Chapter 17. Learning and Memory

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By Julia Shaw We all have times of day when we are not at our best. For me, before 10am, and between 2-4pm, it’s as though my brain just doesn’t work the way it should. I labor to come up with names, struggle to keep my train of thought, and my eloquence drops to the level expected of an eight-year-old. In an effort to blame my brain for this, rather than my motivation, I reached out to a researcher in the area of sleep and circadian neuroscience. Andrea Smit, a PhD student working with Professors John McDonald and Ralph Mistlberger at Simon Fraser University in Canada, was happy to help me find excuses for why my memory is so terribly unreliable at certain times of day. Humans have daily biological rhythms, called circadian rhythms, which affect almost everything that we do. They inform our bodies when it is time to eat and sleep, and they dictate our ability to remember things. According to Smit, “Chronotype, the degree to which someone is a “morning lark” or a “night owl,” is a manifestation of circadian rhythms. In a recent study, Smit used EEG, a type of brain scan, to study the interaction between chronotypes and memory. “Testing extreme chronotypes at multiple times of day allowed us to compare attentional abilities and visual short term memory between morning larks and night owls. Night owls were worse at suppressing distracting visual information and had a worse visual short term memory in the morning as compared with the afternoon,” she says. “Our research shows that circadian rhythms interact with memories even at very early stages of processing within the brain.” © 2017 Scientific American

Keyword: Biological Rhythms; Learning & Memory
Link ID: 23194 - Posted: 02.07.2017

Diana Steele Generations of gurus have exhorted, “Live in the moment!” For Lonni Sue Johnson, that’s all she can do. In 2007, viral encephalitis destroyed Johnson’s hippocampus. Without that crucial brain structure, Johnson lost most of her memories of the past and can’t form new ones. She literally lives in the present. In The Perpetual Now, science journalist Michael Lemonick describes Johnson’s world and tells the story of her life before her illness, in which she was an illustrator (she produced many New Yorker covers), private pilot and accomplished amateur violist. Johnson can’t remember biographical details of her own life, recall anything about history or remember anything new. But remarkably, she can converse expertly about making art and she creates elaborately illustrated word-search puzzles. She still plays viola with expertise and expression and, though she will never remember that she has seen it before, she can even learn new music. Neuroscientists are curious about Johnson’s brain in part because her education and expertise before her illness contrast sharply with that of the most famous amnesiac known to science, Henry Molaison. Lemonick interweaves the story of “Patient H.M.,” as he was known, with Johnson’s biography. Molaison had experienced seizures since childhood and held menial jobs until surgery in his 20s destroyed his hippo-campus. At the time, in the 1950s, Molaison’s subsequent amnesia came as a surprise, prompting a 50-year study of his brain that provided a fundamental understanding of the central role of the hippocampus in forming conscious memories. © Society for Science & the Public 2000 - 2016.

Keyword: Learning & Memory
Link ID: 23189 - Posted: 02.06.2017

Hannah Devlin Science correspondent It sounds like torment for the smoker attempting to quit: handling packets of cigarettes and watching footage of people smoking, without being allowed to light up. However, scientists believe that lengthy exposure to environmental triggers for cravings could be precisely what smokers need to help them quit. The technique, known as extinction therapy, targets the harmful Pavlovian associations that drive addiction with the aim of rapidly “unlearning” them. The latest study, by scientists at the Medical University of South Carolina, found that after two one-hour sessions people smoked significantly fewer cigarettes one month after treatment compared to a control group. The study was not an unqualified success – many participants still relapsed after treatment – but the authors believe the work could pave the way for new approaches to treating addiction. Michael Saladin, the psychologist who led the work, said: “When I initially saw the results from this study it was pretty eye-opening.” In smokers, environmental triggers have typically been reinforced thousands of times so that the sight of a lighter, for instance, becomes inextricably linked to the rush of nicotine that the brain has learned will shortly follow. After quitting an addictive substance, these associations fade slowly over time, but people often flounder in the first days and weeks when cravings are most powerful. Saladin and others believe it is possible to fast-track this process in carefully designed training sessions, to help people over the initial hurdle. © 2017 Guardian News and Media Limited

