Chapter 17. Learning and Memory

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By Anisha Kalidindi The room is pitch black. Every light, from the power button on the computer to the box controlling the microscope, is covered with electrical tape. I feel a gush of air as the high-powered AC kicks on, offsetting the heat emitted from the microscope’s lasers. I take my mouse out of its cage and get ready to image its brain. I’m wearing a red headlamp so I can see, but it is still quite dim. I peer closely at my lab notebook and note the two positions: –1, +2. I recite them repeatedly in a hushed tone, so I don’t forget; it is 1 A.M., after all. I hook the mouse up to the stage of the microscope and then use my handy toothpick to make sure its head position is correct. While there are many unsung heroes of science—veterinarians, lab technicians, graduate students (I might be a bit biased with this one!)—these aren’t the ones I’m talking about. I’m talking about a toothpick that played a significant role in my research project. Advertisement I am lucky enough to have access to a cutting-edge microscope and several other pieces of expensive equipment in my lab. But can also find things you might never guess were used in science: red-light headlamps, black electrical tape, and toothpicks. Using the microscope, I can take a picture of a mouse’s living, working brain through a literal window: a piece of glass that replaces a small piece of the animal’s skull. To image the mouse, we affix a plastic bar on the front of its head and then secure the bar to a head-mounting device on the stage under the microscope lens. Using this mount, we can precisely position the head up and down and right to left. This is where our problem starts. © 2019 Scientific American

Keyword: Learning & Memory
Link ID: 26877 - Posted: 12.06.2019

By Aimee Cunningham Socially isolated and faced with a persistently white polar landscape, a long-term crew of an Antarctic research station saw a portion of their brains shrink during their stay, a small study finds. “It’s very exciting to see the white desert at the beginning,” says physiologist Alexander Stahn, who began the research while at Charité-Universitätsmedizin Berlin. “But then it’s always the same.” The crew of eight scientists and researchers and a cook lived and worked at the German research station Neumayer III for 14 months. Although joined by other scientists during the summer, the crew alone endured the long darkness of the polar winter, when temperatures can plummet as low as –50° Celsius and evacuation is impossible. That social isolation and monotonous environment is the closest thing on Earth to what a space explorer on a long mission may experience, says Stahn, who is interested in researching what effect such travel would have on the brain. Animal studies have revealed that similar conditions can harm the hippocampus, a brain area crucial for memory and navigation (SN: 11/6/18). For example, rats are better at learning when the animals are housed with companions or in an enriched environment than when alone or in a bare cage, Stahn says. But whether this is true for a person’s brain is unknown. Stahn, now at the Perelman School of Medicine at the University of Pennsylvania, and his colleagues used magnetic resonance imaging to capture views of the team members’ brains before their polar stay and after their return. On average, an area of the hippocampus in the crew’s brains shrank by 7 percent over the course of the expedition, compared with healthy people matched for age and gender who didn’t stay at the station, the researchers report online December 4 in the New England Journal of Medicine. © Society for Science & the Public 2000–2019

Keyword: Learning & Memory; Biological Rhythms
Link ID: 26874 - Posted: 12.05.2019

Ian Sample Science editor Scientists have created artificial neurons that could potentially be implanted into patients to overcome paralysis, restore failing brain circuits, and even connect their minds to machines. The bionic neurons can receive electrical signals from healthy nerve cells, and process them in a natural way, before sending fresh signals on to other neurons, or to muscles and organs elsewhere in the body. One of the first applications may be a treatment for a form of heart failure that develops when a particular neural circuit at the base of the brain deteriorates through age or disease and fails to send the right signals to make the heart pump properly. Rather than implanting directly into the brain, the artificial neurons are built into ultra-low power microchips a few millimetres wide. The chips form the basis for devices that would plug straight into the nervous system, for example by intercepting signals that pass between the brain and leg muscles. “Any area where you have some degenerative disease, such as Alzheimer’s, or where the neurons stop firing properly because of age, disease, or injury, then in theory you could replace the faulty biocircuit with a synthetic circuit,” said Alain Nogaret, a physicist who led the project at the University of Bath. The breakthrough came when researchers found they could model live neurons in a computer program and then recreate their firing patterns in silicon chips with more than 94% accuracy. The program allows the scientists to mimic the full variety of neurons found in the nervous system. © 2019 Guardian News & Media Limited

