Links for Keyword: Learning & Memory

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Diana Kwon As Earth rotates around its axis, the organisms that inhabit its surface are exposed to daily cycles of darkness and light. In animals, light has a powerful influence on sleep, hormone release, and metabolism. Work by Takaomi Sakai, a neuroscientist at Tokyo Metropolitan University, and his team suggests that light may also be crucial for forming and maintaining long-term memories. The puzzle of how memories persist in the brain has long been of interest to Sakai. Researchers had previously demonstrated, in both rodents and flies, that the production of new proteins is necessary for maintaining long-term memories, but Sakai wondered how this process persisted over several days given cells’ molecular turnover. Maybe, he thought, an environmental stimulus, such as the light-dark cycles, periodically triggered protein production to enable memory formation and storage. Sakai and his colleagues conducted a series of experiments to see how constant darkness would affect the ability of Drosophila melanogaster to form long-term memories. Male flies exposed to light after interacting with an unreceptive female showed reduced courtship behaviors toward new female mates several days later, indicating they had remembered the initial rejection. Flies kept in constant darkness, however, continued their attempts to copulate. The team then probed the molecular mechanisms of these behaviors and discovered a pathway by which light activates cAMP response element-binding protein (CREB)—a transcription factor previously identified as important for forming long-term memories—within certain neurons found in the mushroom bodies, the memory center in fly brains. © 1986–2020 The Scientist.

Related chapters from BN: Chapter 17: Learning and Memory; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 10: Biological Rhythms and Sleep
Link ID: 27248 - Posted: 05.16.2020

Ashley Yeager Nearly seven years ago, Sheena Josselyn and her husband Paul Frankland were talking with their two-year-old daughter and started to wonder why she could easily remember what happened over the last day or two but couldn’t recall events that had happened a few months before. Josselyn and Frankland, both neuroscientists at the Hospital for Sick Children Research Institute in Toronto, suspected that maybe neurogenesis, the creation of new neurons, could be involved in this sort of forgetfulness. In humans and other mammals, neurogenesis happens in the hippocampus, a region of the brain involved in learning and memory, tying the generation of new neurons to the process of making memories. Josselyn and Frankland knew that in infancy, the brain makes a lot of new neurons, but that neurogenesis slows with age. Yet youngsters have more trouble making long-term memories than adults do, a notion that doesn’t quite jibe with the idea that the principal function of neurogenesis is memory formation. To test the connection between neurogenesis and forgetting, the researchers put mice in a box and shocked their feet with an electric current, then returned the animals to their home cages and either let them stay sedentary or had them run on a wheel, an activity that boosts neurogenesis. Six weeks later, the researchers put the mice back in the box where they had received the shocks. There, the sedentary mice froze in fear, anticipating a shock, but the mice that had run on a wheel didn’t show signs of anxiety. It was as if the wheel-running mice had forgotten they’d been shocked before. © 1986–2020 The Scientist.

Related chapters from BN: Chapter 17: Learning and Memory; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 11: Emotions, Aggression, and Stress
Link ID: 27245 - Posted: 05.14.2020

Catherine Offord No matter how he looked at the data, Albert Tsao couldn’t see a pattern. Over several weeks in 2007 and again in 2008, the 19-year-old undergrad trained rats to explore a small trial arena, chucking them pieces of tasty chocolate cereal by way of encouragement. He then recorded the activity of individual neurons in the animals’ brains as they scampered, one at a time, about that same arena. He hoped that the experiment would offer clues as to how the rats’ brains were forming memories, but “the data that it gave us was confusing,” he says. There wasn’t any obvious pattern to the animals’ neural output at all. Then enrolled at Harvey Mudd College in California, Tsao was doing the project as part of a summer internship at the Kavli Institute for Systems Neuroscience in Norway, in a lab that focused on episodic memory—the type of long-term memory that allows humans and other mammals to recall personal experiences (or episodes), such as going on a first date or spending several minutes searching for chocolate. Neuroscientists suspected that the brain organizes these millions of episodes partly according to where they took place. The Kavli Institute’s Edvard Moser and May-Britt Moser had recently made a breakthrough with the discovery of “grid cells,” neurons that generate a virtual spatial map of an area, firing whenever the animal crosses the part of the map that that cell represents. These cells, the Mosers reported, were situated in a region of rats’ brains called the medial entorhinal cortex (MEC) that projects many of its neurons into the hippocampus, the center of episodic memory formation. Inspired by the findings, Tsao had opted to study a region right next to the MEC called the lateral entorhinal cortex (LEC), which also feeds into the hippocampus. © 1986–2020 The Scientist