Keyword: Drug Abuse; Learning & Memory
Link ID: 23187 - Posted: 02.04.2017

Ah, to sleep, perchance … to shrink your neural connections? That's the conclusion of new research that examined subtle changes in the brain during sleep. The researchers found that sleep provides a time when thebrain's synapses — the connections among neurons—shrink back by nearly 20 percent. During this time, the synapses rest and prepare for the next day, when they will grow stronger while receiving new input—that is, learning new things, the researchers said. Without this reset, known as "synaptic homeostasis," synapses could become overloaded and burned out, like an electrical outlet with too many appliances plugged in to it, the scientists said. "Sleep is the perfect time to allow the synaptic renormalization to occur … because when we are awake, we are 'slaves' of the here and now, always attending some stimuli and learning something," said study co-author Dr. Chiara Cirelli of the University of Wisconsin-Madison Center for Sleep and Consciousness. "During sleep, we are much less preoccupied by the external world … and the brain can sample [or assess] all our synapses, and renormalize them in a smart way," Cirelli told Live Science. Cirelli and her colleague, Dr. Giulio Tononi, also of the University of Wisconsin-Madison, introduced this synaptic homeostasis hypothesis (SHY) in 2003. © 2017 Scientific American

Keyword: Sleep; Learning & Memory
Link ID: 23186 - Posted: 02.04.2017

Carl Zimmer Over the years, scientists have come up with a lot of ideas about why we sleep. Some have argued that it’s a way to save energy. Others have suggested that slumber provides an opportunity to clear away the brain’s cellular waste. Still others have proposed that sleep simply forces animals to lie still, letting them hide from predators. A pair of papers published on Thursday in the journal Science offer evidence for another notion: We sleep to forget some of the things we learn each day. In order to learn, we have to grow connections, or synapses, between the neurons in our brains. These connections enable neurons to send signals to one another quickly and efficiently. We store new memories in these networks. In 2003, Giulio Tononi and Chiara Cirelli, biologists at the University of Wisconsin-Madison, proposed that synapses grew so exuberantly during the day that our brain circuits got “noisy.” When we sleep, the scientists argued, our brains pare back the connections to lift the signal over the noise. In the years since, Dr. Tononi and Dr. Cirelli, along with other researchers, have found a great deal of indirect evidence to support the so-called synaptic homeostasis hypothesis. It turns out, for example, that neurons can prune their synapses — at least in a dish. In laboratory experiments on clumps of neurons, scientists can give them a drug that spurs them to grow extra synapses. Afterward, the neurons pare back some of the growth. Other evidence comes from the electric waves released by the brain. During deep sleep, the waves slow down. Dr. Tononi and Dr. Cirelli have argued that shrinking synapses produce this change. © 2017 The New York Times Company

Keyword: Sleep; Learning & Memory
Link ID: 23184 - Posted: 02.03.2017

Homa Khaleeli The old saying, “If at first you don’t succeed: try, try again”, might need rewriting. Because, according to new research, even if you do succeed, you should still try, try again. “Overlearning”, scientists say, could be the key to remembering what you have learned. In a study of 183 volunteers, participants were asked to spot the orientation of a pattern in an image. It is a task that took eight 20-minute rounds of training to master. Some volunteers, however, were asked to carry on for a further 16 20-minute blocks to “overlearn” before being moved on to another task. When tested the next day, they had retained the ability better than those who had mastered it and then stopped learning. Primary school encourages pupils to wear slippers in class Read more The lead author of the paper, Takeo Watanabe, a professor of cognitive linguistic and psychological sciences, pointed out that: “If you do overlearning, you may be able to increase the chance that what you learn will not be gone.” But what other tricks can help us learn better? According to researchers at Bournemouth University, children who don’t wear shoes in the classroom not only learn, but behave better. Pupils feel more relaxed when they can kick their shoes off at the door says lead researcher Stephen Heppell, which means they are more engaged in lessons. © 2017 Guardian News and Media Limited

