Chapter 7. Life-Span Development of the Brain and Behavior

Follow us on Facebook and Twitter, or subscribe to our mailing list, to receive news updates. Learn more.


Links 1 - 20 of 4707

A daily 30-minute regimen designed to help elderly surgery patients stay oriented can cut the rate of postoperative delirium in half and help them return home sooner, according to a test among 377 volunteers in Taipei. After they were moved out of an intensive care unit, 15.1 percent given conventional treatment experienced delirium. But when hospital workers got patients moving faster, helped them brush their teeth, gave them facial exercises and talked to them in ways to help them understand what was happening, the delirium rate was just 6.6 percent. And while the patients who didn’t get the intervention typically stayed in the hospital for 14 days, those who did were discharged an average two days sooner. The study “draws needed attention to delirium,” which can cause problems when confused patients, for example, try to extricate themselves from the tubes and equipment needed to recover, said Lillian Kao, acute care surgery chief for McGovern Medical School at the University of Texas Health Science Center in Houston, who wasn’t involved with the study. Estimates of delirium’s prevalence vary widely, ranging from 13 percent to 50 percent among people who have non-heart surgery, according to an editorial accompanying the study, which appears in JAMA Surgery. © 1996-2017 The Washington Post

Keyword: Alzheimers; Attention
Link ID: 23674 - Posted: 05.29.2017

Jon Hamilton Impulsive children become thoughtful adults only after years of improvements to the brain's information highways, a team reports in Current Biology. A study of nearly 900 young people ages 8 to 22 found that the ability to control impulses, stay on task and make good decisions increased steadily over that span as the brain remodeled its information pathways to become more efficient. The finding helps explain why these abilities, known collectively as executive function, take so long to develop fully, says Danielle Bassett, an author of the study and an associate professor of bioengineering at the University of Pennsylvania. "A child's ability to run or to see is very well developed by the time they're 8," she says. "However, their ability to inhibit inappropriate responses is not something that's well developed until well into the 20s." The results also suggest it may be possible to identify adolescents at risk of problems related to poor executive function, says Joshua Gordon, director of the National Institute of Mental Health, which helped fund the study. These include "all kinds of disorders such as substance abuse, depression and schizophrenia," he says. The study is part of an effort to understand the brain changes underlying the development of executive function. It used a technology called diffusion imaging that reveals the fibers that make up the brain's information highways. © 2017 npr

Keyword: ADHD; Development of the Brain
Link ID: 23668 - Posted: 05.27.2017

By Julie Steenhuysen, U.S. deaths from Alzheimer's disease rose by more than 50 percent from 1999 to 2014, and rates are expected to continue to rise, reflecting the nation's aging population and increasing life expectancy, American researchers said on Thursday. In addition, a larger proportion of people with Alzheimer's are dying at home rather than a medical facility, according to the report released by the U.S. Centers for Disease Control and Prevention (CDC). Alzheimer’s is the sixth-leading cause of death in the United States, accounting for 3.6 percent of all deaths in 2014, the report said. Researchers have long predicted increased cases of Alzheimer's as more of the nation's baby boom generation passes the age of 65, putting them at higher risk for the age-related disease. The number of U.S. residents aged 65 and older living with Alzheimer's is expected to nearly triple to 13.8 million by 2050. There is no cure for Alzheimer's, a fatal brain disease that slowly robs its victims of the ability to think and care for themselves. According to the report by researchers at the CDC and Georgia State University, 93,541 people died from Alzheimer’s in the United States in 2014, a 54.5 percent increase compared with 1999. © 2017 Scientific American

