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By John Horgan Transcranial magnetic stimulation is becoming an increasingly popular treatment for depression in spite of a lack of objective evidence of effectiveness. Illustration: National Institute of Mental Health. Delving into the history of treatments for mental illness can be depressing. Rather than developing ever-more-potent therapies, psychiatrists and others in the mental-health industry seem merely to recycle old ones. Consider, for example, therapies that stimulate the brain with electricity. In 1901, H. Lewis Jones, a physician, stated in the Journal of Mental Science: "The employment of electricity in medicine has passed through many vicissitudes, being at one time recognized and employed at the hospitals, and again being neglected, and left for the most part in the hands of ignorant persons, who continue to perpetrate the grossest impositions in the name of electricity. As each fresh important discovery in electric science has been reached, men’s minds have been turned anew to the subject, and interest in its therapeutic properties has been stimulated. Then after extravagant hopes and promises of cure, there have followed failures, which have thrown the employment of this agent into disrepute, to be again after time revived and brought into popular favor." Jones’s concerns could apply to our era, when electro-cures for mental illness have once again been "brought into popular favor." Below I briefly review the evidence—or lack thereof--for five electrotherapies: transcranial magnetic stimulation, cranial electrotherapy stimulation, vagus-nerve stimulation, deep-brain stimulation and electroconvulsive therapy.
Link ID: 21092 - Posted: 06.25.2015
By Sarah C. P. Williams Parrots, like the one in the video above, are masters of mimicry, able to repeat hundreds of unique sounds, including human phrases, with uncanny accuracy. Now, scientists say they have pinpointed the neurons that turn these birds into copycats. The discovery could not only illuminate the origins of bird-speak, but might shed light on how new areas of the brain arise during evolution. Parrots, songbirds, and hummingbirds—which can all chirp different dialects, pick up new songs, and mimic sound—all have a “song nuclei” in their brain: a group of interconnected neurons that synchronizes singing and learning. But the exact boundaries of that region are fuzzy; some researchers define it as larger or smaller than others do, depending on what criteria they use to outline the area. And differences between the song nuclei of parrots—which can better imitate complex sounds—and other birds are hard to pinpoint. Neurobiologist Erich Jarvis of Duke University in Durham, North Carolina, was studying the activation of PVALB—a gene that had been previously found in songbirds—within the brains of parrots when he noticed something strange. Stained sections of deceased parrot brains revealed that the gene was turned on at distinct levels within two distinct areas of what he thought was the song nuclei of the birds’ brains. Sometimes, the gene was activated in a spherical central core of the nuclei. But other times, it was only active in an outer shell of cells surrounding that core. When he and collaborators looked more closely, they found that the inner core and the outer shell—like the chocolate and surrounding candy shell of an M&M—varied in many more ways as well.
