Adrienne LaFrance For the better part of the past decade, Mark Kirby has been pouring drinks and booking gigs at the 55 Bar in New York City's Greenwich Village. The cozy dive bar is a neighborhood staple for live jazz that opened on the eve of Prohibition in 1919. It was the year Congress agreed to give American women the right to vote, and jazz was still in its infancy. Nearly a century later, the den-like bar is an anchor to the past in a city that's always changing. For Kirby, every night of work offers the chance to hear some of the liveliest jazz improvisation in Manhattan, an experience that's a bit like overhearing a great conversation. "There is overlapping, letting the other person say their piece, then you respond," Kirby told me. "Threads are picked up then dropped. There can be an overall mood and going off on tangents." Brain areas linked to meaning shut down during improvisational jazz interactions. In other words, this music is syntactic, not semantic. The idea that jazz can be a kind of conversation has long been an area of interest for Charles Limb, an otolaryngological surgeon at Johns Hopkins. So Limb, a musician himself, decided to map what was happening in the brains of musicians as they played. He and a team of researchers conducted a study that involved putting a musician in a functional MRI machine with a keyboard, and having him play a memorized piece of music and then a made-up piece of music as part of an improvisation with another musician in a control room. What researchers found: The brains of jazz musicians who are engaged with other musicians in spontaneous improvisation show robust activation in the same brain areas traditionally associated with spoken language and syntax. In other words, improvisational jazz conversations "take root in the brain as a language," Limb said. © 2014 by The Atlantic Monthly Group

Keyword: Hearing; Language
Link ID: 19275 - Posted: 02.20.2014

By Sandhya Somashekhar, The Food and Drug Administration has approved 24 drugs for the treatment of male sexual dysfunction. For women, that number is zero. The disparity reflects drugmakers’ difficulties in unlocking the secret to revving up women’s sex drive. It also has become a rallying point for women’s advocates and even some members of Congress, who suggest that federal regulators seem more eager to approve sex-enhancing drugs for men than for women. It isn’t every day that political leaders and groups such as the National Organization for Women get involved in the drug- approval process, particularly for “lifestyle” drugs. But the unsuccessful quest for a “female Viagra” is sparking complicated questions about a woman’s right to a pill that may improve her sex life — and about how much of a libido lift is enough to be judged effective by the FDA. A drug called flibanserin, touted by some as the “little pink pill,” the counterpoint to Viagra’s little blue pill, was developed 12 years ago. Last month, women’s groups were disappointed when the FDA asked for further safety tests on the medication. Some critics say the agency — consciously or not — may be succumbing to society’s squeam­ishness about women’s sexual desires compared with those of men. “It looks to me like there are more hurdles being put in front of this drug than there have been on drugs addressing male dysfunction,” said Terry O’Neill, president of NOW. “Obviously, everyone only wants drugs to get on the market if they are proven safe and effective. But we don’t want attitudes to get in the way of a good drug.” © 1996-2014 The Washington Post

Keyword: Sexual Behavior
Link ID: 19274 - Posted: 02.20.2014

by Colin Barras If it's beyond repair, you find something else to do its job. This could soon apply to rods and cones, the light-sensitive cells in our eyes that can wither with age, causing blindness. A drug has been found that coaxes neighbours of ailing cells to do their work for them. In 2012, Richard Kramer at the University of California, Berkeley, discovered that injecting a certain chemical into the eyes of blind mice made normally light-insensitive ganglion cells respond to light. These cells ferry optical signals from the rods and cones to the brain, so the mice regained some ability to see light. But it only worked with ultraviolet light. Now, Kramer's team has found a different drug that does the same with visible light. Just 6 hours after they were injected, blind mice could learn to respond to light in the same way as sighted mice – although Kramer says he doesn't know whether they regained vision or just light sensitivity. When the researchers studied the drug's impact on retinal cells in more detail, they realised it had had no effect on healthy cells. "That's what's particularly remarkable and hopeful about this," says Kramer. "It's possible that if you put this drug in a partially damaged eye it would restore vision to the damaged regions and leave the healthy areas unaffected – although we haven't done the experiments to test that." Gene therapy and stem cell treatments are also being explored as ways to restore sight, but a drug would be simpler and any side effects should be reversible, says Kramer. © Copyright Reed Business Information Ltd

