respectively - the researchers at the University of Oxford concluded Covid was associated with more subsequent brain conditions than other respiratory illnesses. © 2021 BBC.

Keyword: Depression; Alzheimers
Link ID: 27760 - Posted: 04.08.2021

By Jake Buehler Watch a group of lions yawn, and it may seem like nothing more than big, lazy cats acting sleepy, but new research suggests that these yawns may be subtly communicating some important social cues. Yawning is not only contagious among lions, but it appears to help the predators synchronize their movements, researchers report March 16 in Animal Behaviour. The discovery was partially made by chance, says Elisabetta Palagi, an ethologist at the University of Pisa in Italy. While studying play behavior in spotted hyenas in South Africa, she and colleagues often had the opportunity to watch lions (Panthera leo) at the same time. And she quickly noticed that lions yawn quite frequently, concentrating these yawns in short time periods. Yawning is ubiquitous among vertebrates, possibly boosting blood flow to the skull, cooling the brain and aiding alertness, especially when transitioning in and out of rest (SN: 9/8/15). Fish and reptiles will yawn, but more social vertebrates such as birds and mammals appear to have co-opted the behavior for purposes conducive to group living. In many species — like humans, monkeys, and even parakeets (SN: 6/1/15) — yawners can infect onlookers with their “yawn contagion,” leading onlookers to yawn shortly afterwards. Seeing the lions yawn reminded Palagi of her own work on contagious yawning in primates. Curious if the lions’ prodigious yawning was socially linked, Palagi and her team started recording videos of the big cats, analyzing when they were yawning and any behaviors around those times. © Society for Science & the Public 2000–2021

Keyword: Animal Communication; Stress
Link ID: 27759 - Posted: 04.08.2021

Jon Hamilton A study of mice that hear imaginary sounds could help explain human disorders like schizophrenia, which produce hallucinations. D-Keine/Getty Images A technique that induces imaginary sounds in both mice and people could help scientists understand the brain circuits involved in schizophrenia and other disorders that cause hallucinations. The technique appears to offer "a way to study psychotic disorders in animals," says Adam Kepecs, a professor of neuroscience and psychiatry at Washington University School of Medicine in St. Louis. It also shows how levels of the brain chemical dopamine determine the likelihood that a mouse or a person will perceive something that isn't really there, Kepecs and a team report in this week's issue of the journal Science. Until now, scientists have had no good way to study precisely how hallucinations occur in the brain. "This study is valuable because it will allow us to use mice and dig into the cellular, molecular, physiological details," says Eleanor Simpson, a researcher at the New York State Psychiatric Institute. That's important, Simpson says, because it could lead to better treatments for disorders like schizophrenia. "We have drugs that treat hallucinations but they're not very good," she says. "They don't work for everybody and they have a lot of terrible side effects which prevent people from using them." The study came about because "a mouse can't tell you when it's hallucinating," Kepecs © 2021 npr

Keyword: Schizophrenia; Hearing
Link ID: 27758 - Posted: 04.03.2021

By Benedict Carey When I joined the Science staff in 2004, reporters in the department had a saying, a reassuring mantra of sorts: “People will always come to the science section, if only to read about progress.” I think about that a lot as I say goodbye to my job, covering psychiatry, psychology, brain biology and big-data social science, as if they were all somehow related. The behavior beat, as it’s known, allowed tremendous freedom: I wrote about the mental upsides of binge drinking, playing the lotto and sports fandom. I covered basic lab research, the science of learning and memory, the experience of recurrent anguish, through the people who had to live with it. And much, much more. Like most science reporters, I had wanted to report on something big, to have a present-at-the-creation run that would shake up our understanding of mental health problems. At minimum, I expected research that would help people in distress improve their lives. But during my tenure, the science informing mental health care did not proceed smoothly along any trajectory. On the one hand, the field attracted enormous scientific talent, and there were significant discoveries, particularly in elucidating levels of consciousness in brain injury patients who appear unresponsive; and in formulating the first persuasive hypothesis of a cause for schizophrenia, based in brain biology. On the other hand, the science did little to improve the lives of the millions of people living with persistent mental distress. Almost every measure of our collective mental health — rates of suicide, anxiety, depression, addiction deaths, psychiatric prescription use — went the wrong direction, even as access to services expanded greatly. What happened? After 20 years covering the field, here and at The Los Angeles Times, I have a few theories, and some ideas on what might be required to turn things around. © 2021 The New York Times Company