By Megan Cartwright Don’t pet the platypus. I know it’s tempting: Given the chance, I’d want to stroke their thick brown fur, tickle those big webbed feet, and pat that funny duck bill. And why not? What harm could come from this cute, egg-laying mammal from eastern Australia? Plenty. As someone who doesn’t enjoy “long lasting excruciating pain that cannot be relieved with conventional painkillers,” I’d really regret petting a platypus. Especially a male platypus, in late winter, when there’s only one thing on his mind and, even worse, something nasty on his feet. When British biologist Sir Everard Home got ahold of some platypus specimens in 1801, he told his fellow nerds at the Royal Society how the male specimen had a half-inch long “strong crooked spur” on the heel of each rear foot. The female, however, was spur-free. Home suggested that it “is probably by means of these spurs or hooks, that the female is kept from withdrawing herself in the act of copulation.” A very reasonable suggestion. But a wrong one. To be fair to Home, he could only study dead platypuses. If Home could have spent a year hanging out with living platypuses in their river homes, he would’ve seen that this “shy, semi-aquatic, mainly nocturnal” mammal is mostly interested in hunting on the river bottom for delicious insect larvae, crayfish, and shrimp. In other words, the platypus is usually an eater, not a lover. © 2014 The Slate Group
Patricia Neighmond A report finds mixed results when it comes to how well medical marijuana works to calm pain and control symptoms. And, an editorial says states legalizing pot for medical use may be jumping the gun. DAVID GREENE, HOST: Twenty-three states plus the District of Columbia have approved pot for medical use. But a new study in the Journal of the American Medical Association is raising questions about its safety and effectiveness. Here's NPR's Patti Neighmond. PATTI NEIGHMOND, BYLINE: Researchers from the University of Bristol in the United Kingdom reviewed findings from 79 different studies looking at the effect of marijuana on symptoms ranging from chronic pain to sleep difficulties and mental illness. At best, they found only moderate evidence indicating that marijuana reduced nerve pain and pain from cancer. When it came to other conditions, like nausea and vomiting due to chemotherapy, difficulties sleeping or weight loss among HIV patients, there was some anecdotal evidence suggesting that people may be helped by marijuana, but it was just that - anecdote. D'SOUZA: Which is really the bulk of the evidence that the states have used in approving medical marijuana. NEIGHMOND: In an editorial accompanying this study, Dr. Deepak Cyril D'Souza says states legalizing marijuana for medical use may be jumping the gun before good quality evidence is in. D'SOUZA: If a pharmaceutical company, for example, wanted to get a drug approved for a medical condition and they only submitted anecdotal data, there's absolutely no chance that that drug would be approved. NEIGHMOND: D'Souza is a psychiatrist with Yale University's School of Medicine. For years, he's studied the impact of marijuana on mental health. And the big question, he says, is how routine daily use - the way one might use marijuana to treat a medical condition - affects the body and the brain over the long term. Concerns have been raised about memory loss, panic, paranoia and other severe disorders. © 2015 NPR
Keyword: Drug Abuse
Link ID: 21089 - Posted: 06.25.2015
By PETER ANDREY SMITH Eighteen vials were rocking back and forth on a squeaky mechanical device the shape of a butcher scale, and Mark Lyte was beside himself with excitement. ‘‘We actually got some fresh yesterday — freshly frozen,’’ Lyte said to a lab technician. Each vial contained a tiny nugget of monkey feces that were collected at the Harlow primate lab near Madison, Wis., the day before and shipped to Lyte’s lab on the Texas Tech University Health Sciences Center campus in Abilene, Tex. Lyte’s interest was not in the feces per se but in the hidden form of life they harbor. The digestive tube of a monkey, like that of all vertebrates, contains vast quantities of what biologists call gut microbiota. The genetic material of these trillions of microbes, as well as others living elsewhere in and on the body, is collectively known as the microbiome. Taken together, these bacteria can weigh as much as six pounds, and they make up a sort of organ whose functions have only begun to reveal themselves to science. Lyte has spent his career trying to prove that gut microbes communicate with the nervous system using some of the same neurochemicals that relay messages in the brain. Inside a closet-size room at his lab that afternoon, Lyte hunched over to inspect the vials, whose samples had been spun down in a centrifuge to a radiant, golden broth. Lyte, 60, spoke fast and emphatically. ‘‘You wouldn’t believe what we’re extracting out of poop,’’ he told me. ‘‘We found that the guys here in the gut make neurochemicals. We didn’t know that. Now, if they make this stuff here, does it have an influence there? Guess what? We make the same stuff. Maybe all this communication has an influence on our behavior.’’ Since 2007, when scientists announced plans for a Human Microbiome Project to catalog the micro-organisms living in our body, the profound appreciation for the influence of such organisms has grown rapidly with each passing year. Bacteria in the gut produce vitamins and break down our food; their presence or absence has been linked to obesity, inflammatory bowel disease and the toxic side effects of prescription drugs. Biologists now believe that much of what makes us human depends on microbial activity. © 2015 The New York Times Company
