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By Sarah Kaplan Some 250 million years ago, when dinosaurs roamed the Earth and early mammals were little more than tiny, fuzzy creatures that scurried around attempting to evade notice, our ancestors evolved a nifty trick. They started to become active at night. They developed sensitive whiskers and an acute sense of hearing. Their circadian rhythms shifted to let them sleep during the day. Most importantly, the composition of their eyes changed — instead of color-sensing cone photoreceptor cells, they gained thousands of light-sensitive rod cells, which allowed them to navigate a landscape lit only by the moon and stars. Mammals may no longer have to hide from the dinosaurs, but we bear the indelible marks of our scrappy, nocturnal past. Unlike every other vertebrate on land and sea, we still have rod-dominated eyes — human retinas, for example, are 95 percent rods, even though we're no longer active at night. "How did that happen? What is the mechanism that made mammals become so different?" asked Anand Swaroop, chief of the Neurobiology Neurodegeneration and Repair Laboratory at the National Eye Institute. He provides some answers to those questions in a study published in the journal Developmental Cell Monday. The findings are interesting from an evolutionary standpoint, he said, but they're also the keys to a medical mystery. If Swaroop and his colleagues can understand how our eyes evolved, perhaps they can fix some of the problems that evolved with them.
BBC journalist Caroline Wyatt has said she is determined to make the most of her life after being diagnosed with multiple sclerosis (MS). In her first interview since revealing the news last week, Wyatt told the Radio Times: "It is what it is." "I am not angry, and I don't want bitterness to start eating away at me." One of the best known faces of BBC News, Wyatt recently stepped down as the corporation's religious affairs correspondent due to her condition. 'Incredibly blessed' "I feel really sad now because I'm not going to be a correspondent full-time anymore - I physically can't." Wyatt had been struggling with undiagnosed symptoms for 25 years but was only diagnosed with MS last July after she was paralysed down her left side. Wyatt, who was also the BBC's defence correspondent, said she has had moments where she has questioned her own mortality. "Reporting news is often about reporting death, particularly in the places I have been. But it's less terrifying to me to think of being blown up and dying than to think 'gosh, I might decline slowly day by day, losing a little bit of capability every day'." At the moment, she is a bit unsteady on her feet and is struggling with her vision but still says she is "incredibly lucky and incredibly blessed". She is currently on a long summer break but is hoping to return to radio broadcasting later in the year, along with covering the canonisation of Mother Teresa in Rome. In MS the protective layer surrounding nerve fibres in the brain and spinal cord - known as myelin - becomes damaged. The immune system mistakenly attacks the myelin, causing scarring or sclerosis. The damaged myelin disrupts the nerve signals - rather like the short circuit caused by a frayed electrical cable. © 2016 BBC.
Keyword: Multiple Sclerosis
Link ID: 22341 - Posted: 06.21.2016
Laurel Hamers People hooked on cocaine are more likely to stick to other habits, too. They’re also less sensitive to negative feedback that tends to push nonaddicts away from harmful habitual behaviors, new research published in the June 17 Science suggests. The findings might help explain why cocaine addicts will do nearly anything to keep using the drug, despite awareness of its negative consequences. Instead, treatments that encourage new, healthier habits in place of drug use might click better. Similar results have been demonstrated with mice and rats, but the effect hadn’t been well-established in humans. There’s no pharmacological treatment approved by the U.S. Food and Drug Administration that targets cocaine addiction as there is for opioid addiction. So the best treatment currently focuses on changing patients’ behavior — and it’s not easy. “It’s such a devastating situation for families,” says Karen Ersche, a psychologist at the University of Cambridge who led the study. Drug users “know they’ll lose their job. They’ll tell you they want to change, but still they carry on using the drug. It seems incomprehensible.” Habits can be helpful because they free up brainpower for other things. A new driver has to think through every push of the pedal and flick of the turn signal, while an experienced one can perform these actions almost effortlessly, allowing them to also carry on a conversation. But people can also snap out of that automation when necessary, slamming on the brakes when a deer darts across the road. It’s harder for someone addicted to cocaine to get off autopilot. © Society for Science & the Public 2000 - 2016.
