By Wynne Parry, A group of scientists has genetically altered mice so they could "smell" light. That is their neurons responded to light in the same way they would to an odor. This allowed them to study the brain's response without having to deal with the complications associated with smelling. The approach the scientists used to help the mice "smell" the light is called optogenetics. The method uses light to control actions within other specific cells and is broadly applicable. The noses of mice (and humans) are chock-full of sensory neurons that respond to scent molecules that waft by. That odor information gets sent to the olfactory bulb, a part of the brain above the nasal cavities, where the sensory neurons meet up with relay neurons. These two types of neurons then meet within structures called glomeruli. "If you look at two cells receiving input from the same glomerulus, are they just passing it on [in] the same way, or is there something more to it?" said study researcher Venkatesh Murthy from Harvard University, who collaborated with others at Harvard, Cold Spring Harbor Laboratory and in India. A mouse has about 200,000 relay cells, with between 60 and 100 connected to each glomerulus, or hub. Identifying pairs of relay cells that connect to the same glomerulus is difficult, because when a rodent catches a whiff of something, multiple glomeruli go into action, according to Graeme Lowe, a neuroscientist at the independent Monell Chemical Senses Center who was not involved in the research. © The Christian Science Monitor

Keyword: Chemical Senses (Smell & Taste); Vision
Link ID: 14609 - Posted: 11.01.2010

A new stroke prevention clinic in Ottawa is helping patients treated for mini-strokes from developing the full-blown version, doctors report. A transient ischemic attack, or TIA, is a mild stroke that causes stroke symptoms such as sudden numbness of the face, arm or leg. The symptoms last for less than 24 hours and then resolve on their own without disabling neurological effects, but it is a marker for early risk of stroke. At the Ottawa Hospital Stroke Clinic, patients with TIA symptoms are quickly assessed in the emergency department (ED) and referred to the stroke clinic for brain imaging, medication adjustment, counselling about stroke risk factors and surgery in some cases. Dr. Mukul Sharma, deputy director of the Canadian Stroke Network, and his co-authors found that 3.2 per cent of people who experienced TIA at the stroke prevention clinic developed a full-blown stroke within 90 days, compared with about 10 per cent at other centres. "The beauty of this is that we added very few staff," said Sharma, lead author of the study in the November issue of the journal Stroke, and director of The Ottawa Hospital Stroke Clinic. A booking clerk was one of the few staff that was added as part of the program. "It really is that ability to juggle bookings and the acuity of the visit that I think make this process work. I've likened it to getting an orchestra playing the same tune." © CBC 2010

Keyword: Stroke
Link ID: 14608 - Posted: 10.30.2010

By MATTHEW PERRONE WASHINGTON -- Federal health regulators have decided not to approve an experimental diet pill called Qnexa, which had been touted by many experts as the most promising weight-loss drug in more than a decade. The drug's maker, Vivus Inc., said in a statement Thursday that the Food and Drug Administration declined to approve the drug in its present form. The agency asked for more study results and additional information on its possible health risks, including major cardiovascular events and risks for women of childbearing potential. The FDA did not ask for any new clinical studies, but more may be required if the agency's concerns aren't addressed, Vivus said. The company plans to respond to the FDA in about six weeks. "We remain confident in the efficacy and safety profile of Qnexa demonstrated in the clinical development program and look forward to continue working with the FDA towards the approval for the treatment of obesity," Vivus CEO Leland Wilson said in a statement. Vivus, based in Mountain View, Calif., is one of three small drugmakers racing to win approval for their weight-loss drugs. Many analysts picked Qnexa as the most promising contender because of the high level of weight loss reported in company studies: On average, patients lost more than 10 percent total body mass. That compared to weight loss of under 5 percent with drugs currently on the market, like Roche's Xenical. © 2010 The Associated Press

