Chapter 17. Learning and Memory
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By Jason G. Goldman While second nature to many of us, driving a car is actually a fairly complex process. At its most stripped down version, first you sit in the driver’s seat, then you start the engine, then you shift into gear, and then you must simultaneously steer while keeping your foot on the gas pedal. That doesn’t include things like adjusting your mirrors, verifying that you won’t drive into another person or car, and so on. In one sense, it is incredibly impressive that three dogs in New Zealand have learned – in a fairly rudimentary way – to drive a car. They sit in the driver’s seat, shift into gear, operate the steering wheel, and step on the accelerator. Those deserving the true accolades however are not the dogs, but the human trainers for their impressive patience and determination. The training that led man’s best friend to operate a car is no different from the kind of training behind the bird shows found at zoos all over the world, or the dolphin, killer whale, seal, or sea lion displays you might see at Sea World. It’s the same kind of training that scientists use to probe the emotional and cognitive lives of rats, mice, and the other critters that populate their laboratories. At the end of the day, it all comes down to a form of learning first described by Edward L. Thorndike at the beginning of the 1900s, which was later expanded and popularized by B.F. Skinner and taught to every student of Introductory Psychology: operant conditioning. While classical conditioning is a form of learning that binds external stimuli to reflexive, involuntary responses, operant conditioning involves voluntary behaviors, and is maintained over time by the consequences that follow those behaviors. In one experiment, Skinner placed pigeons individually into experimental chambers (sometimes referred to as “Skinner boxes”) that were designed to deliver food rewards at systematic intervals. He found that by rewarding a bird after it displayed a desired behavior, he could motivate the bird to increase the frequency of that particular behavior. © 2012 Scientific American
Keyword: Learning & Memory
Link ID: 17607 - Posted: 12.14.2012
By Brian Mossop Ten years into serving a life sentence for the rape of Jennifer Thompson, Ronald Cotton stepped out of prison a free man. It took that long for DNA evidence to exonerate Cotton, refuting a weak case built mostly on eyewitness accounts. According to Simon's new book In Doubt, despite advances in DNA forensic technologies, eyewitness testimony remains the most common way to nab criminals in the Anglo-American justice system. The problem, however, is that our mind often subconsciously twists the evidence to coincide with our biases, and we end up incarcerating innocent people. Simon, a professor of law and psychology at the University of Southern California, says that the false conviction rate, based on exoneration data from capital murder cases, is estimated to be near 5 percent, although that figure represents only a fraction of those wrongly imprisoned. Eyewitness testimony boils down to how well the witness remembers the event. Studies have shown that a victim of a crime may remember a specific piece of information from the horrid event, such as the attacker's jacket or a strange smell, but fail to recall other details. Investigators are left with a weak profile of the perpetrator. In Cotton's case, the victim initially chose two men from the lineup, and only after repeated questioning from investigators could Thompson say Cotton was her assailant. © 2012 Scientific American
Keyword: Learning & Memory
Link ID: 17564 - Posted: 12.03.2012
Smoking "rots" the brain by damaging memory, learning and reasoning, according to researchers at King's College London. A study of 8,800 people over 50 showed high blood pressure and being overweight also seemed to affect the brain, but to a lesser extent. Scientists involved said people needed to be aware that lifestyles could damage the mind as well as the body. Their study was published in the journal Age and Ageing. Researchers at King's were investigating links between the likelihood of a heart attack or stroke and the state of the brain. Data about the health and lifestyle of a group of over-50s was collected and brain tests, such as making participants learn new words or name as many animals as they could in a minute, were also performed. They were all tested again after four and then eight years. Decline The results showed that the overall risk of a heart attack or stroke was "significantly associated with cognitive decline" with those at the highest risk showing the greatest decline. It also said there was a "consistent association" between smoking and lower scores in the tests. BBC © 2012