Keyword: Drug Abuse
Link ID: 22340 - Posted: 06.20.2016
By Jane E. Brody Smokers who think they are escaping the lung-damaging effects of inhaled tobacco smoke may have to think again, according to the findings of two major new studies, one of which the author originally titled “Myth of the Healthy Smoker.” Chronic obstructive pulmonary disease, or C.O.P.D., may be among the best known dangers of smoking, and current and former smokers can be checked for that with a test called spirometry that measures how much air they can inhale and how much and how quickly they can exhale. Unfortunately, this simple test is often skipped during routine medical checkups of people with a history of smoking. But more important, even when spirometry is done, the new studies prove that the test often fails to detect serious lung abnormalities that cause chronic cough and sputum production and compromise a person’s breathing, energy level, risk of serious infections and quality of life. “Current or former smokers without airflow obstruction may assume that they are disease-free,” but that’s not necessarily the case, one of the research teams pointed out. These researchers projected that there are 35 million current or former smokers older than 55 in the United States with unrecognized smoking-caused lung disease or impairments. Many, if not most, of these people could get worse with time, even if they have quit smoking. They are also unlikely to be referred for pulmonary rehabilitation, a treatment that can head off encroaching disability. Perhaps most important, those currently smoking may be inclined to think they’ve dodged the bullet and so can continue to smoke with impunity. Doctors, who are often reluctant to urge patients with symptoms to quit smoking, may be even less likely to recommend smoking cessation to those with normal spirometry results. Referring to C.O.P.D., one of the researchers, Dr. Elizabeth A. Regan, said, “Smoking is really taking a terrible toll on our society.” Dr. Regan, a clinical researcher at National Jewish Health in Denver, is the lead author of one of the new studies, published last year in JAMA Internal Medicine. “We live happily in the world thinking that only a small percentage of people who smoke get this devastating disease,” she said. “However, the lungs of millions of people in the United States are negatively impacted by smoking, and our methods for identifying their lung disease are relatively insensitive.” © 2016 The New York Times Company
Keyword: Drug Abuse
Link ID: 22339 - Posted: 06.20.2016
Gary Stix Unlike biochemistry and psychology, brain science did not exist as a separate academic field until the middle of the 20th century. In recent decades, neuroscience has emerged as a star among the biological disciplines. In 2014 a workshop organized by the National Academy of Medicine met to ponder the question of whether all bodes well for the scientists-to-be who are now getting their PhDs and laboring away at postdoctoral fellowships. Will the field be able to absorb this wealth of new talent—and is it preparing students with the quantitative skills needed to understand the workings of an organ with some 86 billion neurons and hundreds of trillions of connections among all of those cells? Steven Hyman of the Broad Institute of Harvard and MIT, who helped with the planning of the workshop and was recently president of the Society for Neuroscience (SfN), welcomed the flood of doctoral students choosing neuroscience, but warned: “Insofar as talented young people are discouraged from academic careers by funding levels so low that they produce debilitating levels of competition or simply foreclose opportunities, the U.S. and the world are losing an incredibly precious resource.” I got in touch with one member of the National Academy of Medicine panel, Huda Akil of the University of Michigan Medical School, the lead author on a paper in Neuron that summarized the workshop’s findings. Akil, also a former SfN president, is a noted researcher in the neurobiology of emotions. © 2016 Scientific American,
Link ID: 22338 - Posted: 06.20.2016
By Nancy Szokan Let’s begin by defining something psychologists call “ego depletion.” This is the idea that all of us have only a certain amount of self-control, and if we use up too much in one part of our lives, we will have less to use in others. An early example came from a 1998 study in which participants were tempted with a chocolate treat before being given a difficult puzzle: Those who resisted the temptation seemed to have used up some of their willpower, because they gave up on the puzzle faster than the treat eaters. There have been many subsequent studies about ego depletion, including its apparent effects on physical performance: In 2012, athletes who were given a difficult mental task before a physical challenge exhibited less determination to do well on the sports test than those who hadn’t done the puzzle. But recently a replication study (in which researchers repeat a published experiment to see if they come up with the same results) tested more than 2,000 participants at 24 labs and found the ego depletion effect to be very small or nonexistent. I Which, as Lea Winerman reports, has led such psychologists as Michael Inzlicht of the University of Toronto to a crisis of confidence. Maybe, he thinks, ego depletion and the other social psychological effects he has made a career of studying are “proven” by unreliable research. “I used to think there were errors, but that the errors were minor and it was fine,” Winerman quotes Inzlicht as saying in the June issue of Monitor on Psychology, a publication of the American Psychological Association. “But as I started surveying the field, I started thinking we’ve been making some major mistakes.”
