Chapter 17. Learning and Memory

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By Simon Makin Better Memory through Electrical Brain Ripples Hippocampus Neuron, computer illustration Credit: Kateryna Kon Getty Images Specific patterns of brain activity are thought to underlie specific processes or computations important for various mental faculties, such as memory. One such “brain signal” that has received a lot of attention recently is known as a “sharp wave ripple”—a short, wave-shaped burst of high-frequency oscillations. Researchers originally identified ripples in the hippocampus, a region crucially involved in memory and navigation, as central to diverting recollections to long-term memory during sleep. Then a 2012 study by neuroscientists at the University of California, San Francisco, led by Loren Frank and Shantanu Jadhav, the latter now at Brandeis University, showed that the ripples also play a role in memory while awake. The researchers used electrical pulses to disrupt ripples in rodents’ brains, and showed that, by doing so, performance in a memory task was reduced. However, nobody had manipulated ripples to enhance memory—until now, that is. Researchers at NYU School of Medicine led by neuroscientist György Buzsáki have now done exactly that. In a June 14 study in Science, the team showed that prolonging sharp wave ripples in the hippocampus of rats significantly improved their performance in a maze task that taxes working memory—the brain’s “scratch pad” for combining and manipulating information on the fly. “This is a very novel and impactful study,” says Jadhav, who was not involved in the research. “It’s very hard to do ‘gain-of-function’ studies with physiological processes in such a precise way.” As well as revealing new details about how ripples contribute to specific memory processes, the work could ultimately have implications for efforts to develop interventions for disorders of memory and learning. © 2019 Scientific American

Keyword: Learning & Memory
Link ID: 26330 - Posted: 06.15.2019

Nell Greenfieldboyce At the Marine Biological Laboratory in Woods Hole, Mass., there's a room filled with burbling aquariums. A lot of them have lids weighed down with big rocks. "Octopuses are notorious for being able to, kind of, escape out of their enclosures," says Bret Grasse, whose official title at MBL is "manager of cephalopod operations" — cephalopods being squid, cuttlefish and octopuses. He's part of a team that's trying to figure out the best ways to raise these sea creatures in captivity, so that scientists can investigate their genes and learn the secrets of their strange, almost alien ways. For decades, much of the basic research in biology has focused on just a few, well-studied model organisms like mice, fruit flies, worms and zebrafish. That's because these critters are easy to keep in the laboratory, and scientists have worked out how to routinely alter their genes, leading to all kinds of insights into behavior, diseases and possible treatments. "With these organisms, you could understand what genes did by manipulating them," says Josh Rosenthal, another biologist at MBL. "And that really became an indispensable part of biology." But it's also meant that basic biology has ignored much of the animal kingdom, especially its more exotic denizens. "We're really missing out on, I would say, the diversity of biology's solutions to problems," Rosenthal notes. © 2019 npr

Keyword: Learning & Memory; Evolution
Link ID: 26295 - Posted: 06.04.2019

By Kenneth Miller A model of Ben Barres’ brain sits on the windowsill behind his desk at Stanford University School of Medicine. To a casual observer, there’s nothing remarkable about the plastic lump, 3-D-printed from an MRI scan. Almost lost in the jumble of papers, coffee mugs, plaques and trophies that fill the neurobiologist’s office, it offers no hint about what Barres’ actual gray matter has helped to accomplish: a transformation of our understanding of brains in general, and how they can go wrong. Barres is a pioneer in the study of glia. This class of cells makes up 90 percent of the human brain, but gets far less attention than neurons, the nerve cells that transmit our thoughts and sensations at lightning speed. Glia were long regarded mainly as a maintenance crew, performing such unglamorous tasks as ferrying nutrients and mopping up waste, and occasionally mounting a defense when the brain faced injury or infection. Over the past two decades, however, Barres’ research has revealed that they actually play central roles in sculpting the developing brain, and in guiding neurons’ behavior at every stage of life. “He has made one shocking, revolutionary discovery after another,” says biologist Martin Raff, emeritus professor at University College London, whose own work helped pave the way for those advances. Recently, Barres and his collaborators have made some discoveries that may revolutionize the treatment of neurodegenerative ailments, from glaucoma and multiple sclerosis to Alzheimer’s disease and stroke. What drives such disorders, their findings suggest, is a process in which glia turn from nurturing neurons to destroying them. Human trials of a drug designed to block that change are just beginning.