Related chapters from BN: Chapter 17: Learning and Memory
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 27232 - Posted: 05.05.2020

Amber Dance A mouse finds itself in a box it’s never seen before. The walls are striped on one side, dotted on the other. The orange-like odor of acetophenone wafts from one end of the box, the spiced smell of carvone from the other. The mouse remembers that the orange smell is associated with something good. Although it may not recall the exact nature of the reward, the mouse heads toward the scent. Except this mouse has never smelled acetophenone in its life. Rather, the animal is responding to a false memory, implanted in its brain by neuroscientists at the Hospital for Sick Children in Toronto. Sheena Josselyn, a coauthor on a 2019 Nature Neuroscience study reporting the results of the project, says the goal was not to confuse the rodent, but for the scientists to confirm their understanding of mouse memory. “If we really understand memory, we should be able to trick the brain into remembering something that never happened at all,” she explains. By simultaneously activating the neurons that sense acetophenone and those associated with reward, the researchers created the “memory” that the orange-y scent heralded good things. Thanks to optogenetics, which uses a pulse of light to activate or deactivate neurons, Josselyn and other scientists are manipulating animal memories in all kinds of ways. Even before the Toronto team implanted false memories into mice, researchers were making rodents forget or recall an event with the flick of a molecular light switch. With every flash of light, they test their hypotheses about how these animals—and by extension, people—collect, store, and access past experiences. Scientists are also examining how memory formation and retrieval change with age, how those processes are altered in animal models of Alzheimer’s disease, and how accessing memories can influence an animal’s emotional state. © 1986–2020 The Scientist.

Related chapters from BN: Chapter 17: Learning and Memory; Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 2: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Link ID: 27228 - Posted: 05.02.2020

Diana Kwon As rodents scuttle through a maze, scientists can observe the activity of their brains’ “inner GPS,” neurons that manage spatial orientation and navigation. This positioning system was revealed through two different discoveries, decades apart. In 1971, neuroscientist John O’Keefe found place cells, neurons that are consistently activated when rats are in a specific location, while observing the animals as they ran around an enclosure. More than thirty years later, neuroscientists May-Britt and Edvard Moser used a similar method to identify grid cells, neurons that fire at regular intervals as animals move, enabling them to keep track of navigational cues. It was the early 2010s when neuroscientist Elizabeth Buffalo and her team at Emory University’s Yerkes National Primate Research Center in Atlanta started investigating what the brain’s GPS looks like in primates. While conducting memory tests by tracking the eye movements of primates viewing either familiar or unfamiliar images, the researchers began to wonder: Was this system also active in stationary animals? “They were moving their eyes as they were forming a memory of these pictures,” Buffalo says. “So we thought that maybe this eye movement exploration was something that primates do in an analogous way to how rodents explore as they move around a physical environment.” One of Buffalo’s graduate students, Nathaniel Killian, put this hypothesis to the test. Working with monkeys, he placed electrodes into the entorhinal cortex—the brain region where grid cells are found in rodents—and recoded brain activity while the animals viewed images on a screen. One day, Killian came into a lab meeting with an announcement: he had found grid cells in the primate brain. Although it took many more months to complete additional experiments to validate the results, Buffalo remembers thinking during that meeting, “Wow, we’re seeing something really new.” © 1986–2020 The Scientist

Related chapters from BN: Chapter 17: Learning and Memory
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 27225 - Posted: 05.02.2020