Link ID: 22337 - Posted: 06.20.2016
By Ruth Williams The offspring of certain mice fed a high-fat diet have altered gut microbiomes and may be prone to autism-like behaviors including social deficits, according to a study published today (June 16) in Cell. But treating these offspring with a specific microbial species they lack can rectify the animals’ social behavior. “There’s growing evidence that the microbiome, particularly early in life, can have long-term effects on brain development and behavior,” said anatomist and neuroscientist John Cryan of University College Cork in Ireland who was not involved in the study. “What this paper does is take advantage of the fact that we get our microbiome from our mums, and looks at what happens if the mum disturbs her microbiome during pregnancy.” According to the US Centers for Disease Control and Prevention, one in 68 U.S. children have autism spectrum disorder (ASD). Recent evidence suggests that the risk of ASD is increased for the offspring of mothers with obesity. In both humans and non-human primates, the offspring of obese mothers have also been shown to have abnormal microbiomes. And some people with ASD have imbalanced gut microbes, or dysbiosis. Baylor College of Medicine’s Mauro Costa-Mattioli and colleagues sought to better understand how maternal obesity, the microbiome, and ASD are interconnected. The team turned to mice for answers. The researchers gave female animals high-fat diets before setting up matings, later finding that a “large proportion” of the offspring exhibited ASD-like behaviors, including reduced social interaction, repetitive behaviors, and anxiety. The team analyzed the microbiomes of these offspring, finding that they differed from those of control animals. © 1986-2016 The Scientist
Link ID: 22336 - Posted: 06.18.2016
Lisa Fine Jess Thom says the word "biscuit" about 16,000 times every day. Her brother-in-law counted once. That's just one of the tics that Thom, a London-based performance artist, has to manage as part of her life with Tourette's syndrome, a neurological disorder characterized by involuntary vocal or motor tics. Specialists say the condition affects as many as 300,000 children in the United States, though many are undiagnosed. Thom has had tics since childhood, but she wasn't diagnosed until her 20s. "What disables me ... is other people's misunderstanding," she says. "What's exciting is that it's something we all have power to change." The condition is far more common than many people realize, and many misperceptions about it still exist, says Kevin McNaught, executive vice president of the advocacy group Tourette Association of America. "It's not a rare disorder," McNaught says, citing an estimated 1 in 100 school-age children with the condition, including many who aren't diagnosed until adulthood, if at all. Michael Chichioco, a California high school senior who has Tourette's syndrome, says he used to be bullied at school, with kids trying to trigger him to have outbursts. His tics come out more prominently when he is nervous or excited. © 2016 npr
Link ID: 22335 - Posted: 06.18.2016
By Tanya Lewis The human brain may wind down when asleep, but it doesn’t lose all responsiveness. Researchers from the École Normale Supérieure in Paris and their colleagues recently used electroencephalography (EEG) to monitor the brains of volunteers listening to recordings of spoken words, which they were asked to classify as either objects or animals. Participants were able to classify words during light non-REM (NREM) sleep, but not during either deep NREM sleep or REM sleep, according to a study published today (June 14) in The Journal of Neuroscience. “With an elegant experimental design and sophisticated analyses of neural activity, [the authors] demonstrate the extent to which the sleeping brain is able to process sensory information, depending on sleep depth [or] stage,” Thomas Schreiner of the University of Fribourg in Switzerland, who was not involved in the study, wrote in an email to The Scientist. During sleep, the brain is thought to block out