Keyword: Obesity
Link ID: 14607 - Posted: 10.30.2010

By Christof Koch If you have seen the recent Holly­wood blockbuster Inception, a movie that does to dreaming what The Matrix did for virtual reality, you may have been holding your breath as Ariadne, an architecture student, folded the streets of Paris over herself like a blanket. This stunning sequence, an homage to M. C. Escher, is testimony to the bizarre nature of dreams. Watching it made the neuroscientist in me reflect on what dreams are and how they relate to the brain. The first question is easy to answer. Dreams are vivid, sensorimotor hallucinations with a narrative structure. We experience them consciously—seeing, hearing and touching within environments that appear completely real (though curiously, we do not smell in our dreams). Nor are we mere passive observers: we speak, fight, love and run. Dream consciousness is not the same as wakeful consciousness. We are for the most part unable to introspect—to wonder about our uncanny ability to fly or to meet somebody long dead. Only rarely do we control our dreams; rather things happen, and we go along for the ride. Everyone dreams, including dogs, cats and other mammals. But sleep lab data reveal that people consistently underreport how often and how much. The reason is that dreams are ephemeral. Memory for dreams is very limited and largely restricted to the period before awakening. The only way to remember a dream is to immediately recall it on waking and then write it down or describe it to another person. Only then does its content become encoded in memory. © 2010 Scientific American,

Keyword: Sleep; Attention
Link ID: 14606 - Posted: 10.30.2010

By Laura Sanders The brain uses two different checks to guard against sloppy copy, a new study finds. By using a doctored word processor to sneak errors into typed words and surreptitiously fix typists’ real errors, researchers teased apart the various ways people catch their own mistakes. The study, published in the Oct. 29 Science, highlights the complexity of performance monitoring. Psychologist Gordon Logan and his colleague Matthew Crump of Vanderbilt University in Nashville recruited skilled typists — people who typed more than 40 words a minute using all of their fingers. These subjects were able to type a paragraph about the merits of border collies with over 90 percent accuracy. As the typists pecked away, researchers introduced common typing errors into about 6 percent of the words that appeared on a screen (changing sweat to swaet, swerat or swet, for instance). The program also corrected about 45 percent of the typists’ true errors. In questionnaires after the typing test, subjects by and large took the blame for the introduced errors and took credit for the researchers’ corrections. No matter what he actually typed, when the typist saw that the word on the screen matched the word he had intended to type, he assessed his own performance as accurate. © Society for Science & the Public 2000 - 2010

Keyword: Attention
Link ID: 14605 - Posted: 10.30.2010

Humans are not the only species to prefer to use their right hand -- chimpanzees also share the trait, according to a new study by Spanish scientists. The researchers reached their findings, published in the latest edition of the American Journal of Primatology, after observing 114 chimpanzees from two primate rescue centers, one in Spain and the other in Zambia. The primates were provided with food hidden inside tubes and the scientists monitored them to see which hand they used to get at it, either their fingers or with the help of tools. "The chimpanzees showed a preferential use of the right hand to get the food from the tube," the Catalan Institute of Human Palaeoecology and Social Evolution, which coordinated the study, said in a statement. "This feature had traditionally been considered exclusively human and had been believed to be caused by asymmetries observed in the human brain that are related to the realization of complicated activities that require the use and coordination of both hands." The study also found that female chimpanzees, like their human counterparts, are more likely to be right-handed than males. The researchers said this suggests "that just like in our species, there are shared biological factors, genetic and hormonal, that modulate the functioning of our brain." © 2010 Discovery Communications, LLC

