Chapter 13. Memory, Learning, and Development

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Two independent teams of scientists from the University of Utah and the University of Massachusetts Medical School have discovered that a gene crucial for learning, called Arc, can send its genetic material from one neuron to another by employing a strategy commonly used by viruses. The studies, both published in Cell, unveil a new way that nervous system cells interact. “This work is a great example of the importance of basic neuroscience research,” said Edmund Talley, Ph.D., a program director at the National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institutes of Health. “What began as an effort to examine the behavior of a gene involved in memory and implicated in neurological disorders such as Alzheimer’s disease has unexpectedly led to the discovery of an entirely new process, which neurons may use to send genetic information to one another.” While Arc is known to play a vital role in the brain’s ability to store new information, little is known about precisely how it works. In addition, previous studies had detailed similarities between the Arc protein and proteins found in certain viruses like HIV, but it was unclear how those commonalities influenced the behavior of the Arc protein. The University of Utah researchers began their examination of the Arc gene by introducing it into bacterial cells. To their surprise, when the cells made the Arc protein, it clumped together into a form that resembled a viral capsid, the shell that contains a virus’ genetic information. The Arc “capsids” appeared to mirror viral capsids in their physical structure as well as their behavior and other properties.

Keyword: Learning & Memory
Link ID: 24535 - Posted: 01.17.2018

By LAURA BEIL Millions of American children have been exposed to a parasite that could interfere with their breathing, liver function, eyesight and even intelligence. Yet few scientists have studied the infection in the United States, and most doctors are unaware of it. The parasites, roundworms of the genus Toxocara, live in the intestines of cats and dogs, especially strays. Microscopic eggs from Toxocara are shed in the animals’ feces, contaminating yards, playgrounds and sandboxes. These infectious particles cling to the hands of children playing outside. Once swallowed, the eggs soon hatch, releasing larvae that wriggle through the body and, evidence suggests, may even reach the brain, compromising learning and cognition. The Centers for Disease Control and Prevention periodically tracks positive tests for Toxocara through the National Health and Nutrition Examination Survey. The latest report, published in September in the journal Clinical Infectious Diseases, estimated that about 5 percent of the United States population — or about 16 million people — carry Toxocara antibodies in their blood, a sign they have ingested the eggs. But the risk is not evenly shared: Poor and minority populations are more often exposed. The rate among African Americans was almost 7 percent, according to the C.D.C. Among people living below the poverty line, the infection rate was 10 percent. The odds of a positive test rise with age, but it’s unknown whether this reflects recent infections or simply an accumulation of antibodies from past encounters. Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston, calls Toxocara both one of the most common parasites in the country and arguably the most neglected. © 2018 The New York Times Company

Keyword: Development of the Brain
Link ID: 24530 - Posted: 01.16.2018

By Jessica Wright, The prevalence of autism in the United States remained relatively stable from 2014 to 2016, according to a new analysis. The results were published January 2 in the Journal of the American Medical Association. The researchers report the frequency of autism in the U.S. as 2.24 percent in 2014, 2.41 percent in 2015 and 2.76 percent in 2016, respectively. The new data come from the National Health Interview Survey—a yearly interview in which trained census workers ask tens of thousands of parents about the health of their children. These questions include whether a healthcare professional has ever told them that their child has autism. The new figures, released by the U.S. Centers for Disease Control and Prevention (CDC), represent the highest autism prevalence in the U.S. reported by the agency to date. “We cannot consider autism as rare a condition as people previously thought,” says lead researcher Wei Bao, assistant professor of epidemiology at the University of Iowa. The peak is likely to result from the fact that the data are based on parent reports. These reports may capture children with relatively mild autism features better than do approaches that rely on medical records, Bao says. Autism’s reported prevalence in the U.S. has climbed steadily in the past few decades. Researchers attribute most of this increase to changes in how the prevalence is measured, increased awareness of the condition and shifts in the criteria for diagnosing autism. © 2018 Scientific American,

