By ADAM NAGOURNEY LOS ANGELES — Let Colorado and Washington be the marijuana trailblazers. Let them struggle with the messy details of what it means to actually legalize the drug. Marijuana is, as a practical matter, already legal in much of California. A man panhandled for pot recently on the boardwalk in Venice Beach, Calif., where a variety of marijuana-themed items are for sale. No matter that its recreational use remains technically against the law. Marijuana has, in many parts of this state, become the equivalent of a beer in a paper bag on the streets of Greenwich Village. It is losing whatever stigma it ever had and still has in many parts of the country, including New York City, where the kind of open marijuana use that is common here would attract the attention of any passing law officer. “It’s shocking, from my perspective, the number of people that we all know who are recreational marijuana users,” said Gavin Newsom, the lieutenant governor. “These are incredibly upstanding citizens: Leaders in our community, and exceptional people. Increasingly, people are willing to share how they use it and not be ashamed of it.” Marijuana can be smelled in suburban backyards in neighborhoods from Hollywood to Topanga Canyon as dusk falls — what in other places is known as the cocktail hour — often wafting in from three sides. In some homes in Beverly Hills and San Francisco, it is offered at the start of a dinner party with the customary ease of a host offering a chilled Bombay Sapphire martini. © 2012 The New York Times Company

Keyword: Drug Abuse; Development of the Brain
Link ID: 17624 - Posted: 12.21.2012

Continued high use of marijuana by the nation's eighth, 10th and 12th graders combined with a drop in perceptions of its potential harms in this year's Monitoring the Future survey, an annual survey of eighth, 10th, and 12th-graders conducted by researchers at the University of Michigan. The survey was carried out in classrooms around the country earlier this year, under a grant from the National Institute on Drug Abuse (NIDA), part of the National Institutes of Health. The 2012 survey shows that 6.5 percent of high school seniors smoke marijuana daily, up from 5.1 percent five years ago. Nearly 23 percent say they smoked it in the month prior to the survey, and just over 36 percent say they smoked within the previous year. For 10th graders, 3.5 percent said they use marijuana daily, with 17 percent reporting past month use and 28 percent reporting use in the past year. The use escalates after eighth grade, when only 1.1 percent reported daily use, and 6.5 percent reported past month use. More than 11 percent of eighth graders said they used marijuana in the past year. The Monitoring the Future survey also showed that teens' perception of marijuana’s harmfulness is down, which can signal future increases in use. Only 41.7 percent of eighth graders see occasional use of marijuana as harmful; 66.9 percent see regular use as harmful. Both rates are at the lowest since the survey began tracking risk perception for this age group in 1991. As teens get older, their perception of risk diminishes. Only 20.6 percent of 12th graders see occasional use as harmful (the lowest since 1983), and 44.1 percent see regular use as harmful, the lowest since 1979.

Keyword: Depression; Development of the Brain
Link ID: 17623 - Posted: 12.21.2012

By Yevgeniy Grigoryev and Spoonful of Medicine The recent tragedy in Newtown, Connecticut, perpetrated by 20 year-old Adam Lanza, has intensified the discussion about how mental health is handled and documented in the US. Officials have not provided information about Lanza’s motivation and state of mind, and many are rightfully quick to point out that it is wrong to equate mental illness with the fatal sociopathic actions of a small group of individuals. The conversation about access to mental health care should, however, take into account new data showing an increasing contribution of mental and behavioral disorders to deterioration in the health-related quality of life among teenagers in the US and Canada over the last two decades, and increases elsewhere around the globe. The estimation of ‘years lived with disabilities’, or YLDs, is used as a collective metric to determine how much a particular disorder deprives the population of healthy years of life during a particular window of time. In 2010 just as in 1990, depression ranked as the number two contributor of YLDs, affecting 4% of the global population, eclipsed only by back pain that affected almost 10% of population worldwide. Among 10 to 14 year olds, the top contributor worldwide is iron deficiency. Asthma had been the largest contributor to YLDs for youths in that age range in the US and Canada in 1990, but the study published in The Lancet on Thursday led by researchers at the Institute of Health Metrics and Evaluation (IHME) at the University of Washington, Seattle showed that in this group depression surpassed asthma to claim the number one spot in 2010. In that group, the collective number of ‘years lost to disability’ grew from about 140,000 in 1990 to almost 180,000 in 2010, a 30% increase. Notably, global figures for the same age group show that the number of years lost to disability from depression grew from 4.9 million in 1990 to 5.5 million in 2010, a 13% increase as shown in the graphs below. © 2012 Scientific American