Keyword: Vision
Link ID: 19273 - Posted: 02.20.2014

James Hamblin Brain training is becoming big business. Everywhere you look, someone is talking about neuroplasticity and trying to train your brain. Soon there will be no wild brains left. At the same time, everyone who spends more than two continuous hours using a computer is, according to the American Optometric Association, ruining their eyes with Computer Vision Syndrome. So, Dr. Aaron Seitz might be onto something with his new brain-training program that promises better vision. UltimEyes is a game-based app that's sold as "fun and rewarding" as it improves your vision and "reverse[s] the effects of aging eyes." It doesn't claim to work on the eyes themselves, but on the brain cortex that processes vision—the part that takes blurry puzzle pieces from the eyes and arranges them into a sweet puzzle. (Brain training for memory, the kind we hear about the most on TV, would be the part that lacquers the finished puzzle, frames it, and hangs it on the wall.) A standard 25-minute session using UltimEyes forces your eyes to work in ways they probably don't in everyday life, and its website warns that after the first use, "just like the first time that you go to the gym, your eyes may feel a bit tired. This experience typically goes away by your third session as your visual system adjusts to its new work-out routine." Seitz is a neuroscientist at the University of California, Riverside. To test out his vision-training game, he had players on the university's baseball team use the app. Half the team trained for 30 sessions. For comparison, the other half did no training. © 2014 by The Atlantic Monthly Group

Keyword: Vision; Learning & Memory
Link ID: 19272 - Posted: 02.20.2014

Ian Sample, science correspondent, in Chicago Regular brisk walks can slow down the shrinking of the brain and the faltering mental skills that old age often brings, scientists say. Studies on men and women aged 60 to 80 found that taking a short walk three times a week increased the size of brain regions linked to planning and memory over the course of a year. The prefrontal cortex and hippocampus increased in size by only 2% or 3%, but that was enough to offset the steady shrinkage doctors expected to see over the same period. "It may sound like a modest amount but that's actually like reversing the age clock by about one to two years," said Professor Kirk Erickson, a neuroscientist at the University of Pittsburgh. "While the brain is shrinking, we actually saw not a levelling out but an increase in the size of these regions. It was better than before we started the study." People who took part in the study scored higher on spatial memory tests, and some reported feeling more mentally alert, according to Erickson. "They feel better, they feel as if the fog has lifted. Anecdotally, it seems to benefit these cognitive functions," he said. Erickson recruited more than 100 adults who confessed to doing little if any exercise in their daily lives. Half were randomly assigned to walk for 30 to 45 minutes three days a week. The rest spent a similar amount of time doing stretching exercises. Medical scans showed minor increases in the two brain regions in both groups. But the effect was greater in the walkers, Erickson said at the annual meeting of the American Association for the Advancement of Science. © 2014 Guardian News and Media Limited