Keyword: Laterality
Link ID: 14604 - Posted: 10.30.2010

Melissa Dahl writes: You know that saying "the left hand doesn't know what the right is doing"? For people with a strange disorder called alien hand syndrome, that's literally true -- the neuropsychiatric condition makes them feel as if one of their hands has taken on a mind of its own. "An alien hand is an arm and hand that moves when the person to whom that arm belongs does not intend it to move," says Dr. Ken Heilman, a neurologist at the University of Florida College of Medicine in Gainesville, Fla. Heilman goes on to note that there are many neurological conditions that cause an arm to move unintentionally -- like seizures or tremors, and movement disorders such as chorea, dystonia and athetosis. Here's the difference: In each of those cases, if the arm moves, it's pretty much just flailing about purposelessly, "but with an alien hand, the movement appears to be purposeful." Creepy. Heilman recalls one patient whose hands actually fought over fashion: Her right hand took a pair of red shoes out of the closet. Her left hand -- the "alien" hand -- pulled the red shoes out of her right hand, put them back and picked up a pair of blue shoes. When the right hand went again for the red shoes, the left hand slammed the closet door on the right hand. A German neurologist and psychiatrist named Kurt Goldstein was the first to report a case of alien hand syndrome in 1908. His patient's left hand seemed to do whatever it pleased, including, at least once, an attempt to throttle its owner. It's most commonly the result of an injury to an area of the brain called the corpus callosum. © 2010 msnbc.com

Keyword: Laterality; Attention
Link ID: 14603 - Posted: 10.30.2010

By Pallab Ghosh A US researcher has said he plans to electronically record and interpret dreams. Writing in the journal Nature, researchers said they have developed a system capable of recording higher-level brain activity. "We would like to read people's dreams," says the lead scientist Dr Moran Cerf. The aim is not to interlope, but to extend our understanding of how and why people dream. For centuries, people have been fascinated by dreams and what they might mean; in ancient Egypt for example, they were thought to be messages from the gods. More recently, dream analysis has been used by psychologists as a tool to understand the unconscious mind. But the only way to interpret dreams was to ask people about the subject of their dreams after they had woken up. The eventual aim of Dr Cerf's project is to develop a system that would enable psychologists to corroborate people's recollections of their dream with an electronic visualisation of their brain activity. "There's no clear answer as to why humans dream," according to Dr Cerf. "And one of the questions we would like to answer is when do we actually create this dream?" BBC © MMX

Keyword: Sleep; Brain imaging
Link ID: 14602 - Posted: 10.28.2010

by Liz Day A recent study used functional magnetic resonance imaging to see how love affects the brain. Its calculations of love has attracted plenty of attention. For example, the time taken to "fall in love" clocks in at about one-fifth of a second, not the six months of romantic dinners and sharing secrets some might expect. Also, 12 areas of the brain work together during the love process, releasing euphoria-inducing chemicals like dopamine, oxytocin, adrenaline and vasopressin. Love's high is similar to cocaine's rush. Love influences sophisticated intellectual processes of the brain too. When a person feels in love, their mental representation, metaphors and even body image are also affected. Researchers from Syracuse University, West Virginia University and the Geneva University Psychiatric Center retrospectively reviewed pertinent neuroimaging literature. They published their findings in a recent issue of the Journal of Sexual Medicine. Overall, they found, love is really good for you. Couples who had just fallen in love had significantly higher levels of nerve growth factor, or NGF. NGF is crucial to the survival of sympathetic and sensory neurons. Some believe NGF can reduce neural degeneration. Not a bad side effect. © 2010 Discovery Communications, LLC

Keyword: Sexual Behavior; Attention
Link ID: 14601 - Posted: 10.28.2010

by Catherine de Lange It's a familiar feeling. After a large meal you feel full, but a glimpse of a slice of gooey, rich chocolate cake is enough to get you salivating again. Could it be possible to prevent our brains from responding so strongly to the sight of tantalising treats? The answer is yes, according to new research which suggests that some anti-obesity drugs work by dulling this brain response to the sight of appetising, high-calorie food. Paul Fletcher from the University of Cambridge and colleagues wanted to understand how drugs that help people lose weight affect the brain. To find out, they gave 24 obese people either the anti-obesity drug Sibutramine or a placebo for two weeks and then scanned their brains while showing them pictures of high- or low-calorie foods, such as chocolate cake or broccoli. Not only did volunteers taking the drug eat less and lose weight during the two weeks of the study, their hypothalamus and amygdala – areas of the brain involved in reward – also responded more weakly to the sight of high-calorie foods than those given the placebo. "This is the first evidence that an anti-obesity drug changes brain function," says Ed Bullmore, who is also at the University of Cambridge and also worked on the study. More importantly, says Bullmore, it shows how these brain changes are correlated with a change in eating behaviour, and ultimately weight loss. © Copyright Reed Business Information Ltd.