Keyword: Alzheimers
Link ID: 23667 - Posted: 05.27.2017

By James Hendrix Having witnessed the success of combination therapy in HIV, cancer and heart disease, the time has come for Alzheimer’s disease. At meetings convened by the Alzheimer’s Association and others, a consensus is emerging that the most effective Alzheimer’s treatments may be those that attack the disease on multiple fronts. Looking back for a moment… In the 1980s, the world faced a new, unknown virus. HIV/AIDS was spreading virtually unchecked, devastating millions of lives and spurring lively scientific debate. Today, an HIV diagnosis is no longer a death sentence. AIDS-related deaths have fallen by 45 percent since their peak in 2005 according to UNAIDS, a United Nations program for global action against the spread of the virus. As researchers learned more about HIV, they developed new classes of antiviral medications—each attacking the virus in a unique way. Physicians eventually began prescribing two or more of these drugs together and emerging scientific evidence started revealing the most effective combinations. Today, a powerful three-drug antiviral “cocktail” is allowing people with HIV to live long lives. Advances in understanding the progression of Alzheimer’s point to a number of underlying biological processes involved in the development of the disease. By leveraging this knowledge, we now have a singular opportunity to pioneer new approaches against Alzheimer’s, including combination therapies. © 2017 Scientific American,

Keyword: Alzheimers
Link ID: 23655 - Posted: 05.24.2017

By Diana Kwon Age as a state of mind is not just the stuff of birthday card clichés. In recent years, scientists have plumbed the molecular depths of the body and surfaced with tell-tale biomarkers of aging, some of which extend to the brain. Now, researchers are harnessing another tool, neuroimaging, to measure the organ’s age, and using that to predict how long a person will live. “People are searching for the tree rings of humans,” James Cole, a research associate at Imperial College London, told The Scientist. Cole and his colleagues recently devised their own technique of predicting the biological age of people’s brains using a combination of machine learning and magnetic resonance imaging (MRI) scans. In a study published last month (April 25) in Molecular Psychiatry, the team reported that this technique was able to predict mortality in humans—people with “older” brains, they found, had greater risk of dying before age 80. To create this marker of brain aging, the researchers first trained a machine-learning algorithm to analyze structural brain scans from a healthy reference sample containing 2,001 individuals between 18 and 90 years old. Then, they used this tool to predict brain age in the Lothian Birth Cohort, a group of 669 adults, all born in 1936. Based on the algorithm’s assessment, individuals who had brains that were “older” than their actual, chronological age also tended to have an increased risk of dying sooner and lower performance on various fitness measures, such as lung function, walking speed, and fluid intelligence. © 1986-2017 The Scientist

Keyword: Development of the Brain; Alzheimers
Link ID: 23654 - Posted: 05.24.2017

Carl Zimmer In a significant advance in the study of mental ability, a team of European and American scientists announced on Monday that they had identified 52 genes linked to intelligence in nearly 80,000 people. These genes do not determine intelligence, however. Their combined influence is minuscule, the researchers said, suggesting that thousands more are likely to be involved and still await discovery. Just as important, intelligence is profoundly shaped by the environment. Still, the findings could make it possible to begin new experiments into the biological basis of reasoning and problem-solving, experts said. They could even help researchers determine which interventions would be most effective for children struggling to learn. “This represents an enormous success,” said Paige Harden, a psychologist at the University of Texas, who was not involved in the study. For over a century, psychologists have studied intelligence by asking people questions. Their exams have evolved into batteries of tests, each probing a different mental ability, such as verbal reasoning or memorization. In a typical test, the tasks might include imagining an object rotating, picking out a shape to complete a figure, and then pressing a button as fast as possible whenever a particular type of word appears. Each test-taker may get varying scores for different abilities. But over all, these scores tend to hang together — people who score low on one measure tend to score low on the others, and vice versa. Psychologists sometimes refer to this similarity as general intelligence. It’s still not clear what in the brain accounts for intelligence. Neuroscientists have compared the brains of people with high and low test scores for clues, and they’ve found a few. Brain size explains a small part of the variation, for example, although there are plenty of people with small brains who score higher than others with bigger brains. © 2017 The New York Times Company