Keyword: Autism
Link ID: 24522 - Posted: 01.12.2018

Helen Shen For someone who’s not a Sherlock superfan, cognitive neuroscientist Janice Chen knows the BBC’s hit detective drama better than most. With the help of a brain scanner, she spies on what happens inside viewers’ heads when they watch the first episode of the series and then describe the plot. Chen, a researcher at Johns Hopkins University in Baltimore, Maryland, has heard all sorts of variations on an early scene, when a woman flirts with the famously aloof detective in a morgue. Some people find Sherlock Holmes rude while others think he is oblivious to the woman’s nervous advances. But Chen and her colleagues found something odd when they scanned viewers’ brains: as different people retold their own versions of the same scene, their brains produced remarkably similar patterns of activity1. Chen is among a growing number of researchers using brain imaging to identify the activity patterns involved in creating and recalling a specific memory. Powerful technological innovations in human and animal neuroscience in the past decade are enabling researchers to uncover fundamental rules about how individual memories form, organize and interact with each other. Using techniques for labelling active neurons, for example, teams have located circuits associated with the memory of a painful stimulus in rodents and successfully reactivated those pathways to trigger the memory. And in humans, studies have identified the signatures of particular recollections, which reveal some of the ways that the brain organizes and links memories to aid recollection. Such findings could one day help to reveal why memories fail in old age or disease, or how false memories creep into eyewitness testimony. These insights might also lead to strategies for improved learning and memory. © 2018 Macmillan Publishers Limited,

Keyword: Learning & Memory
Link ID: 24520 - Posted: 01.11.2018

Nicola Davis The quest to develop drugs to treat Alzheimer’s disease has experienced a new setback, with a promising medication failing to show benefits in the latest series of clinical trials. Earlier trials had suggested that the drug idalopirdine, from the Danish international pharmaceutical company Lundbeck, might improve cognition in those with Alzheimer’s disease when taken alongside existing drugs – known as cholinesterase inhibitors – acting to improve symptoms rather than stopping the disease from developing. But the latest trials have dashed such hopes. “I was personally very excited,” said professor Clive Ballard, co-author of the study from the University of Exeter, pointing out that previous trials had appeared promising. “It is very disappointing that it then didn’t pan out.” Analysis This may be a turning point in treating neurodegenerative diseases Success in trials for Huntington’s and Spinal Muscular Atrophy, raises hopes that diseases such as Alzheimer’s and ALS could be tackled using a new class of drugs Read more Writing in the Journal of the American Medical Association, an international team of researchers report how they carried out three clinical trials involving a total of 2,525 participants in 34 countries, to explore the impact of idalopirdine. All participants were aged 50 years or older and had mild to moderate Alzheimer’s disease. © 2018 Guardian News and Media Limited

Keyword: Alzheimers
Link ID: 24514 - Posted: 01.10.2018

Eric Nyquist for Quanta Magazine Brains, beyond their signature achievements in thinking and problem solving, are paragons of energy efficiency. The human brain’s power consumption resembles that of a 20-watt incandescent lightbulb. In contrast, one of the world’s largest and fastest supercomputers, the K computer in Kobe, Japan, consumes as much as 9.89 megawatts of energy — an amount roughly equivalent to the power usage of 10,000 households. Yet in 2013, even with that much power, it took the machine 40 minutes to simulate just a single second’s worth of 1 percent of human brain activity. Now engineering researchers at the California NanoSystems Institute at the University of California, Los Angeles, are hoping to match some of the brain’s computational and energy efficiency with systems that mirror the brain’s structure. They are building a device, perhaps the first one, that is “inspired by the brain to generate the properties that enable the brain to do what it does,” according to Adam Stieg, a research scientist and associate director of the institute, who leads the project with Jim Gimzewski, a professor of chemistry at UCLA. The device is a far cry from conventional computers, which are based on minute wires imprinted on silicon chips in highly ordered patterns. The current pilot version is a 2-millimeter-by-2-millimeter mesh of silver nanowires connected by artificial synapses. Unlike silicon circuitry, with its geometric precision, this device is messy, like “a highly interconnected plate of noodles,” Stieg said. And instead of being designed, the fine structure of the UCLA device essentially organized itself out of random chemical and electrical processes. All Rights Reserved © 2018