Keyword: Learning & Memory
Link ID: 23173 - Posted: 02.01.2017

By SHERI FINK, STEVE EDER and MATTHEW GOLDSTEIN A group of brain performance centers backed by Betsy DeVos, the nominee for education secretary, promotes results that are nothing short of stunning: improvements reported by 91 percent of patients with depression, 90 percent with attention deficit disorder, 90 percent with anxiety. The treatment offered by Neurocore, a business in which Ms. DeVos and her husband, Dick, are the chief investors, consists of showing movies to patients and interrupting them when the viewers become distracted, in an effort to retrain their brains. With eight centers in Michigan and Florida and plans to expand, Neurocore says it has assessed about 10,000 people for health problems that often require medication. “Is it time for a mind makeover?” the company asks in its advertising. “All it takes is science.” But a review of Neurocore’s claims and interviews with medical experts suggest its conclusions are unproven and its methods questionable. Neurocore has not published its results in peer-reviewed medical literature. Its techniques — including mapping brain waves to diagnose problems and using neurofeedback, a form of biofeedback, to treat them — are not considered standards of care for the majority of the disorders it treats, including autism. Social workers, not doctors, perform assessments, and low-paid technicians with little training apply the methods to patients, including children with complex problems. In interviews, nearly a dozen child psychiatrists and psychologists with expertise in autism and attention deficit hyperactivity disorder, or A.D.H.D., expressed caution regarding some of Neurocore’s assertions, advertising and methods. “This causes real harm to children because it diverts attention, hope and resources,” said Dr. Matthew Siegel, a child psychiatrist at Maine Behavioral Healthcare and associate professor at Tufts School of Medicine, who co-wrote autism practice standards for the American Academy of Child and Adolescent Psychiatry. “If there were something out there that was uniquely powerful and wonderful, we’d all be using it.” © 2017 The New York Times Company

Keyword: Learning & Memory
Link ID: 23171 - Posted: 01.31.2017

By Andrew Joseph, Public health officials on Thursday said they had detected a bizarre cluster of cases in which patients in Massachusetts developed amnesia over the past few years — a highly unusual syndrome that could be connected to opioid use. The officials have identified only 14 cases so far. But officials said it’s possible that clinicians have simply missed other cases. The patients were all relatively young — they ranged in age from 19 to 52. Thirteen of the 14 patients identified had a substance use disorder, and the 14th patient tested positive for opioids and cocaine on a toxicology screen. “What we’re concerned about is maybe a contaminant or something else added to the drug might be triggering this,” said Dr. Alfred DeMaria, the state epidemiologist at the Massachusetts Department of Public Health and an author of the new report. “Traditionally there’s no evidence that the drugs themselves can do this.” The pattern emerged when Dr. Jed Barash, a neurologist at Lahey Hospital and Medical Center in Burlington, Mass., reported four of the amnesia cases to the state’s public health department. The department then sent out an alert to specialists, including neurologists and emergency physicians, asking about similar cases, ultimately identifying 10 more from 2012 to 2016 at hospitals in eastern Massachusetts. (The patients included one person who lived in New Hampshire and one person who was visiting Massachusetts from Washington state.) © 2017 Scientific American,

Keyword: Drug Abuse; Learning & Memory
Link ID: 23163 - Posted: 01.28.2017

By Anil Ananthaswamy People with post-traumatic stress disorder often get flashbacks that can be triggered by an innocuous smell or sound. Now a study that linked unrelated memories and separated them again, suggests that one day we may be able to decouple memories and prevent flashbacks in people with PTSD. Individual memories are stored in groups of neurons – an idea first proposed by psychologist Donald Hebb in 1949. Only now are we developing sophisticated techniques for examining these ensembles of neurons. To see whether two independent memories can become linked, Kaoru Inokuchi at the University of Toyama in Japan, and colleagues used a standard method for creating memories in mice. When mice are exposed to pain, they can learn to link this with associated stimuli, a taste, for example. The team trained mice to form two separate fear memories. First, the mice learned to avoid the sugary taste of saccharine. Whenever they licked a bottle filled with saccharine solution, they were injected with lithium chloride, which induces nausea. Disconnecting memories A few days later, the same mice were taught to associate a tone with a mild electric shock. This caused the mice to freeze whenever they heard it, even if it wasn’t followed with a shock. They remembered the tone as a traumatic experience. © Copyright Reed Business Information Ltd.