Keyword: Intelligence; Genes & Behavior
Link ID: 23650 - Posted: 05.23.2017

By PERRI KLASS, M.D. Why do children wake up early when they are young but want to stay in bed till noon as teenagers? Experts say it’s biology. Adolescents’ bodies want to stay up late and sleep late, putting them out of sync with what their school schedules demand of them. So kids have trouble waking up, and they often find themselves feeling drowsy in morning algebra class. But that chronic sleepiness can affect their health and well-being, their behavior, and even their safety; it becomes genuinely dangerous when sleepy teenagers get behind the wheel. At a recent conference on adolescent sleep, health and school start times, at which I gave a brief keynote, several experts made compelling arguments supporting the idea that middle and high school start times should shift to 8:30 a.m. or later, as recommended by the American Academy of Pediatrics and the American Academy of Sleep Medicine. Brian Tefft, a senior researcher with the AAA Foundation for Traffic Safety, talked about “drowsy driving.” He cited an annual study that asks, “In the past 30 days how often have you driven when you were so tired that you had a hard time keeping your eyes open?” Over the past five years, on average, a quarter of the 16- to 18-year-old licensed drivers reported driving in that condition at least once, and 2 percent said fairly often or regularly. The argument is that teenagers who face very early school start times are at risk of regular sleep deprivation. Driving after sleeping only four to five hours a night is associated with a similar crash risk as driving with an alcohol level at the legal limit. Sleeping less than four hours puts you at the same risk as driving with double the legal alcohol limit. (This is not only true for adolescents, but for all of us.) Drowsy driving may not be the only risk that tired teenagers take. Wendy Troxel, a clinical psychologist and senior behavioral and social scientist at RAND, talked about the “adolescent health paradox,” that teenagers, who are in a developmental period of physical strength and resilience, face disproportionately high mortality rates. Unintentional injury (especially car crashes) is high on the list of causes, followed by homicide and suicide. © 2017 The New York Times Company

Keyword: Sleep; Development of the Brain
Link ID: 23648 - Posted: 05.23.2017

By Esther Landhuis On the heels of one failed drug trial after another, a recent study suggests people with early Alzheimer’s disease could reap modest benefits from a device that uses magnetic fields to produce small electric currents in the brain. Alzheimer’s is a degenerative brain disorder that afflicts more than 46 million people worldwide. At present there are no treatments that stop or slow its progression, although several approved drugs offer temporary relief from memory loss and other cognitive symptoms by preventing the breakdown of chemical messengers among nerve cells. The new study tested a regimen that combines computerized cognitive training with a procedure known as repetitive transcranial magnetic stimulation (rTMS). The U.S. Food and Drug Administration has cleared rTMS devices for some migraine sufferers as well as for people with depression who have not responded to antidepressant medications. Last month at the 13th International Conference on Alzheimer’s and Parkinson’s Diseases in Vienna, Israel-based Neuronix reported results of a phase III clinical trial of its therapy system, known as neuroAD, in Alzheimer’s patients. More than 99 percent of Alzheimer’s drug trials have failed. The last time a phase III trial for a wholly new treatment succeeded (not just a combination of two already approved drugs) was about 15 years ago. The recent study did not test a drug but rather a device, which usually has an easier time gaining FDA clearance. NeuroAD has been approved for use in Europe and the U.K., where six weeks of therapy costs about $6,700. The system is not commercially available in the U.S., but based on the latest results the company submitted an application for FDA clearance last fall. © 2017 Scientific American

Keyword: Alzheimers
Link ID: 23635 - Posted: 05.19.2017

Susan Milius The supermoms of the mammal world are big, shy redheads. Studying growth layers in orangutan teeth shows that mothers can nurse their youngsters for eight-plus years, a record for wild mammals. Teeth from a museum specimen of a young Bornean orangutan (Pongo pygmaeus) don’t show signs of weaning until 8.1 years of age. And a Sumatran orangutan (P. abelii) was still nursing during the few months before it was killed at 8.8 years, researchers report May 17 in Science Advances. Tests also show that youngsters periodically start to taper off their dependence on their mother’s milk and then, perhaps if solid food grows scarce, go back to what looks like an all-mom diet. Such on-again, off-again nursing cycles aren’t known in other wild mammals, says study coauthor Tanya Smith, an evolutionary anthropologist at Griffith University in Nathan, Australia. Marks of milk drinking Two images of a cross section of a first molar from a 4.5-year-old Bornean orangutan are shown. At left, numbers indicate days from birth (dotted line, starting with 0) when particular spots formed. At right, colors indicate concentrations of barium, which increase (shading toward red) when the youngster depended more on mother’s milk. A greenish swath at the top indicates nursing as an infant that gave way to blue as solid food became part of the diet. Yellow and red streaks indicate repeated times when the youngster again depended mostly on milk for nutrition. oragutan molar |© Society for Science & the Public 2000 - 2017.