Sarah Schwartz A person’s sense of smell may reveal a lot about his or her identity. A new test can distinguish individuals based upon their perception of odors, possibly reflecting a person’s genetic makeup, scientists report online June 22 in Proceedings of the National Academy of Sciences. Most humans perceive a given odor similarly. But the genes for the molecular machinery that humans use to detect scents are about 30 percent different in any two people, says neuroscientist Noam Sobel of the Weizmann Institute of Science in Rehovot, Israel. This variation means that nearly every person’s sense of smell is subtly different. Nobody had ever developed a way to test this sensory uniqueness, Sobel says. Sobel and his colleagues designed a sensitive scent test they call the “olfactory fingerprint.” In an experiment, test subjects rated how strongly 28 odors such as clove or compost matched 54 adjectives such as “nutty” or “pleasant.” An olfactory fingerprint describes individuals’ perceptions of odors’ similarities, not potentially subjective scent descriptions. All 89 subjects in the study had distinct olfactory fingerprints. The researchers calculated that just seven odors and 11 descriptors could have identified each individual in the group. With 34 odors, 35 descriptors, and around five hours of testing per person, the scientists estimate they could individually identify about 7 billion different people, roughly the entire human population. © Society for Science & the Public 2000 - 2015.
By Kiona Smith-Strickland Are crows the smartest animals of all? Many scientists think that corvids — the family of birds that includes crows, ravens, rooks and jays — may be among the most intelligent animals on Earth, based on their ability to solve problems, make tools and apparently consider both possible future events and other individuals’ states of mind. “There’s a lot of research that has been done with both ravens and crows because they are such intelligent species,” said Margaret Innes, an assistant curator at the Maryland Zoo in Baltimore. Even in humans, defining and measuring intelligence is difficult, and it’s more complicated in other species, which have very different body shapes and have evolved for their niche in the environment. However, scientists who study cognition have defined a few measures of intelligence: recognizing oneself in a mirror, solving complex problems, making tools, using analogies and symbols, and reasoning about what others are thinking. For a long time, biologists expected most of these mental feats to be unique to primates. The great apes — chimpanzees, orangutans and gorillas — succeed at nearly all of these tasks, from making and using tools to learning large vocabularies of symbols, as well as recognizing themselves in mirrors. A select few other mammals also meet most of the accepted criteria for intelligence. Dogs and dolphins, for instance, are very good at tasks involving social intelligence, such as communication, conflict resolution and reasoning about what others are thinking. Dolphins are also capable of basic tool use — for instance, carrying sea sponges in their mouths to shield their noses from scrapes and bumps as they forage on the ocean floor.
Carl Zimmer Certain people, researchers have discovered, can’t summon up mental images — it’s as if their mind’s eye is blind. This month in the journal Cortex, the condition received a name: aphantasia, based on the Greek word phantasia, which Aristotle used to describe the power that presents visual imagery to our minds. I find research like this irresistible. It coaxes me to think about ways to experience life that are radically different from my own, and it offer clues to how the mind works. And in this instance, I played a small part in the discovery. In 2005, a 65-year-old retired building inspector paid a visit to the neurologist Adam Zeman at the University of Exeter Medical School. After a minor surgical procedure, the man — whom Dr. Zeman and his colleagues refer to as MX — suddenly realized he could no longer conjure images in his mind. Dr. Zeman couldn’t find any description of such a condition in medical literature. But he found MX’s case intriguing. For decades, scientists had debated how the mind’s eye works, and how much we rely on it to store memories and to make plans for the future. MX agreed to a series of examinations. He proved to have a good memory for a man of his age, and he performed well on problem-solving tests. His only unusual mental feature was an inability to see mental images. Dr. Zeman and his colleagues then scanned MX’s brain as he performed certain tasks. First, MX looked at faces of famous people and named them. The scientists found that certain regions of his brain became active, the same ones that become active in other people who look at faces. © 2015 The New York Times Company
Link ID: 21085 - Posted: 06.23.2015