external stimuli through a gating mechanism at the level of the thalamus. But experiments dating back to the 1960s have shown that certain types of stimuli, such as hearing one’s name, can filter through and trigger awakening. However, the mechanisms that allow the brain to selectively take in information during sleep remain unknown. “When we fall asleep, it’s pretty similar to a coma because we lose consciousness of our self and of the [outside] world,” study coauthor Thomas Andrillon, a neuroscientist at the École Normale Supérieure, told The Scientist. The question was “whether the brain could still monitor what was going on around, just to be sure the environment was still safe,” he added. © 1986-2016 The Scientist
By Karen Weintraub Many people think they can teach themselves to need less sleep, but they’re wrong, said Dr. Sigrid Veasey, a professor at the Center for Sleep and Circadian Neurobiology at the University of Pennsylvania’s Perelman School of Medicine. We might feel that we’re getting by fine on less sleep, but we’re deluding ourselves, Dr. Veasey said, largely because lack of sleep skews our self-awareness. “The more you deprive yourself of sleep over long periods of time, the less accurate you are of judging your own sleep perception,” she said. Multiple studies have shown that people don’t functionally adapt to less sleep than their bodies need. There is a range of normal sleep times, with most healthy adults naturally needing seven to nine hours of sleep per night, according to the National Sleep Foundation. Those over 65 need about seven to eight hours, on average, while teenagers need eight to 10 hours, and school-age children nine to 11 hours. People’s performance continues to be poor while they are sleep deprived, Dr. Veasey said. Extended vacations are the best times to assess how much sleep you truly need. Once you catch up on lost sleep and are not sleep deprived, the amount you end up sleeping is a good measure how much you need every night. You can ask yourself the questions, “Do you feel that your brain is much sharper, your temper is better, you’re paying attention more effectively? If those answers are yes, than definitely get the sleep,” said Dr. Veasey, who realized -- to her chagrin -- that she needs nine hours of sleep a night to function effectively. Health issues like pain, sleep apnea or autoimmune disease can increase people's need for sleep, said Andrea Meredith, a neuroscientist at the University of Maryland School of Medicine. © 2016 The New York Times Company
Link ID: 22333 - Posted: 06.18.2016
In a study of stroke patients, investigators confirmed through MRI brain scans that there was an association between the extent of disruption to the brain’s protective blood-brain barrier and the severity of bleeding following invasive stroke therapy. The results of the National Institutes of Health-funded study were published in Neurology. These findings are part of the Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution (DEFUSE)-2 Study, which was designed to see how MRIs can help determine which patients undergo endovascular therapy following ischemic stroke caused by a clot blocking blood flow to the brain. Endovascular treatment targets the ischemic clot itself, either removing it or breaking it up with a stent. The blood-brain barrier is a layer of cells that protects the brain from harmful molecules passing through the bloodstream. After stroke, the barrier is disrupted, becoming permeable and losing control over what gets into the brain. “The biggest impact of this research is that information from MRI scans routinely collected at a number of research hospitals and stroke centers can inform treating physicians on the risk of bleeding,” said Richard Leigh, M.D., a scientist at NIH’s National Institute of Neurological Disorders and Stroke (NINDS) and an author on the study. In this study, brain scans were collected from more than 100 patients before they underwent endovascular therapy, within 12 hours of stroke onset. Dr. Leigh and his team obtained the images from DEFUSE-2 investigators.