Keyword: Depression; Development of the Brain
Link ID: 17622 - Posted: 12.21.2012

By Scicurious Depression is a disease with a difficult set of symptoms. Not only are the symptoms difficult to describe (how do you really describe anhedonia, before you know the word for it?), symptoms of depression manifest in different ways for different people. One person will eat more, sleep all the time, move slowly. Another will eat almost nothing, never sleep, and be irritable and nervous. They are both depressed. The only universal symptom is the feeling of…depression, and the need for successful treatment. Treatments which often take several weeks to work, are often ineffective, and which come with a host of side effects. So I was particularly intrigued when Nature published two papers this week looking at the role of dopamine in depressive-like behavior. What I particularly like is that these two papers have somewhat opposite results, due to different behavioral methods, something which I think highlights some of the problems associated with studying depression. Ed Yong covered both of the studies together fabulously over at Not Exactly Rocket Science, but I’d like to look at them both separately, to take a deeper look at each one, see what they’ve achieved, and what other questions they raise. Today we are on the second of the two papers, one which has a similar angle to the first paper, but an entirely different result. Yesterday’s paper looked at how changes in dopamine cell firing from the ventral tegmental area (which projects to areas like the prefrontal cortex and the nucleus accumbens) can impact depressive-like behaviors in mice and rats. Today’s paper looks at the ventral tegmental area as well, but instead of cutting on or turning “off” cell firing, the authors of this study looked at different types of neuronal activity, and the effects in socially defeated mice. © 2012 Scientific American

Keyword: Depression
Link ID: 17621 - Posted: 12.19.2012

Daniel Cressey The search for a drug to treat Alzheimer’s disease could be being undermined by flaws in a test used in clinical trials to assess patients. And though few experts would blame the test for the recent failures of potential new drugs, a major push is now on to produce more sensitive ways of measuring the progress of the disease. During the past few years, a number of clinical trials have produced disappointing results for high-profile drugs, and some pharmaceutical companies have abandoned Alzheimer’s disease altogether, frustrated by the high costs and difficulty of producing a drug with a measurable effect. Jeremy Hobart, a neurologist at the Plymouth University Peninsula Schools of Medicine and Dentistry, UK, says that flaws in the ADAS-Cog test could be partly responsible. In many trials branded ‘failures’, the ADAS-Cog (Alzheimer’s Disease Assessment Scale — Cognitive Behaviour section) has been used as the key test of whether a drug is working. The test scores patients on 11 components using a variety of tasks relating to memory, language and praxis (the planning of movement to achieve a purpose), such as word recognition and remembering instructions. Lower scores indicate better cognitive performance and so less severe disease. There is, says Hobart, an argument that any study that has used ADAS-Cog may have underestimated changes in and differences between patients given the drug and controls. In two papers in Alzheimer’s & Dementia, Hobart and his colleagues detail flaws in the test that undermine its utility. © 2012 Nature Publishing Group

Keyword: Alzheimers
Link ID: 17620 - Posted: 12.19.2012

By Judy Stone We’ve touched on some of the many disturbing things that happened during the clinical trial on which Dan Markingson committed suicide. In my first post, I asked how a psychotic, homicidal patient who was involuntarily hospitalized in a psychiatric hospital could give an informed consent for participation in a clinical trial. There appeared to have been abuse of a vulnerable patient and extraordinary coercion—participate in this trial or be committed to a psych hospital seems to have been the bottom line. In my second post, we looked at investigator responsibilities, delegation of authority, and Good Clinical Practice tenets, all of which were violated with no consequences. Now we turn to the need to disclose conflicts of interest (COI), again a basic clinical research ethics principle that was violated. There are so many obvious conflicts of interest that it is hard to know quite where to start. The most obvious and egregious COI was that shown by Dr. Stephen Olson, who acted as both Dan Markingson’s treating physician and as Principle Investigator on the CAFÉ study. As Dr. Harrison Pope, a Harvard expert, concluded in his testimony, Olson “failed to meet the standards for good clinical practice both as a principal investigator and as the study physician for Mr. Markingson.” He failed his ethical responsibilities to Dan. © 2012 Scientific American