Skinny jeans can seriously damage muscles and nerves, doctors have said. A 35-year-old woman had to be cut out of a pair after her calves ballooned in size, the medics said in the Journal of Neurology, Neurosurgery and Psychiatry. She had spent hours squatting to empty cupboards for a house move in Australia. By evening, her feet were numb and she found it hard to walk. Doctors believe the woman developed a condition called compartment syndrome, made worse by her skinny jeans. Compartment syndrome is a painful and potentially serious condition caused by bleeding or swelling within an enclosed bundle of muscles - in this case, the calves. The condition caused the woman to trip and fall and, unable to get up, she then spent several hours lying on the ground. On examination at the Royal Adelaide Hospital, her lower legs were severely swollen. Although her feet were warm and had enough blood supplying them, her muscles were weak and she had lost some feeling. As the pressure had built in her lower legs, her muscles and nerves became damaged. She was put on an intravenous drip and after four days was able to walk unaided. Other medics have reported a number of cases where patients have developed tingly, numb thighs from wearing the figure-hugging low-cut denim trousers - although the chance of it happening is still slim for most people. Priya Dasoju, professional adviser at the Chartered Society of Physiotherapy, said: "As with many of these warnings, the very unfortunate case highlighted is an extreme one. © 2015 BBC
Keyword: Movement Disorders
Link ID: 21084 - Posted: 06.23.2015
By Amanda Montañez As someone who works at the intersection of art and science, I have always found it easy to make the case that all artists are scientists. From the moment we pick up a crayon and make our first mark, we are experimenting. The perceived successes and failures of our craft are indelibly tied to the many variables—physical, chemical and psychological—inherent in the experiences of creating and consuming works of art. Yet, it seems a longer stretch, somehow, to argue that all scientists are artists. At the very least, in my experience, scientists seem less willing to claim this alternate title. In fact, almost anyone who does not see her or himself as artistically inclined tends to be a little too quick to proclaim, “Oh, I’m not an artist. I can’t even draw a straight line!” With a sigh, I’ll avoid the temptation to digress into the utter irrelevance of straight lines and one’s ability to draw them. Instead, I’d like to posit the idea that, while we may not all identify as artists, scientists, of all people, really should be artists. Throughout history, much of scientific discovery and advancement has hinged not just on our ability to see certain things, but also on our capacity to reproduce what we see in faithful, critical and/or meaningful ways. The drawings of the famous Spanish neuroscientist Santiago Ramón y Cajal provide an ideal example of this phenomenon. In the late 1800s, using a novel histological staining technique developed by Italian physician Camillo Golgi, Ramón y Cajal spent countless hours examining brain tissues under the microscope and recording what he saw in pen and ink.
Keyword: Brain imaging
Link ID: 21083 - Posted: 06.23.2015
By Nicholas Bakalar Exposure to air pollution may hasten brain aging, a new study has found. Researchers studied 1,403 women without dementia who were initially enrolled in a large health study from 1996 to 1998. They measured their brain volume with M.R.I. scans in 2005 and 2006, when the women were 71 to 89 years old. Using residential histories and air pollution data, they estimated their exposure to air pollution from 1999 to 2006. They used data recorded at monitoring sites on exposure to PM 2.5 — tiny particulate matter that easily penetrates the lungs. Each increase of 3.49 micrograms per cubic centimeter cumulative exposure to pollutants was associated with a 6.23 cubic centimeter decrease in white matter, the equivalent of one to two years of brain aging. The association remained after adjusting for many variables, including age, smoking, physical activity, blood pressure, body mass index, education and income. Previous studies have shown that air pollution can cause inflammation and damage to the vascular system, but this study, in The Annals of Neurology, showed damage to the brain itself. “This tells us that the damage air pollution can impart goes beyond the circulatory system,” said the lead author, Dr. Jiu-Chiuan Chen, an associate professor of preventive medicine at the Keck School of Medicine at the University of Southern California. “Particles in the ambient air are an environmental neurotoxin to the aging brain.” © 2015 The New York Times Company
By THE ASSOCIATED PRESS NEW HAVEN, Connecticut — To the untrained eye, it looked like a seismograph recording of a violent earthquake or the gyrations of a very volatile day on Wall Street — jagged peaks and valleys in red, blue and green, displayed on a wall. But the story it told was not about geology or economics. It was a glimpse into the brains of Shaul Yahil and Shaw Bronner, two researchers at a Yale lab, as they had a little chat. "This is a fork," Yahil observed, describing the image on his computer. "A fork is something you use to stab food while you're eating it. Common piece of cutlery in the West." "It doesn't look like a real fancy sterling silver fork, but very useful," Bronner responded. And then she described her own screen: "This looks like a baby chimpanzee ..." The jagged, multicolored images depicted what was