Keyword: Sexual Behavior; Development of the Brain
Link ID: 23632 - Posted: 05.18.2017

Tina Hesman Saey Face-to-face, a human and a chimpanzee are easy to tell apart. The two species share a common primate ancestor, but over millions of years, their characteristics have morphed into easily distinguishable features. Chimps developed prominent brow ridges, flat noses, low-crowned heads and protruding muzzles. Human noses jut from relatively flat faces under high-domed crowns. Those facial features diverged with the help of genetic parasites, mobile bits of genetic material that insert themselves into their hosts’ DNA. These parasites go by many names, including “jumping genes,” “transposable elements” and “transposons.” Some are relics of former viruses assimilated into a host’s genome, or genetic instruction book. Others are self-perpetuating pieces of genetic material whose origins are shrouded in the mists of time. “Transposable elements have been with us since the beginning of evolution. Bacteria have transposable elements,” says evolutionary biologist Josefa González. She doesn’t think of transposons as foreign DNA. They are parts of our genomes — like genes. “You cannot understand the genome without understanding what transposable elements are doing,” says González, of the Institute of Evolutionary Biology in Barcelona. She studies how jumping genes have influenced fruit fly evolution. Genomes of most organisms are littered with the carcasses of transposons, says Cédric Feschotte, an evolutionary geneticist at the University of Utah in Salt Lake City. Fossils of the DNA parasites build up like the remains of ancient algae that formed the white cliffs of Dover. One strain of maize, the organism in which Nobel laureate Barbara McClintock first discovered transposable elements in the 1940s, is nearly 85 percent transposable elements (SN: 12/19/09, p. 9). Corn is an extreme example, but humans have plenty, too: Transposable elements make up nearly half of the human genome. |© Society for Science & the Public 2000 - 2017

Keyword: Development of the Brain; Genes & Behavior
Link ID: 23627 - Posted: 05.17.2017

By TAMAR LEWIN Nearly 40 years after the world was jolted by the birth of the first test-tube baby, a new revolution in reproductive technology is on the horizon — and it promises to be far more controversial than in vitro fertilization ever was. Within a decade or two, researchers say, scientists will likely be able to create a baby from human skin cells that have been coaxed to grow into eggs and sperm and used to create embryos to implant in a womb. The process, in vitro gametogenesis, or I.V.G., so far has been used only in mice. But stem cell biologists say it is only a matter of time before it could be used in human reproduction — opening up mind-boggling possibilities. With I.V.G., two men could have a baby that was biologically related to both of them, by using skin cells from one to make an egg that would be fertilized by sperm from the other. Women with fertility problems could have eggs made from their skin cells, rather than go through the lengthy and expensive process of stimulating their ovaries to retrieve their eggs. “It gives me an unsettled feeling because we don’t know what this could lead to,” said Paul Knoepfler, a stem cell researcher at the University of California, Davis. “You can imagine one man providing both the eggs and the sperm, almost like cloning himself. You can imagine that eggs becoming so easily available would lead to designer babies.” © 2017 The New York Times Company

Keyword: Stem Cells; Development of the Brain
Link ID: 23622 - Posted: 05.17.2017