Keyword: Robotics; Learning & Memory
Link ID: 26872 - Posted: 12.04.2019

By Gaby Maimon What is the biological basis of thought? How do brains store memories? Questions like these have intrigued humanity for millennia, but the answers still remain largely elusive. You might think that the humble fruit fly, Drosophila melanogaster, has little to add here, but since the 1970s, scientists have actually been studying the neural basis of higher brain functions, like memory, in these insects. Classic work––performed by several labs, including those of Martin Heisenberg and Seymour Benzer––focused on studying the behavior of wild-type and genetically mutated Drosophila in simple learning and memory tasks, ultimately leading to the discovery of several key molecules and other underlying mechanisms. However, because one could not peer into the brain of behaving flies to eavesdrop on neurons in action, this field, in its original form, could only go so far in helping to explain the mechanisms of cognition. In 2010, when I was a postdoctoral researcher in the lab of Michael Dickinson, we developed the first method for measuring electrical activity of neurons in behaving Drosophila. A similar method was developed in parallel by Johannes Seelig and Vivek Jayaraman. In these approaches, one glues a fly to a custom plate that allows one to carefully remove the cuticle over the brain and measure neural activity via electrodes or fluorescence microscopy. Even though the fly is glued in place, the animal can still flap her wings in tethered flight or walk on an air-cushioned ball, which acts like a spherical treadmill beneath her legs. These technical achievements attracted the attention of the Drosophila neurobiology community, but should anyone really care about seeing a fly brain in action beyond this small, venerable, group of arthropod-loving nerds (of which I'm honored to be a member)? In other words, will these methods help to reveal anything of general relevance beyond flies? Increasingly, the answer looks to be yes. © 2019 Scientific American

Keyword: Learning & Memory
Link ID: 26871 - Posted: 12.04.2019

By Lisa Sanders, M.D “Where am I?” the 68-year-old man asked. His daughter explained again: He was at Yale-New Haven Hospital in Connecticut. He had been found on the ground in the parking lot of the grocery store near his apartment. The man nodded, as if taking it all in, but minutes later asked again: Where am I? He had never had any memory issues before, but now he couldn’t remember that it was Saturday. Didn’t remember that he spent the morning moving the last of the boxes he had stored at his daughter’s house to his new apartment. He didn’t even remember that he had spent the past few months hashing out a pretty messy divorce. His soon-to-be ex-wife was also in the E.R., and again and again he asked her: Are we really getting divorced? Why? What happened? Earlier that day, his daughter received a call from the hospital saying that her father had fallen outside the supermarket and was brought in by an ambulance called by a good Samaritan. No one could tell her any more than that, and her father clearly didn’t remember. He had a scrape on his right cheek and over his eye, but otherwise he seemed fine. Except he couldn’t remember the events of the recent past. When asked his name and address, he responded promptly, but the address he gave was the house he shared for many years with his future ex-wife. He seemed stunned to find out he no longer lived there. The doctor in the E.R. was also surprised by the extent of the man’s memory loss. He seemed to have lost both his retrograde memory, recall of the events of the recent past, and his anterograde memory, the ability to form new memories from the present. But on examination, everything else seemed basically normal — except that his blood pressure was high, and he had the scrapes on his face. There was no sign of infection. His kidneys and liver seemed to be working just fine. A head CT scan showed no injuries to the bones of the face, the spinal cord in the neck or the brain. There was no trace of alcohol or drugs in his system. After a few hours, the man’s memory was still not functioning properly, and he was admitted to the hospital. © 2019 The New York Times Company

Keyword: Learning & Memory
Link ID: 26854 - Posted: 11.26.2019

By Tina Hesman Saey Picking embryos based on genetics might not give prospective parents the “designer baby” they’re after. DNA predictions of height or IQ might help would-be parents select an embryo that would grow into a child who is, at most, only about three centimeters taller or about three IQ points smarter than an average embryo from the couple, researchers report November 21 in Cell. But offspring predicted by their DNA to be the tallest among siblings were actually the tallest in only seven of 28 real families, the study found. And in five of those families, the child predicted to be tallest was actually shorter than the average for the family. Even if it were ethical to select embryos based on genetic propensity for height or intelligence, “the impact of doing so is likely to be modest — so modest that it’s not likely to be practically worth it,” says Amit Khera, a physician and geneticist at the Center for Genomics Medicine at Massachusetts General Hospital in Boston who was not involved in the new study. For years, couples have been able to use genetic diagnosis to screen out embryos carrying a disease-causing DNA variant. The procedure, called preimplantation genetic diagnosis, or PGD, involves creating embryos through in vitro fertilization. Clinic staff remove a single cell from the embryo and test its DNA for genetic variants that cause cystic fibrosis, Tay-Sachs or other life-threatening diseases caused by defects in single genes. © Society for Science & the Public 2000–2019