Keyword: Glia; Learning & Memory
Link ID: 26258 - Posted: 05.22.2019

By Benedict Carey The research on brain stimulation is advancing so quickly, and the findings are so puzzling, that a reader might feel tempted to simply pre-order a genius cap from Amazon, to make sense of it all later. In just the past month, scientists reported enhancing the working memory of older people, using electric current passed through a skullcap, and restoring some cognitive function in a brain-damaged woman, using implanted electrodes. Most recently, the Food and Drug Administration approved a smartphone-size stimulator intended to alleviate attention-deficit problems by delivering electric current through a patch placed on the forehead. Last year, another group of scientists announced that they, too, had created a brain implant that boosts memory storage. All the while, a do-it-yourself subculture continues to grow, of people who are experimenting with placing electrodes in their skulls or foreheads for brain “tuning.” Predicting where all these efforts are headed, and how and when they might converge in a grand methodology, is an exercise in rank speculation. Neuro-stimulation covers too many different techniques, for various applications and of varying quality. About the only certainties are the usual ones: that a genius cap won’t arrive anytime soon, and that any brain-zapping gizmo that provides real benefit also is likely to come with risk. Nevertheless, the field is worth watching because it hints at some elementary properties of brain function. Unlike psychiatric drugs, or psychotherapy, pulses of current can change people’s behavior very quickly, and reliably. Turn the current on and things happen; turn it off and the effect stops or tapers. © 2019 The New York Times Company

Keyword: Learning & Memory; Alzheimers
Link ID: 26232 - Posted: 05.14.2019

By Cara Giaimo Here’s a pop quiz for you. Tom is taller than Dick. Dick is taller than Harry. Who’s taller, Harry or Tom? If you said Tom, congratulations! You just demonstrated what’s called “transitive inference” — the ability to compare things indirectly, based on previous juxtapositions. But before you pat yourself on the back too much, you should know that this skill was recently demonstrated by another creature: the humble paper wasp that might be living in your backyard right now. In the summer of 2017, researchers at the University of Michigan put two species of paper wasps through a transitive inference test. A statistically significant portion of the time, the wasps passed. Other animals — including rats, geese and cichlid fish — have also exhibited this capacity. But this study, which was published Tuesday in Biology Letters, is the first to successfully showcase it in an invertebrate (honeybees failed a similar test in 2004). Paper wasps are found on every continent except Antarctica. You might be near some right now. “They tend to nest in the eaves of houses, or inside barbecue grills,” said Elizabeth Tibbetts, the study’s lead author. In a previous study, Dr. Tibbetts showed that individual female wasps can identify one another by their distinct facial patterns, which resemble Rorschach ink blots. “When two wasps meet, they learn, ‘Oh, that’s what Suzy looks like,’” she said. “And the next time they meet, they remember who Suzy is.” In the spring, the females spend a lot of time brawling, getting in each other’s faces and trading slaps with their appendages. These matchups look like schoolyard tussles. “Some wasps will be fighting; some wasps will be watching the fights,” said Dr. Tibbetts. “It’s a very exciting time.” The wasps remember the winners and losers, and use them to establish a social hierarchy: the strongest reproduce, while the weaker ones do all the work. © 2019 The New York Times Company

Keyword: Evolution; Learning & Memory
Link ID: 26229 - Posted: 05.11.2019

By Dana G. Smith Training software that emulates brain networks to identify dog breeds or sports equipment is by now old news. But getting such an AI network to learn a process on its own that is innate to early child development is truly novel. In a paper published Wednesday in Science Advances, a neural network distinguished between different quantities of things, even though it was never taught what a number is. The neural net reprised a cognitive skill innate to human babies, monkeys and crows, among others. Without any training, it suddenly could tell the difference between larger and smaller amounts—a skill called numerosity, or number sense. Many believe number sense is an essential precursor to our ability to count and do more complex mathematics. But questions have persisted about how this ability spontaneously comes about in the young brain. To research its development, scientists from the University of Tübingen in Germany used a deep-learning system designed to mimic the human brain to see if numerosity would emerge without having to train the software. “We were trying to simulate the workings of the visual system of our brain by building a deep-learning network, an artificial neural network,” says Andreas Nieder, a professor in the Institute of Neurobiology at Tübingen and senior author on the new paper. “The big question was, how is it possible that our brain and the brain of animals can spontaneously represent the number of items in a visual scene?” © 2019 Scientific American