Alva Noë Sometimes the mind wanders. Thoughts pop into consciousness. Ideas or images are present when just a moment before they were not. Scientists recently have been turning their attention to making sense of this. One natural picture of the phenomenon goes something like this. Typically, our thoughts and feelings are shaped by what we are doing, by what there is around us. The world captures our attention and compels our minds this way or that. What explains the fact that you think of a red car when there is a red car in front of you is, well, the red car. And similarly, it is that loud noise that causes you to orient yourself to the commotion that is producing it. In such cases, we might say, the mind is coupled to the world around it and the world, in a way, plays us the way a person might play a piano. But sometimes, even without going to sleep, we turn away from the world. We turn inward. We are contemplative or detached. We decouple ourselves from the environment and we are set free, as it were, to let our minds play themselves. This natural picture has gained some support from the discovery of the so-called Default Mode Network. The DMN is a network of neural systems whose activation seems to be suppressed by active engagement with the world around us; DMN, in contrast, is activated (or rather, it tends to return to baseline levels of activity) precisely when we detach ourselves from what's going on around us. The DMN is the brain running in neutral. One of the leading hypotheses to explain mind-wandering and the emergence of spontaneous thoughts is that this is the result of the operation of the brain's Default Mode Network. (See this for a review of this literature.) © 2016 npr
Link ID: 22331 - Posted: 06.18.2016
Laura Sanders If you want to lock new information into your brain, try working up a sweat four hours after first encountering it. This precisely timed trick, described June 16 in Current Biology, comes courtesy of 72 people who learned the location of 90 objects on a computer screen. Some of these people then watched relaxing nature videos, while others worked up a sweat on stationary bikes, alternating between hard and easy pedaling for 35 minutes. This workout came either soon after the cram session or four hours later. Compared with both the couch potatoes and the immediate exercisers, the people who worked out four hours after their learning session better remembered the objects’ locations two days later. The delayed exercisers also had more consistent activity in the brain’s hippocampus, an area important for memory, when they remembered correctly. That consistency indicates that the memories were stronger, Eelco van Dongen of the Donders Institute in the Netherlands and colleagues propose. The researchers don’t yet know how exercise works its memory magic, but they have a guess. Molecules sparked by aerobic exercise, including the neural messenger dopamine and the protein BDNF, may help solidify memories by reorganizing brain cell connections. Citations E. van Dongen et al. Physical exercise performed four hours after learning improves memory retention and increases hippocampal pattern similarity during retrieval. Current Biology. Published online June 16, 2016. doi: 10.1016/j.cub.2016.04.071. © Society for Science & the Public 2000 - 2016
Keyword: Learning & Memory
Link ID: 22330 - Posted: 06.18.2016
Ian Sample Science editor Brain scans have highlighted “striking” differences between the brains of young men with antisocial behavioural problems and those of their better-behaved peers. The structural changes, seen as variations in the thickness of the brain’s cortex or outer layer of neural tissue, may result from abnormal development in early life, scientists at Cambridge University claim. But while the images show how the two groups of brains differ on average, the scans cannot be used to identify individuals with behavioural issues, nor pinpoint specific developmental glitches that underpin antisocial behaviour. Led by Luca Passamonti, a neurologist at Cambridge, the researchers scanned the brains of 58 young men aged 16 to 21 who had been diagnosed with conduct disorder, defined by persistent problems that ranged from aggressive and destructive behaviour, to lying and stealing, carrying weapons or staying out all night. When compared with brain scans from 25 healthy men of the same age, the scientists noticed clear differences. Those diagnosed with conduct disorder before the age of 10 had similar variations in the thickness of the brain’s cortex. “It may be that problems they experience in childhood affect and delay the way the cortex is developing,” said Passamonti. But the brains of men diagnosed with behavioural problems in adolescence differed in another way. Scans on them showed fewer similarities in cortical thickness than were seen in the healthy men. That, Passamonti speculates, may arise when normal brain maturation, such as the “pruning” of neurons and the connections between them, goes awry. © 2016 Guardian News and Media Limited