By Asher Elbein Rufous treepies, birds in the crow family native to South and Southeast Asia, usually eat insects, seeds or fruits. But some of them have learned to eat fire. Well, not exactly, but close. At a small temple in the Indian state of Gujarat, the caretakers regularly set out small votive candles made with clarified butter. The birds flit down to steal the candles, extinguish the butter-soaked wicks with a quick shake of their heads and then gulp them down. This willingness to experiment with new foods and ways of foraging is an indicator of behavioral flexibility, and some scientists think it is evidence that certain species of birds might be less vulnerable to extinction. “The idea is that if a species has individuals that are capable of these novel behaviors, they’ll respond with changes in their behavior more easily than individuals from species that do not tend to produce novel behaviors like that,” said Louis Lefebvre, a professor at McGill University in Montreal and an author on the study. “The idea is pretty simple. The problem was to be able to test it in a convincing way.” A team of researchers, led by Simon Ducatez of Spain’s Center for Research on Ecology and Forestry Applications and including Dr. Lefebvre, combed through 204 ornithological journals for mentions of novel behaviors and feeding innovations, comparing the number of sightings in each species with their risk of extinction. Their results were published this month in Nature Ecology & Evolution. Dr. Lefebvre said the approach provided backup to earlier cognition experiments he had led with wild-caught birds, such as testing their ability to figure out how to open boxes full of food. © 2020 The New York Times Company

Related chapters from BN: Chapter 17: Learning and Memory; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 27220 - Posted: 04.29.2020

By Simon Makin Our recollection of events is usually not like a replay of digital video from a security camera—a passive observation that faithfully reconstructs the spatial and sensory details of everything that happened. More often memory segments what we experience into a string of discrete, connected events. For instance, you might remember that you went for a walk before lunch at a given time last week without recalling the soda bottle strewn on the sidewalk, the crow cawing in the oak tree in your yard or the chicken salad sandwich you ate upon your return. Your mind designates a mental basket for “walk” and a subsequent bin for “lunch” that, once accessed, make many of these finer details available. This arrangement raises the question of how the brain performs such categorization. A new study by neuroscientist Susumu Tonegawa of the Massachusetts Institute of Technology and his colleagues claims to have discovered the neural processing that makes this organization of memory into discrete units possible. The work has implications for understanding how humans generalize knowledge, and it could aid efforts to develop AI systems that learn faster. A brain region called the hippocampus is critical for memory formation and also seems to be involved in navigation. Neurons in the hippocampus called “place” cells selectively respond to being in specific locations, forming a cognitive map of the environment. Such spatial information is clearly important for “episodic” (autobiographical rather than factual) memory. But so, too, are other aspects of experience, such as changing sensory input. There is evidence that neurons in the hippocampus encode sensory changes by altering the frequency at which they fire, a phenomenon termed “rate remapping.” According to research by neuroscientist Loren Frank of the University of California, San Francisco, and his colleagues, such changes may also encode information about where an animal has been and where it is going, enabling rate remapping to represent trajectories of travel. © 2020 Scientific American

Related chapters from BN: Chapter 17: Learning and Memory
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 27187 - Posted: 04.14.2020

Anne Trafton | MIT News Office Imagine you are meeting a friend for dinner at a new restaurant. You may try dishes you haven’t had before, and your surroundings will be completely new to you. However, your brain knows that you have had similar experiences — perusing a menu, ordering appetizers, and splurging on dessert are all things that you have probably done when dining out. MIT neuroscientists have now identified populations of cells that encode each of these distinctive segments of an overall experience. These chunks of memory, stored in the hippocampus, are activated whenever a similar type of experience takes place, and are distinct from the neural code that stores detailed memories of a specific location. The researchers believe that this kind of “event code,” which they discovered in a study of mice, may help the brain interpret novel situations and learn new information by using the same cells to represent similar experiences. “When you encounter something new, there are some really new and notable stimuli, but you already know quite a bit about that particular experience, because it’s a similar kind of experience to what you have already had before,” says Susumu Tonegawa, a professor of biology and neuroscience at the RIKEN-MIT Laboratory of Neural Circuit Genetics at MIT’s Picower Institute for Learning and Memory. Tonegawa is the senior author of the study, which appears today in Nature Neuroscience. Chen Sun, an MIT graduate student, is the lead author of the paper. New York University graduate student Wannan Yang and Picower Institute technical associate Jared Martin are also authors of the paper.