Keyword: Learning & Memory; Development of the Brain
Link ID: 26218 - Posted: 05.09.2019

By Veronique Greenwood You’re holed up with colleagues in a meeting room for two hours, hashing out a plan. Risks are weighed, decisions are made. Then, as you emerge, you realize it was much, much warmer and stuffier in there than in the rest of the office. Small rooms can build up heat and carbon dioxide from our breath — as well as other substances — to an extent that might surprise you. And as it happens, a small body of evidence suggests that when it comes to decision making, indoor air may matter more than we have realized. At least eight studies in the last seven years have looked at what happens specifically in a room accumulating carbon dioxide, a main ingredient in our exhalations. While the results are inconsistent, they are also intriguing. They suggest that while the kinds of air pollution known to cause cancer and asthma remain much more pressing as public health concerns, there may also be pollutants whose most detrimental effects are on the mind, rather than the body. So can you trust the decisions made in small rooms? How much does the quality of air indoors affect your cognitive abilities? And as our knowledge of indoor air’s effects grows, do we need to revise how we design and use our buildings? Buildings in the United States have grown better sealed in the last 50 years, helping reduce energy used in heating and cooling. That’s also made it easier for gasses and other substances released by humans and our belongings to build up inside. Although indoor air quality is not as well monitored as the air outdoors, scientists and ventilation professionals have extensively monitored carbon dioxide indoors. © 2019 The New York Times Company

Keyword: Learning & Memory
Link ID: 26216 - Posted: 05.07.2019

/ By Elizabeth Svoboda As he neared his 50s, Anthony Andrews realized that living inside his own head felt different than it used to. The signs were subtle at first. “My wife started noticing that I wasn’t getting through things,” Andrews says. Every so often, he’d experience what he calls “cognitive voids,” where he’d get dizzy and blank out for a few seconds. It wasn’t just that he would lose track of things, as if the thought bubble over his head had popped. Over time, Andrews’ issues became more pronounced. It wasn’t just that he would lose track of things, as if the thought bubble over his head had popped. A dense calm had descended on him like a weighted blanket. “I felt like I was walking through the swamp,” says Andrews, now 54. He had to play internet chess each morning to penetrate the mental murk. In 2016, Anthony Andrews and his wife Mona were told he likely had CTE, a neurodegenerative disorder caused by repeated head impacts. With his wife, Mona, by his side, Andrews went to doctor after doctor racking up psychiatric diagnoses. One told him he had ADHD. Another thought he was depressed, and another said he had bipolar disorder. But the drugs and therapies they prescribed didn’t seem to help. “After a month,” Andrews recalls of these treatments, “I knew it’s not for me.” Copyright 2019 Undark

Keyword: Learning & Memory; Brain Injury/Concussion
Link ID: 26215 - Posted: 05.07.2019

By Gretchen Reynolds A single, moderate workout may immediately change how our brains function and how well we recognize common names and similar information, according to a promising new study of exercise, memory and aging. The study adds to growing evidence that exercise can have rapid effects on brain function and also that these effects could accumulate and lead to long-term improvements in how our brains operate and we remember. Until recently, scientists thought that by adulthood, human brains were relatively fixed in their structure and function, especially compared to malleable tissues, like muscle, that continually grow and shrivel in direct response to how we live our lives. But multiple, newer experiments have shown that adult brains, in fact, can be quite plastic, rewiring and reshaping themselves in various ways, depending on our lifestyles. Exercise, for instance, is known to affect our brains. In animal experiments, exercise increases the production of neurochemicals and the numbers of newborn neurons in mature brains and improves the animals’ thinking abilities. Similarly, in people, studies show that regular exercise over time increases the volume of the hippocampus, a key part of the brain’s memory networks. It also improves many aspects of people’s thinking. But substantial questions remain about exercise and the brain, including the time course of any changes and whether they are short-term or, with continued training, become lasting. That particular issue intrigued scientists at the University of Maryland. They already had published a study in 2013 with older adults looking at the long-term effects of exercise on portions of the brain involved in semantic-memory processing. © 2019 The New York Times Company