going on in the two researchers' heads — two brains in conversation, carrying out an intricate dance of internal activity. This is no parlor trick. The brain-tracking technology at work is just a small part of the quest to answer abiding questions about the workings of a three-pound chunk of fatty tissue with the consistency of cold porridge. How does this collection of nearly 100 billion densely packed nerve cells, acting through circuits with maybe 100 trillion connections, let us think, feel, act and perceive our world? How does this complex machine go wrong and make people depressed, or delusional, or demented? What can be done about that? These are the kinds of questions that spurred President Barack Obama to launch the BRAIN initiative in 2013. Its aim: to spur development of new tools to investigate the brain. Europe and Japan are also pursuing major efforts in brain research. © 2015 The New York Times Company
Keyword: Brain imaging
Link ID: 21081 - Posted: 06.22.2015
Patricia Neighmond We all know that listening to music can soothe emotional pain, but Taylor Swift, Jay-Z and Alicia Keys can also ease physical pain, according to a study of children and teenagers who had major surgery. The analgesic effects of music are well known, but most of the studies have been done with adults and most of the music has been classical. Now a recent study finds that children who choose their own music or audiobook to listen to after major surgery experience less pain. The catalyst for the research was a very personal experience. Sunitha Suresh was a college student when her grandmother had major surgery and was put in intensive care with three other patients. This meant her family couldn't always be with her. So they decided to put her favorite south Indian classical Carnatic music on an iPod, so she could listen around the clock. It was very calming, Sunitha says. "She knew that someone who loved her had left that music for her and she was in a familiar place." This may be the most efficient way to get in shape, but it may also be the least fun. Suresh could see the music relaxed her grandmother and made her feel less anxious, but she wondered if she also felt less pain. That would make sense, because anxiety can make people more vulnerable to pain. At the time Suresh was majoring in biomedical engineering with a minor in music cognition at Northwestern University where her father, Santhanam Suresh, is a professor of anesthesiology and pediatrics. © 2015 NPR
Keyword: Pain & Touch
Link ID: 21080 - Posted: 06.22.2015
Children who have a good memory are better at telling lies, say child psychology researchers. They tested six and seven-year-olds who were given an opportunity to cheat in a trivia game and then lie about their actions. Children who were good liars performed better in tests of verbal memory - the number of words they could remember. This means they are good at juggling lots of information, even if they do tell the odd fib. Writing in the Journal of Experimental Child Psychology, researchers from the Universities of North Florida, Sheffield and Stirling, recruited 114 children from four British schools for their experiment. Using hidden cameras during a question-and-answer game, they were able to identify the children who peeked at the answer to a fictitious question, even though they were told not to. A potentially surprising finding (for parents) is that only a quarter of the children cheated by looking at the answer. Further questioning allowed the researchers to work out who was a good liar or a bad liar. They were particularly interested in children's ability to maintain a good cover story for their lie. In separate memory tests, the good liars showed they had a better working memory for words - but they didn't show any evidence of being better at remembering pictures (visuo-spatial memory). The researchers said this was because lying involves keeping track of lots of verbal information, whereas keeping track of images is less important. © 2015 BBC
by Kate Solomon Jean-Dominique Bauby famously wrote The Diving Bell and The Butterfly by blinking as an assistant read out the alphabet, but locked-in patients could soon have a much easier way to communicate. For the first time, scientists have successfully transcribed brainwaves as text, which could mean that those unable to speak could use the system to "talk" via a computer. Carried out by a group of informatics, neuroscience and medical researchers at Albany Medical Centre, the team managed to identify the brainwaves relating to speech by using electrocorticographic (ECoG) technology to monitor the frontal and temporal lobes of seven epileptic volunteers. This involves using needles to record signals directly from a person's neurons; it's an invasive procedure requiring an incision through the skull. The participants then read aloud from a sample text while machine learning algorithms pulled out the most likely word sequence from the signals recorded by the EcOG. Existing speech-to-text tools then transcribed the continuously spoken speech directly from the brain activity. Error rates were as low as 25 percent during the study, which means the potential for the system is pretty vast. The findings could offer locked-in and mute patients a valuable communication method but it also means humans could one day communicate directly with a computer without needing any intermediary equipment.