By Simon J Makin “One hundred repetitions three nights a week for four years – sixty-two thousand four hundred repetitions make one truth.” These are the thoughts of Bernard Maxwell as he reflects on The World State’s sleep-teaching technique, hypnopaedia, in Aldous Huxley’s Brave New World, before concluding: “Idiots!” Huxley was using the idea to explore social conditioning and control in a dystopian future, rather than what we might call “useful” learning, but the promise of effortless learning while we sleep is an idea that refuses to go away, as evidenced by the continued existence of dubious sleep learning “courses”. The possibility was dismissed scientifically in the 1950s after an experiment showing that people who were played the answers to a list of questions while they slept could not recall any of them the next day, unless they had also shown electrical brain activity indicating they were waking up. But evidence is now growing that the sleeping brain can, in fact, be taught in certain, limited ways. The most striking demonstration of this comes from a recent study published in Nature Neuroscience, in which people learned to associate sounds with smells while they were asleep. Pleasant and unpleasant odours were paired with different sounds played to sleeping participants and their “sniff responses” were measured. Pleasant smells provoked stronger sniffs and when the sounds paired with these smells were later played alone they still provoked stronger sniffs than those that had been paired with unpleasant odours. This was true both while the participants were still asleep and after they awoke and, unsurprisingly, they had no awareness of having learned anything. This is a limited form of learning known as conditioning, famous since Pavlov and his dog, and it can’t be used for learning anything as complex as, say, language vocab. © 2012 Scientific American
Sandrine Ceurstemont, editor, New Scientist TV Improving your mathematical skills could now be as easy as playing a Kinect video game in a hat. In preliminary tests of the system, developed by Roi Cohen Kadosh and colleagues from the University of Oxford, participants were better with numbers after just two days of training. In this video, our technology features editor Sally Adee gives the game a go while testing a new cap that wirelessly delivers electrical brain stimulation. The device is controlled by a computer, which controls things like the duration of the zapping. Although it can stimulate various brain regions, in this case it sends current to the right parietal cortex. "The parietal region is involved in numerical understanding," says Cohen Kadosh. "So amplifying the function of this region should lead to a better performance." So far, the team has shown that brain stimulation while doing computer-based mathematics exercises helped maintain better mathematical skills in adults even six months later. But Cohen Kadosh thinks that the Kinect game is much more promising as a training tool because it's fun and engaging. By requiring a player to represent a fraction by moving their body to position it on a line, the gameplay also integrates three key components linked to mathematical ability: numerical understanding, the ability to perceive the spatial relationship of visual representations and embodiment. Cohen Kadosh believes this enhances the training. © Copyright Reed Business Information Ltd
By Hal Arkowitz and Scott O. Lilienfeld When Mick Jagger first sang “What a drag it is getting old,” he was 23 years old. Now at 69, he is still a veritable Jumpin' Jack Flash on stage. Jagger seems to have found the secret to staying physically fit in his advancing years, but getting old can be a drag on the psyche. Many older adults fear memory loss and worry they are headed down the road to dementia, such as Alzheimer's disease. Every time they forget their keys, leave a door unlocked or fail to remember a name, they are reminded of this nagging concern. In most cases, however, such annoying incidents are part of normal age-related memory loss, not a sign of impending dementia. Although lots of older adults think such a decline is inevitable, there is good news for many of them. Researchers have developed an array of helpful methods and activities that exercise our minds and bodies that can help keep the older mind in relatively good condition. In this column, we examine the most promising ways to shore up memory in the normal aging brain. Memory is not a single entity. The term encompasses several types of remembering, not all of which decline with age. For instance, older people still retain their vocabulary, along with general knowledge about the world (semantic memory). They can also perform certain routine tasks, such as making an omelet or typing on a computer (procedural memory), about as well as they could when they were younger. People do become worse, however, at recalling recent events in their lives (episodic memory) or where they first learned a piece of information (source memory), managing the temporary storage of short-term information (working memory), and remembering to do things in the future (prospective memory). © 2012 Scientific American
By SINDYA N. BHANOO Fairywrens teach their chicks a password, a unique note, to differentiate them from imposters. “We call this an incubation call,” said Mark Hauber, an animal behaviorist at Hunter College at the City University of New York and an author of the study, which appears in the journal Current Biology. “The more times the mother calls, the better the mimicry of the chicks.” The teaching begins a few days before the birds hatch. And while “the cuckoo chick is very adaptable and tries out many begging calls until it sounds similar to the fairywren,” Dr. Hauber said, it also has a shorter incubation period. So it hatches several days before fairywren chicks, leaving it little time to practice and perfect the passwordlike call of the fairywren mother. Generally, when a cuckoo hatches it throws out the other eggs in the nest. When a mother does not hear her unique call from her babies, she abandons the nest. Male fairywrens help their mates care for their young, so the mother teaches her mate and any other helpers the password through the performance of a special song. “In the future we’d like to do some brain imaging on the embryos using noninvasive functional M.R.I.’s,” Dr. Hauber said. “We want to see how these embryos are listening, practicing and learning these relevant vocalizations.” © 2012 The New York Times Company