Keyword: Genes & Behavior; Intelligence
Link ID: 26847 - Posted: 11.23.2019

By Veronique Greenwood A few years back, Ryan Herbison, then a graduate student in parasitology at the University of Otago, painstakingly collected about 1,300 earwigs and more than 2,500 sandhoppers from gardens and a beach in New Zealand. Then, he dissected and examined the insides of their heads. This macabre scavenger hunt was in search of worms that lay coiled within some of the insects. The worms are parasites that force earwigs and sandhoppers to march into bodies of water, drowning themselves so the worms’ aquatic offspring can thrive. “Like a back-seat driver, but a bit more sinister,” said Mr. Herbison, describing these mind-controlling parasites. “And sometimes they may just grab the steering wheel.” Just how they do that, though, has remained a bit of a mystery. But in a paper published Wednesday in Proceedings of the Royal Society B, Mr. Herbison and fellow researchers reported that the parasites seemed to be manipulating the production of host proteins involved in generating energy and movement in their unfortunate hosts. The analysis is limited, but the researchers speculated that the parasites may be affecting neuronal connections in the bugs’ brains and perhaps even interfering with memory in a way that puts the hosts at risk. Parasites use a variety of similar strategies. Some make cat urine suicidally attractive to mice, which are promptly eaten so that the parasites can go through the next phase of their life cycle in the cat. Others prompt ants to expose themselves on high tree branches, the better to be eaten by birds. And still others cause snails to hang out in open spaces, with swollen eyestalks pulsing like neon signs, for apparently the same reason. © 2019 The New York Times Company

Keyword: Learning & Memory; Evolution
Link ID: 26845 - Posted: 11.22.2019

Ruth Williams After copulation, Drosophila melanogaster females are able to create long-term memories of unpleasant events—electric shocks—that virgin females cannot, according to a study published today in Science Advances (November 20). The authors suspect the memory boost may improve the chance of survival of the female during the subsequent egg-laying period as well as guide her choice of laying sites. Whatever the reason, the enhanced memory joins a list of physiological and behavioral effects on female flies that result from sex. “It’s quite impressive and convincing [data],” says entomologist Elwyn Isaac of the University of Leeds who was not involved in the research. “They propose that the sex peptide gets into the [female’s] circulation and somehow gets across the blood brain barrier [to activate memory].” It’s “very interesting,” Isaac continues, because until now, sex peptide—a protein produced in the male reproductive system and found in ejaculate—was thought to act on sensory neurons in the female’s uterus. These neurons produce a receptor protein to which sex peptide binds and are thought to be necessary for the peptide’s many effects on females, which include ramping up ovulation, increasing egg-laying behavior, changing food preference to a high-protein diet, and causing the female to reject other males. But, the authors of the new study, “show definitely that those neurons are not required for this [long-term memory] effect,” Isaac says. Indeed, deletion of the receptor in these neurons made no difference to the flies’ long-term memory formation after sex. © 1986–2019 The Scientist

Keyword: Learning & Memory; Sexual Behavior
Link ID: 26843 - Posted: 11.22.2019

By R. Douglas Fields Neuroscientists have always presumed that learning and memory depend on strengthening or weakening the connection points between neurons (synapses), increasing or decreasing the likelihood that the cell is going to pass along a message to its neighbor. But recently some researchers have started pursuing a completely different theory that does not involve changing the strength of synaptic transmission; in fact, it does not even involve neurons. Instead other types of brain cells, called glia, are responsible. A new study from the University of Toronto, published on-line this week in the journal Neuron furnishes support for this theory. It provides evidence that the basic act of learning whether one’s environs are safe or not, a behavior common to all animals, depends on glial cells that form the fatty sheath called myelin—electrical insulation that covers nerve fibers. The new theory postulates that establishing indelible memories that can be recalled long after sensory input or training on a task involves an interaction between glia and peculiar brain waves produced during sleep. “The role of myelin in cognitive functions has been largely neglected, an omission elegantly rectified by this paper,” says myelin researcher Bernard Zalc, at the Sorbonne Université in Paris, commenting on this new study. Traditionally researchers who study the myelin insulation on nerve fibers, called axons, have focused on diseases, such as multiple sclerosis, in which the fatty sheath is damaged. In multiple sclerosis, neural transmission fails, causing wide-ranging disabilities. Much like the plastic coating on a copper wire, myelin was understood to be vital for neural transmission but inert and irrelevant to information processing and memory storage. © 2019 Scientific American

