Chapter 16. None
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By JIM DWYER The real world of our memory is made of bits of true facts, surrounded by holes that we Spackle over with guesses and beliefs and crowd-sourced rumors. On the dot of 10 on Wednesday morning, Anthony O’Grady, 26, stood in front of a Dunkin’ Donuts on Eighth Avenue in Manhattan. He heard a ruckus, some shouts, then saw a police officer chase a man into the street and shoot him down in the middle of the avenue. Moments later, Mr. O’Grady spoke to a reporter for The New York Times and said the wounded man was in flight when he was shot. “He looked like he was trying to get away from the officers,” Mr. O’Grady said. Another person on Eighth Avenue then, Sunny Khalsa, 41, had been riding her bicycle when she saw police officers and the man. Shaken by the encounter, she contacted the Times newsroom with a shocking detail. “I saw a man who was handcuffed being shot,” Ms. Khalsa said. “And I am sorry, maybe I am crazy, but that is what I saw.” At 3 p.m. on Wednesday, the Police Department released a surveillance videotape that showed that both Mr. O’Grady and Ms. Khalsa were wrong. Contrary to what Mr. O’Grady said, the man who was shot had not been trying to get away from the officers; he was actually chasing an officer from the sidewalk onto Eighth Avenue, swinging a hammer at her head. Behind both was the officer’s partner, who shot the man, David Baril. And Ms. Khalsa did not see Mr. Baril being shot while in handcuffs; he is, as the video and still photographs show, freely swinging the hammer, then lying on the ground with his arms at his side. He was handcuffed a few moments later, well after he had been shot. © 2015 The New York Times Company
Keyword: Learning & Memory
Link ID: 20939 - Posted: 05.16.2015
By Tina Hesman Saey A man who had been blind for 50 years allowed scientists to insert a tiny electrical probe into his eye. The man’s eyesight had been destroyed and the photoreceptors, or light-gathering cells, at the back of his eye no longer worked. Those cells, known as rods and cones, are the basis of human vision. Without them, the world becomes gray and formless, though not completely black. The probe aimed for a different set of cells in the retina, the ganglion cells, which, along with the nearby bipolar cells, ferry visual information from the rods and cones to the brain. No one knew whether those information-relaying cells still functioned when the rods and cones were out of service. As the scientists sent pulses of electricity to the ganglion cells, the man described seeing a small, faint candle flickering in the distance. That dim beacon was a sign that the ganglion cells could still send messages to the brain for translation into images. That 1990s experiment and others like it sparked a new vision for researcher Zhuo-Hua Pan of Wayne State University in Detroit. He and his colleague Alexander Dizhoor wondered if, instead of tickling the cells with electricity, scientists could transform them to sense light and do what rods and cones no longer could. The approach is part of a revolutionary new field called optogenetics. Optogeneticists use molecules from algae or other microorganisms that respond to light or create new molecules to do the same, and insert them into nerve cells that are normally impervious to light. By shining light of certain wavelengths on the molecules, researchers can control the activity of the nerve cells. © Society for Science & the Public 2000 - 2015
Link ID: 20938 - Posted: 05.16.2015
by Rachel Ehrenberg It was the dress that launched a million tweets. In February, a mother-in-law-to-be sent a picture of a dress she was considering wearing to her daughter’s Grace’s wedding to Grace and her fiancé. The couple couldn’t agree on the dress’s color: was it blue and black or white and gold? (White and gold, obviously.) The disagreement prompted the daughter to post the picture on social media, recruiting other opinions. That post caused such a stir that BuzzFeed picked it up, asking the masses to weigh in. And then the Internet went haywire. Within a few days, the original BuzzFeed article had more than 37 million hits. Serious news outlets interviewed neuroscientists and psychologists about color perception and optical illusions. Bevil Conway, a neuroscientist at Wellesley College, was one of those scientists. At the time, he thought the hullabaloo