By GRETCHEN REYNOLDS In recent years, some research has suggested that a high-fat diet may be bad for the brain, at least in lab animals. Can exercise protect against such damage? That question may have particular relevance now, with the butter-and cream-laden holidays fast approaching. And it has prompted several new and important studies. The most captivating of these, presented last month at the annual meeting of the Society for Neuroscience in New Orleans, began with scientists at the University of Minnesota teaching a group of rats to scamper from one chamber to another when they heard a musical tone, an accepted measure of the animals’ ability to learn and remember. For the next four months, half of the rats ate normal chow. The others happily consumed a much greasier diet, consisting of at least 40 percent fat. Total calories were the same in both diets. After four months, the animals repeated the memory test. Those on a normal diet performed about the same as they had before; their cognitive ability was the same. The high-fat eaters, though, did much worse. Then, half of the animals in each group were given access to running wheels. Their diets didn’t change. So, some of the rats on the high-fat diet were now exercising. Some were not. Ditto for the animals eating the normal diet. For the next seven weeks, the memory test was repeated weekly in all of the groups. During that time, the performance of the rats eating a high-fat diet continued to decline so long as they didn’t exercise. Copyright 2012 The New York Times Company
Seniors who take common medications to treat insomnia, anxiety, itching or allergies may have symptoms of forgetfulness or trouble concentrating, a new review concludes. About 90 per cent of people aged 65 and older take at least one prescription medication and almost half take five or more, studies suggest. About 90 per cent of people aged 65 and older take at least one prescription medication, U.S. research suggests.About 90 per cent of people aged 65 and older take at least one prescription medication, U.S. research suggests. (iStock) As people increasingly report memory and attention problems and seek testing for early dementia, researchers in Montreal wanted to see how medications can induce such symptoms. Dr. Cara Tannenbaum, research chair at the Montreal Geriatric University Institute and her co-authors in Montreal, Calgary, Australia and the U.S. reviewed 162 studies on medications most likely to affect memory, creating what's called an amnesia effect, or affect brain functions like attention and concentration that are called non-amnestic. "There is a consistent body of evidence suggesting that drug-induced mild cognitive impairment can occur with episodic use of medications for insomnia, anxiety, [itching] or allergy symptoms," the study's authors concluded in the journal Drugs & Aging. "Combined amnestic and non-amnestic deficits occur with the use of benzodiazepine agents and may partially underlie older adults' frequent complaints of forgetfulness or difficulty concentrating." © CBC 2012
The brain holds in mind what has just been seen by synchronizing brain waves in a working memory circuit, an animal study supported by the National Institutes of Health suggests. The more in-sync such electrical signals of neurons were in two key hubs of the circuit, the more those cells held the short-term memory of a just-seen object. Charles Gray, Ph.D., of Montana State University, Bozeman, and colleagues, report their findings Nov. 1, 2012, online, in the journal Science Express. "This work demonstrates, for the first time, that there is information about short term memories reflected in in-sync brainwaves," explained Gray. "The Holy Grail of neuroscience has been to understand how and where information is encoded in the brain. This study provides more evidence that large scale electrical oscillations across distant brain regions may carry information for visual memories," said NIMH director Thomas R. Insel, M.D. Prior to the study, scientists had observed synchronous patterns of electrical activity between the two circuit hubs after a monkey saw an object, but weren’t sure if the signals actually represent such short-term visual memories in the brain. Rather, it was thought that such neural oscillations might play the role of a traffic cop, directing information along brain highways. To find out more, Gray, Rodrigo Salazar Ph.D., and Nick Dotson of Montana State and Steven Bressler, Ph.D., at Florida Atlantic University, Boca Raton, recorded electrical signals from groups of neurons in both hubs of two monkeys performing a visual working memory task. To earn a reward, the monkeys had to remember an object — or its location — that they saw momentarily on a computer screen and correctly match it. The researchers expected to see the telltale boost in synchrony during a delay period immediately after an object disappeared from the screen, when the monkey had to hold information briefly in mind.