Keyword: Learning & Memory
Link ID: 26832 - Posted: 11.19.2019

By Gary Stix Socrates famously railed against the evils of writing. The sage warned that it would “introduce forgetfulness into the soul of those who learn it: they will not practice using their memory because they will put their trust in writing.” He got a few things wrong. For one, people nurture Socrates’ memory because of all of the books written about him. But he also was off the mark in his musings about a forgetfulness of the soul. If anything, it appears that just the opposite holds: a study of hundreds of illiterate people living at the northern end of an island considered to be a world media capital roundly contradicts the father of Western philosophy. Evaluations of the elderly in the environs of Manhattan’s Washington Heights (the neighborhood immortalized by a Lin-Manuel Miranda musical) reveal that the very act of reading or writing—largely apart from any formal education—may help protect against the forgetfulness of dementia. “The people who were illiterate in the study developed dementia at an earlier age than people who were literate in the study,” says Jennifer J. Manly, senior author of the paper, which appeared on November 13in Neurology. Earlier studies trying to parse this topic had not been able to disentangle the role of reading and writing from schooling to determine whether literacy, by itself, could be a pivotal factor safeguarding people against dementia later in life. The researchers conducting the new study, who are mostly at Columbia University’s Vagelos College of Physicians and Surgeons, recruited 983 people with four years or less of schooling who were part of the renowned Washington Heights–Inwood Columbia Community Aging Project. Of that group, 238 were illiterate, which was determined by asking the participants point-blank, “Did you ever learn to read or write?”—followed by reading tests administered to a subsample. Even without much time in school, study subjects sometimes learned from other family members. © 2019 Scientific American

Keyword: Alzheimers; Language
Link ID: 26819 - Posted: 11.14.2019

By Karinna Hurley Part of the Museum of Natural History in Paris, the Jardin des Plantes, on the left bank of the Seine River, hosts a collection of galleries and gardens. A couple of miles away, the larger museum also includes the Museum of Mankind, which is, in part, an exploration of what it means to be human. There, like in many other museums worldwide, you can view a collection of stone tools used by the earliest humans. Tool use was long believed to be unique to our species—a defining feature, like language. Utilizing objects to achieve goals is not just a demonstration of advanced cognitive capabilities; it is largely through our symbolic and material tools that we share and transmit culture. In 1960 primatologist Jane Goodall observed wild chimpanzees making and using tools. A connection between humans and other animals, in how we think and learn, was captivating news. Since then, scientists have gone on to establish tool use in a relatively small number of other species. And observations of learning to use a tool from other group members, rather than instinctively, have been even more rare—until now. The Jardin des Plantes is also home to a special couple, Priscilla and Billie. Along with at least one of their daughters, these Visayan warty pigs—residents of the garden’s zoo—are the first in any pig species to be identified using tools and, even more remarkably, to apparently transmit this behavior through social learning. The discovery was made by chance by ecologist Meredith Root-Bernstein, who was watching the family from outside its enclosure. Priscilla, working on building a nest, picked up a piece of bark in her mouth and used it to aid her digging. For six weeks Root-Bernstein frequently returned to the zoo to try to again catch her in the act. Although she didn’t do so, she did notice the digging tool moved among different areas of the enclosure and always near a recently constructed nest. © 2019 Scientific American