By Mitch Leslie After years of fasting, the Buddha’s “legs were like bamboo sticks, his backbone was like a rope, his chest was like an incomplete roof of a house, his eyes sank right inside, like stones in a deep well,” according to one account. The Buddha didn’t get what he wanted from this extreme fasting—enlightenment—but a new study suggests that a diet that replicates some effects of milder deprivation may not only lower your weight but also confer other benefits. Researchers report that following the diet for just 5 days a month improves several measures of health, including reducing the risk of developing cardiovascular disease. Eating shortens life, and not just because overindulgence can lead to diseases such as diabetes. A diet that cuts food intake by up to 40%, known as calorie restriction, increases longevity in a variety of organisms and forestalls cancer, heart disease, and other late-life illnesses. Although some short-term studies suggest that calorie restriction provides metabolic benefits to people, nobody has confirmed that it also increases human life span. The closest researchers have come are two large, long-term studies of monkeys, and they conflict about whether meager rations increase longevity. Even if calorie restriction could add years to our lives, almost no one can muster the willpower to eat so little day after day, year after year. An alternative that might be more, er, palatable is fasting, the temporary abstinence from food. Gerontological researcher Valter Longo of the University of Southern California in Los Angeles and colleagues have shown that fasting eases side effects of chemotherapy such as fatigue and weakness, and animal studies suggest that it produces health advantages similar to calorie restriction. © 2015 American Association for the Advancement of Science.
Link ID: 21077 - Posted: 06.20.2015
By Tina Rosenberg Elle is a mess. She’s actually talented, attractive and good at her job, but she feels like a fraud — convinced that today’s the day she’ll flunk a test, lose a job, mess up a relationship. Her colleague Moody also sabotages himself. He’s a hardworking, nice person, but loses friends because he’s grumpy, oversensitive and gets angry for no reason. If you suffer from depression or anxiety as Elle and Moody do, spending time with them could help. They are characters in a free online program of cognitive behavioral therapy called MoodGYM, which leads users through quizzes and exercises — therapy without the therapist. Cognitive behavioral therapy is a commonly used treatment for depression, anxiety and other conditions. With it, the therapist doesn’t ask you about your mother — or look at the past at all. Instead, a cognitive behavioral therapist aims to give patients the skills to manage their moods by helping them identify unhelpful thoughts like “I’m worthless,” “I’ll always fail” or “people will always let me down.” Patients learn to analyze them and replace them with constructive thoughts that are more accurate or precise. For example, a patient could replace “I fail at everything” with “I succeed at things when I’m motivated and I try hard.” That new thought in turn changes feelings and behaviors. The success of cognitive behavioral therapy is well known; many people consider it the most effective therapy for depression. What is not widely known, at least in the United States, is that you don’t need a therapist to do it. Scores of studies have found that online C.B.T. works as well as conventional face-to-face cognitive behavioral therapy – as long a there is occasional human support or coaching. “For common mental disorders like anxiety and depression, there is no evidence Internet-based treatment is less effective than face-to-face therapy,” said Pim Cuijpers, professor of clinical psychology at the Vrije Universiteit Amsterdam and a leading researcher on computer C.B.T. © 2015 The New York Times Company
Link ID: 21076 - Posted: 06.20.2015