Keyword: Schizophrenia
Link ID: 17619 - Posted: 12.19.2012

By Wynne Parry and LiveScience NEW YORK — While jazz musician Vijay Iyer played a piece on the piano, he wore an expression of intense concentration. Afterward, everyone wanted to know: What was going on in his head? The way this music is often taught, "they tell you, you must not be thinking when you are playing," Iyer said after finishing his performance of John Coltrane's "Giant Steps," a piece that requires improvisation. "I think that is an impoverished view of what thought is. … Thought is distributed through all of our actions." Iyer's performance opened a panel discussion on music and the mind at the New York Academy of Sciences on Wednesday (Dec. 13). Music elicits "a splash" of activity in many parts of the brain, said panelist Jamshed Bharucha, a neuroscientist and musician, after moderator Steve Paulson of the public radio program "To the Best of Our Knowledge" asked about the brain's response to music. "I think you are asking a question we can only scratch the surface of in terms of what goes on in the brain," Bharucha said. [Why Music Moves Us] Creativity in the brain scanner Charles Limb, a surgeon who studies the neuroscience of music, is attempting to better understand creativity by putting jazz musicians and rappers in a brain-imaging scanner called a functional MRI, which measures blood flow in the brain, and asking them to create music or rap once in there. © 2012 Scientific American

Keyword: Hearing; Emotions
Link ID: 17618 - Posted: 12.19.2012

By AMY HARMON Amid reports from neighbors and classmates that the gunman in the shooting rampage in, Newtown, Conn., had an autism variant known as Asperger syndrome, adults with the condition and parents of children with the diagnosis are fighting what they fear may be a growing impression that it is associated with premeditated violence. Individuals with autism spectrum disorders, who are often bullied in school and in the workplace, frequently do suffer from depression, anxiety and suicidal thoughts. A divorce mediator who met with the parents of Adam Lanza, the gunman, during their divorce told The Associated Press that the couple had said that their son’s condition had been diagnosed as Asperger syndrome. But experts say there is no evidence that they are more likely than any other group to commit violent crimes. “Aggression in autism spectrum disorders is almost never directed to people outside the family or immediate caregivers, is almost never planned, and almost never involves weapons,” said Dr. Catherine Lord, director of the Center for Autism and the Developing Brain at NewYork-Presbyterian hospital. “Each of these aspects of the current case is more common in other populations than autism.” Dr. Lord said that in an unpublished review of data tracking several hundred adults with autism over at least the past five years, she and fellow researchers had found no use of weapons. Among more than 1,000 older children and adolescents in that study, only 2 percent were reported by parents to have used an implement aggressively toward a nonfamily member — fewer than in a control group. That finding was repeated in another set of data that she analyzed over the weekend at the request of The New York Times. © 2012 The New York Times Company

Keyword: Autism; Aggression
Link ID: 17617 - Posted: 12.19.2012

By Deborah Kotz, Globe Staff Unconfirmed news reports after the Connecticut school shooting that gunman Adam Lanza had been diagnosed with a milder form of autism prompted strongly-worded statements from autism advocacy groups that the developmental disorder was not associated with “planned violence.” Psychologists who treat people with autism point out that pre-meditated violence toward others isn’t one of the traits associated with the disorder in the psychiatric diagnostic manual. While some individuals may thrash out violently when feeling emotionally overwhelmed -- usually those at the extreme end of the autism spectrum -- there’s no evidence linking the condition to the type of forethought required to pack guns into a car, shoot through the entrance of a locked school, and methodically gun down tiny strangers in pigtails and baseball caps. “Autism is related to different ways of processing information in the brain, but not in those areas related to violence,” said Dr. Donnah Nickerson-Reti, a neurodevelopmental psychiatrist with a private practice in Boston. Generally, people on the autism spectrum tend to be driven by rules and logic, making them highly cognizant of laws that shouldn’t be broken and taking extreme efforts not to break them, she said. “Can autistic individuals get flooded emotionally and act irrationally?” said Nickerson-Reti. “Of course they can, like everyone else, but that’s not a defining characteristic.” © 2012 NY Times Co.