Keyword: Learning & Memory; Robotics
Link ID: 24500 - Posted: 01.08.2018

By HENRY ALFORD Here in the valley of my mid-50s, I try not to get into a swivet over my occasionally faulty memory: Sometimes the mind has a mind of its own. But when I read this chilling passage — “I am dementing. I am dementing. I am dementing.” — from Gerda Saunders’s recent memoir “Memory’s Last Breath: Field Notes on My Dementia,” I found myself starting to panic. In a world increasingly dominated by the Google/Apple/Facebook/Amazon hegemony, we hear a lot about the threat to privacy. But isn’t memory just as vulnerable? Now that, as the former New Republic editor Franklin Foer writes in “World Without Mind: The Existential Threat of Big Tech,” “our phone is an extension of our memory; we’ve outsourced basic functions to algorithms,” doesn’t the world seem like an ever-larger parking lot that has mysteriously swallowed our Toyota? Don’t we all wish, now more than ever, that acquaintances came equipped with their own “Previously on this series …” trailer? Mr. Foer and Ms. Saunders aren’t the only writers on this beat. Recent books by Robert Sapolsky, Michael Lemonick, Felicia Yap, Emily Barr, Dale Bredesen, Val Emmich, Oliver Sacks and Elizabeth Rosner, among others, have addressed the theme of non-historical memory. Last July alone, more than a dozen books specifically about the topic, most of them self-published, were released. You’d expect the themes of amnesia or powers of recall to be prevalent in thrillers or in memoirs by trauma survivors or over-beveraged rock stars, but even literary fiction is getting in on the act. In Rachel Khong’s sly, diaristic “Goodbye, Vitamin,” a 30-year-old who moves back home learns she has to care for a dementing father who has started leaving his pants in trees. In Alissa Nutting’s outrageous sex comedy “Made for Love,” a woman on the lam from her tech pioneer husband discovers that he has implanted a chip in her brain that allows him to download all her experiences. © 2018 The New York Times Company

Keyword: Learning & Memory
Link ID: 24499 - Posted: 01.08.2018

By Meredith Wadman For the first time, scientists have produced evidence in living humans that the protein tau, which mars the brain in Alzheimer’s disease, spreads from neuron to neuron. Although such movement wasn’t directly observed, the finding may illuminate how neurodegeneration occurs in the devastating illness, and it could provide new ideas for stemming the brain damage that robs so many of memory and cognition. Tau is one of two proteins—along with β-amyloid—that form unusual clumps in the brains of people with Alzheimer’s disease. Scientists have long debated which is most important to the condition and, thus, the best target for intervention. Tau deposits are found inside neurons, where they are thought to inhibit or kill them, whereas β-amyloid forms plaques outside brain cells. Researchers at the University of Cambridge in the United Kingdom combined two brain imaging techniques, functional magnetic resonance imaging and positron emission tomography (PET) scanning, in 17 Alzheimer’s patients to map both the buildup of tau and their brains’ functional connectivity—that is, how spatially separated brain regions communicate with each other. Strikingly, they found the largest concentrations of the damaging tau protein in brain regions heavily wired to others, suggesting that tau may spread in a way analogous to influenza during an epidemic, when people with the most social contacts will be at greatest risk of catching the disease. © 2018 American Association for the Advancement of Science.