Keyword: Learning & Memory
Link ID: 26199 - Posted: 05.02.2019

Yao-Hua Law When it comes to migration science, birds rule. Although many mammals — antelopes, whales, bats — migrate, too, scientists know far less about how those animals do it. But a new device, invented by animal navigation researcher Oliver Lindecke, could open a new way to test how far-ranging bats find their way. Lindecke, of Leibniz Institute for Zoo and Wildlife Research in Germany, has been studying bat migration since 2011. He started with analyzing different forms of hydrogen atoms in wild bats to infer where they had flown from. But figuring out how the bats knew where to go was trickier. Lindecke needed a field setup that let him test what possible cues from nature helped bats navigate across vast distances. The first step was studying in which direction the bats first take flight. Such experiments on birds typically involve confining the animals in small, enclosed spaces. But that doesn’t work for bats, which tend to fall asleep in such spaces. So he invented what he calls the circular release box: a flat-bottom, funnel-shaped container topped by a wider lid. To escape, the bat crawls up the wall and takes off from the edge. Bat tracks in a layer of chalk (Lindecke says he was inspired by a snow-covered Berlin street) indicate where the bat took off. In August 2017, Lindecke captured 54 soprano pipistrelle bats (Pipistrellus pygmaeus) in a large, 50-meter-wide trap at the Pape Ornithological Research Station in Latvia as the animals were migrating along the coast of the Baltic Sea toward Central Europe. Experiments with the new device showed that the adult bats flew straight in the direction in which they took off, Lindecke and colleagues report online March 1 in the Journal of Zoology. |© Society for Science & the Public 2000 - 2019

Keyword: Animal Migration
Link ID: 26159 - Posted: 04.20.2019

In a study of healthy volunteers, National Institutes of Health researchers found that our brains may solidify the memories of new skills we just practiced a few seconds earlier by taking a short rest. The results highlight the critically important role rest may play in learning. “Everyone thinks you need to ‘practice, practice, practice’ when learning something new. Instead, we found that resting, early and often, may be just as critical to learning as practice,” said Leonardo G. Cohen, M.D., Ph.D., senior investigator at NIH’s National Institute of Neurological Disorders and Stroke and a senior author of the paper published in the journal Current Biology. “Our ultimate hope is that the results of our experiments will help patients recover from the paralyzing effects caused by strokes and other neurological injuries by informing the strategies they use to ‘relearn’ lost skills.” The study was led by Marlene Bönstrup, M.D., a postdoctoral fellow in Dr. Cohen’s lab. Like many scientists, she held the general belief that our brains needed long periods of rest, such as a good night’s sleep, to strengthen the memories formed while practicing a newly learned skill. But after looking at brain waves recorded from healthy volunteers in learning and memory experiments at the NIH Clinical Center, she started to question the idea. The waves were recorded from right-handed volunteers with a highly sensitive scanning technique called magnetoencephalography. The subjects sat in a chair facing a computer screen and under a long cone-shaped brain scanning cap. The experiment began when they were shown a series of numbers on a screen and asked to type the numbers as many times as possible with their left hands for 10 seconds; take a 10 second break; and then repeat this trial cycle of alternating practice and rest 35 more times. This strategy is typically used to reduce any complications that could arise from fatigue or other factors.