Keyword: Alzheimers
Link ID: 19271 - Posted: 02.20.2014

By ALAN SCHWARZ Jerry, 9 years old, dissolved into his Game Boy while his father described his attentional difficulties to the family pediatrician. The child began flitting around the room distractedly, ignoring the doctor’s questions and squirming in his chair — but then he leapt up and yelled: “Freeze! What do you think is the problem here?” Nine-year-old Jerry was in fact being played by Dr. Peter Jensen, one of the nation’s most prominent child psychiatrists. On this Sunday in January in New York, Dr. Jensen was on a cross-country tour, teaching pediatricians and other medical providers how to properly evaluate children’s mental health issues — especially attention deficit hyperactivity disorder, which some doctors diagnose despite having little professional training. One in seven children in the United States — and almost 20 percent of all boys — receives a diagnosis of A.D.H.D. by the time they turn 18, according to the Centers for Disease Control and Prevention. It narrowly trails asthma as the most common long-term medical condition in children. Increasing concern about the handling of the disorder has raised questions about the training doctors receive before diagnosing the condition and prescribing stimulants like Adderall or Concerta, sometimes with little understanding of the risks. The medications can cause sleep problems, loss of appetite and, in rare cases, delusions. Because the disorder became a widespread national health concern only in the past few decades, many current pediatricians received little formal instruction on it, sometimes only several hours, during their seven years of medical school and residency. But the national scarcity of child psychiatrists has placed much of the burden for evaluating children’s behavioral problems on general pediatricians and family doctors, a reality that Dr. Jensen and others are trying to address through classes that emphasize role-playing exercises and spirited debate. © 2014 The New York Times Company

Keyword: ADHD; Development of the Brain
Link ID: 19270 - Posted: 02.19.2014

By NICHOLAS RICCARDI, Associated Press COLORADO SPRINGS, Colo. (AP) — The doctors were out of ideas to help 5-year-old Charlotte Figi. Suffering from a rare genetic disorder, she had as many as 300 grand mal seizures a week, used a wheelchair, went into repeated cardiac arrest and could barely speak. As a last resort, her mother began calling medical marijuana shops. Two years later, Charlotte is largely seizure-free and able to walk, talk and feed herself after taking oil infused with a special pot strain. Her recovery has inspired both a name for the strain of marijuana she takes that is bred not to make users high — Charlotte's Web — and an influx of families with seizure-stricken children to Colorado from states that ban the drug. "She can walk, talk; she ate chili in the car," her mother, Paige Figi, said as her dark-haired daughter strolled through a cavernous greenhouse full of marijuana plants that will later be broken down into their anti-seizure components and mixed with olive oil so patients can consume them. "So I'll fight for whomever wants this." Doctors warn there is no proof that Charlotte's Web is effective, or even safe. In the frenzy to find the drug, there have been reports of non-authorized suppliers offering bogus strains of Charlotte's Web. In one case, a doctor said, parents were told they could replicate the strain by cooking marijuana in butter. Their child went into heavy seizures. "We don't have any peer-reviewed, published literature to support it," Dr. Larry Wolk, the state health department's chief medical officer, said of Charlotte's Web. Still, more than 100 families have relocated since Charlotte's story first began spreading last summer, according to Figi and her husband. The relocated families have formed a close-knit group in Colorado Springs, the law-and-order town where the dispensary selling the drug is located. They meet for lunch, support sessions and hikes. © 2014 Hearst Communications, Inc.

Keyword: Epilepsy; Drug Abuse
Link ID: 19269 - Posted: 02.19.2014

By GRETCHEN REYNOLDS Watching participants in slopestyle and half-pipe skiing and snowboarding flip, curl, cartwheel and otherwise contort themselves in the air during the Winter Olympics competition, many of us have probably wondered not only how the athletes managed to perform such feats but also why. Helpfully, a recent study of the genetics of risk-taking intimates that their behavior may be motivated, at least in part, by their DNA. For some time, scientists and many parents have suspected that certain children are born needing greater physical stimulation than others, suggesting that sensation seeking, as this urge is known in psychological terms, has a genetic component. A thought-provoking 2006 study of twins, for instance, concluded that risk-taking behavior was shared by the pairs to a much greater extent than could be accounted for solely by environmental factors. If one twin sought out risks, the other was likely to do so as well. But finding which genes or, more specifically, which tiny snippets of DNA within genes, might be influencing the desire to huck oneself off of a snow-covered slope has proven to be troublesome. In recent years, scientists zeroed in on various sections of genes that affect the brain’s levels of or response to the neurotransmitter dopamine, a substance that is known to influence our feelings of pleasure, reward and gratification. People who engage in and enjoy extreme, daredevil conduct, researchers presumed, would likely process dopamine differently than those of us content to watch. But the results of some early genetic studies comparing dopamine-related portions of genes with sensation seeking were inconsistent. Some found that people with certain variations within genes, including a gene called DRD4 that is believed to be closely involved in the development and function of dopamine receptors in our brain, gravitated toward risky behavior. Others, though, found no such links. But most of these studies focused on so-called deviant risk-taking, such as gambling and drug addiction. © 2014 The New York Times Company