Keyword: Alzheimers; Brain imaging
Link ID: 24496 - Posted: 01.06.2018

By Meredith Wadman Chya* (pronounced SHY-a), who is not quite 10 years old, recently spent an unusual day at the University of Maryland School of Medicine in Baltimore. Part of the time she was in a "cool" brain scanner while playing video games designed to test her memory and other brain-related skills. At other points, she answered lots of questions about her life and health on an iPad. A slender Baltimore third grader who likes drawing, hip hop, and playing with her pet Chihuahua, Chya is one of more than 6800 children now enrolled in an unprecedented examination of teenage brain development. The Adolescent Brain Cognitive Development Study—or ABCD Study—will complete its 2-year enrollment period in September, and this month will release a trove of data from 4500 early participants into a freely accessible, anonymized database. Ultimately, the study aims to follow 10,000 children for a decade as they grow from 9- and 10-year-olds into young adults. Supported by the first chunk of $300 million pledged by several institutes at the National Institutes of Health (NIH) in Bethesda, Maryland, teams at 21 sites around the United States are regularly using MRI machines to record the structure and activity of these young brains. They're also collecting reams of psychological, cognitive, and environmental data about each child, along with biological specimens such as their DNA. In addition to providing the first standardized benchmarks of healthy adolescent brain development, this information should allow scientists to probe how substance use, sports injuries, screen time, sleep habits, and other influences may affect—or be affected by—a maturing brain. © 2017 American Association for the Advancement of Science.

Keyword: Development of the Brain; Schizophrenia
Link ID: 24488 - Posted: 01.04.2018

Brian Mann When Bella Doolittle heard her diagnosis last February of early-onset Alzheimer's, she sat in the car outside the doctor's office and cried. "He said, 'Well, we figured out what's going on with you and this is it.' And I'm like, 'No it's not.' " Doolittle's husband, Will Doolittle, sits next to her on the couch, recalling how she grilled the doctor. "You asked, 'How long does this take? How long do I have?' And he said, 'On average, eight years.' That really upset you." "That really pissed me off," Bella says, laughing now at the memory. "Absolutely. I mean, I was pretty devastated. I'm like, eight years? I'm not even wrinkly yet." Researchers say as many as 200,000 Americans experience Alzheimer's younger than the typical age of 65, developing dementia-like symptoms in their 40s and 50s. For people like Bella, the diagnosis can feel overwhelming and bring feelings of shame. They fear losing memories, careers, and parts of their identity. Bella is a young-looking 59, wearing a T-shirt and a mop of red hair. On the day NPR visited her home in Glens Falls in upstate New York, where they raised four kids, Bella was in the kitchen making her signature Christmas gift. "It's homemade Kahlúa, the best you will ever drink," she says. "I have my vanilla beans imported from Madagascar." Bella Doolittle remembers how she first became aware that something was wrong. For a while before the diagnosis, she just felt "off." Her brain would get fuzzy and then it got worse. © 2018 npr

Keyword: Alzheimers
Link ID: 24478 - Posted: 01.02.2018

By C. CLAIBORNE RAY Q. Did cranial deformation as practiced by the ancient Mayans change or impair brain function? A. The famous slanted forehead that was apparently a mark of high rank among pre-Columbian Mayans was achieved by various forms of compression of the head in infancy. It is believed by many researchers to have had no significant effect on cranial capacity and how the brain worked, the conclusion of a 1989 study of skulls in The American Journal of Physical Anthropology. But there is no direct evidence to support this contention, no large study comparing brain development in living populations that do and do not practice head flattening. An extensive review article in the journal Anthropology in 2003 speculated that the practice of compression had the potential to damage the delicate developing frontal lobe, as is seen in certain conditions. The authors speculated that such damage could have impaired vision, object recognition, hearing ability, memory, attentiveness and concentration. These factors in turn might have contributed to behavior disorders and difficulty in learning new information. Still other researchers suggest that the diverging conclusions can be attributed to how the skull measurements are done. The compression may have affected the shape of the face more than the brain itself, they said. © 2018 The New York Times Company