Related chapters from BN: Chapter 17: Learning and Memory; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 14: Attention and Higher Cognition
Link ID: 27174 - Posted: 04.07.2020

Researchers at the National Institutes of Health have discovered in mice what they believe is the first known genetic mutation to improve cognitive flexibility—the ability to adapt to changing situations. The gene, KCND2, codes for a protein that regulates potassium channels, which control electrical signals that travel along neurons. The electrical signals stimulate chemical messengers that jump from neuron to neuron. The researchers were led by Dax Hoffman, Ph.D., chief of the Section on Neurophysiology at NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). It appears in Nature Communications. The KCND2 protein, when modified by an enzyme, slows the generation of electrical impulses in neurons. The researchers found that altering a single base pair in the KCND2 gene enhanced the ability of the protein to dampen nerve impulses. Mice with this mutation performed better than mice without the mutation in a cognitive task. The task involved finding and swimming to a slightly submerged platform that had been moved to a new location. Mice with the mutation found the relocated platform much faster than their counterparts without the mutation. The researchers plan to investigate whether the mutation will affect neural networks in the animals’ brains. They added that studying the gene and its protein may ultimately lead to insights on the nature of cognitive flexibility in people. It also may help improve understanding of epilepsy, schizophrenia, Fragile X syndrome, and autism spectrum disorder, which all have been associated with other mutations in KCND2.

Related chapters from BN: Chapter 17: Learning and Memory
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 27148 - Posted: 03.30.2020

May-Britt Moser & Edvard Moser There was something of the Viking about Per Andersen. The intrepid and steadfast Norwegian was renowned for his attacks on the deepest puzzle of the brain: how its wiring and electrical activity give rise to behaviour and experience. When he was a student in the 1950s, most neuroscientists studied accessible parts of the mammalian nervous system — the junctions between nerves and muscles, say. Andersen worked on the cerebral cortex, which processes higher-level functions: perception, voluntary movement, planning and abstract thinking. His pioneering recordings of electrical activity in the hippocampus — a part of the cortex involved in memory — launched a new era in physiological understanding of the brain and laid the foundations of modern systems neuroscience. He died on 17 February, aged 90. In 1949, it was predicted that learning might depend on repeated activity strengthening the connections — synapses — in networks of neurons. Andersen saw that this was the case in the hippocampus. As the effect was too fleeting to account directly for memory storage, he encouraged his student Terje Lømo to investigate. In 1973, in one of the greatest discoveries of twentieth-century neuroscience, Lømo and British visiting scholar Tim Bliss reported from Andersen’s laboratory that many bursts of electrical stimulation at certain frequencies enhanced connectivity for hours or days. This phenomenon — long-term potentiation (LTP) — remains the main explanation for how we form and store memories (T. V. P. Bliss and T. Lømo J. Physiol. 232, 331–356; 1973). We met Andersen as students, in the late 1980s. Our work with him on LTP and animal learning found differences in function between regions of the hippocampus and demonstrated changes in connectivity related to behaviour. His hunch that we should record activity from single cells led to our discovery of specialized neurons in the cortex that support the sense of where the body is in space. The work was a direct result of his insight. © 2020 Springer Nature Limited

Related chapters from BN: Chapter 17: Learning and Memory
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 27130 - Posted: 03.21.2020