Keyword: Autism; Aggression
Link ID: 17616 - Posted: 12.19.2012

By Sandra G. Boodman, For the first decade of his life, every doctor who saw Jack DeWitt inevitably zeroed in on the harrowing circumstances of his premature birth. Delivered by emergency Caesarean section in December 1999, doctors universally ascribed his developmental problems to his being born six weeks early, said his mother, Ruth DeWitt. “It always came back to that.” When Jack’s walking became odd at age 5, doctors chalked it up to a mild form of cerebral palsy that can occur in children born too soon. “We were okay with it,” his mother said, because mild cerebral palsy would not “affect the length of his life or his enjoyment of it.” Jack’s parents were also reassured by his ability to catch up; with help, he mastered various skills: jumping, walking and writing in cursive. But by age 10, when his ability to walk badly deteriorated, a reevaluation by his doctors resulted in a very different diagnosis and prognosis. “We had all those years of feeling that he was a normal, healthy kid with some challenges,” his mother recalled. Discovering what was really wrong has been a heavy blow, magnified by Jack’s perceptive awareness of its implications. Ruth DeWitt, who lives with her family in Howell, Mich., outside Ann Arbor, was in the hospital undergoing a test for preeclampsia, or pregnancy-induced hypertension, when she began hemorrhaging, a sign of placental abruption. The life-threatening condition occurs when the placenta prematurely detaches from a woman’s uterus. Rushed into surgery, Jack was born weighing 3 pounds, 9 ounces, and was transferred to the neonatal intensive care unit at the University of Michigan Medical Center. Small but strong, he needed oxygen but no ventilator, and he came home 15 days later. © 1996-2012 The Washington Post

Keyword: Movement Disorders; Genes & Behavior
Link ID: 17615 - Posted: 12.18.2012

By CLAUDIA DREIFUS In a world of proliferating professions, S. Matthew Liao has a singular title: neuroethicist. Dr. Liao, 40, the director of the bioethics program at New York University, deploys the tools of philosophy, history, psychology, religion and ethics to understand the impact of neuroscientific breakthroughs. You’re a philosopher by training. How did philosophy lead to neuroethics? Mine’s the typical immigrant’s story. My family moved to Cincinnati from Taiwan in the early 1980s. Once here, my siblings gravitated towards the sciences. I was the black sheep. I was in love with the humanities. So I didn’t go to M.I.T. — I went to Princeton, where I got a degree in philosophy. This, of course, worried my parents. They’d never met a philosopher with a job. Do you have any insight on why scientific careers are so attractive to new Americans? You don’t need to speak perfect English to do science. And there are job opportunities. Define neuroethics. It’s a kind of subspecialty of bioethics. Until very recently, the human mind was a black box. But here we are in the 21st century, and now we have all these new technologies with opportunities to look inside that black box — a little. With functional magnetic imaging, f.M.R.I., you can get pictures of what the brain is doing during cognition. You see which parts light up during brain activity. Scientists are trying to match those lights with specific behaviors. At the same time this is moving forward, there are all kinds of drugs being developed and tested to modify behavior and the mind. So the question is: Are these new technologies ethical? © 2012 The New York Times Company