Keyword: Depression; Stress
Link ID: 27757 - Posted: 04.03.2021

By Perri Klass, M.D. When parents bring their children in for medical care these days, there is no such thing as a casual, “Hey, how’s it going?” We doctors walk into every exam room prepared to hear a story of sadness and stress, or at the very least, of coping and keeping it together in this very hard year, full of isolation, loss, tragedy and hardship, with routines disrupted and comfort hard to come by. Parents have carried heavy burdens of stress and responsibility, worrying about themselves but also watching their children struggle, and there is worldwide concern about depression and suicidality among young people. But it isn’t only the adults and the young adults and teenagers who are suffering and sad; young children can also experience depression, but it can look very different, which makes it challenging for parents — or doctors — to recognize it and provide help. Rachel Busman, a clinical psychologist at the Child Mind Institute in New York City, said that it can be hard to think about depression in younger children because we picture childhood as a time of innocence and joy. But as many as 2 to 3 percent of children ages 6 to 12 can have serious depression, she said. And children with anxiety disorders, which are present in more than 7 percent of children aged 3 to 17, are also at risk for depression. Dr. Helen Egger, until recently the chair of child and adolescent psychiatry at N.Y.U. Langone Health, said that according to her epidemiologic research, between 1 and 2 percent of young children — as young as 3 — are depressed Depression was originally conceived of as an adult problem. Maria Kovacs, professor of psychiatry at the University of Pittsburgh School of Medicine, said that in the 1950s and ’60s, there were child psychiatrists who believed that children did not have sufficient ego development to feel depression, but that research that she and other colleagues did in the ’70s showed that “school age children can suffer from diagnosable depression.” © 2021 The New York Times Company

Keyword: Depression; Development of the Brain
Link ID: 27756 - Posted: 04.03.2021

By Jake Buehler Fairy wrasses are swimming jewels, flitting and flouncing about coral reefs. The finger-length fishes’ brash, vibrant courtship displays are meant for mates and rivals, and a new study suggests that the slow waxing and waning of ice sheets and glaciers may be partly responsible for such a variety of performances. A new genetic analysis of more than three dozen fairy wrasse species details the roughly 12 million years of evolution that produced their vast assortment of shapes, colors and behaviors. And the timing of these transformations implies that the more than 60 species of fairy wrasses may owe their great diversity to cyclic sea level changes over the last few millions of years, scientists report February 23 in Systematic Biology. Within the dizzying assembly of colorful reef fishes, fairy wrasses (Cirrhilabrus) can’t help but stand out. They are the most species-rich genus in the second most species-rich fish family in the ocean, says Yi-Kai Tea, an ichthyologist at the University of Sydney. “That is quite a bit of biodiversity,” says Tea, who notes that new fairy wrasse species are identified every year. Despite this taxonomic footprint, Tea says, scientists knew “next to nothing” about the fairy wrasses’ evolutionary history or why there were so many species. © Society for Science & the Public 2000–2021.