Keyword: Learning & Memory
Link ID: 17456 - Posted: 11.06.2012
By MARGALIT FOX Arthur R. Jensen, an educational psychologist who ignited an international firestorm with a 1969 article suggesting that the gap in intelligence-test scores between black and white students might be rooted in genetic differences between the races, died on Oct. 22 at his home in Kelseyville, Calif. He was 89. His death was confirmed by the University of California, Berkeley, where he was an emeritus professor in the Graduate School of Education. Professor Jensen was deeply interested in differential psychology, a field whose central question — What makes people behave and think differently from one another? — strikes at the heart of the age-old nature-nurture debate. Because of his empirical work in the field on the quantification of general intelligence (a subject that had long invited a more diffuse, impressionistic approach), he was regarded by many colleagues as one of the most important psychologists of his day. But a wider public remembered him almost exclusively for his 1969 article “How Much Can We Boost I.Q. and Achievement?” Published in The Harvard Educational Review, a scholarly journal, the article quickly became — and remains even now — one of the most controversial in psychology. In the article, Professor Jensen posited two types of learning ability. Level I, associative ability, entailed the rote retention of facts. Level II, conceptual ability, involved abstract thinking and problem-solving. This type, he argued, was roughly equivalent to general intelligence, denoted in psychology by the letter “g.” © 2012 The New York Times Company
By DAN HURLEY IN the back room of a suburban storefront previously occupied by a yoga studio, Nick Vecchiarello, a 16-year-old from Glen Ridge, N.J., sits at a desk across from Kathryn Duch, a recent college graduate who wears a black shirt emblazoned with the words “Brain Trainer.” Spread out on the desk are a dozen playing cards showing symbols of varying colors, shapes and sizes. Nick stares down, searching for three cards whose symbols match. “Do you see it?” Ms. Duch asks encouragingly. “Oh, man,” mutters Nick, his eyes shifting among the cards, looking for patterns. Across the room, Nathan Veloric, 23, studies a list of numbers, looking for any two in a row that add up to nine. With tight-lipped determination, he scrawls a circle around one pair as his trainer holds a stopwatch to time him. Halfway through the 50 seconds allotted to complete the exercise, a ruckus comes from the center of the room. “Nathan’s here!” shouts Vanessa Maia, another trainer. Approaching him with a teasing grin, she claps her hands like an annoying little sister. “Distraction!” she shouts. “Distraction!” There is purpose behind the silliness. Ms. Maia is challenging the trainees to stay focused on their tasks in the face of whatever distractions may be out there, whether Twitter feeds, the latest Tumblr posting or old-fashioned classroom commotion. On this Wednesday evening at the Upper Montclair, N.J., outlet of LearningRx, a chain of 83 “brain training” franchises across the United States, the goal is to improve cognitive skills. LearningRx is one of a growing number of such commercial services — some online, others offered by psychologists. Unlike traditional tutoring services that seek to help students master a subject, brain training purports to enhance comprehension and the ability to analyze and mentally manipulate concepts, images, sounds and instructions. In a word, it seeks to make students smarter. © 2012 The New York Times Company
By Gary Stix Nicotine enhances the ability to focus and remember. The alkaloid acts in a similar manner to the brain’s own signaling molecule, acetylcholine. It interacts with eponymous receptors on the surface of nerve cells to regulate signaling in the brain. The role of the nicotinic-acetylcholine receptors throughout the central nervous system is so wide-ranging that new discoveries about the molecule continue apace. A recent study published in Nature Neuroscience found that one type of nicotinic receptor acts as a key element in a cell that appears to perform a critical function in regulating memory. A team of researchers—led by one group from Uppsala University in Sweden and another from Rio Grande do Norte in Brazil—found that a type of nicotinic receptor on a cell called oriens lacunosum-moleculare (OLM-alpha 2) seems to be involved in turning on a critical circuit in the hippocampus, a brain structure involved with memory formation. “This cell has a significant influence on the incoming information to the hippocampus,” says Klas Kullander from Uppsala University. When this circuit is switched on, visual, auditory or other inputs to the hippocampus are targeted for additional processing of the incoming information, perhaps a means of flagging its importance so that it can be directed to the cerebral cortex for long-term storage of memory. The on-state of this circuit “prioritizes more intense local processing of the information,” Kullander says. “It lets the hippocampus dwell on the information longer.” © 2012 Scientific American