Keyword: Miscellaneous
Link ID: 17614 - Posted: 12.18.2012

By Scicurious Depression is a disease with a difficult set of symptoms. Not only are the symptoms difficult to describe (how do you really describe anhedonia, before you know the word for it?), symptoms of depression manifest in different ways for different people. One person will eat more, sleep all the time, move slowly. Another will eat almost nothing, never sleep, and be irritable and nervous. They are both depressed. The only universal symptom is the feeling of…depression, and the need for successful treatment. Treatments which often take several weeks to work, are often ineffective, and which come with a host of side effects. So I was particularly intrigued when Nature published two papers this week looking at the role of dopamine in depressive-like behavior. What I particularly like is that these two papers have somewhat opposite results, due to different behavioral methods, something which I think highlights some of the problems associated with studying depression. Ed Yong covered both of the studies together fabulously over at Not Exactly Rocket Science, but I’d like to look at them both separately, to take a deeper look at each one, see what they’ve achieved, and what other questions they raise. So I will start with one today, and post the other tomorrow, looking at both sides. While you often hear about serotonin in studies of depression (serotonin is, after all, a target of many current antidepressants), there are many other neurotransmitters and systems that are also under investigation, and many of them are bearing some fruitful results. Ketamine, for example. And of course there is the role of dopamine. © 2012 Scientific American

Keyword: Depression
Link ID: 17613 - Posted: 12.18.2012

By ANAHAD O'CONNOR Chronic sleep loss has many downsides, among them weight gain, depression and irritability. But now scientists have found a new one: It also weakens your tolerance for pain. In recent studies, researchers have shown that losing sleep may disrupt the body’s pain signaling system, heightening sensitivity to painful stimuli. Though it is not clear why, one theory is that sleep loss increases inflammation throughout the body. Catching up on sleep if you are behind may reduce inflammation. Scientists believe this could have implications for people with chronic pain. It could also have an impact on the effects of painkillers, which appear to be blunted after chronic sleep loss. In one study published in the journal Sleep, scientists at the sleep disorders and research center at Henry Ford Hospital in Detroit recruited 18 healthy adults and split them into two groups. One was allowed to sleep for an average of nine hours, while the other averaged two fewer hours of sleep each night. To assess pain thresholds, the researchers measured how long the subjects were able to hold a finger to a source of radiant heat. After four nights, the group that was allowed to sleep the longest was able to withstand the painful stimuli much longer, by about 25 percent on average. Several studies in the past have had similar findings, including one in 2006 that showed that one night of cutting sleep in half could significantly reduce a person’s threshold for physical pain. Copyright 2012 The New York Times Company

Keyword: Sleep; Pain & Touch
Link ID: 17612 - Posted: 12.18.2012

By James Gallagher Health and science reporter, BBC News Unrivalled control of a robotic arm has been achieved using a paralysed woman's thoughts, a US study says. Jan Scheuermann, who is 53 and paralysed from the neck down, was able to deftly grasp and move a variety of objects just like a normal arm. Brain implants were used to control the robotic arm, in the study reported in the Lancet medical journal. Experts in the field said it was an "unprecedented performance" and a "remarkable achievement". Jan was diagnosed with spinocerebellar degeneration 13 years ago and progressively lost control of her body. She is now unable to move her arms or legs. She was implanted with two sensors - each four millimetres by four millimetres - in the motor cortex of her brain. A hundred tiny needles on each sensor pick up the electrical activity from about 200 individual brain cells. "The way that neurons communicate with each other is by how fast they fire pulses, it's a little bit akin to listening to a Geiger counter click, and it's that property that we lock onto," said Professor Andrew Schwartz from the University of Pittsburgh. The pulses of electricity in the brain are then translated into commands to move the arm, which bends at the elbow, wrist and could grab an object. BBC © 2012

Keyword: Robotics
Link ID: 17611 - Posted: 12.17.2012

By DOUGLAS MARTIN Dr. William F. House, a medical researcher who braved skepticism to invent the cochlear implant, an electronic device considered to be the first to restore a human sense, died on Dec. 7 at his home in Aurora, Ore. He was 89. The cause was metastatic melanoma, his daughter, Karen House, said. Dr. House pushed against conventional thinking throughout his career. Over the objections of some, he introduced the surgical microscope to ear surgery. Tackling a form of vertigo that doctors had believed was psychosomatic, he developed a surgical procedure that enabled the first American in space to travel to the moon. Peering at the bones of the inner ear, he found enrapturing beauty. Even after his ear-implant device had largely been supplanted by more sophisticated, and more expensive, devices, Dr. House remained convinced of his own version’s utility and advocated that it be used to help the world’s poor. Today, more than 200,000 people in the world have inner-ear implants, a third of them in the United States. A majority of young deaf children receive them, and most people with the implants learn to understand speech with no visual help. Hearing aids amplify sound to help the hearing-impaired. But many deaf people cannot hear at all because sound cannot be transmitted to their brains, however much it is amplified. This is because the delicate hair cells that line the cochlea, the liquid-filled spiral cavity of the inner ear, are damaged. When healthy, these hairs — more than 15,000 altogether — translate mechanical vibrations produced by sound into electrical signals and deliver them to the auditory nerve. Dr. House’s cochlear implant electronically translated sound into mechanical vibrations. His initial device, implanted in 1961, was eventually rejected by the body. But after refining its materials, he created a long-lasting version and implanted it in 1969. © 2012 The New York Times Company