was interesting mostly because it showed how passionately people feel about color (as in, insanely riled-up and deeply offended by alternative views). He joked with NPR’s Robert Siegel, off air, that the story was “fluff,” Conway told me. Well, there’s nothing like a little research to turn fluff into gold (or blue or black). Conway, coauthor of a study appearing online May 14 in Current Biology that explores people’s perceptions of the dress, now calls the phenomenon “profound.” “I think it will go down as one of the most important discoveries in color vision in the last 10 years,” Conway says. “And all because of a crazy photograph.” In those February interviews, Conway (and some other scientists) explained the disparity of opinions on the dress in terms of “color constancy,” a feature of perception that allows us to identify colors under different lighting conditions. If we see a red poisonous snake or a red delicious apple, we need to be able to identify it as red (and dangerous or delicious), whether in bright sunlight or the gloom of clouds. © Society for Science & the Public 2000 - 2015
Link ID: 20937 - Posted: 05.16.2015
Barbara J. King Last Friday in the Washington Post, Charles Krauthammer asked which contemporary practices will be deemed "abominable" in the future, in the way that we today think of human enslavement. He then offered his own opinion: "I've long thought it will be our treatment of animals. I'm convinced that our great-grandchildren will find it difficult to believe that we actually raised, herded and slaughtered them on an industrial scale — for the eating." Krauthammer goes on to predict that meat-eating will become "a kind of exotic indulgence," because "science will find dietary substitutes that can be produced at infinitely less cost and effort." I don't often agree with Krauthammer's views, and his animal column is no exception. His breezy attitude on animal biomedical testing does animals no favors. (It's perhaps only fair to note that I have similar concerns about Alva's conclusions on animal testing from his 13.7 post published that same day.) But, still, Krauthammer does a terrific job of awakening people to many issues related to animals' suffering. And he's not alone. On April 17, I joined other scientists and activists on the radio show To the Point hosted by Warren Olney, to discuss this question: Is Animal Liberation Going Mainstream? In the 34-minute segment, we discussed the public outcry against SeaWorld's treatment of orcas, Ringling Bros.' plan to retire elephants from the circus in three years, and the rightness or wrongness of keeping animals in zoos — all issues brought up by Krauthammer in his column. © 2015 NPR
Keyword: Animal Rights
Link ID: 20935 - Posted: 05.16.2015
By Virginia Morell Hyenas long ago mastered one of the keys to Facebook success: becoming the friend of a friend. The most common large carnivore in Africa, spotted hyenas (Crocuta crocuta), are known for their socially sophisticated behaviors. They live in large, stable clans (as pictured above), which can include as many as 100 individuals. They can tell clan members apart, discriminating among their maternal and paternal kin. They’re also choosy about their pals and form tight bonds only with specific members—the friends of their friends, researchers report in the current issue of Ecology Letters. And it’s this ability to form lasting friendships—or “cohesive clusters,” as the scientists describe a triad of friends—that is most important in maintaining the animals’ social structure. To reach this conclusion, the scientists analyzed more than 50,000 observations of social interactions among spotted hyenas in Kenya’s Maasai Mara National Reserve over 20 years. They found that individual traits, including the hyena’s sex and social rank, as well as environmental factors such as the amount of rainfall and prey abundance, all play a role in the animals’ social dynamics. But the most consistently influential factor was the ability of individual hyenas to form and maintain those tight friendships. The study used a new modeling method, which the researchers say can help other scientists better understand the sociality of other species. And that includes the human animal, who, the scientists note, are also prone to “cohesive clusters,” whether living as hunter-gatherers or as users of social media. © 2015 American Association for the Advancement of Science.