Keyword: Learning & Memory; Brain imaging
Link ID: 26137 - Posted: 04.13.2019

By Gina Kolata Allan Gallup, a retired lawyer and businessman, grew increasingly forgetful in his last few years. Eventually, he could no longer remember how to use a computer or the television. Although he needed a catheter, he kept forgetting and pulling it out. It was Alzheimer’s disease, the doctors said. So after Mr. Gallup died in 2017 at age 87, his brain was sent to Washington University in St. Louis to be examined as part of a national study of the disease. But it wasn’t just Alzheimer’s disease, the researchers found. Although Mr. Gallup’s brain had all the hallmarks — plaques made of one abnormal protein and tangled strings of another — the tissue also contained clumps of proteins called Lewy bodies, as well as signs of silent strokes. Each of these, too, is a cause of dementia. Mr. Gallup’s brain was typical for an elderly patient with dementia. Although almost all of these patients are given a diagnosis of Alzheimer’s disease, nearly every one of them has a mixture of brain abnormalities. For researchers trying to find treatments, these so-called mixed pathologies have become a huge scientific problem. Researchers can’t tell which of these conditions is the culprit in memory loss in a particular patient, or whether all of them together are to blame. Another real possibility, noted Roderick A. Corriveau, who directs dementia research programs at the National Institute of Neurological Disorders and Stroke, is that these abnormalities are themselves the effects of a yet-to-be-discovered cause of dementia. These questions strike at the very definition of Alzheimer’s disease. And if you can’t define the condition, how can you find a treatment? © 2019 The New York Times Company

Keyword: Alzheimers; Brain imaging
Link ID: 26125 - Posted: 04.09.2019

By Benedict Carey Anyone above a certain age who has drawn a blank on the name of a favorite uncle, a friend’s phone number or the location of a house key understands how fragile memory is. Its speed and accuracy begin to slip in one’s 20s and keep slipping. This is particularly true for working memory, the mental sketch pad that holds numbers, names and other facts temporarily in mind, allowing decisions to be made throughout the day. On Monday, scientists reported that brief sessions of specialized brain stimulation could reverse this steady decline in working memory, at least temporarily. The stimulation targeted key regions in the brain and synchronized neural circuits in those areas, effectively tuning them to one another, as an orchestra conductor might tune the wind section to the strings. The findings, reported in the journal Nature Neuroscience, provide the strongest support yet for a method called transcranial alternating current stimulation, or tACS, as a potential therapy for memory deficits, whether from age-related decline, brain injury or, perhaps, creeping dementia. In recent years, neuroscientists have shown that memory calls on a widely distributed network in the brain, and it coordinates those interactions through slow-frequency, thrumming rhythms called theta waves, akin to the pulsing songs shared among humpback whales. The tACS technology is thought to enable clearer communication by tuning distant circuits to one another. The tACS approach is appealing for several reasons, perhaps most of all because it is noninvasive; unlike other forms of memory support, it involves no implant, which requires brain surgery. The stimulation passes through the skull with little sensation. Still, a widely available therapy is likely years away, as the risks and benefits are not fully understood, experts said. © 2019 The New York Times Company

Keyword: Learning & Memory; Alzheimers
Link ID: 26123 - Posted: 04.09.2019

Laura Sanders Brains have long been star subjects for neuroscientists. But the typical “brain in a jar” experiments that focus on one subject in isolation may be missing a huge part of what makes us human — our social ties. “There’s this assumption that we can understand how the mind works by just looking at individual minds, and not looking at them in interactions,” says social neuroscientist Thalia Wheatley of Dartmouth College. “I think that’s wrong.” To answer some of the thorniest questions about the human brain, scientists will have to study the mind as it actually exists: steeped in social connections that involve rich interplay among family, friends and strangers, Wheatley argues. To illustrate her point, she asked the audience at a symposium in San Francisco on March 26, during the annual meeting of the Cognitive Neuroscience Society, how many had talked to another person that morning. Nearly everybody in the crowd of about 100 raised a hand. Everyday social interactions may seem inconsequential. But recent work on those who have been isolated, such as elderly people and prisoners in solitary confinement, suggests otherwise: Brains deprived of social interaction stop working well (SN: 12/8/18, p. 11). “That’s a hint that it’s not just that we like interaction,” Wheatley says. “It’s important to keep us healthy and sane.” |© Society for Science & the Public 2000 - 2019