Keyword: Development of the Brain
Link ID: 24475 - Posted: 01.02.2018

/ By Michael Schulson Late last month, Senate Minority Leader Chuck Schumer took a break from the tax bill debate to talk with reporters about genetics. It takes just a few minutes to put some spit into a vial, but that little bit of spit can yield volumes of deeply intimate data. In a press conference, the New York senator criticized how direct-to-consumer genetic testing companies — outfits like 23andMe and AncestryDNA — discuss and handle users’ genetic information. “What those companies can do with all that data — your most sensitive and deepest info, your genetics — is not clear, and in some cases not fair and not right,” said Schumer. Schumer called on the Federal Trade Commission to launch an investigation into genetic testing companies’ privacy and disclosure practices, though the commercial and regulatory tides seem — at least for now — to be going in the other direction. Discounted prices for 23andMe dropped below $50 earlier this year, and sales of AncestryDNA kits are breaking records: In the weekend after Thanksgiving, the company said it had sold around 1.5 million genetic tests. That’s more units than 23andMe sold in its first eight years on the market. Last spring, for the first time, the Food and Drug Administration approved an over-the-counter test that tells consumers their genetic risk for a variety of conditions, from Parkinson’s and Alzheimer’s to Celiac disease and numerous blood diseases. And a new FDA policy announced at the beginning of November is likely to allow a wave of new, health-oriented genetic screening products to enter the market. Copyright 2017 Undark

Keyword: Genes & Behavior
Link ID: 24466 - Posted: 12.29.2017

Girls who go through puberty early could be more likely to experience depression and behaviour problems that last into their 20s compared to peers who start menstruation later, a U.S. study suggests. Researchers studied data on nearly 7,800 women who had their first menstrual cycle at an average age of 12. The women were interviewed four times, starting around age 16 and continuing until about age 28. Girls who went through puberty earlier than most were more likely to become depressed, and their symptoms were also more severe in adolescence, the study found. The younger the age at the first period, the stronger the association between early puberty and mental health problems; It was stronger for girls who started menstruation at age 8 than at age 10, for example. With earlier puberty, girls were also more likely to have behaviour issues that led to things like stealing, lying, breaking into buildings and selling drugs. The link lasted into young adulthood. Interestingly, the magnitude of the association between puberty and these psychological difficulties remains stable, meaning that puberty is as strongly associated with depressive symptoms and antisocial behaviour during adulthood as it is during adolescence, said lead study author Jane Mendle, a researcher at Cornell University in Ithaca, New York. ©2017 CBC/Radio-Canada.

Keyword: Depression; Hormones & Behavior
Link ID: 24463 - Posted: 12.28.2017

By Emily Anthes Men with autism respond differently to human odors — and the social signals that they contain — than do their neurotypical peers, according to a new study. The results suggest that men with autism misread social signals present in human odors — causing them to misinterpret others’ emotions. Human sweat contains chemicals believed to convey social and emotional information. For instance, when women smell sweat collected from men watching scary movies, they are more likely to describe faces with ambiguous expressions as fearful. Advertisement In the new study, researchers exposed men to sweat collected from people who were skydiving. Unlike controls, men with autism do not show increased skin conductance, a measure of physiological arousal, to this ‘fear sweat.’ They are also more likely than controls to trust a mannequin that emits this scent. “I think this could be a meaningful aspect of impaired social interaction,” says lead investigator Noam Sobel, professor of neurobiology at the Weizmann Institute of Science in Rehovot, Israel. “Humans constantly engage in social chemo-signaling; we do this all the time, and it shapes our interactions,” he says. “And somehow these mechanisms work differently in autism.” Several studies have examined olfaction in people with autism. Researchers have found, for example, that children with autism inhale odors differently than their typical peers do, and some children with the condition may be particularly sensitive to smells. © 2017 Scientific American

Keyword: Autism; Chemical Senses (Smell & Taste)
Link ID: 24459 - Posted: 12.26.2017