Keyword: Obesity; Drug Abuse
Link ID: 14600 - Posted: 10.28.2010

by Adrian M Owen You might think it's obvious that one person is smarter than another. But there are few more controversial areas of science than the study of intelligence and, in reality, there's not even agreement among researchers about what this word actually means. Unlike weight and height, which are unambiguous, there is no absolute measure of intelligence, just as there are no absolute measures of honesty or physical fitness. Nonetheless, over the decades, legions of scientists have devised tests that can show that one person is smarter than another just as surely as Olympic events can shed light on how much you can lift or how far you can jump. Now my team at the UK Medical Research Council's Cognition and Brain Sciences Unit in Cambridge has come up with the ultimate test of intelligence. Like many researchers before us, we began by looking for the smallest number of tests that could cover the broadest range of cognitive skills that are believed to contribute to intelligence, from memory to planning. But we went one step further. Thanks to recent work with brain scanners, we could make sure that the tests involved as much of the brain as possible – from the outer layers, responsible for higher thought, to deeper-lying structures such as the hippocampus, which is involved in memory. Here's a longer explanation of the theory and evidence that we used when devising the tests. © Copyright Reed Business Information Ltd.

Keyword: Intelligence; Attention
Link ID: 14599 - Posted: 10.28.2010

by Michael Marshall In 1958, Disney released a documentary called White Wilderness, which showed the wildlife of the Arctic on the cinema screen. David Attenborough it ain't. The film is now notorious for containing faked footage of something that simply doesn't happen: lemmings committing suicide en masse. Realising that the Arctic rodents did not collectively top themselves, the film-makers resorted to trickery. After producing footage of the lemmings migrating by placing them on a snow-covered turntable, they shipped some of them to a cliff overlooking a river and herded them over the edge. The resulting footage (available on YouTube and still shocking today) shows hordes of lemmings plummeting off a cliff, with the culpable humans studiously out of frame. It helped cement the myth of lemming mass suicide in popular culture. Yet had the film-makers looked a little closer, they would have found that lemmings really are bizarre creatures. Finally, the true nature of lemming behaviour is being revealed. Lemmings are small rodents, related to hamsters, gerbils and mice. There are over 20 species, all found in the far north, including Canada, Scandinavia and Russia. Unlike many Arctic animals, lemmings do not hibernate through the winter. Instead, they forage along runs and tunnels dug beneath the snow layer. This allows them to carry on breeding even as temperatures drop to -20 °C, driving the population up. In most species the population grows for three years, then crashes to near-extinction in the fourth. © Copyright Reed Business Information Ltd.

Keyword: Stress; Sexual Behavior
Link ID: 14598 - Posted: 10.28.2010

By The Editors Nearly 20 years ago a small study advanced the notion that listening to Mozart’s Sonata for Two Pianos in D Major could boost mental functioning. It was not long before trademarked “Mozart effect” products appealed to neurotic parents aiming to put toddlers on the fast track to the Ivy League. Georgia’s governor even proposed giving every newborn there a classical CD or cassette. The evidence for Mozart therapy turned out to be flimsy, perhaps nonexistent, although the original study never claimed anything more than a temporary and limited effect. In recent years, however, neuroscientists have examined the benefits of a concerted effort to study and practice music, as opposed to playing a Mozart CD or a computer-based “brain fitness” game once in a while. Advanced monitoring techniques have enabled scientists to see what happens inside your head when you listen to your mother and actually practice the violin for an hour every afternoon. And they have found that music lessons can produce profound and lasting changes that enhance the general ability to learn. These results should disabuse public officials of the idea that music classes are a mere frill, ripe for discarding in the budget crises that constantly beset public schools. Studies have shown that assiduous instrument training from an early age can help the brain to process sounds better, making it easier to stay focused when absorbing other subjects, from literature to tensor calculus. The musically adept are better able to concentrate on a biology lesson despite the racket in the classroom or, a few years later, to finish a call with a client when a colleague in the next cubicle starts screaming at an underling. They can attend to several things at once in the mental scratch pad called working memory, an essential skill in this era of multitasking. © 2010 Scientific American