Keyword: Hearing; Robotics
Link ID: 17610 - Posted: 12.17.2012

By Kate Clancy I tend to go to bed freezing, especially so in the winter, so I pile our flannel sheet, blanket, and down comforter over me when I settle in to sleep. A few times each menstrual cycle, clustered together in the luteal phase between ovulation and menses, I wake up from sleep completely soaked in my own sweat – not a delightful sight or experience. Usually I get up, change pajamas, and try to find a dry spot on the bed to go back to sleep (I promise the sheets eventually get washed, but I’m not about to wake my husband – and sometimes daughter – to change the bed at 3am). These night sweats started when I was still intensively breastfeeding my daughter and was marathon training, when she was under a year old. At first, I thought it was because we were co-sleeping and we slept next to each other. But I never experienced them next to my husband before that point, and he is a six foot four heat generating machine. When the marathon was over and I returned to less strenuous activity, breastfeeding frequency was also starting to decline. I didn’t get any night sweats again for quite some time. Then there was roller derby. At first, roller derby was a pastime, a recreational activity where I got to learn something totally new and hang out with women I respected. But of course, being the competitive person I am, it became an obsession, and in addition to roller derby practices I was working out quite a lot on my own time. Over the last year I’ve made additional nutritional adjustments to further improve my performance, and I’ve increased the intensity of my off-skates workouts. I work out a minimum of five hours a week, but in the middle of the season it is usually a minimum of nine hours per week. © 2012 Scientific American

Keyword: Hormones & Behavior
Link ID: 17609 - Posted: 12.17.2012

By Mark Changizi The human fascination with color never ceases to amaze me. Our perceptual experience is filled with shapes and pitches and textures and timbres and depths and on and on, yet color seems to get the lion share of our excitement and philosophical attention. Color seems somehow more artistic than our other perceptual dimensions; it’s simply wonderful to behold, as evinced by the double rainbow guy; and we can’t resist wondering what it would be like to see dimensions of color beyond our own. In fact, RadioLab recently put out a great show on color that nicely conveys the romance we all have toward it. Question is: Why do we find color so enthralling? One of the reasons may be that the world can seem arbitrarily labeled in color, as if a painter dabbed over everything in order to make it beautiful… and that naturally makes us wonder what a different artist might do. What sort of splendor is a bird—who has an extra dimension of color beyond ours—treated to, for example? While I, too, feel the wonder of color, I don’t share this above intuition about color and its arbitrariness. It’s an unfortunate intuition, one that seeps its way not only into the minds of laymen, but into our “enhancement” products and even the hallowed halls of philosophy. In trying to explain what’s wrong with the intuition, let me begin with a thought experiment concerning a product that gives the wearer “shape enhancement” vision. “With our sunglasses’ shape-enhancement filter, you’ll see the world with more vibrant and interesting shapes. Round things will be rounder, regular polygons more muted…”