Keyword: Evolution; Intelligence
Link ID: 26817 - Posted: 11.14.2019

Jon Hamilton There's new evidence that girls start out with the same math abilities as boys. A study of 104 children from ages 3 to 10 found similar patterns of brain activity in boys and girls as they engaged in basic math tasks, researchers reported Friday in the journal Science of Learning. "They are indistinguishable," says Jessica Cantlon, an author of the study and professor of developmental neuroscience at Carnegie Mellon University. The finding challenges the idea that more boys than girls end up in STEM fields (science, technology, engineering, and mathematics) because they are inherently better at the sort of thinking those fields require. It also backs other studies that found similar math abilities in males and females early in life. "The results of this study are not too surprising because typically we don't see sex differences at the ages assessed in this study or for the types of math tasks they did, which were fairly simple," says David Geary, a psychologist and curator's distinguished professor at the University of Missouri who was not involved in the research. But there is evidence of sex differences in some exceptional older students, Geary says. For example, boys outnumber girls by about three to one when researchers identify adolescents who achieve "very, very high-end performance in mathematics," Geary says, adding that scientists are still trying to understand why that gap exists. © 2019 npr

Keyword: Sexual Behavior; Learning & Memory
Link ID: 26803 - Posted: 11.08.2019

By Sara Manning Peskin, M.D. At 66, Bob Karger was losing language. It was not the tip-of-the-tongue feeling that melts when you recall a sought-after word. He had lost the connection between sounds and meaning — the way ba-na-na recalls a soft, yellow fruit or ea-gle calls to mind a large bird of prey. In a recent conversation, he had thought acorns grew on pine trees. Mr. Karger did not know how to use items around the house, either. When he picked up a can opener, he would not realize it could remove the top from a tin. If he held a hammer, he might grasp it by the head, turning it around in his palm, not knowing he could swing it into a nail. His world was filled with incomprehensible items. His wife, Sandy Karger, noticed other changes. When she told her husband about a family member who died, Mr. Karger laughed instead of comforting her. He tipped excessively, slipping $20 bills to strangers, because they reminded him of close friends. He fixated on obese people. “Look at that person, they’re really fat,” he would say loudly, in public. Overcome by impatience, he would push people ahead of him in line at the store. “Can’t you hurry up?” he’d yell. “Do you really need to buy that?” In other ways, Mr. Karger’s mind was as sharp as it had ever been. He could remember upcoming appointments and recent dinners. He didn’t repeat himself in conversation. His long-term memory was at times better than Ms. Karger’s. After two years of worsening symptoms, the Kargers found Dr. Murray Grossman at the University of Pennsylvania. Dr. Grossman is short and charismatic, a quick-witted Montreal native who has mentored me since I began training in neurology. For the past several decades, he has pioneered research on neurodegenerative diseases that change behavior and language. When he saw Mr. Karger in 2007, the diagnosis was clear within the hour: Mr. Karger had a type of frontotemporal dementia. © 2019 The New York Times Company

Keyword: Alzheimers; Learning & Memory
Link ID: 26799 - Posted: 11.07.2019

By David Z. Hambrick, Daisuke S. Katsumata Disagreements are virtually inevitable in a romantic relationship. More than 90 percent of couples argue, according to a survey by the University of Michigan’s Institute for Social Research, with nearly half quarreling at least once a month. Common topics of marital disagreement are money, sex and time spent together. None of this will surprise anyone who has been in a long-term relationship. But a new study indicates that a cognitive ability may help to explain why some couples are more successful in resolving their differences. University of North Carolina Greensboro psychologist Levi Baker and his colleagues report that spouses who were high in working memory capacity had better memory for each other’s statements in discussions about problems. In turn, these couples showed greater progress in resolving their problems over time. The study suggests that it’s not just dogged commitment that gets couples through rough spots, but a cognitive factor that directly affects the quality of partners’ communication with each other. The sample included 101 couples (93 heterosexual, 7 lesbian and 1 gay) that had been married for less than three months. Working individually, the newlyweds first completed tests of working memory capacity, which is the ability to hold information in the focus of attention over a short period, as when following what someone is saying to you in a conversation. In one of the tests used by Baker and his colleagues, called “operation span,” the test-taker sees an arithmetic problem on the screen and attempts to solve it, after which a letter appears. After some number of these trials, the person is prompted to recall the letters in the order in which they were presented. © 2019 Scientific American