By R. Douglas Fields Our concepts of how the two and a half pounds of flabby flesh between our ears accomplish learning date to Ivan Pavlov’s classic experiments, where he found that dogs could learn to salivate at the sound of a bell. In 1949 psychologist Donald Hebb adapted Pavlov’s “associative learning rule” to explain how brain cells might acquire knowledge. Hebb proposed that when two neurons fire together, sending off impulses simultaneously, the connections between them—the synapses—grow stronger. When this happens, learning has taken place. In the dogs’ case, it would mean the brain now knows that the sound of a bell is followed immediately by the presence of food. This idea gave rise to an oft-quoted axiom: “Synapses that fire together wire together.” The theory proved sound, and the molecular details of how synapses change during learning have been described in detail. But not everything we remember results from reward or punishment, and in fact, most experiences are forgotten. Even when synapses do fire together, they sometimes do not wire together. What we retain depends on our emotional response to an experience, how novel it is, where and when the event occurred, our level of attention and motivation during the event, and we process these thoughts and feelings while asleep. A narrow focus on the synapse has given us a mere stick-figure conception of how learning and the memories it engenders work. It turns out that strengthening a synapse cannot produce a memory on its own, except for the most elementary reflexes in simple circuits. Vast changes throughout the expanse of the brain are necessary to create a coherent memory. Whether you are recalling last night’s conversation with dinner guests or using an acquired skill such as riding a bike, the activity of millions of neurons in many different regions of your brain must become linked to produce a coherent memory that interweaves emotions, sights, sounds, smells, event sequences and other stored experiences. Because learning encompasses so many elements of our experiences, it must incorporate different cellular mechanisms beyond the changes that occur in synapses. This recognition has led to a search for new ways to understand how information is transmitted, processed and stored in the brain to bring about learning. In the past 10 years neuroscientists have come to realize that the iconic “gray matter” that makes up the brain’s outer surface—familiar from graphic illustrations found everywhere, from textbooks to children’s cartoons—is not the only part of the organ involved in the inscription of a permanent record of facts and events for later recall and replay. It turns out that areas below the deeply folded, gray-colored surface also play a pivotal role in learning. © 2020 Scientific American

Related chapters from BN: Chapter 17: Learning and Memory; Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 1: Cells and Structures: The Anatomy of the Nervous System
Link ID: 27114 - Posted: 03.12.2020

In a study of epilepsy patients, researchers at the National Institutes of Health monitored the electrical activity of thousands of individual brain cells, called neurons, as patients took memory tests. They found that the firing patterns of the cells that occurred when patients learned a word pair were replayed fractions of a second before they successfully remembered the pair. The study was part of an NIH Clinical Center trial for patients with drug-resistant epilepsy whose seizures cannot be controlled with drugs. “Memory plays a crucial role in our lives. Just as musical notes are recorded as grooves on a record, it appears that our brains store memories in neural firing patterns that can be replayed over and over again,” said Kareem Zaghloul, M.D., Ph.D., a neurosurgeon-researcher at the NIH’s National Institute of Neurological Disorders and Stroke (NINDS) and senior author of the study published in Science. Dr. Zaghloul’s team has been recording electrical currents of drug-resistant epilepsy patients temporarily living with surgically implanted electrodes designed to monitor brain activity in the hopes of identifying the source of a patient’s seizures. This period also provides an opportunity to study neural activity during memory. In this study, his team examined the activity used to store memories of our past experiences, which scientists call episodic memories. In 1957, the case of an epilepsy patient H.M. provided a breakthrough in memory research. H.M could not remember new experiences after part of his brain was surgically removed to stop his seizures. Since then, research has pointed to the idea that episodic memories are stored, or encoded, as neural activity patterns that our brains replay when triggered by such things as the whiff of a familiar scent or the riff of a catchy tune. But exactly how this happens was unknown.

Related chapters from BN: Chapter 17: Learning and Memory
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 27098 - Posted: 03.06.2020

By Cindi May Music makes life better in so many ways. It elevates mood, reduces stress and eases pain. Music is heart-healthy, because it can lower blood pressure, reduce heart rate and decrease stress hormones in the blood. It also connects us with others and enhances social bonds. Music can even improve workout endurance and increase our enjoyment of challenging activities. The fact that music can make a difficult task more tolerable may be why students often choose to listen to it while doing their homework or studying for exams. But is listening to music the smart choice for students who want to optimize their learning? A new study by Manuel Gonzalez of Baruch College and John Aiello of Rutgers University suggests that for some students, listening to music is indeed a wise strategy, but for others, it is not. The effect of music on cognitive functioning appears not to be “one-size-fits-all” but to instead depend, in part, on your personality—specifically, on your need for external stimulation. People with a high requirement for such stimulation tend to get bored easily and to seek out external input. Those individuals often do worse, paradoxically, when listening to music while engaging in a mental task. People with a low need for external stimulation, on the other hand, tend to improve their mental performance with music. But other factors play a role as well. Gonzalez and Aiello took a fairly sophisticated approach to understanding the influence of music on intellectual performance, assessing not only listener personality but also manipulating the difficulty of the task and the complexity of the music. Whether students experience a perk or a penalty from music depends on the interplay of the personality of the learner, the mental task, and the music. © 2020 Scientific American