by Sarah Zielinski Last year in Australia, I visited Featherdale Wildlife Park where, in a couple of areas, kangaroos and wallabies hop amongst the tourists. For a dollar, you can buy an ice cream cone full of grass for the marsupials to eat. But if you’re not careful, an animal will quickly grab the cone out of your hand and feed itself. Now I’m wishing that I had paid more attention to that grabbing motion. Kangaroos are lefties, scientists report June 18 in Current Biology. And the preference for one hand over the other may be linked to the ability to walk on two legs. Humans show a definite preference for one hand over the other, usually the right. This handedness had been considered a distinctly human trait. But scientists have found more and more evidence that other species have such preferences as well. Female domestic cats, for instance, tend to use their right paws and males their left. Andrey Giljov of Saint Petersburg State University in Russia and colleagues were curious about the evolution of handedness and looked to marsupials, since these animals are an early offshoot of the mammal lineage. They observed four species in the wild — red kangaroos, eastern gray kangaroos, red-necked wallabies and Goodfellow’s tree kangaroos — performing tasks such as grooming and feeding. © Society for Science & the Public 2000 - 2015.
Link ID: 21075 - Posted: 06.20.2015
by Bob Holmes Lions might be one of the biggest threats to hyenas, but that doesn't stop the smaller animals teaming up to steal from the big cats. Nora Lewin from Michigan State University in East Lansing and her colleagues observed the mobbing behaviour at the Masai Mara National Reserve in Kenya. Hyenas were also spotted banding together to keep lions away from their dens. The mobbing involves a surprising degree of cooperation and communication. Male lions, which actively pursue and kill hyenas, are much more of a danger than females, who usually just make threats. This could be why the hyenas in the video above are confronting females. The team suggests the hyenas can identify their opponent's age and sex before deciding as a group whether or not to mob it. Levin and her colleagues are now investigating how the hyenas communicate to make a group decision. The findings were reported on 13 June at the annual meeting of the Animal Behavior Society in Anchorage, Alaska. © Copyright Reed Business Information Ltd.
Helen Shen Boosting activity in neurons that have stored happy memories might help to treat depression — at least according to results in mice. In a study published today (17 June) in Nature, neuroscientist Susumu Tonegawa and his colleagues at the Massachusetts Institute of Technology in Cambridge report how they reversed a depression-like state in rodents by using light to stimulate clusters of brain cells believed to have stored memories of a positive experience1. The findings are preliminary, but they hint that areas of the brain involved in storing memories could one day be a target to treat mental disorders in humans, says Tonegawa. “I want to be very careful not to give false expectations to patients. We are doing very basic science,” he adds. “This is exactly the type of work that psychiatry needs right now,” says Robert Malenka, a behavioural scientist at Stanford University in California. “This is an elegant paper.” The work has grown out of studies by Tonegawa’s lab and others that aimed to locate the memory ‘engram’ — the physical trace of a memory, thought to be encoded in an ensemble of neurons2–6. In 2012, Tonegawa and his team provided one of the clearest demonstrations of an engram. They engineered mice with light-sensitive proteins that were expressed when neurons fired. As a result, they could track any neurons that activated while the mice were given a fearful memory by being trained with repeated electric shocks to be scared of a cage3. The researchers later used blue flashes of light to make the same neurons fire again — a technique known as optogenetics — and found that they could make the animals freeze up, presumably because the fearful memory had been reawoken. © 2015 Nature Publishing Group