Michaeleen Doucleff It's not every day that surgeons develop a new brain surgery that could save tens of thousands of babies, even a hundred thousand, each year. And it's definitely not every day that the surgery is developed in one of the world's poorest countries. But that's exactly what neurosurgeons from Boston and Mbale, Uganda, report Wednesday in the New England Journal of Medicine. The treatment is for a scary condition in which a baby's head swells up, almost like balloon. It's called hydrocephalus, or "water on the brain." But a more accurate description is "spinal fluid inside the brain." Inside our brains, there are four chambers that continually fill up and release spinal fluid. So their volume stays constant. In babies with hydrocephalus, the chambers don't drain properly. They swell up, putting pressure on the brain. If left untreated about half the children will die, and the others will be badly disabled. Traditionally doctors treat hydrocelphalus in the U.S. with what's called a shunt: They place a long tube in the baby's brain, which allows the liquid to drain into the child's stomach. © 2017 npr

Keyword: Development of the Brain
Link ID: 24453 - Posted: 12.22.2017

Laura Sanders Globs of an inflammation protein beckon an Alzheimer’s protein and cause it to accumulate in the brain, a study in mice finds. The results, described in the Dec. 21/28 Nature, add new details to the relationship between brain inflammation and Alzheimer’s disease. Researchers suspect that this inflammatory cycle is an early step in the disease, which raises the prospect of being able to prevent the buildup of amyloid-beta, the sticky protein found in brains of people with Alzheimer’s disease. “It is a provocative paper,” says immunologist Marco Colonna of Washington University School of Medicine in St. Louis. Finding an inflammatory protein that can prompt A-beta to clump around it is “a big deal,” he says. Researchers led by Michael Heneka of the University of Bonn in Germany started by studying specks made of a protein called ASC that’s produced as part of the inflammatory response. (A-beta itself is known to kick-start this inflammatory process.) Despite being called specks, these are large globs of protein that are created by and then ejected from brain immune cells called microglia when inflammation sets in. A-beta then accumulates around these ejected ASC specks in the space between cells, Haneke and colleagues now propose. Specks of a type of inflammation protein called ASC (red) form the core of amyloid-beta plaques (green) in the brain of a 4-month-old mouse (top) and in the brain of a person who had Alzheimer’s disease (bottom). |© Society for Science & the Public 2000 - 2017.

Keyword: Alzheimers
Link ID: 24448 - Posted: 12.21.2017

By NICHOLAS BAKALAR Eating leafy greens may help slow mental decline. Researchers studied 960 men and women ages 58 to 99 who completed food frequency questionnaires and had two or more cognitive assessments over an average of almost five years of follow-up. Among many other foods, the researchers recorded the number of servings of lettuce, spinach, kale and collard greens. At least twice over the course of the study they administered cognitive tests covering memory, spatial ability and perceptual speed. Those who ate the most leafy vegetables — one to two servings a day — scored the equivalent of 11 years younger on tests of mental ability than those who ate little or none. Greens contain lutein, folate, beta carotene and other nutrients known to affect aging. Could the same effect be obtained with supplements containing these nutrients? Probably not. “The evidence for supplements is not positive, either from observational studies or clinical trials,” said the lead author, Martha Clare Morris, a professor of epidemiology at Rush University in Chicago. “The nutrients in food have many different forms and interactions. A specific formulation put in a pill with the same effect? That’s wishful thinking.” The study, in Neurology, controlled for smoking, physical activity and other factors, but it is observational, and does not prove cause and effect. © 2017 The New York Times Company