Related chapters from BN: Chapter 17: Learning and Memory; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 14: Attention and Higher Cognition
Link ID: 27093 - Posted: 03.05.2020

Ian Sample Science editor It’s the sort a sneaky trick only a gull would learn: by watching how people handle their food, the birds can work out when there are snacks to be had. Researchers found that herring gulls were more likely to peck at items left on the ground if humans had pretended to eat them first. The study suggests that gulls take cues from human behaviour to help them home in on tasty scraps in the rubbish people leave behind. “People don’t tend to think of wild animals as using cues from humans like this,” said Madeleine Goumas, a researcher at the University of Exeter. “It’s the kind of behaviour that’s more often associated with domesticated animals or those kept in captivity.” Goumas, who has become one of the more prominent gull researchers in Britain, reported last year that maintaining eye contact can deter seagulls from snatching food. In tests with bags of chips in seaside towns, she found that staring the birds out put them off their daring raids. To follow up that work, Goumas wanted to see whether gulls pick up on subtle human cues to help them find their next meal. And so she set off to the Cornish towns of Falmouth, St Ives, Newquay and Penzance, and Plymouth in Devon, armed with shop-bought flapjacks in shiny blue wrappers, a supply of blue sponges, and a pair of dark glasses. For the first experiment, Goumas donned the sunglasses and walked towards her chosen bird, carrying a bucket with a flapjack in each hand. When she was about eight metres from the gull, she sat down, flipped the buckets over so they concealed the snacks, and pushed them out to her sides. She then lifted off the buckets, picked up one of the flapjacks, stood up and pretended to eat it. After 20 seconds, she put the flapjack back and retreated a safe distance. © 2020 Guardian News & Media Limited

Related chapters from BN: Chapter 17: Learning and Memory
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 27078 - Posted: 02.27.2020

Amy Schleunes New Zealand’s North Island robins (Petroica longipes), known as toutouwai in Maori, are capable of remembering a foraging task taught to them by researchers for up to 22 months in the wild, according to a study published on February 12 in Biology Letters. These results echo the findings of a number of laboratory studies of long-term memory in animals, but offer a rare example of a wild animal retaining a learned behavior with no additional training. The study also has implications for conservation and wildlife management: given the birds’ memory skills, researchers might be able to teach them about novel threats and resources in their constantly changing habitat. “This is the first study to show [memory] longevity in the wild,” says Vladimir Pravosudov, an animal behavior researcher at the University of Nevada, Reno, who was not involved in the study. Rachael Shaw, a coauthor and behavioral ecologist at Victoria University in New Zealand, says she was surprised that the birds remembered the new skill she had taught them. “Wild birds have so much that they have to contend with in their daily lives,” she says. “You don’t really expect that it’s worth their while to retain this learned task they hardly had the opportunity to do, and they can’t predict that they will have an opportunity to do again.” Shaw is generally interested in the cognitive abilities of animals and the evolution of intelligence, and the toutouwai, trainable food caching birds that can live up to roughly 10 years, make perfect subjects for her behavioral investigations. “They’ve got this kind of boldness and curiosity that a lot of island bird species share,” says Shaw. These qualities make them vulnerable to predation by invasive cats, rats, and ermines (also known as stoats), but also inquisitive and relatively unafraid of humans, an ideal disposition for testing memory retention in the field. © 1986–2020 The Scientist

Related chapters from BN: Chapter 17: Learning and Memory; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 27053 - Posted: 02.20.2020