Katherine Hobson American Indian and Alaska Native families are much more likely to have an infant die suddenly and unexpectedly, and that risk has remained higher than in other ethnic groups since public health efforts were launched to prevent sudden infant death syndrome in the 1990s. African-American babies also face a higher risk, a study finds. American Indians and Alaska Natives had a rate of 177.6 sudden unexplained infant deaths per 100,000 live births in 2013 (down from 237.5 per 100,000 in 1995) compared with 172.4 for non-Hispanic blacks (down from 203), 84.5 for non-Hispanic whites (down from 93), 49.3 for Hispanics (down from 62.7) and 28.3 for Asians and Pacific Islanders (down from 59.3). The declines were statistically significant only among non-Hispanic blacks, Hispanics and Asians/Pacific Islanders. "There are still significant gaps and disparities between races and ethnicities," says Lori Feldman-Winter, a professor of pediatrics at Cooper University Health Care in Camden, N.J., who wasn't involved with this study but was a co-author of the most recent sleep guidelines from the American Academy of Pediatrics, released in the fall. Overall rates of sudden unexpected infant death, which includes sudden infant death syndrome as well as accidental suffocation or strangulation in bed and other unexplained deaths, declined sharply in the five or so years after a national campaign was launched in 1994 to encourage caregivers to put babies to sleep on their backs. But the rates have not declined since 2000. Researchers at the Centers for Disease Control and Prevention wanted to know whether those changes were uniform across racial and ethnic groups. © 2017 npr

Keyword: Development of the Brain; Sleep
Link ID: 23616 - Posted: 05.16.2017

By Hannah Furfaro, Children whose fathers are highly intelligent are at a 31 percent higher risk of autism than those whose fathers are of average intelligence, according to unpublished results presented today at the 2017 International Meeting for Autism Research in San Francisco, California. The work supports observations that date back to the 1940s, when Leo Kanner and Hans Asperger noted in separate reports that the fathers of children with autism tended to be highly intelligent and in several cases worked in technical fields. A 2012 study also showed that children from regions in the Netherlands where high-tech jobs are prevalent are more likely to have autism than those who live in other regions. In the new study, lead investigator Renee Gardner, assistant professor at Karolinska Institutet in Stockholm, set out to investigate whether the historical lore has validity. She and her colleagues matched medical records for 309,803 children whose fathers were conscripted into the Swedish military with their father’s scores on the technical portion of the Swedish intelligence quotient (IQ) test. They found a one-third higher risk of autism in children whose fathers’ IQ scores are 111 or higher than in those whose fathers’ scores cluster around 100. The researchers controlled for possible confounding factors such as families’ socioeconomic status and parental age, education level and history of inpatient psychiatric treatment. IQ indicators: They found the opposite relationship between a father’s IQ and his child’s chances of having intellectual disability or attention deficit hyperactivity disorder (ADHD). In particular, children of men with an IQ of 75 or below had a four-and-a-half times higher risk of intellectual disability. The chance of ADHD was 65 percent higher than average for children whose fathers had an IQ in that low range. © 2017 Scientific American

Keyword: Autism; Intelligence
Link ID: 23614 - Posted: 05.15.2017

by Laura Sanders One of the most pressing and perplexing questions parents have to answer is what to do about screen time for little ones. Even scientists and doctors are stumped. That’s because no one knows how digital media such as smartphones, iPads and other screens affect children. The American Academy of Pediatrics recently put out guidelines, but that advice was based on a frustratingly slim body of scientific evidence, as I’ve covered. Scientists are just scratching the surface of how screen time might influence growing bodies and minds. Two recent studies point out how hard these answers are to get. But the studies also hint that the answers might be important. In the first study, Julia Ma at the University of Toronto and colleagues found that, in children younger than 2, the more time spent with a handheld screen, such as a smartphone or tablet, the more likely the child was to show signs of a speech delay. Ma presented the work May 6 at the 2017 Pediatric Academic Societies Meeting in San Francisco. The team used information gleaned from nearly 900 children’s 18-month checkups. Parents answered a questionnaire about their child’s mobile media use and then filled out a checklist designed to identify heightened risk of speech problems. This checklist is a screening tool that picks up potential signs of trouble; it doesn’t offer a diagnosis of a language delay, points out study coauthor Catherine Birken, a pediatrician at The Hospital for Sick Children in Toronto. Going into the study, the researchers didn’t have expectations about how many of these toddlers were using handheld screens. “We had very little clues, because there is almost no literature on the topic,” Birken says. “There’s just really not a lot there.” |© Society for Science & the Public 2000 - 2017