Keyword: Learning & Memory; Intelligence
Link ID: 26790 - Posted: 11.05.2019

By Christoph Droesser In 2004, a paper appeared in the journal Psychological Science, titled “Music Lessons Enhance IQ.” The author, composer and University of Toronto Mississauga psychologist Glenn Schellenberg, had conducted an experiment with 144 children randomly assigned to four groups: one learned the keyboard for a year, one took singing lessons, one joined an acting class, and a control group had no extracurricular training. The IQ of the children in the two musical groups rose by an average of seven points in the course of a year; those in the other two groups gained an average of 4.3 points. Schellenberg had long been skeptical of the science underpinning claims that music education enhances children’s abstract reasoning, math, or language skills. If children who play the piano are smarter, he says, it doesn’t necessarily mean they are smarter because they play the piano. It could be that the youngsters who play the piano also happen to be more ambitious or better at focusing on a task. Correlation, after all, does not prove causation. The 2004 paper was specifically designed to address those concerns. And as a passionate musician, Schellenberg was delighted when he turned up credible evidence that music has transfer effects on general intelligence. But nearly a decade later, in 2013, the Education Endowment Foundation funded a bigger study with more than 900 students. That study failed to corroborate Schellenberg’s findings, finding no evidence that music lessons improved math and literacy skills.

Keyword: Learning & Memory; Intelligence
Link ID: 26788 - Posted: 11.04.2019

Specialized brain activation “replays” the possible routes that rats can take as they navigate a space, helping them keep track of the paths they’ve already taken and choose among the routes that they can take next, according to a National Institutes of Health-funded study published in the journal Neuron. “These findings reveal an internal ‘replay’ process in the brain that allows animals to learn from past experiences to form memories of paths leading toward goals, and subsequently to recall these paths for planning future decisions,” said Shantanu Jadhav, Ph.D., assistant professor at Brandeis University, Waltham, Massachusetts, and senior author of the study. “These results help us better understand how coordinated activation at the level of neurons can contribute to the complex processes involved in learning and decision-making.” The hippocampus, a structure located in the middle of the brain, is critical to learning and memory and contains specialized “place” cells that relay information about location and orientation in space. These place cells show specific patterns of activity during navigation that can be “replayed” later in forward or reverse order, almost as if the brain were fast-forwarding or rewinding through routes the rats have taken. In previous research, Jadhav and colleagues had discovered these replay events, marked by bursts of neural activity called sharp-wave ripples, lead to coordinated activity in the hippocampus and the prefrontal cortex, an area of the brain just behind the forehead that is involved in decision-making.

Keyword: Learning & Memory
Link ID: 26775 - Posted: 10.31.2019

By Zeynep Tufekci More than a billion people around the world have smartphones, almost all of which come with some kind of navigation app such as Google or Apple Maps or Waze. This raises the age-old question we encounter with any technology: What skills are we losing? But also, crucially: What capabilities are we gaining? Talking with people who are good at finding their way around or adept at using paper maps, I often hear a lot of frustration with digital maps. North/south orientation gets messed up, and you can see only a small section at a time. And unlike with paper maps, one loses a lot of detail after zooming out. I can see all that and sympathize that it may be quite frustrating for the already skilled to be confined to a small phone screen. (Although map apps aren’t really meant to be replacements for paper maps, which appeal to our eyes, but are actually designed to be heard: “Turn left in 200 feet. Your destination will be on the right.”) But consider what digital navigation aids have meant for someone like me. Despite being a frequent traveler, I’m so terrible at finding my way that I still use Google Maps almost every day in the small town where I have lived for many years. What looks like an inferior product to some has been a significant expansion of my own capabilities. I’d even call it life-changing. Part of the problem is that reading paper maps requires a specific skill set. There is nothing natural about them. In many developed nations, including the U.S., one expects street names and house numbers to be meaningful referents, and instructions such as “go north for three blocks and then west” make sense to those familiar with these conventions. In Istanbul, in contrast, where I grew up, none of those hold true. For one thing, the locals rarely use street names. Why bother when a government or a military coup might change them—again. House and apartment numbers often aren’t sequential either because after buildings 1, 2 and 3 were built, someone squeezed in another house between 1 and 2, and now that’s 4. But then 5 will maybe get built after 3, and 6 will be between 2 and 3. Good luck with 1, 4, 2, 6, 5, and so on, sometimes into the hundreds, in jumbled order. Besides, the city is full of winding, ancient alleys that intersect with newer avenues at many angles. © 2019 Scientific American