Keyword: Learning & Memory
Link ID: 17443 - Posted: 11.03.2012
David Cyranoski More than a decade of research hinting that magnesium supplements might boost your brain power is finally being put to the test in a small clinical trial. The research, led by biopharmaceutical company Magceutics of Hayward, California, began testing the ability of its product Magtein to boost magnesium ion (Mg2+) levels in the brain earlier this month. The trial will track whether the ions can decrease anxiety and improve sleep quality, as well as following changes in the memory and cognitive ability of participants. But critics caution that the trial in just 50 people is too small to draw definitive conclusions. Neuroscientist Guosong Liu of the Massachusetts Institute of Technology in Cambridge, who founded Magceutics, plans eventually to test whether Magtein can be used to treat a wider range of conditions, including attention deficit hyperactivity disorder (ADHD) and Alzheimer’s disease. But Liu knows that it will be difficult to convince other scientists that something as simple as a magnesium supplement can have such profound effects. It is almost “too good to be true”, he says. Many scientists contacted by Nature agreed with that sentiment. One clinical researcher cautioned against “over-excitement about a magic drug for a major disorder”. And others wonder whether the study will even be able to prove anything conclusively. “I am very sceptical that the proposed trial will provide the answer to the question being tested,” says Stephen Ferguson, a biochemist at the University of Western Ontario in London, Ontario. © 2012 Nature Publishing Group
By Daisy Yuhas We're all familiar with the feeling—waking up from a restless night only to realize that this will be a very long, sleepy day. Recent research reveals that honeybees are also sensitive to sleep deprivation, and although a cup of coffee may give you a morning buzz, the bees aren't so lucky. Neurobiologists at the Free University of Berlin have found that sleepy bees fail to remember lessons learned the day before, a finding that could help scientists discover the neural processes involved in sleep and memory formation. They present their research October 25 in the Journal of Experimental Biology. "We started with the idea that we could look for a neural substrate of learning and memory in bees, since they have a wonderful memory, can be easily trained, and we know their brain well at the neuronal level," says study co-author Randolf Menzel. After characterizing how honeybees find their way home when released in a new location, the scientists captured and then released bees in unfamiliar territory some 600 meters from their hive. In addition to tracking how long the bees needed to return home, the researchers monitored bee sleep. Bees take brief naps throughout the day in addition to longer periods of nocturnal sleep. (Snoozing bees are easy to spot because their antennae droop.) The scientists made their observations both by watching bees in person and by tracking their activity via radio-frequency devices that they glued onto some of the insects. © 2012 Scientific American
by Sara Reardon Sleeping helps us reset our brains and calm our emotions. Perhaps it can do more, though: if sleepers are exposed to odours they associate with bad memories, it appears they can lose the fear those memories bring. Previous studies have shown that sleep helps eliminate fear in general. But whether it is possible to focus this effect through the careful use of odours has not been tested in humans. Katherina Hauner and Jay Gottfried of Northwestern University in Evanston, Illinois, exposed subjects to four pictures of faces and a series of inoffensive smells such as mint. When one of the faces appeared, the volunteers got a painful electric shock. Afterwards, the researchers measured the amount of electricity conducted by the subjects' skin – a measure that goes up when afraid, because the sweat produced is a good conductor. The researchers found that conductance spiked whenever the volunteers saw the face associated with the shock. They then let half the subjects sleep, and exposed this group to variable amounts of the odour that had been presented along with the "painful" face. The next day, these volunteers were much less afraid of the face – and those with the least fear were those that had received the highest exposure to the odour while asleep. Brain scans also showed that brain areas associated with fear and with memory were less active after this exposure. © Copyright Reed Business Information Ltd.