By Aleszu Bajak Can the various puzzles and quizzes associated with commercial brain-training games really improve cognitive function — or better yet, stave off cognitive decline? To date, the scientific evidence is murky, but that hasn’t kept companies from trying to cash-in on consumers’ native desire for quick fixes to complex health problems. The most famous among such companies is probably Lumosity, a product of San Francisco-based Lumos Labs, which once marketed its suite of web-based games and mobile apps as being “built on proven neuroscience,” and by encouraging users to “harness your brain’s neuroplasticity and train your way to a brighter life.” Exercising your brain with online brain-training games like Lumosity (above) or Smart Brain Aging sounds like a great idea, but the science is still murky. Exercising your brain with online brain-training games like Lumosity (above) or Smart Brain Aging sounds like a great idea, but the science is still murky. Those claims were among several that attracted the attention of the Federal Trade Commission, which earlier this year filed a complaint against the company. Lumosity was ultimately slapped with $50 million in fines for deceiving consumers — although $48 million of that was reportedly suspended by a district court, because the company was financially unable to pay the full amount. “Lumosity preyed on consumers’ fears about age-related cognitive decline, suggesting their games could stave off memory loss, dementia, and even Alzheimer’s disease,” said Jessica Rich, Director of the FTC’s Bureau of Consumer Protection, in a statement accompanying the settlement. “But Lumosity simply did not have the science to back up its ads.” Copyright 2016 Undark
By Clare Wilson Pass the sick bag. A device that allows people to empty a portion of their stomach contents into a toilet after a meal has just got the go-ahead from the US Food and Drug Administration. The device is approved for use by people who are severely obese, defined as having a body mass index of over 35 kg/m2. The stomach-churning device, which is already available in some European countries, involves a tube being placed into the stomach in a short surgical procedure. The end of the tube contains a valve that lies flush against the skin. Normally it is kept closed, but after meals, the person can connect the valve to another tube to drain about a third of their partially digested food into the toilet. It cannot remove more food than this, because the end of the internal tube is positioned higher than most of the stomach’s contents. Manufacturer Aspire Bariatrics, based in Pennsylvania, says users need to chew their food well and eat more slowly to stop the 6 millimetre tube from getting blocked, and that this in itself helps reduce overeating. “You get some solid chunks,” says Kathy Crothall, head of Aspire Bariatrics. “If a patient doesn’t chew their food very carefully they won’t get anything out of this device.” The device, called AspireAssist, has a safety feature within the valve that means it can only be used three times a day for up to six weeks. After this time it stops working and part of the device must be replaced. © Copyright Reed Business Information Ltd.
Link ID: 22327 - Posted: 06.16.2016
Susan Milius The Nyctibatrachus humayuni frogs live only in India’s Western Ghats, a region of still-unexplored biodiversity. Video now shows that the mating male of the species positions himself loosely on a female’s back, with his hands on the ground or leaves. From this position, called a dorsal straddle, the male then releases sperm directly onto the female’s back. Then, in an unusual move, he retreats before she lays the eggs. Sperm trickling down the female’s back and legs fertilize the eggs, an international research team reports June 14 in PeerJ. It’s the first time biologists have documented this loose straddling position. More typically, male frogs, which don’t deliver sperm into a female reproductive tract, hold tight and contact freshly deposited eggs to fertilize them. Bombay night frogs do on occasion crawl over their eggs, but researchers found the eggs are already fertilized. Biologists studying the challenges of external fertilization have previously cataloged six basic forms of male frog mating grasp, or amplexus. Four take some kind of back-hug approach or a head straddle. Other species position themselves rump-to-rump or, in what’s called glued amplexus, with the male dangling from a behemoth female. Position is hardly the only unexpected feature of courting Bombay night frogs. Females give courtship croaks, one of only a few dozen female-vocal species among the 6,500-plus known kinds of frogs. © Society for Science & the Public 2000 - 2016
Keyword: Sexual Behavior
Link ID: 22326 - Posted: 06.16.2016