Link ID: 20934 - Posted: 05.16.2015
By Jonathan Webb Science reporter, BBC News A cluster of cells in the brain of a fly can track the animal's orientation like a compass, a study has revealed. Fixed in place on top of a spherical treadmill, a fruit fly walked on the spot while neuroscientists peered into its brain using a microscope. Watching the neurons fire inside a donut-shaped brain region, they saw activity sweep around the ring to match the direction the animal was headed. Mammals have similar "head direction cells" but this is a first for flies. The findings are reported in the journal Nature. Crucially, the compass-like activity took place not only when the animal was negotiating a virtual-reality environment, in which screens gave the illusion of movement, but also when it was left in the dark. "The fly is using a sense of its own motion to pick up which direction it's pointed," said senior author Dr Vivek Jayaraman, from the Howard Hughes Medical Institute's Janelia Research Campus. In some other insects, such as monarch butterflies and locusts, brain cells have been observed firing in a way that reflects the animal's orientation to the pattern of polarised light in the sky - a "sun compass". But the newly discovered compass in the fly brain works more like the "head directions cells" seen in mammals, which rapidly set up a directional system for the animal based on landmarks in the surrounding scene. "A key thing was incorporating the fly's own movement," Dr Jayaraman told the BBC. "To see that its own motion was relevant to the functioning of this compass - that was something we could only see if we did it in a behaving animal." © 2015 BBC
Keyword: Learning & Memory
Link ID: 20933 - Posted: 05.14.2015
Thomas R. Clandinin & Lisa M. Giocomo An analysis reveals that fruit-fly neurons orient flies relative to cues in the insects' environment, providing evidence that the fly's brain contains a key component for drawing a cognitive map of the insect's surroundings. See Article p.186 Animals need accurate navigational skills as they go about their everyday lives. Many species, from ants to rodents, navigate on the basis of visual landmarks, and this is complemented by path integration, in which neuronal cues about the animal's own motion are used to track its location relative to a starting point. In mammals, these different types of navigation are integrated by neurons called head-direction cells1. In this issue, Seelig and Jayaraman2 (page 186) provide the first evidence that certain neurons in fruit flies have similar properties to head-direction cells, encoding information that orients the insects relative to local landmarks. Head-direction cells act as a neuronal compass that generates a cognitive map of an animal's environment. The activity of each head-direction cell increases as the animal faces a particular direction, with different cells preferentially responding to different directions1, 3. Rather than certain cells always responding to north, south and so on, the direction in which the cells fire is set up arbitrarily when the animal encounters new visual landmarks. The signals are then updated by self-motion cues as the animal navigates. Studying head-direction cells in mammals is challenging because of the complexity of the mammalian brain. By contrast, the small fly brain is a good model for studying neuronal activity. © 2015 Macmillan Publishers Limited.
Keyword: Learning & Memory
Link ID: 20932 - Posted: 05.14.2015
Anya Kamenetz Are you a pen-clicker? A hair-twirler? A knee-bouncer? Did you ever get in trouble for fidgeting in class? Don't hang your head in shame. All that movement may be helping you think. A new study suggests that for children with attention disorders, hyperactive movements meant better performance on a task that requires concentration. The researchers gave a small group of boys, ages 8 to 12, a sequence of random letters and numbers. Their job: Repeat back the numbers in order, plus the last letter in the bunch. All the while, the kids were sitting in a swiveling chair. For the subjects with ADHD, moving and spinning in the chair were correlated with better performance. For typically developing kids, however, it was the opposite: the more they moved, the worse they did on the task. Dustin Sarver at the University of Mississippi Medical Center is the lead author of this study. ADHD is his field, and he has a theory as to why fidgeting helps these kids. "We think that part of the reason is that when they're moving more they're increasing their alertness." That's right — increasing. The prevailing scientific theory on attention disorders holds that they are caused by chronic underarousal of the brain. That's why stimulants are prescribed as treatment. Sarver believes that slight physical movements "wake up" the nervous system in much the same way that Ritalin does, thus improving cognitive performance. © 2015 NPR
Link ID: 20931 - Posted: 05.14.2015