Ian Sample Science editor Consuming a western diet for as little as one week can subtly impair brain function and encourage slim and otherwise healthy young people to overeat, scientists claim. Researchers found that after seven days on a high fat, high added sugar diet, volunteers in their 20s scored worse on memory tests and found junk food more desirable immediately after they had finished a meal. The finding suggests that a western diet makes it harder for people to regulate their appetite, and points to disruption in a brain region called the hippocampus as the possible cause. “After a week on a western-style diet, palatable food such as snacks and chocolate becomes more desirable when you are full,” said Richard Stevenson, a professor of psychology at Macquarie University in Sydney. “This will make it harder to resist, leading you to eat more, which in turn generates more damage to the hippocampus and a vicious cycle of overeating.” Previous work in animals has shown that junk food impairs the hippocampus, a brain region involved in memory and appetite control. It is unclear why, but one idea is that the hippocampus normally blocks or weakens memories about food when we are full, so looking at a cake does not flood the mind with memories of how nice cake can be. “When the hippocampus functions less efficiently, you do get this flood of memories, and so food is more appealing,” Stevenson said. To investigate how the western diet affects humans, the scientists recruited 110 lean and healthy students, aged 20 to 23, who generally ate a good diet. Half were randomly assigned to a control group who ate their normal diet for a week. The other half were put on a high energy western-style diet, which featured a generous intake of Belgian waffles and fast food. © 2020 Guardian News & Media Limited

Related chapters from BN: Chapter 17: Learning and Memory; Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 27050 - Posted: 02.19.2020

By Laura Sanders Immune cells in the brain chew up memories, a new study in mice shows. The finding, published in the Feb. 7 Science, points to a completely new way that the brain forgets, says neuroscientist Paul Frankland of the Hospital for Sick Children Research Institute in Toronto, who wasn’t involved in the study. That may sound like a bad thing, but forgetting is just as important as remembering. “The world constantly changes,” Frankland says, and getting rid of unimportant memories — such as a breakfast menu from two months ago — allows the brain to collect newer, more useful information. Exactly how the brain stores memories is still debated, but many scientists suspect that connections between large groups of nerve cells are important (SN: 1/24/18). Forgetting likely involves destroying or changing these large webs of precise connections, called synapses, other lines of research have suggested. The new result shows that microglia, immune cells that can clear debris from the brain, “do exactly that,” Frankland says. Microglia are master brain gardeners that trim extra synapses away early in life, says Yan Gu, a neuroscientist at Zhejiang University School of Medicine in Hangzhou, China. Because synapses have a big role in memory storage, “we started to wonder whether microglia may induce forgetting by eliminating synapses,” Gu says. Gu’s team first gave mice an unpleasant memory: mild foot shocks, delivered in a particular cage. Five days after the shocks, the mice would still freeze in fear when they were placed in the cage. But 35 days later, they had begun to forget and froze less often in the room. © Society for Science & the Public 2000–2020

Related chapters from BN: Chapter 17: Learning and Memory; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 11: Emotions, Aggression, and Stress
Link ID: 27026 - Posted: 02.07.2020

By Charles Zanor We all know people who say they have “no sense of direction,” and our tendency is almost always to minimize such claims rather than take them at full force. Yet for some people that description is literally true, and true in all circumstances: If they take a single wrong turn on an established route they often become totally lost. This happens even when they are just a few miles from where they live. Ellen Rose had been a patient of mine for years before I realized that she had this life-long learning disability. Advertisement I was made aware of it not long after I moved my psychology office from Agawam, Massachusetts to Suffield, Connecticut, just five miles away. I gave Ellen a fresh set of directions from the Springfield, Massachusetts area that took her south on Interstate 91 to Exit 47W, then across the Connecticut River to Rte 159 in Suffield. I thought it would pose no problem at all for her. A few minutes past her scheduled appointment time she called to say that she was lost. She had come south on Route 91 and had taken the correct exit, but she got confused and almost immediately hooked a right onto a road going directly north, bringing her back over the Massachusetts line to the town of Longmeadow. She knew this was wrong but did not know how to correct it, so I repeated the directions to get on 91 South and so on. Minutes passed, and then more minutes passed, and she called again to say that somehow she had driven by the exit she was supposed to take and was in Windsor, Connecticut. I kept her on the phone and guided her turn by turn to my office. Advertisement When I asked her why she hadn’t taken Exit 47W, she said that she saw it but it came up sooner than she expected so she kept going. This condition—developmental topographic disorientation—didn’t even have a formal name until 2009, when Giuseppe Iaria reported his first case in the journal Neuropsychologia. To understand DTD it is best to begin by saying that there are two main ways that successful travelers use to navigate their environment. © 2020 Scientific American,