Keyword: Emotions; Genes & Behavior
Link ID: 19268 - Posted: 02.19.2014

By Geoffrey Mohan Stress can damage the brain. The hormones it releases can change the way nerves fire, and send circuits into a dangerous feedback loop, leaving us vulnerable to anxiety, depression and post-traumatic stress disorder. But how stress accomplishes its sinister work on a cellular level has remained mysterious. Neuroscientists at a UC Berkeley lab have uncovered evidence that a well-known stress hormone trips a switch in stem cells in the brain, causing them to produce a white matter cell that ultimately can change the way circuits are connected in the brain. This key step toward hardening wires, the researchers found, may be at the heart of the hyper-connected circuits associated with prolonged, acute stress, according to the study published online Tuesday in the journal Molecular Psychiatry. The findings strengthen an emerging view that cells once written off as little more than glue, insulation and scaffolding may regulate and reorganize the brain's circuitry. Researchers examined a population of stem cells in the brain’s hippocampus, an area critical to fusing emotion and memory, and one that has been known to shrink under the effects of prolonged acute stress. Under normal circumstances, these cells form new neurons or glia, a type of white matter. Los Angeles Times Copyright 2014

Keyword: Stress; Glia
Link ID: 19267 - Posted: 02.19.2014

by Clare Wilson A monkey controlling the hand of its unconscious cage-mate with its thoughts may sound like animal voodoo, but it is a step towards returning movement to people with spinal cord injuries. The hope is that people who are paralysed could have electrodes implanted in their brains that pick up their intended movements. These electrical signals could then be sent to a prosthetic limb, or directly to the person's paralysed muscles, bypassing the injury in their spinal cord. Ziv Williams at Harvard Medical School in Boston wanted to see if sending these signals to nerves in the spinal cord would also work, as this might ultimately give a greater range of movement from each electrode. His team placed electrodes in a monkey's brain, connecting them via a computer to wires going into the spinal cord of an anaesthetised, unconscious monkey. The unconscious monkey's limbs served as the equivalent of paralysed limbs. A hand of the unconscious monkey was strapped to a joystick, controlling a cursor that the other monkey could see on a screen. Williams's team had previously had the conscious monkey practise the joystick task for itself and had recorded its brain activity to work out which signals corresponded to moving the joystick back and forth. Through trial and error, they deduced which nerves to stimulate in the spinal cord of the anaesthetised monkey to produce similar movements in that monkey's hand. When both parts were fed to the computer, the conscious monkey was able to move the "paralysed" monkey's hand to make the cursor hit a target. © Copyright Reed Business Information Ltd.