by Jessica Hamzelou Painful needle heading your way? A sharp intake of breath might be all that is needed to make that injection a little more bearable. When you are stressed, your blood pressure rises to fuel your brain or limbs should you need to fight or flee. But your body has a natural response for calming back down. Pressure sensors on blood vessels in your lungs can tell your brain to bring the pressure back down, and the signals from these sensors also make the brain dampen the nervous system, leaving you less sensitive to pain. This dampening mechanism might be why people with higher blood pressures appear to have higher pain thresholds. Gustavo Reyes del Paso at the University of Jaén in Spain wondered whether holding your breath – a stress-free way of raising blood pressure and triggering the pressure sensors – might also raise a person's pain threshold. To find out, he squashed the fingernails of 38 people for 5 seconds while they held their breath. Then he repeated the test while the volunteers breathed slowly. Both techniques were distracting, but the volunteers reported less pain when breath-holding than when slow breathing. Reyes del Paso thinks holding your breath might be a natural response to the expectation of pain. "Several of our volunteers told us they already do this when they are in pain," he says. But he doesn't think the trick will work for a stubbed toe or unexpected injury. You have to start before the pain kicks in, he says, for example, in anticipation of an injection. © Copyright Reed Business Information Ltd
Keyword: Pain & Touch
Link ID: 20930 - Posted: 05.14.2015
Robinson Meyer Brett Redding felt like he was out of options. “It started with little things—having trouble making eye contact,” he told me. Soon it got worse. Redding, a 28-year-old salesman in Seattle, found himself freaking out during normal, everyday conversations. He worried any time his boss wanted to talk. He would dread his regular sales calls, and the city’s booming housing market—he works in construction—seemed to make his ever-increasing meetings all the more crushing. He was suffering social anxiety, a common but debilitating mental illness. “I was afraid of losing my job because I couldn’t do it,” he says. His meetings with a therapist weren’t working, and he didn’t “want to mess with antidepressants.” “I’ve always been so social—I’ve never had issues with looking people in the eye and talking with people,” he says. That’s when Redding’s girlfriend saw an ad on Craigslist that promised an online program could help treat Redding’s social anxiety through methods proven by science. “I had nothing to lose,” he says—so he signed up. That service is now called Joyable. I first saw Joyable when an ad for it appeared in Facebook on my phone. “90 percent of our clients see their anxiety decline,” said the ad, next to a sun-glinted, bokeh-heavy photo of a blonde woman. I clicked on. Joyable’s website, full of affable sans serifs and cheery salmon rectangles, looks Pinterest-esque, at least in its design. Except its text didn’t discuss eye glasses or home decor but “evidence-based” methods shown to reduce social anxiety. I knew those phrases: “Evidence-based” is the watchword of cognitive behavioral therapy, or CBT, the treatment now considered most effective for certain anxiety disorders. Joyable dresses a psychologists’s pitch in a Bay Area startup’s clothes. © 2015 by The Atlantic Monthly Group.
Link ID: 20929 - Posted: 05.14.2015
Jon Hamilton When the brain needs to remember a phone number or learn a new dance step, it creates a circuit by connecting different types of neurons. But scientists still don't know how many types of neurons there are or exactly what each type does. "How are we supposed to understand the brain and help doctors figure out what schizophrenia is or what paranoia is when we don't even know the different components," says Christof Koch, president and chief scientific officer of the Allen Institute for Brain Science, a nonprofit research center in Seattle. So the institute is creating a freely available online database that will eventually include thousands of nerve cells. For now, the Allen Cell Types Database has detailed information on 240 mouse cells, including their distinctive shapes. More than 100 years ago, Golgi staining on nerve cells opened the gates to modern neuroscience. Scientists recently developed the Technicolor version of Golgi staining, Brainbow, allowing more detailed reconstructions of brain circuits. "They look like different trees," Koch says. "Some fan out at the top. Some are like a Christmas tree; they fan out at the bottom. Others are like three-dimensional fuzz balls." The database also describes each cell by the electrical pattern it generates. And eventually it will include information about which genes are expressed. Once researchers have a complete inventory of details about the brain's building blocks, they'll need to know which combinations of blocks can be connected, Koch says. After all, he says, it is these connections that make us who we are. © 2015 NPR