Keyword: Learning & Memory; Stress
Link ID: 23156 - Posted: 01.27.2017

By Helen Briggs BBC News The idea that dogs are more intelligent than cats has been called into question. Japanese scientists say cats are as good as dogs at certain memory tests, suggesting they may be just as smart. A study - involving 49 domestic cats - shows felines can recall memories of pleasant experiences, such as eating a favourite snack. Dogs show this type of recollection - a unique memory of a specific event known as episodic memory. Humans often consciously try to reconstruct past events that have taken place in their lives, such as what they ate for breakfast, their first day in a new job or a family wedding. These memories are linked with an individual take on events, so they are unique to that person. Saho Takagi, a psychologist at Kyoto University, said cats, as well as dogs, used memories of a single past experience, which may imply they have episodic memory similar to that of humans. "Episodic memory is viewed as being related to introspective function of the mind; our study may imply a type of consciousness in cats," she told BBC News. "An interesting speculation is that they may enjoy actively recalling memories of their experience like humans." The Japanese team tested 49 domestic cats on their ability to remember which bowl they had already eaten out of and which remained untouched, after a 15-minute interval. © 2017 BBC

Keyword: Learning & Memory; Evolution
Link ID: 23143 - Posted: 01.25.2017

By Ingfei Chen Learning Morse code, with its tappity-tap rhythms of dots and dashes, could take far less effort—and attention—than one might think. The trick is a wearable computer that engages the sensory powers of touch, according to a recent pilot study. The results suggest that mobile devices may be able to teach us manual skills, almost subconsciously, as we go about our everyday routines. Ph.D. student Caitlyn Seim and computer science professor Thad Starner of the Georgia Institute of Technology tinker with haptics, the integration of vibrations or other tactile cues with computing gadgets. Last September at the 20th International Symposium on Wearable Computers in Heidelberg, Germany, they announced that they had programmed Google Glass to passively teach its wearers Morse code—with preliminary signs of success. For the study, 12 participants wore the smart glasses while engrossed in an online game on a PC. During multiple hour-long sessions, half the players heard Google Glass's built-in speaker repeatedly spelling out words and felt taps behind the right ear (from a bone-conduction transducer built into the frames) for the dots and dashes corresponding to each letter. The other six participants heard only the audio, without the corresponding vibrations. After each run of game playing, all the players were asked to tap out letters in Morse code using a finger on the touch pad of the smart glasses; for example, if they tapped “dot-dot,” an “i” would pop up on the visual display. The brief testing essentially prompted them to try to learn the code. After four one-hour sessions, the group that had received tactile cues could tap a pangram (a sentence using the entire alphabet) with 94 percent accuracy. The audio-only group eventually achieved 47 percent accuracy, learning solely from their trial-and-error inputs. © 2017 Scientific American