Keyword: Development of the Brain; Sleep
Link ID: 23608 - Posted: 05.13.2017

By Andy Coghlan Combining multiple tests could help doctors distinguish between two leading causes of cognitive decline at an earlier stage. Being able to separate the earliest signs of Alzheimer’s from another degenerative brain condition called dementia with Lewy bodies (DLB) could be crucial to finding treatments for both kinds of dementia. When someone starts to exhibit mild cognitive impairments, it is often difficult to tell whether these might be the earliest signs of Alzheimer’s or DLB, or just normal age-related declines in cognition. Yet this distinction is vital: so far, despite billions of dollars spent on research, progress towards drugs that stabilise or cure dementia has stalled. Many blame the failure on treating people too late and argue that the same drugs might work better if given a decade or two before symptoms fully develop. Now, Dilman Sadiq at University College London and her colleagues have attempted to rectify this problem by analysing clinical histories, the results of cognitive tests and psychiatric interviews with 429 people originally diagnosed with mild cognitive impairment, who were monitored for up to 14 years. Each person was diagnosed at one UK hospital between 1994 and 2015. Of this group, 107 progressed to Alzheimer’s, 21 to DLB and 164 remained stable with mild cognitive impairment. The rest developed a mixture of other conditions. Sadiq’s team used their findings to identify a variety of tests and symptom profiles that appear to predict which condition a person might get at the earliest stage of the disease. © Copyright New Scientist Ltd.

Keyword: Alzheimers
Link ID: 23607 - Posted: 05.13.2017

Amy Maxmen Cells that prune connections between neurons in babies’ brains as they grow are thought to have a role in autism spectrum disorder. Now, a study suggests that the number and behaviour of these cells — called microglia — vary in boys and girls, a finding that could help to explain why many more boys are diagnosed with autism and related disorders. Donna Werling, a neurogeneticist at the University of California, San Francisco, and her colleagues found that genes associated with microglia are more active in male brains than in female brains in the months before birth. “This suggests there is something fundamentally different about male and female brain development,” she says. The research, to be presented on 13 May at the International Meeting for Autism Research in San Francisco, California, is still preliminary. Very little is known about how microglial trimming behaviour affects brain development. But the study by Werling’s team “is the kind of work that makes you say ‘Wow, this is really interesting, and we should take it seriously’”, says Kevin Pelphrey, a neuroscientist at Yale School of Medicine in New Haven, Connecticut. There are two to five times many males with autism as females. Although the disorder — whose cause remains elusive — is widely acknowledged to be underdiagnosed in girls, psychiatrists agree that there is a significant disparity between the numbers of male and female cases. It suggests that biological differences between the sexes are involved. © 2017 Macmillan Publishers Limited,

Keyword: Autism; Glia
Link ID: 23605 - Posted: 05.12.2017

Ian Sample Science editor A landmark project to map the wiring of the human brain from womb to birth has released thousands of images that will help scientists unravel how conditions such as autism, cerebral palsy and attention deficit disorders arise in the brain. The first tranche of images come from 40 newborn babies who were scanned in their sleep to produce stunning high-resolution pictures of early brain anatomy and the intricate neural wiring that ferries some of the earliest signals around the organ. The initial batch of brain scans are intended to give researchers a first chance to analyse the data and provide feedback to the senior scientists at King’s College London, Oxford University and Imperial College London who are leading the Developing Human Connectome Project, which is funded by €15m (£12.5m) from the EU. The images show the intricate neural wiring that ferries some of the earliest signals around the brain. Hundreds of thousands more images will be released in the coming months and years. Most will come from a thousand sleeping babies, but another 500 have had their brains scanned while still in the womb. “The challenge is that you are imaging one person inside another person and both of them move,” said Jo Hajnal, professor of imaging science at King’s College London, who developed new MRI technology for the project. Taking brain scans of sleeping babies is hard enough. At the start of the project in 2013, more than 10% of the scans failed when babies woke up in the middle of the two to three hour procedure. Now the babies are fed and prepared for their scans at their mother’s side before they are carried to the scanner. To cut the odds of the babies waking, scientists tweaked the scanner software to stop it making sudden noises.