Keyword: Learning & Memory
Link ID: 26122 - Posted: 04.09.2019

By Carl Zimmer In 2011, Dr. Dena Dubal was hired by the University of California, San Francisco, as an assistant professor of neurology. She set up a new lab with one chief goal: to understand a mysterious hormone called Klotho. Dr. Dubal wondered if it might be the key to finding effective treatments for dementia and other disorders of the aging brain. At the time, scientists only knew enough about Klotho to be fascinated by it. Mice bred to make extra Klotho lived 30 percent longer, for instance. But scientists also had found Klotho in the brain, and so Dr. Dubal launched experiments to see whether it had any effect on how mice learn and remember. The results were startling. In one study, she and her colleagues found that extra Klotho protects mice with symptoms of Alzheimer’s disease from cognitive decline. “Their thinking, in every way that we could measure them, was preserved,” said Dr. Dubal. She and her colleagues also bred healthy mice to make extra Klotho. They did better than their fellow rodents on learning mazes and other cognitive tests. Klotho didn’t just protect their brains, the researchers concluded — it enhanced them. Experiments on more mice turned up similar results. “I just couldn’t believe it — was it true, or was it just a false positive?” Dr. Dubal recalled. “But here it is. It enhances of cognition even in a young mouse. It makes them smarter.” Five years have passed since Dr. Dubal and her colleagues began publishing these extraordinary results. Other researchers have discovered tantalizing findings of their own, suggesting that Klotho may protect against other neurological disorders, including multiple sclerosis and Parkinson’s disease. © 2019 The New York Times Company

Keyword: Learning & Memory; Alzheimers
Link ID: 26105 - Posted: 04.02.2019

Emma Yasinski In the 1970s, scientists discovered that certain neurons in the hippocampus—an area of the brain involved in learned and memory—would fire in response to particular locations. They were called “place cells,” explains Charlotte Boccara, a researcher at the University of Oslo. “They were deemed important for spatial representation . . . a bit like the ‘You Are Here’ signal’ on a map.” But it wasn’t until 2005 that researchers discovered the brain’s grid cells, which they believed function as that map. These cells, found adjacent to the hippocampus in the medial entorhinal cortex (MEC), self-organize into a pattern of hexagons that serve as coordinates to help animals make sense of their surroundings and the signals from our place cells. A pair of studies published today (March 28) in Science suggests that this map may not be as rigid as once thought. The experiments demonstrated that, in rats at least, the cellular activity within these grids changes as the animals learn and remember where they can find food rewards. “These are wonderful studies,” says György Buzsáki, a neuroscientist at New York University who was not involved in either of them. “When ideas converge from multiple, different directions, and they converge and come to the same conclusion, the result is always stronger.” In the first study, Boccara, then a researcher at the Institute of Science and Technology Austria, and her team placed rats one by one in a cheeseboard maze, a flat board drilled full of holes. They hid three food rewards in different holes then scattered food dust over the entire surface so the rats would not be able to sniff their ways to the reward. The rats explored the maze until they found the prizes and repeated the task until they learned to go straight to the food instead of foraging. The next day, the researchers conducted the same experiment but changed the locations of the rewards. © 1986 - 2019 The Scientist.

Keyword: Learning & Memory
Link ID: 26094 - Posted: 03.30.2019

Laura Sanders SAN FRANCISCO — Seizures during sleep can scramble memories — a preliminary finding that may help explain why people with epilepsy sometimes have trouble remembering. The sleeping brain normally rehashes newly learned material, a nocturnal rehearsal that strengthens those memories. Neuroscientist Jessica Creery and her colleagues forced this rehearsal by playing certain sounds while nine people with epilepsy learned where on a screen certain pictures of common objects were located. Then, while the subjects later slept, the researchers played the sounds to call up some of the associated memories. This sneaky method of strengthening memories, called targeted memory reactivation, worked as expected for five people who didn’t have seizures during the process. When these people woke up, they remembered the picture locations reactivated by a tone better than those that weren’t reactivated during sleep, said Creery, of Northwestern University in Evanston, Ill. She presented the research March 25 at the annual meeting of the Cognitive Neuroscience Society. The opposite was true, however, for four people who had mild seizures, detected only by electrodes implanted deep in the brain, while they slept. For these people, memory reactivation during sleep actually worsened memories, making the reactivated memories weaker than the memories that weren’t reactivated during sleep. The combination of seizures and memory reactivation “seems like it’s actually scrambling the memory,” Creery says, a finding that suggest that seizures somehow accelerate forgetting. |© Society for Science & the Public 2000 - 2019