Keyword: Vision
Link ID: 17608 - Posted: 12.17.2012

By Jason G. Goldman While second nature to many of us, driving a car is actually a fairly complex process. At its most stripped down version, first you sit in the driver’s seat, then you start the engine, then you shift into gear, and then you must simultaneously steer while keeping your foot on the gas pedal. That doesn’t include things like adjusting your mirrors, verifying that you won’t drive into another person or car, and so on. In one sense, it is incredibly impressive that three dogs in New Zealand have learned – in a fairly rudimentary way – to drive a car. They sit in the driver’s seat, shift into gear, operate the steering wheel, and step on the accelerator. Those deserving the true accolades however are not the dogs, but the human trainers for their impressive patience and determination. The training that led man’s best friend to operate a car is no different from the kind of training behind the bird shows found at zoos all over the world, or the dolphin, killer whale, seal, or sea lion displays you might see at Sea World. It’s the same kind of training that scientists use to probe the emotional and cognitive lives of rats, mice, and the other critters that populate their laboratories. At the end of the day, it all comes down to a form of learning first described by Edward L. Thorndike at the beginning of the 1900s, which was later expanded and popularized by B.F. Skinner and taught to every student of Introductory Psychology: operant conditioning. While classical conditioning is a form of learning that binds external stimuli to reflexive, involuntary responses, operant conditioning involves voluntary behaviors, and is maintained over time by the consequences that follow those behaviors. In one experiment, Skinner placed pigeons individually into experimental chambers (sometimes referred to as “Skinner boxes”) that were designed to deliver food rewards at systematic intervals. He found that by rewarding a bird after it displayed a desired behavior, he could motivate the bird to increase the frequency of that particular behavior. © 2012 Scientific American

Keyword: Learning & Memory
Link ID: 17607 - Posted: 12.14.2012

by Kai Kupferschmidt Human beings tend to avoid places that smell of urine. But to mice, there is something positively addictive about the scent; they like to go back to a spot where they found the excretions again and again. Now, researchers have discovered that this behavior is triggered by a single protein in the urine of male mice. Mice use scent to mark their territory, advertise their social dominance, and convey information about their health and reproductive status. But these are usually volatile pheromones that disperse quickly, and it has remained unclear what exactly stimulates a female to be attracted to a specific male. Previous research had shown that female laboratory mice often return to a place where they have come across cage bedding soiled by males. Now, researchers at the University of Liverpool in the United Kingdom have confirmed this. Female mice spent five times as much time in a place where they had encountered a dish with male urine than at a place where they encountered water. Just 10 minutes of exposure to the urine was enough for the mice to show this place preference even after 14 days. However, if the mice were prevented from by a mesh screen touching the urine with their nose, the place seemed to lose its attractiveness. "That suggested that the story was not as simple as everybody assumed and volatile pheromones were not responsible," says behavioral ecologist Jane Hurst, one of the authors of the study. By separating the urine into different fractions, the scientists showed that a protein called darcin that they had identified in 2005—and which mice can only detect if their noses touch the urine—is responsible for the frequent visits. Pure darcin, produced in cell culture in the lab, elicited the same reaction, the authors report online today in Science. © 2010 American Association for the Advancement of Science.

Keyword: Chemical Senses (Smell & Taste); Sexual Behavior
Link ID: 17606 - Posted: 12.14.2012

By JAMES DAO Reviving a 20-year debate over illnesses of veterans of the 1991 Persian Gulf war, a new scientific paper presents evidence that nerve agents released by the bombing of Iraqi chemical weapons depots just before the ground war began could have carried downwind and fallen on American troops staged in Saudi Arabia. The paper, published in the journal Neuroepidemiology, tries to rebut the longstanding Pentagon position, supported by many scientists, that neurotoxins, particularly sarin gas, could not have carried far enough to sicken American forces. The authors are James J. Tuite and Dr. Robert Haley, who has written several papers asserting links between chemical exposures and gulf war illnesses. They assembled data from meteorological and intelligence reports to support their thesis that American bombs were powerful enough to propel sarin from depots in Muthanna and Falluja high into the atmosphere, where winds whisked it hundreds of miles south to the Saudi border. Once over the American encampments, the toxic plume could have stalled and fallen back to the surface because of weather conditions, the paper says. Though troops would have been exposed to low levels of the agent, the authors assert that the exposures may have continued for several days, increasing their impact. Though chemical weapons detectors sounded alarms in those encampments in the days after the January 1991 bombing raids, they were viewed as false by many troops, the authors report. © 2012 The New York Times Company

Keyword: Stress; Neurotoxins
Link ID: 17605 - Posted: 12.14.2012