Keyword: Robotics
Link ID: 19266 - Posted: 02.19.2014

By PAUL VITELLO Alison Jolly, an American-born primatologist whose research in the forests of Madagascar shed new light on the evolution of social intelligence and helped disprove a longstanding scientific tenet that males were dominant in every primate species, died on Feb. 6 in Lewes, East Sussex, England. She was 76. The cause was breast cancer, said Barbara Orlando, a longtime friend. Dr. Jolly’s two major insights emerged from her 1960s field studies of the lemur, a primate whose development in relative isolation on the island of Madagascar makes the species something akin to a living fossil. Dr. Jolly cited lemurs’ complex social relationships as evidence of an unexplored trail in one of anthropology’s great mysteries: the evolution of higher intelligence. Writing in the journal Science in 1966, she suggested that the many hours lemurs spent in play, mutual grooming and social networking — activities that establish the social ties and hierarchies that determine access to food, mate selection and migration patterns — may have been as important to the evolution of intelligence as the development of weapons and tools of hunting and protection, then considered the hallmarks of evolutionary advance. More unnerving to colleagues was her discovery that in some primate species, females run the show. The finding upended a bedrock assertion in evolutionary biology — based on studies of chimpanzees and orangutans in captivity — that males dominated females in every primate species, including humans. “Females have social, spatial and feeding priority over males,” Dr. Jolly wrote in describing the feeding, mating, child-rearing and recreational habits of the ring-tailed lemur, one of about 100 recognized species of lemur, of which more than a dozen are female-dominant. Among the ring-tailed lemurs, Dr. Jolly wrote in “Lemur Behavior: A Madagascar Field Study,” “all females, whether dominant or subordinate in the female hierarchy, are dominant over males.” © 2014 The New York Times Company

Keyword: Evolution; Sexual Behavior
Link ID: 19265 - Posted: 02.19.2014

By DENISE GRADY The experiment was not for the squirmish. Volunteers were made to itch like crazy on one arm, but not allowed to scratch. Then they were whisked into an M.R.I. scanner to see what parts of their brains lit up when they itched, when researchers scratched them and when they were finally allowed to scratch themselves. The scientific question was this: Why does it feel so good to scratch an itch? “It’s quite intriguing to see how many brain centers are activated,” said Dr. Gil Yosipovitch, chairman of dermatology at the Temple University School of Medicine and director of the Temple Center for Itch (he conducted the experiment while working at Wake Forest School of Medicine). “There is no one itch center. Everyone wants that target, but it doesn’t work in real life like that.” Instead, itching and scratching engage brain areas involved not only in sensation, but also in mental processes that help explain why we love to scratch: motivation and reward, pleasure, craving and even addiction. What an itch turns on, a scratch turns off — and scratching oneself does it better than being scratched by someone else. The study results were published in December in the journal PLOS One. Itching was long overshadowed by pain in both research and treatment, and was even considered just a mild form of pain. But millions of people suffer from itching, and times have changed. Research has found nerves, molecules and cellular receptors that are specific for itching and set it apart from pain, and the medical profession has begun to take it seriously as a debilitating problem that deserves to be studied and treated. Within the last decade, there has been a flurry of research into what causes itching and how to stop it. Along with brain imaging, studies have begun to look at gene activity and to map the signals that flow between cells in the skin, the immune system, the spinal cord and the brain. © 2014 The New York Times Company

Keyword: Pain & Touch
Link ID: 19264 - Posted: 02.18.2014

Elephants, both African and Asian, have long been considered empathetic animals. They help baby elephants stuck in mud holes, use their trunks to lift other elephants that are injured or dying, and even reportedly reassure distressed individual elephants with a gentle touch of their trunk. But it’s one thing to witness something that looks like consolation, and another to prove that this is what elephants are doing. Now, scientists have shown that African elephants do indeed get distressed when they see others in trouble, and they reach out to console them—just as we do when we see someone suffering. Elephants, thus, join a short list of other animals, including great apes, canines, and some birds, that scientists have shown to reassure others. The study “is the first to investigate responses to distress by Asian elephants,” which “is inherently difficult to assess because one has to wait for opportunities to arise spontaneously,” says Shermin de Silva, an behavioral ecologist at the Uda Walawe Elephant Research Project in Sri Lanka. It would not be ethical to intentionally create stressful situations for the animals as a test, she notes—which is why, until now, researchers have had to rely on well-documented, but anecdotal observations of wild and captive elephants to back up claims that they reassure each other. Joshua Plotnik, a behavioral ecologist at Mahidol University in Kanchanaburi, Thailand, and Frans de Waal, a primatologist at Emory University, got around this problem by comparing Asian elephants’ behaviors during times of stress to periods when little upset them. For one to two weeks every month for nearly a year, Plotnik spent 30 to 180 minutes daily watching and recording 26 captive Asian elephants. The animals ranged in age from 3 to 60 years old and lived at the 30-acre Elephant Nature Park in northern Thailand. Most of the elephants, aside from mother-juvenile pairs, were unrelated, and did not live in family groups as wild elephants do. Instead, the park’s Mahouts, or keepers, organized them into six groups which they then guided through a daily routine—bathing and feeding them in the morning, and tethering them at night. But during the day, the elephants were left alone to roam and graze at will. © 2014 American Association for the Advancement of Science