Keyword: Alzheimers
Link ID: 24446 - Posted: 12.21.2017

/ By Carrie Arnold Jim and Ida Hall buried their daughter Jerra in a family plot at the bottom of a grassy rise. Several times a year, Jim Hall drives just over a mile from his home on North Main Street in the town of St. Louis, Michigan to Jerra’s headstone in the back corner of Oak Grove Cemetery in his 1997 Chevy pickup. In the 12 years since complications from a rare heart defect claimed the life of their brown-haired toddler, her family continues to cover her grave with stuffed animals (frogs were her favorite). Hall gently sweeps off the leaves and debris covering the childhood paraphernalia and wipes his callused hands on a pair of worn jeans, his tall frame stooped by grief. He stops and stares at the inscription: “Two years, two months, too little.” “We didn’t know what else to write,” he said. “When your daughter is born with a heart condition and doesn’t survive, you just wonder.” Jim Hall’s exposure to PBB as a child makes him valuable in the hunt for the answer to a burning scientific question: Can a father’s exposure to environmental toxins impact the health of his progeny? Jerra’s headstone sits where an umbrella of majestic oaks gives way to the dreadlocks of vines and grasses of a small wetland in the geographic center of Michigan’s Lower Peninsula, a little more than a mile from the chemical plant that once produced a toxic flame retardant called PBB, short for polybrominated biphenyl. Hall can’t help but think it may have killed his little girl. Copyright 2017 Undark

Keyword: Development of the Brain; Epigenetics
Link ID: 24439 - Posted: 12.19.2017

By Sarah DeWeerdt Older men and women are more likely than young ones to have a child with autism, according to multiple studies published in the past decade. Especially regarding fathers, this effect is one of the most consistent findings in the epidemiology of autism. The link between a mother’s age and autism is more complex: Women seem to be at an increased risk both when they are much older and much younger than average, according to some studies. Nailing down why either parent’s age influences autism risk has proved difficult, however. How do we know that older men are at elevated risk of fathering a child with autism? Epidemiologists have gathered data on large numbers of families and calculated how often men of different ages have a child with autism. The first rigorous study of this type, published in 2006, drew on medical records of 132,000 Israeli adolescents. It showed that men in their 30s were 1.6 times as likely to have a child with autism as men younger than 30. Men in their 40s had a sixfold increase in risk. Since then, scientists have conducted similar analyses of data on children born in California, Denmark and Sweden, as well as of an international data set on 5.7 million children. Nearly all of this research has shown an increased prevalence of autism among the children of older fathers. At what age does the risk increase for men? No one knows. The age ranges and ages of the men differ across studies, making results hard to compare. Overall, the findings indicate that the risk increases steadily over time rather than suddenly rising after a certain age. © 1996-2017 The Washington Post

Keyword: Autism; Epigenetics
Link ID: 24436 - Posted: 12.18.2017

Jon Hamilton Older brains may forget more because they lose their rhythm at night. During deep sleep, older people have less coordination between two brain waves that are important to saving new memories, a team reports in the journal Neuron. "It's like a drummer that's perhaps just one beat off the rhythm," says Matt Walker, one of the paper's authors and a professor of neuroscience and psychology at the University of California, Berkeley. "The aging brain just doesn't seem to be able to synchronize its brain waves effectively." The finding appears to answer a long-standing question about how aging can affect memory even in people who do not have Alzheimer's or some other brain disease. "This is the first paper that actually found a cellular mechanism that might be affected during aging and therefore be responsible for a lack of memory consolidation during sleep," says Julie Seibt, a lecturer in sleep and plasticity at the University of Surrey in the U.K. Seibt was not involved in the new study. To confirm the finding, though, researchers will have to show that it's possible to cause memory problems in a young brain by disrupting these rhythms, Seibt says. The study was the result of an effort to understand how the sleeping brain turns short-term memories into memories that can last a lifetime, says Walker, the author of the book Why We Sleep. "What is it about sleep that seems to perform this elegant trick of cementing new facts into the neural architecture of the brain?" To find out, Walker and a team of scientists had 20 young adults learn 120 pairs of words. "Then we put electrodes on their head and we had them sleep," he says. The electrodes let researchers monitor the electrical waves produced by the brain during deep sleep. They focused on the interaction between slow waves, which occur every second or so, and faster waves called sleep spindles, which occur more than 12 times a second. © 2017 npr

Keyword: Sleep; Learning & Memory
Link ID: 24433 - Posted: 12.18.2017