Keyword: Learning & Memory
Link ID: 23138 - Posted: 01.24.2017

Ian Sample Science editor Tempting as it may be, it would be wrong to claim that with each generation humans are becoming more stupid. As scientists are often so keen to point out, it is a bit more complicated than that. A study from Iceland is the latest to raise the prospect of a downwards spiral into imbecility. The research from deCODE, a genetics firm in Reykjavik, finds that groups of genes that predispose people to spend more years in education became a little rarer in the country from 1910 to 1975. The scientists used a database of more than 100,000 Icelanders to see how dozens of gene variants that affect educational attainment appeared in the population over time. They found a shallow decline over the 65 year period, implying a downturn in the natural inclination to rack up qualifications. But the genes involved in education affected fertility too. Those who carried more “education genes” tended to have fewer children than others. This led the scientists to propose that the genes had become rarer in the population because, for all their qualifications, better educated people had contributed less than others to the Icelandic gene pool. Spending longer in education and the career opportunities that provides is not the sole reason that better educated people tend to start families later and have fewer children, the study suggests. Many people who carried lots of genes for prolonged education left the system early and yet still had fewer children that the others. “It isn’t the case that education, or the career opportunities it provides, prevents you from having more children,” said Kari Stefansson, who led the study. “If you are genetically predisposed to have a lot of education, you are also predisposed to have fewer children.” © 2017 Guardian News and Media Limited

Keyword: Intelligence; Genes & Behavior
Link ID: 23113 - Posted: 01.17.2017

Michelle Trudeau When Samantha Deffler was young, her mother would often call her by her siblings' names — even the dog's name. "Rebecca, Jesse, Molly, Tucker, Samantha," she says. A lot of people mix up children's names or friends' names, but Deffler is a cognitive scientist at Rollins College, in Winter Park, Fla., and she wanted to find out why it happens. So she did a survey of 1,700 men and women of different ages, and she found that naming mistakes are very common. Most everyone sometimes mixes up the names of family and friends. Her findings were published in the journal Memory & Cognition. "It's a normal cognitive glitch," Deffler says. It's not related to a bad memory or to aging, but rather to how the brain categorizes names. It's like having special folders for family names and friends names stored in the brain. When people used the wrong name, overwhelmingly the name that was used was in the same category, Deffler says. It was in the same folder. And there was one group who was especially prone to the naming mix-ups. "Moms, especially moms," Deffler says. "Any mom I talked to says, 'You know, I've definitely done this.'" It works something like this: Say you've got an armful of groceries and you need some quick help from one of your kids. Your brain tries to rapidly retrieve the name from the family folder, but it may end up retrieving a related name instead, says Neil Mulligan, a cognitive scientist at UNC Chapel Hill. © 2017 npr

Keyword: Learning & Memory
Link ID: 23106 - Posted: 01.16.2017

Alison Abbott Bats have brain cells that keep track of their angle and distance to a target, researchers have discovered. The neurons, called ‘vector cells’, are a key piece of the mammalian’s brain complex navigation system — and something that neuroscientists have been seeking for years. Our brain’s navigation system has many types of cells, but a lot of them seem designed to keep track of where we are. Researchers know of ‘place’ cells, for example, which fire when animals are in a particular location, and ‘head direction’ cells that fire in response to changes in the direction the head is facing. Bats also have a kind of neuronal compass that enables them to orient themselves as they fly. The vector cells, by contrast, keep spatial track of where we are going. They are in the brain’s hippocampus, which is also where ‘place’ and ‘head-direction’ cells were discovered. That’s a surprise, considering how well this area has been studied by researchers, says Nachum Ulanovsky, who led the team at the Weizmann Institute of Science in Rehovot, Israel, that discovered the new cells. His team published their findings in Science on 12 January1. Finding the cells "was one of those very rare discovery moments in a researcher’s life,” says Ulanovsky. “My heart raced, I started jumping around.” The trick to finding them was a simple matter of experimental design, he says. © 2017 Macmillan Publishers Limited