Keyword: Emotions; Evolution
Link ID: 19263 - Posted: 02.18.2014

By GREGORY COWLES David Stuart MacLean’s first book, “The Answer to the Riddle Is Me,” opens with a scene out of Robert Ludlum: The protagonist wakes from a blackout to find himself on a crowded train platform in India, with no idea who he is or what he’s doing in a foreign country. The catch is that the protagonist is Mr. MacLean himself, and his book isn’t an international thriller but a “memoir of amnesia,” as his agreeably paradoxical subtitle puts it — the true story of how his memory was wiped clean and how that condition has subsequently affected his life. It is all the more thrilling for that. In 2002, Mr. MacLean was a 28-year-old Fulbright scholar visiting India to research a novel. It wasn’t his first trip; he had gone a few years earlier and stayed for months. But this time around, his anti-malaria medication touched off a break with reality as sudden as it was severe. He hallucinated angels and demons, and felt his thoughts “puddling in the carpet near the doorway and sloshing down the hall.” Delirious, he agreed with the police officer who surmised he must be a drug addict, and apologized profusely for misdeeds he had never committed. At the hospital, a nurse called him “the most entertaining psychotic that they’d ever had.” As harrowing as this territory is, Mr. MacLean makes an affable, sure-footed guide. In his descriptions, you can recognize the good fiction writer he must have been even before amnesia forced him to view the world anew; if the writer’s task is to “make it new,” then losing your memory turns out to be an unexpected boon. An avid drinker before his breakdown, he recoils the first time he tries Scotch again, thinking it smells “like Band-Aids.” He can’t remember his girlfriend of a year, but her voice is “faintly familiar, like the smell of the car heater the first time you turn it on in the fall.” He grasps at hope when his parents arrive to take him home: “I still didn’t have my memory, but I now had an outline of myself, like a tin form waiting for batter.” © 2014 The New York Times Company

Keyword: Learning & Memory
Link ID: 19262 - Posted: 02.18.2014

By James Gallagher Health and science reporter, BBC News A tool for predicting the risk of clinical depression in teenage boys has been developed by researchers. Looking for high levels of the stress hormone cortisol and reports of feeling miserable, lonely or unloved could find those at greatest risk. Researchers at the University of Cambridge want to develop a way of screening for depression in the same way as heart problems can be predicted. However, their method was far less useful in girls. Teenage years and early adulthood are a critical time for mental health - 75% of disorders develop before the age of 24. But there is no way to accurately say who will or will not develop depression. Risky combination Now researchers say they have taken the "first step" towards a screening tool. Tests on 1,858 teenagers, reported in Proceedings of the National Academy of Sciences, combined hormone levels and mood questionnaires to assess risk. They showed that having both high cortisol levels and depressive mood symptoms posed a higher risk of depression than either factor alone and presented a risk of clinical depression 14 times that of those with low cortisol and no depressive symptoms. Around one in six boys was in the high-risk category and half of them were diagnosed with clinical depression during the three years of study. One of the researchers, Prof Ian Goodyer, said: "Depression is a terrible illness that will affect as many as 10 million people in the UK at some point in their lives. "Through our research, we now have a very real way of identifying those teenage boys most likely to develop clinical depression. BBC © 2014