Keyword: Brain imaging
Link ID: 20927 - Posted: 05.14.2015
By SABRINA TAVERNISE WASHINGTON — What would make a smoker more likely to quit, a big reward for succeeding or a little penalty for failing? That is what researchers wanted to know when they assigned a large group of CVS employees, their relatives and friends to different smoking cessation programs. The answer offered a surprising insight into human behavior. Many more people agreed to sign up for the reward program, but once they were in it, only a small share actually quit smoking. A far smaller number agreed to risk the penalty, but those who did were twice as likely to quit. The trial, which was described in The New England Journal of Medicine on Wednesday, was the largest yet to test whether offering people financial incentives could lead to better health. It used theories about human decision making that have been developed in psychology and economics departments over several decades and put them into practice with more than 2,500 people who either worked at CVS Caremark, the country’s largest drugstore chain by sales, or were friends or relatives of those employees. Researchers found that offering incentives was far more effective in getting people to stop smoking than the traditional approach of giving free smoking cessation help, such as counseling or nicotine replacement therapy like gum, medication or patches. But they also found that requiring a $150 deposit that would be lost if the person failed to stay off cigarettes for six months nearly doubled the chances of success. “Adding a bit of a stick was much better than a pure carrot,” said Dr. Scott Halpern, deputy director of the Center for Health Incentives and Behavioral Economics at the University of Pennsylvania School of Medicine, who led the study. © 2015 The New York Times Company
Keyword: Drug Abuse
Link ID: 20925 - Posted: 05.14.2015
Alison Abbott It is only when you read the words that Andreas Vesalius wrote as an angry young man in the 1540s that you get a feeling for what drove him to document every scrap of human anatomy his eye could see. His anger was directed at Galen, the second-century physician whose anatomical teachings had been held as gospel for more than a millennium. Roman Empire law had barred Galen from dissecting humans, so he had extrapolated as best he could from animal dissections — often wrongly. Human dissections were also banned in most of sixteenth-century Europe, so Vesalius travelled to wherever they were allowed. He saw Galen's errors and dared to report them, most explicitly in his seven-volume De Humani Corporis Fabrica (On the Fabric of the Human Body), which he began aged 24, working with some of the best art professionals of the time. His mission to learn through direct and systematic observation marked the start of a new way of doing science. In Brain Renaissance, neuroscientists Marco Catani and Stefano Sandrone present a translation from the Latin of the Fabrica's last volume, which focuses on the brain. Through it we can appreciate Vesalius's extraordinary attention to detail, and his willingness to believe his eyes, even when what he saw contradicted established knowledge. We learn his anatomical vocabulary. For example, he called the rounded surface protuberances near the brain stem “buttocks” and “testes”; these are now known as the inferior and superior colliculi, or 'little hills', which process sound and vision. © 2015 Macmillan Publishers Limited.
Keyword: Brain imaging
Link ID: 20924 - Posted: 05.14.2015
By Gareth Cook Much has been written on the wonders of human memory: the astounding feats of recall, the way memories shape our identity and are shaped by them, memory as a literary theme and a historical one. But what of forgetting? This is the topic of a new book by Douwe Draaisma, author of The Nostalgia Factory and a professor of the history of psychology at the University of Groningen. In Forgetting, Draaisma considers dreaming, amnesia, dementia and all of the ways that our minds — and lives — are shaped by memory’s opposite. He answered questions from Mind Matters editor Gareth Cook. What is your earliest memory and why, do you suppose, have you not forgotten it? Quite a few early memories in the Netherlands involve bicycles, and mine is no exception. I was two-and-a-half years old when my aunts walked my mother to the train station. They had taken a bike along to transport her bags. I was sitting on the back of the bike. Suddenly the whole procession came to a halt when my foot got caught between the spokes. I’m pretty sure this memory is accurate, since I had to see a doctor and there is a dated medical record. It’s a brief, snapshot-like memory, black-and-white. I don’t remember any pain, but I do remember the consternation among my mom and her sisters. Looking back on this memory from a professional perspective, I would say that it has the flash-like character typical for first memories from before age 3; ‘later’ first memories are usually a bit longer and more elaborate. It also fits the pattern of being about pain and danger. Roughly three in four first memories are associated with negative emotions. This may have an evolutionary origin: I never again had my foot between the spokes. And neither have any of my children. © 2015 Scientific American