Keyword: Attention; Learning & Memory
Link ID: 26768 - Posted: 10.30.2019

Pien Huang Alexandra Chen was a trauma specialist working in Lebanon and Jordan when she noticed that a specific group of kids were struggling in schools. Chen kept getting referrals for refugee students who had fled the war in Syria. They were having trouble focusing and finishing schoolwork. Some had even dropped out of school. She wondered to what extent the different stressors they faced — exposure to violence in Syria, lack of resources or concerns for the future — affected how they navigate their daily lives. Specifically, she wondered, which had a bigger impact: past trauma or the poverty they now lived in? Experts she wrote to said they didn't know and advised her to investigate the question herself. Chen, who's now getting her Ph.D. at Harvard, worked with a team to devise a study that aimed to untangle the threads of poverty, trauma and other adversities. They studied 240 teen Syrian refugees, comparing them with a group of 210 Jordanian youth who were also considered at-risk but didn't have a background of war. The researchers gave the teenagers surveys to gauge trauma and insecurity. To determine poverty, they asked the teens whether their families had items such as bedframes, cars, TVs, smartphones, refrigerators and water heaters. © 2019 npr

Keyword: Learning & Memory; Stress
Link ID: 26762 - Posted: 10.29.2019

By Jocelyn Kaiser HOUSTON, TEXAS—Two years ago, news headlines began to appear about a development that made many human geneticists uneasy. A U.S. company planned to offer a test for embryos created through in vitro fertilization (IVF) that screened the entire genome for DNA variants linked to cognitive ability, in order to help couples avoid having children with intellectual impairment. Many ethicists fear such multigene analyses could one day be used to screen embryos for desirable traits as well, such as tall stature or high IQ. For those disturbed by the prospect, a study reported here last week at the annual meeting of the American Society of Human Genetics (ASHG) may come as a relief: For now, the strategy would not work very well. Researchers, led by statistical geneticist Shai Carmi of the Hebrew University of Jerusalem, calculated exactly how much of a boost in IQ or height could be expected by scanning for relevant DNA markers in a batch of embryos and choosing those with the highest scores. The result: The gains would be slight, and prospective parents might even end up discarding their tallest or smartest potential offspring. The work "is the first to empirically test the viability of screening embryos" for traits that are influenced by many genes, says sociologist and demographer Melinda Mills of the University of Oxford in the United Kingdom. Such embryo screening goes beyond today's testing for single-gene disorders and currently "isn't plausible," she concludes. © 2019 American Association for the Advancement of Science.

Keyword: Intelligence; Genes & Behavior
Link ID: 26753 - Posted: 10.25.2019

By Veronique Greenwood To the rippling sound of an aquarium pump, a small crab comes around the corner. It moves sideways, sticking close to the walls. But when it catches sight of a mussel — laid as a reward at the end of the maze it has just walked — the crab breaks into a skipping run, throwing itself on the treat with abandon. This crustacean, one of many shore crabs scooped by researchers from under a pier in Swansea, Wales, had just completed an intriguing feat: Without any guidance from researchers, it found its way to the end of a small maze. According to a paper in Biology Letters on Wednesday, shore crabs can learn to navigate a lab-rat-style maze and remember it weeks later. While crabs that have never seen the maze before bump around aimlessly, experienced crabs race to the finish line with no wrong turns. The study, one of the few to look at whether crustaceans can perform such feats, suggests that crabs are quite capable of remembering routes. Maze running could also be a way to measure the effects of changes in the sea, like ocean acidification and warming, on crabs’ cognitive abilities. Crabs often clamber through complex landscapes in their daily lives, says Edward Pope, a marine biologist at Swansea University who is an author of the new study. So, it is not particularly surprising that crabs would be able to find their way through a maze and even be able to remember it later. What was surprising, however, was just how clear the results of the study were. During the first week of the experiment, no crabs got to the end of the maze without taking wrong turns, some of them detouring six or seven times. By week four, some could race to the end flawlessly. Even the worst-performing crab took no more than three wrong turns. To see how the crabs would perform when there was no food in the maze, and thus no trace in the water of a snack to guide them, the researchers waited a couple of weeks and put the crabs back in the maze. They also tested crabs that had never seen the maze. “The conditioned animals all ran to the end of the maze expecting there to be food,” Dr. Pope said. © 2019 The New York Times Company

Keyword: Learning & Memory; Evolution
Link ID: 26751 - Posted: 10.25.2019