Keyword: Depression; Hormones & Behavior
Link ID: 19261 - Posted: 02.18.2014

By MAGGIE KOERTH-BAKER If you are pulled over on suspicion of drunken driving, the police officer is likely to ask you to complete three tasks: Follow a pen with your eyes while the officer moves it back and forth; get out of the car and walk nine steps, heel to toe, turn on one foot and go back; and stand on one leg for 30 seconds. Score well on all three of these Olympic events, and there’s a very good chance that you are not drunk. This so-called standard field sobriety test has been shown to catch 88 percent of drivers under the influence of alcohol. But it is nowhere near as good at spotting a stoned driver. In a 2012 study published in the journal Psychopharmacology, only 30 percent of people under the influence of THC, the active ingredient in marijuana, failed the field test. And its ability to identify a stoned driver seems to depend heavily on whether the driver is accustomed to being stoned. A 21-year-old on his first bender and a hardened alcoholic will both wobble on one foot. But the same is not necessarily true of a driver who just smoked his first joint and the stoner who is high five days a week. In another study, 50 percent of the less frequent smokers failed the field test. As more states legalize medical and recreational marijuana, distinctions like these will grow more and more important. But science’s answers to crucial questions about driving while stoned — how dangerous it is, how to test for impairment, and how the risks compare to driving drunk — have been slow to reach the general public. “Our goal is to put out the science and have it used for evidence-based drug policy,” said Marilyn A. Huestis, a senior investigator at the National Institute on Drug Abuse. “But I think it’s a mishmash.” © 2014 The New York Times Company

Keyword: Drug Abuse
Link ID: 19260 - Posted: 02.18.2014

By Brian Palmer, The death of Philip Seymour Hoffman this month has raised many questions about drug addiction, among them: What do drugs such as heroin do to the brain to make them so addictive? Can these chemical changes be undone? Over the past 20 years, research into drug addiction has identified several chemical and physical changes to the brain brought on by addictive substances. There is a wad of nerve cells in the central part of your brain, measuring about half an inch across, called the nucleus accumbens. When you eat a doughnut, have sex or do something else that your brain associates with survival and breeding, this region is inundated with dopamine, a neurotransmitter. This chemical transaction is partly responsible for the experience of pleasure you get from these activities. Drugs such as heroin also trigger this response, but the dopamine surge from drugs is faster and long-lasting. When a person repeatedly subjects his nucleus accumbens to this narcotic-induced flood, the nerve cells that dopamine acts upon become exhausted from stimulation. The brain reacts by dampening its dopamine response — not just to heroin or cocaine, but probably to all forms of pleasurable behavior. In addition, some of the receptors themselves appear to die off. As a result, hyper-stimulating drugs become the only way to trigger a palpable dopamine response. Drug addicts seek larger and larger hits to achieve an ever-diminishing pleasure experience, and they have trouble feeling satisfaction from the things that healthy people enjoy. Behavioral conditioning also plays a role. Once your brain becomes accustomed to the idea that eating a doughnut or having sex will provide pleasure, just seeing a doughnut or an attractive potential mate triggers the dopamine cascade into the nucleus accumbens. That’s part of the reason it is so difficult for recovering drug addicts to stay clean over the long term. Sights, sounds and smells associated with the drug high — needles, for example, or the friends with whom they used to get high — prime this dopamine response, and the motivation to seek the big reward of a drug hit builds. © 1996-2014 The Washington Post