Keyword: Learning & Memory
Link ID: 20918 - Posted: 05.13.2015
Jessica Hamzelou Don't be too hard on them. Amoebas that weasel their way into our brains and chow down on our grey matter aren't welcome, but it's how our immune system reacts that's really lethal. Setting the story straight could help us deal with them better. Brain-eating amoebas (Naegleria fowleri) are found in warm freshwater pools around the world, feeding on bacteria. If someone swims in one of these pools and gets water up their nose, the amoeba heads for the brain in search of a meal. Once there, it starts to destroy tissue by ingesting cells and releasing proteins that make other cells disintegrate. The immune system launches a counter-attack by flooding the brain with immune cells, causing inflammation and swelling. It seldom works: of the 132 people known to have been infected in the US since 1962, only three survived. Brain-eating amoeba infections are more common elsewhere. "In Pakistan, we have something like 20 deaths per year," says Abdul Mannan Baig at the Aga Khan University in Karachi. There is no standard treatment. Doctors in the US have recently started trying to kill the amoebas with miltefosine, a drug known to work on the leishmaniasis parasite. Mannan thinks they should take a different approach, because the immune response may be more damaging than the amoeba itself. The problem is that enzymes released by the immune cells can also end up destroying brain tissue. And the swelling triggered by the immune system eventually squashes the brainstem, fatally shutting off communication between the body and the brain. © Copyright Reed Business Information Ltd
Link ID: 20917 - Posted: 05.13.2015
By C. CLAIBORNE RAY Q. I heard that people can’t look at a color in one room and then pick it out of a set of similar colors in the next room. But there are people with perfect pitch, so are there people with “perfect hue”? A. “The short answer is no,” said Mark D. Fairchild, director of the program of color science at the Munsell Color Science Laboratory of Rochester Institute of Technology. “Color is almost always judged relative to other colors,” Dr. Fairchild said, and the human ability to remember colors over any period of time, or even from room to room, is extremely poor. “Based on memory alone, we can probably reliably identify tens of colors, with some people perhaps able to study hard and get up to a hundred or so,” he said. “If we were to learn a systematic way to scale colors, we might be able to get up to several hundred.” If colors are compared side by side, however, “then we can easily distinguish several thousand colors, and some estimate more than a million,” Dr. Fairchild said. Such ability is somewhat analogous to differentiating tones in hearing, he said. Almost everyone can distinguish tones when they are compared in close succession, he said, but only a very small percentage of people have what is called perfect pitch or absolute pitch: the ability to recall and identify tones after a considerable period of time, without a reference tone for comparison. “Unfortunately, color appearance seems to be even more difficult to remember,” Dr. Fairchild said, “to the point that we don’t speak of anyone as having perfect hue.” © 2015 The New York Times Company
Link ID: 20916 - Posted: 05.13.2015
By Simon Makin After wandering around an unfamiliar part of town, can you sense which direction to travel to get back to the subway or your car? If so, you can thank your entorhinal cortex, a brain area recently identified as being responsible for our sense of direction. Variation in the signals in this area might even explain why some people are better navigators than others. The new work adds to a growing understanding of how our brain knows where we are. Groundbreaking discoveries in this field won last year's Nobel Prize in Physiology or Medicine for John O'Keefe, a neuroscientist at University College London, who discovered “place cells” in the hippocampus, a brain region most associated with memory. These cells activate when we move into a specific location, so that groups of them form a map of the environment. O'Keefe shared the prize with his former students Edvard Moser and May-Britt Moser, both now at the Kavli Institute for Systems Neuroscience in Norway, who discovered “grid cells” in the entorhinal cortex, a region adjacent to the hippocampus. Grid cells have been called the brain's GPS system. They are thought to tell us where we are relative to where we started. A third type—head-direction cells, also found in the entorhinal region—fires when we face a certain direction (such as “toward the mountain”). Together these specialized neurons appear to enable navigation, but precisely how is still unclear. For instance, in addition to knowing which direction we are facing, we need to know which direction to travel. Little was known about how or where such a goal-direction signal might be generated in the brain until the new study. © 2015 Scientific American