Keyword: Sexual Behavior; Evolution
Link ID: 27755 - Posted: 04.03.2021

By Rachel Aviv Elizabeth Loftus was in Argentina, giving talks about the malleability of memory, in October, 2018, when she learned that Harvey Weinstein, who had recently been indicted for rape and sexual assault, wanted to speak with her. She couldn’t figure out how to receive international calls in her hotel room, so she asked if they could talk in three days, once she was home, in California. In response, she got a series of frantic e-mails saying that the conversation couldn’t wait. But, when Weinstein finally got through, she said, “basically he just wanted to ask, ‘How can something that seems so consensual be turned into something so wrong?’ ” Loftus, a professor at the University of California, Irvine, is the most influential female psychologist of the twentieth century, according to a list ­compiled by the Review of General Psychology. Her work helped usher in a paradigm shift, rendering obsolete the archival model of memory—the idea, dominant for much of the twentieth century, that our memories exist in some sort of mental library, as literal representations of past events. According to Loftus, who has published twenty-four books and more than six hundred papers, memories are reconstructed, not replayed. “Our representation of the past takes on a living, shifting reality,” she has written. “It is not fixed and immutable, not a place way back there that is preserved in stone, but a living thing that changes shape, expands, shrinks, and expands again, an amoeba-­like creature.” George A. Miller, one of the founders of cognitive psychology, once said in a speech to the American Psychological Association that the way to advance the field was “to give psychology away.” Loftus, who is seventy-six, adopts a similar view, seizing any opportunity to elaborate on what she calls the “flimsy curtain that separates our imagination and our memory.” In the past forty-five years, she has testified or consulted in more than three hundred cases, on behalf of people wrongly accused of robbery and murder, as well as for high-profile defendants like Bill Cosby, Jerry Sandusky, and the Duke lacrosse players accused of rape, in 2006. “If the MeToo movement had an office, Beth’s picture would be on the ten-most-wanted list,” her brother Robert told me. © 2021 Condé Nast.

Keyword: Learning & Memory
Link ID: 27754 - Posted: 03.31.2021

By Lisa Sanders, M.D. The dental hygienist greeted her longtime patient enthusiastically. Unexpectedly, the 68-year-old woman burst into tears. “I feel so bad,” she said, her voice cracking with emotion. “I’m worried I might be dying.” She was always tired, as if all her energy had been sucked out. And she felt a strange dread that something awful was happening to her. And if that weren’t enough, for the past couple of weeks she had lost much of her hearing in her right ear. She was sure she had a brain tumor — though none of her doctors thought so. After offering sympathy, the dental assistant realized she had something more to offer: “We have a dental CT scanner. Should we get a CT of your head?” The patient was amazed. Yes — she would very much like a CT scan of her head. It would cost her $150, the technician told her. At that point, it seemed like a bargain. And, just like that, it was done. And there was a mass. It wasn’t on the right side, where she thought her trouble lay. It was on the left. And it wasn’t in her ear, but in the sinus behind her cheek. That was confusing. She thanked the tech for the scan. She had an ENT and would send the images to him to see what he thought. That right ear had been giving the patient trouble for more than 20 years, she reminded her ear, nose and throat doctor in Prescott, Ariz., when she spoke with him. In her 40s she developed terrible vertigo. She was living in Atlanta then and saw an ENT there who told her she probably had Ménière’s disease, a disorder induced by increased pressure in the inner ear. The cause is unknown, though in some cases it appears to run in families. And it’s characterized by intermittent episodes of vertigo usually accompanied by a sensation of fullness in the ear, as well as tinnitus and hearing loss. These symptoms can be present from the start, but often develop over time. There’s no definitive test for the disease, though evidence of the increased pressure is sometimes visible on an M.R.I. © 2021 The New York Times Company