Keyword: Sleep; Epilepsy
Link ID: 26083 - Posted: 03.27.2019

By Benedict Carey Whatever its other properties, memory is a reliable troublemaker, especially when navigating its stockpile of embarrassments and moral stumbles. Ten minutes into an important job interview and here come screenshots from a past disaster: the spilled latte, the painful attempt at humor. Two dates into a warming relationship and up come flashbacks of an earlier, abusive partner. The bad timing is one thing. But why can’t those events be somehow submerged amid the brain’s many other dimming bad memories? Emotions play a role. Scenes, sounds and sensations leave a deeper neural trace if they stir a strong emotional response; this helps you avoid those same experiences in the future. Memory is protective, holding on to red flags so they can be waved at you later, to guide your future behavior. But forgetting is protective too. Most people find a way to bury, or at least reshape, the vast majority of their worst moments. Could that process be harnessed or somehow optimized? Perhaps. In the past decade or so, brain scientists have begun to piece together how memory degrades and forgetting happens. A new study, published this month in the Journal of Neuroscience, suggests that some things can be intentionally relegated to oblivion, although the method for doing so is slightly counterintuitive. For the longest time, forgetting was seen as a passive process of decay and the enemy of learning. But as it turns out, forgetting is a dynamic ability, crucial to memory retrieval, mental stability and maintaining one’s sense of identity. © 2019 The New York Times Company

Keyword: Learning & Memory
Link ID: 26070 - Posted: 03.23.2019

By Paul Raeburn When the brain remembers, proteins in two locations deep within the organ—the amygdala and hippocampus—encode the memory until it is stored, or “consolidated” in the vernacular. Neuroscientists once thought that a memory, when put in its place, became permanent and stable. That’s a problem for patients with post-traumatic stress disorder (PTSD), plagued by crippling, debilitating memories that they cannot shake. “We wish that we could somehow target unpleasant or pathological memories and reduce their emotional strength,” says Bryan A. Strange, founder of the Laboratory of Clinical Science at the Universidad Politécnica de Madrid. During the past two decades or so, it has become clear that these memories are not fixed and unshakable. They can be manipulated in ways that might ultimately ease the suffering of patients, not just ones with a PTSD diagnosis but also those afflicted by phobias, depression and other stress-related conditions. Strange is among the researchers looking for leads to tamp down toxic memories. He and his colleagues reported in a Science Advances paper on March 20 that the anesthetic propofol can be used to alter such recollections, if administered in the right circumstances. © 2019 Scientific American

Keyword: Stress; Learning & Memory
Link ID: 26064 - Posted: 03.22.2019

By Pam Belluck Could people’s eyes and ears help fix the damage Alzheimer’s disease does to the brain? Just by looking at flashing light and listening to flickering sound? A new study led by a prominent M.I.T. neuroscientist offers tantalizing promise. It found that when mice engineered to exhibit Alzheimer’s-like qualities were exposed to strobe lights and clicking sounds, important brain functions improved and toxic levels of Alzheimer’s-related proteins diminished. What’s more, the rapid-fire soundtrack appeared to make mice better at cognitive and memory skills, like navigating mazes and recognizing objects. Of course, mice are not people. And many drugs that have helped Alzheimer’s-engineered mice haven’t done much for people with Alzheimer’s, which affects 44 million people worldwide, including 5.5 million Americans. Also, because the technique didn’t have long-lasting effects — results faded about a week after the sensory stimulation was stopped — any therapy developed from the research might have to be repeated regularly. Still, seeing that a noninvasive daily dose of light and sound could have such significant effects in mice give some experts reason for optimism. “It’s exciting, I think,” said Dr. Lennart Mucke, director of the Gladstone Institute of Neurological Disease, who was not involved in the study. “Reading the paper made me quite enthusiastic about seeing this move forward into some well-crafted clinical trials.” The experiments were led by Li-Huei Tsai, director of MIT’s Picower Institute for Learning and Memory. She and her colleagues showed that light and sound delivered to mice at a certain frequency — 40 hertz or 40 flashes or clicks per second — appears to synchronize the rhythm of the brain’s gamma waves, which is disrupted in patients with Alzheimer’s. Gamma waves are among several types of electrical brain waves believed to be involved in concentration, sleep, perception and movement. The experiment setup where flickering light and sound were delivered to Alzheimer’s-engineered mice in the tubs.CreditPicower Institute for Learning and Memory, M.I.T. © 2019 The New York Times Company

Keyword: Alzheimers; Learning & Memory
Link ID: 26040 - Posted: 03.15.2019