Keyword: Development of the Brain; Brain imaging
Link ID: 23599 - Posted: 05.10.2017

By Jane C. Hu New evidence suggests that the earliest traces of a language can stay with us into adulthood, even if we no longer speak or understand the language itself. And early exposure also seems to speed the process of relearning it later in life. In the new study, recently published in Royal Society Open Science, Dutch adults were trained to listen for sound contrasts in Korean. Some participants reported no prior exposure to the language; others were born in Korea and adopted by Dutch families before the age of six. All participants said they could not speak Korean, but the adoptees from Korea were better at distinguishing between the contrasts and more accurate in pronouncing Korean sounds. “Language learning can be retained subconsciously, even if conscious memories of the language do not exist,” says Jiyoun Choi, postdoctoral fellow at Hanyang University in Seoul and lead author of the study. And it appears that just a brief period of early exposure benefits learning efforts later; when Choi and her collaborators compared the results of people adopted before they were six months old with results of others adopted after 17 months, there were no differences in their hearing or speaking abilities. “It's exciting that these effects are seen even among adults who were exposed to Korean only up to six months of age—an age before which babbling emerges,” says Janet Werker, a professor of psychology at the University of British Columbia, who was not involved with the research. Remarkably, what we learn before we can even speak stays with us for decades. © 2017 Scientific American,

Keyword: Language; Development of the Brain
Link ID: 23598 - Posted: 05.10.2017

By Michael Price Unless you’re colorblind, you probably have a pretty good idea of what red, green, and blue are. Yet those labels are arbitrary divisions of the color spectrum; there’s no definitive point where the wavelengths of light we call orange turn into red. So cognitive scientists have long wondered whether we learn our labels from our culture or inherit them from our biology. Now, a study finds that infants see red, yellow, green, blue, and purple as different color categories, suggesting that at least some distinctions may be hardwired. “I find it really compelling,” says Michael Webster, a psychologist who studies visual perception at the University of Nevada in Reno, who wasn’t involved in the study. “This isn’t going to immediately change anyone’s mind. But it’s another piece in the puzzle, and it’s a very nice piece.” Scientists can’t just ask a newborn what it knows, so they use a trick known as “infant looking time” to figure out what’s in babies’ brains. The idea is that an infant’s gaze will linger on something unfamiliar for longer than something familiar, giving researchers a window into what babies expect—and what surprises them. Applying this to color research, scientists led by Anna Franklin, a perception and cognition researcher at the University of Sussex in the United Kingdom, showed 179 infants aged 46 months 14 different swaths of color, each from a different part of the color wheel. Researchers showed one swath several times before displaying a hue from the next range over. If the infants looked at the new hue longer than the previous one, experimenters concluded that the babies considered it a different color. © 2017 American Association for the Advancement of Science

Keyword: Vision; Development of the Brain
Link ID: 23596 - Posted: 05.09.2017

By Michael Le Page In some cultures, it’s traditional for elders to smoke grass, a practice said to help them pass on tribal knowledge. It turns out that they might just be onto something. Teenagers who toke perform less well on memory and attention tasks while under the influence. But low doses of the active ingredient in cannabis, THC, might have the opposite effect on the elderly, reversing brain ageing and restoring learning and memory – at least according to studies of mice. “We repeated these experiments many times,” says team leader Andreas Zimmer at the University of Bonn, Germany. “It’s a very robust and profound effect.” Zimmer’s team has been studying the mammalian endocannabinoid system, which is involved in balancing out our bodies’ response to stress. THC affects us by mimicking similar molecules in this system, calming us down. The researchers discovered that mice with genetic mutations that stop this endocannabinoid system from working properly age faster than normal mice, and show more cognitive decline. This made Zimmer wonder if stimulating the endocannabinoid system in elderly mice might have the opposite effect. To find out, the team gave young (2-month-old), middle-aged (12-month-old) and elderly (18-month-old) mice a steady dose of THC. The amount they received was too small to give them psychoactive effects. After a month, the team tested the mice’s ability to perform cognitive tasks, such as finding their way around mazes, or recognising other individuals. © Copyright Reed Business Information Ltd.

Keyword: Drug Abuse; Development of the Brain
Link ID: 23593 - Posted: 05.09.2017