Keyword: Hearing
Link ID: 27753 - Posted: 03.31.2021

By Kathryn Schulz One of the most amazing things I have ever witnessed involved an otherwise unprepossessing house cat named Billy. This was some years ago, shortly after I had moved into a little rental house in the Hudson Valley. Billy, a big, bad-tempered old tomcat, belonged to the previous tenant, a guy by the name of Phil. Phil adored that cat, and the cat—improbably, given his otherwise unenthusiastic feelings about humanity—returned the favor. On the day Phil vacated the house, he wrestled an irate Billy into a cat carrier, loaded him into a moving van, and headed toward his new apartment, in Brooklyn. Thirty minutes down I-84, in the middle of a drenching rainstorm, the cat somehow clawed his way out of the carrier. Phil pulled over to the shoulder but found that, from the driver’s seat, he could neither coax nor drag the cat back into captivity. Moving carefully, he got out of the van, walked around to the other side, and opened the door a gingerly two inches—whereupon Billy shot out, streaked unscathed across two lanes of seventy-mile-per-hour traffic, and disappeared into the wide, overgrown median. After nearly an hour in the pouring rain trying to make his own way to the other side, Phil gave up and, heartbroken, continued onward to his newly diminished home. Some weeks later, at a little before seven in the morning, I woke up to a banging at my door. Braced for an emergency, I rushed downstairs. The house had double-glass doors flanked by picture windows, which together gave out onto almost the entire yard, but I could see no one. I was standing there, sleep-addled and confused, when up onto his hind legs and into my line of vision popped an extremely scrawny and filthy gray cat. I gaped. Then I opened the door and asked the cat, idiotically, “Are you Billy?” He paced, distraught, and meowed at the door. I retreated inside and returned with a bowl each of food and water, but he ignored them and banged again at the door. Flummoxed, I took a picture and texted it to my landlord with much the same question I had asked the cat: “Is this Billy?” © 2021 Condé Nast.

Keyword: Animal Migration
Link ID: 27752 - Posted: 03.31.2021

By Gretchen Reynolds Brisk walking improves brain health and thinking in aging people with memory impairments, according to a new, yearlong study of mild cognitive impairment and exercise. In the study, middle-aged and older people with early signs of memory loss raised their cognitive scores after they started walking frequently. Regular exercise also amplified the healthy flow of blood to their brains. The changes in their brains and minds were subtle but consequential, the study concludes, and could have implications not just for those with serious memory problems, but for any of us whose memories are starting to fade with age. Most of us, as we get older, will find that our ability to remember and think dulls a bit. This is considered normal, if annoying. But if the memory loss intensifies, it may become mild cognitive impairment, a medical condition in which the loss of thinking skills grows obvious enough that it becomes worrisome to you and others around you. Mild cognitive impairment is not dementia, but people with the condition are at heightened risk of developing Alzheimer’s disease later. Scientists have not yet pinpointed the underlying causes of mild cognitive impairment, but there is some evidence that changes in blood flow to the brain can contribute. Blood carries oxygen and nutrients to brain cells and if that stream sputters, so can the vitality of neurons. Unfortunately, many people experience declines in the flow of blood to their brains with age, when their arteries stiffen and hearts weaken. © 2021 The New York Times Company

Keyword: Alzheimers; Learning & Memory
Link ID: 27751 - Posted: 03.31.2021

Jennifer Hellmann Parents who are exposed to predators pass on information about risky environments to their offspring through changes in gene expression – but how that information affects offspring differs depending on the sex of the parent. My colleagues and I showed this using sticklebacks – a small species of freshwater fish whose brightly colored males care for developing eggs – in a series of papers recently published in the Journal of Animal Ecology. First, we exposed mothers and fathers to predators. Then we looked at their offspring and measured behavior as well as how genes were expressed in their brains. We found that the sex of the parent exposed to predators matters, but surprisingly, the sex of the offspring also changed how the information influenced behavior. Predator‐exposed fathers produced bolder sons that took more risks, but the father’s experiences had no effect on the boldness of daughters. Predator‐exposed mothers, on the other hand, produced more anxious daughters and also more anxious sons. These sons and daughters had different patterns of gene expression, matching our behavioral results. We also studied whether these changes persisted into a second generation. In grandkids, we again found complicated patterns of sex-specific inheritance. So how does this work? It’s not that experiences have changed what genes the parents pass on. Rather, what changes is how those genes are expressed in the offspring. This variability in gene expression is called epigenetics. Stickleback eggs showing embryos growing inside. Through epigenetics, a parent can pass down information to the next generation of sticklebacks like the ones growing in these eggs. Jennifer Hellman, CC BY-ND © 2010–2021, The Conversation US, Inc.

Keyword: Epigenetics; Stress
Link ID: 27750 - Posted: 03.31.2021