By Gretchen Reynolds Physical activity is good for our brains. A wealth of science supports that idea. But precisely how exercise alters and improves the brain remains somewhat mysterious. A new study with mice fills in one piece of that puzzle. It shows that, in rodents at least, strenuous exercise seems to beneficially change how certain genes work inside the brain. Though the study was in mice, and not people, there are encouraging hints that similar things may be going on inside our own skulls. For years, scientists have known that the brains of animals and people who regularly exercise are different than the brains of those who are sedentary. Experiments in animals show that, for instance, exercise induces the creation of many new cells in the hippocampus, which is a part of the brain essential for memory and learning, and also improves the survival of those fragile, newborn neurons. Researchers believe that exercise performs these feats at least in part by goosing the body’s production of a substance called brain-derived neurotropic factor, or B.D.N.F., which is a protein that scientists sometimes refer to as “Miracle-Gro” for the brain. B.D.N.F. helps neurons to grow and remain vigorous and also strengthens the synapses that connect neurons, allowing the brain to function better. Low levels of B.D.N.F. have been associated with cognitive decline in both people and animals. Exercise increases levels of B.D.N.F. in brain tissue. But scientists have not understood just what it is about exercise that prompts the brain to start pumping out additional B.D.N.F. So for the new study, which was published this month in the journal eLIFE, researchers with New York University’s Langone Medical Center and other institutions decided to microscopically examine and reverse engineer the steps that lead to a surge in B.D.N.F. after exercise. They began by gathering healthy mice. Half of the animals were put into cages that contained running wheels. The others were housed without wheels. For a month, all of the animals were allowed to get on with their lives. Those living with wheels ran often, generally covering several miles a day, since mice like to run. The others remained sedentary. © 2016 The New York Times Company
Megan Scudellari Shinya Yamanaka looked up in surprise at the postdoc who had spoken. “We have colonies,” Kazutoshi Takahashi said again. Yamanaka jumped from his desk and followed Takahashi to their tissue-culture room, at Kyoto University in Japan. Under a microscope, they saw tiny clusters of cells — the culmination of five years of work and an achievement that Yamanaka hadn't even been sure was possible. Two weeks earlier, Takahashi had taken skin cells from adult mice and infected them with a virus designed to introduce 24 carefully chosen genes. Now, the cells had been transformed. They looked and behaved like embryonic stem (ES) cells — 'pluripotent' cells, with the ability to develop into skin, nerve, muscle or practically any other cell type. Yamanaka gazed at the cellular alchemy before him. “At that moment, I thought, 'This must be some kind of mistake',” he recalls. He asked Takahashi to perform the experiment again — and again. Each time, it worked. Over the next two months, Takahashi narrowed down the genes to just four that were needed to wind back the developmental clock. In June 2006, Yamanaka presented the results to a stunned room of scientists at the annual meeting of the International Society for Stem Cell Research in Toronto, Canada. He called the cells 'ES-like cells', but would later refer to them as induced pluripotent stem cells, or iPS cells. “Many people just didn't believe it,” says Rudolf Jaenisch, a biologist at the Massachusetts Institute of Technology in Cambridge, who was in the room. But Jaenisch knew and trusted Yamanaka's work, and thought it was “ingenious”. © 2016 Macmillan Publishers Limited,
By Ashley P. Taylor Sleep is known to aid memory and learning. For example, people who learn something, sleep on it, and are tested on the material after they wake up tend to perform better than those who remain awake in the interim. Within that general phenomenon, however, there’s a lot of unexplained variation. University of California, Riverside, sleep researcher Sara Mednick wondered “what else might be going during that sleep period that helps people’s memories,” she told The Scientist. As it turns out, activity of the autonomic nervous system (ANS) explains a large part of this variation, Mednick and colleagues show in a paper published today (June 13) in PNAS. The researchers measured not only the electrical activity of the brain during sleep, but also that of the heart, providing an indicator of ANS activity. They found that the beat-to-beat variation in heart rate accounted for much of the previously unexplained variation in how well people performed on memory and creativity tests following a nap. “There is a good possibility that this additional measure [heart-rate variability] may help account for discrepant findings in the sleep-dependent memory consolidation literature,” sleep and cognition researcher Rebecca Spencer of the University of Massachusetts, Amherst, who was not involved in the work, wrote in an email. “Perhaps we put too large of a focus on sleep physiology from the CNS [central nervous system] and ignore a significant role of the ANS.” © 1986-2016 The Scientist