Keyword: Learning & Memory; Hearing
Link ID: 23097 - Posted: 01.13.2017

By Peter Godfrey-Smith Adapted from Other Minds: The Octopus, the Sea and the Deep Origins of Consciousness, by Peter Godfrey-Smith. Copyright © 2016 by Peter Godfrey-Smith. Someone is watching you, intently, but you can't see them. Then you notice, drawn somehow by their eyes. You're amid a sponge garden, the seafloor scattered with shrublike clumps of bright orange sponge. Tangled in one of these sponges and the gray-green seaweed around it is an animal about the size of a cat. Its body seems to be everywhere and nowhere. The only parts you can keep a fix on are a small head and the two eyes. As you make your way around the sponge, so, too, do those eyes, keeping their distance, keeping part of the sponge between the two of you. The creature's color perfectly matches the seaweed, except that some of its skin is folded into tiny, towerlike peaks with tips that match the orange of the sponge. Eventually it raises its head high, then rockets away under jet propulsion. A second meeting with an octopus: this one is in a den. Shells are strewn in front, arranged with some pieces of old glass. You stop in front of its house, and the two of you look at each other. This one is small, about the size of a tennis ball. You reach forward a hand and stretch out one finger, and one octopus arm slowly uncoils and comes out to touch you. The suckers grab your skin, and the hold is disconcertingly tight. It tugs your finger, tasting it as it pulls you gently in. The arm is packed with sensors, hundreds of them in each of the dozens of suckers. The arm itself is alive with neurons, a nest of nervous activity. Behind the arm, large round eyes watch you the whole time. © 2017 Scientific American

Keyword: Learning & Memory; Evolution
Link ID: 23095 - Posted: 01.13.2017

Dima Amso, The early years of parenthood involve so many rewarding firsts—when your infant cracks a toothless grin, when he crawls and later walks, and, of course, when he utters a real, nonbabble word. A mother once told me she found it sad that if she were to pass away suddenly, her toddler wouldn't remember her or these exciting years. It is true that most of us don't remember much, if anything, from our infancy. So at what point do children start making long-term memories? I must first explain the different types of memory we possess. As I type this, I am using procedural memory—a form of motor memory in which my fingers just know how to type. In contrast, declarative memories represent two types of long-term recall—semantic and episodic. Semantic memory allows us to remember general facts—for example, that Alfred Hitchcock directed the film Vertigo; episodic memory encompasses our ability to recall personal experiences or facts—that Vertigo is my favorite film. Episodic memories are most relevant for understanding our childhood recollections. Making an episodic memory requires binding together different details of an event—when it happened and where, how we felt and who was there—and retrieving that information later. The processes involve the medial temporal lobes, most notably the hippocampus, and portions of the parietal and prefrontal cortices, which are very important in memory retrieval. Imaging studies often show that the same regions that encode an episode—for example, the visual cortex for vivid visual experiences—are active when we recall that memory, allowing for a kind of “mental time travel” or replay of the event. © 2017 Scientific American

Keyword: Learning & Memory; Development of the Brain
Link ID: 23077 - Posted: 01.10.2017

Riley Beggin Matt Herich uses a tDCS device that was made by another student he met on Reddit. Four 9-volt batteries and sticky self-adhesive electrodes are connected by a circuit board that sends a constant small current to the user's brain. Courtesy of Matt Herich Last October, Matt Herich was listening to the news while he drove door to door delivering pizzas. A story came on the radio about a technology that sends an electric current through your brain to possibly make you better at some things — moving, remembering, learning. He was fascinated. The neurotechnology is called transcranial direct current stimulation, or tDCS for short. At its simplest, the method involves a device that uses little more than a 9-volt battery and some electrodes to send a low-intensity electrical current to a targeted area of the brain, typically via a headset. More than a 1,000 studies have been published in peer-reviewed journals over the last decade suggesting benefits of the technique — maybe regulating mood, possibly improving language skills — but its effects, good or bad, are far from clear. Although researchers see possibilities for tDCS in treating diseases and boosting performance, it's still an exploratory technology, says Mark George, editor-in-chief of Brain Stimulation, a leading journal on neuromodulation. And leading experts have warned against at-home use of such devices. © 2017 npr