Related chapters from BN: Chapter 17: Learning and Memory; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 14: Attention and Higher Cognition
Link ID: 27021 - Posted: 02.05.2020

Scott Grafton When people ask me about the “mind-body connection,” I typically suggest walking on an icy sidewalk. Skip the yoga, mindfulness, or meditation, and head to the corner on a cold, windy, snowy day. Every winter, much of North America becomes exceedingly slippery with ice. Emergency rooms across the continent see a sharp uptick in fractured limbs and hips as people confidently trudge outside in such conditions, unveiling a profound disconnection between what people believe and what they can actually do with their bodies. One might think that a person could call on experience from years past to adjust their movement or provide a little insight or caution. But the truth is that the body forgets what it takes to stay upright in these perilous conditions. Why is there so much forgetting and relearning on an annual basis? We remember how to ride a bike. Why can’t we remember how to walk on ice? I attempt to answer this and other questions concerning the connection (or lack thereof) between motion in the mind and motion by the body in my new book, Physical Intelligence: The Science of How the Body and the Mind Guide Each Other Through Life. Pantheon, January 2020 Falling on ice reveals a delicate tradeoff that the brain must reconcile as it pilots the body. On the one hand, it needs to build refined motor programs to execute skills such as walking, running, and throwing. On the other hand, those programs can’t be too specific. There is a constant need to tweak motor plans to account for dynamic conditions. When I throw a backpack on, my legs don’t walk in the same way as they do without the pack: my stance widens, my stride shortens. Often, the tweaking needs to happen in moments. As I pick the pack up, I need to lean in or I could tip myself over. Just as importantly, as soon as I put it down, I need to forget I ever held it in the first place. © 1986–2020 The Scientist

Related chapters from BN: Chapter 11: Motor Control and Plasticity; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 13: Memory and Learning
Link ID: 27001 - Posted: 01.28.2020

By Betsy Mason Despite weighing less than half an ounce, mountain chickadees are able to survive harsh winters complete with subzero temperatures, howling winds and heavy snowfall. How do they do it? By spending the fall hiding as many as 80,000 individual seeds, which they then retrieve — by memory — during the winter. Their astounding ability to keep track of that many locations puts their memory among the most impressive in the animal kingdom. It also makes chickadees an intriguing subject for animal behavior researchers. Cognitive ecologist Vladimir Pravosudov of the University of Nevada, Reno, has dedicated his career to studying this tough little bird’s amazing memory. Writing in 2013 on the cognitive ecology of food caching in the Annual Review of Ecology, Evolution, and Systematics, he and coauthor Timothy Roth argued that answers to big questions about the evolution of cognition may lie in the brains of these little birds. In July, at a meeting of the Animal Behavior Society in Chicago, Pravosudov presented his group’s latest research on the wild chickadees that live in the Sierra Nevada mountains. He and his graduate students were able to show for the first time that an individual bird’s spatial memory has a direct impact on its survival. The team did this by building an experimental contraption that uses radio-frequency identification (RFID) technology and electronic leg bands to test individual birds’ memory in the wild and then track their longevity. The researchers found that the birds with the best memory were most likely to survive the winter. What are some of the big ideas driving your work on chickadees? If some species are smart, or not smart, the question is: Why? Cognitive ecologists like me are specifically trying to figure out which ecological factors may have shaped the evolution of these differences in cognition. In other words, the idea is to understand the ecological and evolutionary reasons for variation in cognition. © 2020 Annual Reviews, Inc

Related chapters from BN: Chapter 17: Learning and Memory
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 26968 - Posted: 01.17.2020