Keyword: Drug Abuse
Link ID: 19259 - Posted: 02.18.2014

By DOUGLAS QUENQUA The smell of a person’s earwax depends partly on his ethnic origin, a new study reports, suggesting that the substance could be an overlooked source of personal information. The earwax of Caucasian men contains more volatile organic compounds than that of East Asian men, researchers at the Monell Chemical Senses Center in Philadelphia found. Twelve such compounds are common to both groups, they said, but 11 of those are more plentiful in Caucasians. Monell researchers have previously found that underarm odor contains clues to a person’s age, health and sex. They suspected that earwax might contain similar markers, since a 2006 study found that a gene related to underarm odor, which also varies by ethnicity, helps determine a person’s type of earwax. (East Asians are more likely to have dry earwax, for example.) "We’re at the beginning of exploring a new and interesting biofluid secretion that has not been looked at in this manner before," said George Preti, an organic chemist at Monell and the senior author of the new study, which was published in The Journal of Chromatography B. Because of the fatty nature of earwax, or cerumen, Dr. Preti says it is a probable repository for odorants produced by diseases and the environment, and hence a potentially valuable diagnostic tool. A 2013 study showed that a whale’s earwax contains evidence of the animal’s exposure to pollutants and stress hormones, and earwax odor in humans is a known indicator of branched-chain ketoaciduria, also known as maple syrup urine disease. © 2014 The New York Times Company

Keyword: Chemical Senses (Smell & Taste)
Link ID: 19258 - Posted: 02.18.2014

Ian Sample, science correspondent, in Chicago A woman's diet in early life has more impact on her baby's birth weight than the food she eats as an adult, researchers say. The surprise finding suggests that you are what your mother ate, and that a woman's diet in her adult life has less influence on her baby's health than previously thought. Prof Christopher Kuzawa at Northwestern University in Illinois said that women's bodies seemed to "buffer" the supply of nutrients to their unborn babies, meaning that foetuses were partly protected from changes in women's diets. Kuzawa advised pregnant women to follow a healthy diet, but said they need not worry about every calorie because their health and diet as a toddler could be more important for their baby. "There is some good news here for expectant mothers. Although there certainly are some harmful things to avoid during pregnancy, and some supplements to take to make sure some important bases are covered, the mother's body seems to do a good job of buffering overall nutritional supply to her growing baby," he said. "Within the bounds of a healthy balanced diet, the overall quantity of food that a mother eats is unlikely to have large effects on her baby's birth weight," he added. The findings emerged from a 30-year study that followed more than 3,000 pregnant women in the Philippines whose children have now begun to have babies of their own. Kuzawa said that while there was good evidence that unborn children benefit from their mothers taking extra folate and that they are harmed by toxins such as lead, mercury, excessive alcohol and bisphenol A, which is used to make some plastics, the picture was less clear on the roles of calories, protein, fat and carbohydrates. © 2014 Guardian News and Media Limited

Keyword: Development of the Brain; Obesity
Link ID: 19257 - Posted: 02.17.2014

By CATHERINE SAINT LOUIS Does chocolate really hurt dogs? It can, depending on their weight and how much they eat, so be vigilant this Valentine’s Day. Stimulants in chocolate can lead to vomiting, diarrhea, agitation and life-threatening elevated heart rates or seizures. “Dogs have no off button,” said Dr. Tina Wismer, the medical director of the ASPCA Animal Poison Control Center. “If you or I ate 10 percent of our body weight in chocolate, we’d have the same problems. A 10-pound dog can easily eat a pound of chocolate.” The darker the chocolate, the more toxic it is. For a 20-pound dog, 9 ounces of milk chocolate can cause seizures, but it takes only 1.5 ounces of baker’s chocolate, she said. Signs of chocolate poisoning usually appear six to 12 hours after ingestion, according to The Merck Veterinary Manual. “Seizures due to toxicity don’t stop unless you treat them,” Dr. Wismer said. So head to the emergency clinic or veterinarian if you come home to find your dog vomiting repeatedly and extremely agitated, and certainly if the pet is unconscious and its limbs are shaking. By contrast, dogs who vomit once and fall sleep can be watched at home, she said. Unlike cats, dogs like sweets. So it’s best to keep chocolate stored away and off countertops, which are no match for a motivated climber. © 2014 The New York Times Company

Keyword: Epilepsy; Obesity
Link ID: 19256 - Posted: 02.17.2014