Keyword: Learning & Memory
Link ID: 23071 - Posted: 01.09.2017

By LISA FELDMAN BARRETT Think about the people in your life who are 65 or older. Some of them are experiencing the usual mental difficulties of old age, like forgetfulness or a dwindling attention span. Yet others somehow manage to remain mentally sharp. My father-in-law, a retired doctor, is 83 and he still edits books and runs several medical websites. Why do some older people remain mentally nimble while others decline? “Superagers” (a term coined by the neurologist Marsel Mesulam) are those whose memory and attention isn’t merely above average for their age, but is actually on par with healthy, active 25-year-olds. My colleagues and I at Massachusetts General Hospital recently studied superagers to understand what made them tick. Our lab used functional magnetic resonance imaging to scan and compare the brains of 17 superagers with those of other people of similar age. We succeeded in identifying a set of brain regions that distinguished the two groups. These regions were thinner for regular agers, a result of age-related atrophy, but in superagers they were indistinguishable from those of young adults, seemingly untouched by the ravages of time. What are these crucial brain regions? If you asked most scientists to guess, they might nominate regions that are thought of as “cognitive” or dedicated to thinking, such as the lateral prefrontal cortex. However, that’s not what we found. Nearly all the action was in “emotional” regions, such as the midcingulate cortex and the anterior insula. My lab was not surprised by this discovery, because we’ve seen modern neuroscience debunk the notion that there is a distinction between “cognitive” and “emotional” brain regions. © 2017 The New York Times Company

Keyword: Alzheimers; Learning & Memory
Link ID: 23045 - Posted: 01.02.2017

Alan Yu Being overweight can raise your blood pressure, cholesterol and risk for developing diabetes. It could be bad for your brain, too. A diet high in saturated fats and sugars, the so-called Western diet, actually affects the parts of the brain that are important to memory and make people more likely to crave the unhealthful food, says psychologist Terry Davidson, director of the Center for Behavioral Neuroscience at American University in Washington, D.C. He didn't start out studying what people ate. Instead, he was interested in learning more about the hippocampus, a part of the brain that's heavily involved in memory. He was trying to figure out which parts of the hippocampus do what. He did that by studying rats that had very specific types of hippocampal damage and seeing what happened to them. In the process, Davidson noticed something strange. The rats with the hippocampal damage would go to pick up food more often than the other rats, but they would eat a little bit, then drop it. Davidson realized these rats didn't know they were full. He says something similar may happen in human brains when people eat a diet high in fat and sugar. Davidson says there's a vicious cycle of bad diets and brain changes. He points to a 2015 study in the Journal of Pediatrics that found obese children performed more poorly on memory tasks that test the hippocampus compared with kids who weren't overweight. He says if our brain system is impaired by that kind of diet, "that makes it more difficult for us to stop eating that diet. ... I think the evidence is fairly substantial that you have an effect of these diets and obesity on brain function and cognitive function." © 2016 npr

Keyword: Obesity; Learning & Memory
Link ID: 23039 - Posted: 12.31.2016

By Drake Baer Convergent evolution is what happens when nature takes different courses from different starting points to arrive at similar results. Consider bats, birds, and butterflies developing wings; sharks and dolphins finding fins; and echidnas and porcupines sporting spines. Or, if you want to annoy a traditionalist scientist, talk about humans and octopuses — and how they may both have consciousness. This is the thrust of Other Minds: The Octopus, the Sea, and the Deep Origins of Consciousness, a new book by the scuba-diving, biology-specializing philosopher Peter Godfrey-Smith, originally of Australia and now a distinguished professor at the City University of New York’s graduate center. The book was written up by Olivia Judson in The Atlantic, and you should read the whole thing, but what I find mesmerizing is how categorically other the eight-tentacled ink-squirters are, and how their very nature challenges our conceptualizations of intelligence. “If we can make contact with cephalopods as sentient beings, it is not because of a shared history, not because of kinship, but because evolution built minds twice over,” Godfrey-Smith is quoted as saying. “This is probably the closest we will come to meeting an intelligent alien.” (He’s not the first to think so: The Hawaiian creation myth holds that octopuses are the only creatures left over from an earlier incarnation of the Earth, making them more proto-terrestrials than extraterrestrials.) © 2016, New York Media LLC.

Keyword: Evolution; Learning & Memory
Link ID: 23020 - Posted: 12.26.2016