Keyword: Learning & Memory
Link ID: 20915 - Posted: 05.13.2015
By Smitha Mundasad Health reporter There has been a worrying rise in the number of working-age men and women having strokes, a charity has warned. In England in 2014 there were 6,221 hospital admissions for men aged 40-54 - a rise of 1,961 on 14 years earlier, a Stroke Association study shows. Experts said unhealthy lifestyles were partly to blame for the rise, though the growing population and changes to hospital practice also played a part. Overall the rate of strokes is going down in the UK, however. Researchers say based on their findings strokes should not be considered as a disease of the old. Strokes are caused by blood clots or bleeds to the brain and can lead to long-lasting disability. The majority occur in people aged over 65, and though rates are decreasing in this group, this report suggests growing numbers of younger people are at risk. Experts analysed national hospital admission data spanning 2000 to 2014. Trends for people in their 40s and early 50s appeared to be getting worse. In women aged 40-54, there were an extra 1,075 strokes recorded in 2014, compared with 2000. Experts said growing obesity levels, sedentary lives and unhealthy diets - which raise the risks of dangerous blood clots - all played a part. And they argued strokes among this age group had long-lasting personal and financial impacts on individuals and their families, as well as on the economy. Recovering patients can find it difficult to return to work and should have more support from employers, the report suggests. Jon Barrick, of the Stroke Association, said: "These figures show stroke can no longer be seen as a disease of older people. "There is an alarming increase in the numbers of people having a stroke in working age. © 2015 BBC.
Link ID: 20912 - Posted: 05.12.2015
Tina Hesman Saey COLD SPRING HARBOR, N.Y. — Taming animals makes an impression on their DNA. Domesticated animals tend to have genetic variants that affect similar biological processes, such as brain and facial development and fur coloration. Alex Cagan of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, reported the results May 6 at the Biology of Genomes conference. Cagan and colleagues examined DNA in Norway rats (Rattus norvegicus) that had been bred for 70 generations to be either tame or aggressive toward humans. Docility was associated with genetic changes in 1,880 genes in the rats. American minks (Neovison vison) bred for tameness over 15 generations had tameness-associated variants in 525 genes, including 82 that were also changed in the rats. The researchers also compared other domesticated animals, including dogs, cats, pigs and rabbits, with their wild counterparts. The domestic species and the minks had tameness-associated changes in genes for epidermal growth factor and associated proteins that stimulate growth of cells. Those proteins are important for the movement of neural crest cells within an embryo. That finding seems to support a recent hypothesis that changes in neural crest cells could be responsible for domestication syndrome, physical traits, including floppy ears, spotted coats and juvenile faces, which accompany tameness in many domestic animals. © Society for Science & the Public 2000 - 2015.
Andrew Griffin Scientists have created an electronic memory cell that mimics the way that human brains work, potentially unlocking the possibility of the making bionic brains. The cell can process and store multiple bits of information, like the human brain. Scientists hope that developing it could make for artificial cells that simulate the brain’s processes, leading to treatments for neurological conditions and for replica brains that scientists can experiment on. The new cells have been likened to the difference between having an on-off light switch and a dimmer, or the difference between black and white pictures or those with full colour, including shade light and texture. While traditional memory cells for computers can only process one binary thing at a time, the new discovery allows for much more complex memory processes like those found in the brain. They are also able to retain previous information, allowing for artificial systems that have the extraordinary memory powers found in human beings. While the new discovery is a long way from leading to a bionic brain, the discovery is an important step towards the dense and fast memory cells that will be needed to imitate the human brain's processes. “This is the closest we have come to creating a brain-like system with memory that learns and stores analog information and is quick at retrieving this stored information,” Sharath Sriram, who led the project, said.