By SINDYA N. BHANOO Most people have a moment or two they would rather not remember. The brain has two opposite ways of dealing with those memories, researchers report in a new study. The first is to simply block out the memory. The second is to recall a substitute memory. Take the case of a fight with a loved one, said Roland Benoit, a cognitive neuroscientist at the Medical Research Council Cognition and Brain Sciences Unit in Cambridge, England. “You don’t want to think about it because you want to just go on with life,” Dr. Benoit said. “You can somehow push it out, or you could try to think of something else, like maybe that nice vacation to France you had together.” Dr. Benoit and his colleagues asked study participants to associate the words “beach” and “Africa.” Then one group was told to avoid thinking about the associated words altogether. Another group was told to start thinking about the word “snorkel” in association with “beach,” rather than “Africa.” The participants were put under a functional M.R.I. scanner, and the researchers found that in the case of memory substitution, the left prefrontal cortex works in conjunction with the hippocampus, an area of the brain connecting to conscious remembering. But when an unwanted memory is simply suppressed or blocked out, the prefrontal cortex actually inhibits the functioning of the hippocampus. © 2012 The New York Times Company
Keyword: Learning & Memory
Link ID: 17406 - Posted: 10.23.2012
By Laura Sanders NEW ORLEANS — Fearful associations can be knocked back during sleep, research in mice shows. After receiving an injection of a drug, a nasty link between a scent and a painful foot shock faded as the mice slumbered. The results are preliminary but may ultimately show how to get around a roadblock in treatments for people with post-traumatic stress disorder: Traumatic associations can be weakened in a doctor’s office, but those memories can flood back when triggered by specific events in everyday life. The new finding suggests that the hazy world of sleep, lacking any particular real-world context, might be a better place to diminish such memories. Neuroscientist Asya Rolls of Stanford University and colleagues taught mice that when they smelled jasmine, a foot shock was not far behind. A day later, as the mice slept, the researchers wafted the smell over the animals, strengthening and solidifying the scary link between jasmine and pain. A day after that, the mice froze in fear when they caught a whiff of jasmine, even though the animals were in an entirely new room unassociated with the original shock. But Rolls and her team could interrupt this sleep-strengthening process with the antibiotic anisomycin, injected into the amygdala—a brain structure involved in memory storage. Before the mice were exposed to jasmine during sleep, the researchers injected some of them with the drug. The next day, these mice didn’t freeze as much as the mice that didn’t get the drug. The results suggest that during sleep, traumatic memories, such as the kind that plague people with PTSD, can be effectively weakened. © Society for Science & the Public 2000 - 2012
by Helen Thomson, New Orleans HUMANS are constantly searching for an elixir of youth - could it be that an infusion of young blood holds the key? This seems to be true for mice, at least. According to research presented this week at the Society for Neuroscience conference in New Orleans, Louisiana, giving young blood to old mice can reverse some of the effects of age-related cognitive decline. Last year, Saul Villeda, then at Stanford University in California, and colleagues showed they could boost the growth of new cells in the brains of old mice by giving them a blood infusion from young mice (Nature, doi.org/c9jwvm). "We know that blood has this huge effect on brain cells, but we didn't know if its effects extended beyond cell regeneration," he says. Now the team has tested for changes in cognition by linking the circulatory systems of young and old mice. Once the blood of each conjoined mouse had fully mixed with the other, the researchers analysed their brains. Tissue from the hippocampus of old mice given young blood showed changes in the expression of 200 to 300 genes, particularly in those involved in synaptic plasticity, which underpins learning and memory. They also found changes in some proteins involved in nerve growth. The infusion of young blood also boosted the number and strength of neuronal connections in an area of the brain where new cells do not grow. This didn't happen when old mice received old blood. © Copyright Reed Business Information Ltd.
Sitting exams and tests is often a nerve-racking experience, but being anxious beforehand may boost a candidate's grades, researchers say. A study published in the British Journal of Psychology finds being anxious only has a negative impact on results if a child's memory is poor. But if a young person has a good memory, a tendency to feel anxious is linked with getting better marks. The research assessed 96 children aged 12 to 14 in memory and anxiety tests. A questionnaire established how anxious the children usually felt, and the results were measured against their ability to perform computerised tests involving "complex" or working-memory skills. "We found that for individuals with low working-memory capacity, increases in [a tendency towards] anxiety were related to decreases in cognitive test performance," the study says. "For those with high working-memory capacity, however, the pattern of results was reversed. An increase in [a tendency towards] anxiety was linearly associated with higher test scores. "These effects were not better accounted for by gender, age, or time of testing." Poor memory The researchers say the results of the study should encourage education professionals to target help at anxious children with poor complex memory skills. BBC © 2012