Keyword: Hearing; Attention
Link ID: 14597 - Posted: 10.28.2010

By Colm O'Dushlaine The psychologist Rollo May once described depression as “the inability to construct a future”. According to the National Institute for Mental Health this “inability” can affect up to 14.8 million Americans – 7% of the population – in a given year, at an annual cost of $100 billion. That’s about five times the renewable energy budget of the United States. We hear many things about how great we’re getting at saving the planet with our hybrids and off-shore wind farms; we hear far less about how we’re doing in combating or preventing depression. This month, however, has brought some potentially exciting news: two genetic studies with major ramifications for the treatment and diagnosis of Major Depressive Disorder. As a psychiatric geneticist, it is rare that I see such clear insights into distinct genetic mechanisms of psychiatric illnesses. Research into bipolar disorder and schizophrenia –- the disorders I spend most of my time working on –- would benefit a great deal from breakthrough studies such as these. One new study, published in Nature Medicine, suggests that a pathway called MAPK – and one gene in particular from this pathway, MPK-1 – are significantly dysregulated in certain areas of the brains of individuals with major depression. These results were obtained by looking for significant gene expression changes in post-mortem brains from 21 individuals with Major Depressive Disorder compared to 18 matched controls. The researchers, led by Yale’s Vanja Duric, confirmed their results in rat and mouse models. And they showed that not only did raising MPK-1 levels lead to depressive symptoms, but that antidepressant treatment reduced the expression of MPK-1. © 2010 Scientific American, a Division of Nature America, Inc.

Keyword: Depression; Genes & Behavior
Link ID: 14596 - Posted: 10.28.2010

by Carl Zimmer In some of the world’s oldest medical texts­­—papyrus scrolls from ancient Egypt, clay tablets from Assyria—people complain about noise in their ears. Some of them call it a buzzing. Others describe it as whispering or even singing. Today we call such conditions tinnitus. In the distant past, doctors offered all sorts of strange cures for it. The Assyrians poured rose extract into the ear through a bronze tube. The Roman writer Pliny the Elder suggested that earthworms boiled in goose grease be put in the ear. Medieval Welsh physicians in the town of Myddfai recommended that their patients take a freshly baked loaf of bread ($) out of the oven, cut it in two, “and apply to both ears as hot as can be borne, bind and thus produce perspiration, and by the help of god you will be cured.” Early physicians based these prescriptions on what they believed tinnitus to be. Some were convinced it was caused by wind that got trapped inside the ear and swirled around endlessly, so they tried to liberate the wind by drilling a hole into the bones around the ear or using a silver tube to suck air out of the ear canal. The treatments didn’t work, but they did have an internal logic. Today tinnitus continues to resist medicine’s best efforts, despite being one of the more common medical disorders. Surveys show that between 5 and 15 percent of people say they have heard some kind of phantom noise for six months or more; some 1 to 3 percent say tinnitus lowers their quality of life. Tinnitus can force people to withdraw from their social life, make them depressed, and give them insomnia. © 2010, Kalmbach Publishing Co.

Keyword: Hearing
Link ID: 14595 - Posted: 10.28.2010

By Laura Sanders Using nothing but thoughts, people can coax a brain cell that likes Marilyn Monroe to overpower a Josh Brolin–favoring cell in a dominance battle that brings her image up on a computer screen, a study appearing October 28 in Nature shows. The paper expands on data presented last year at the Society for Neuroscience’s annual meeting in Chicago (SN: 11/21/09, p. 9) and shows how the brain makes choices about what to pay attention to in a sensory-rich world. Study coauthor Moran Cerf and his colleagues eavesdropped on single neurons with electrodes that had already been implanted for medical reasons in the brains of people with epilepsy. These cells fired when the person saw particular people, places or things, such as the Eiffel tower, Bill Clinton or bananas. The team set up neuron contests by linking cell recordings to a computer that flashed images on a screen. In one trial, a Monroe neuron and a Brolin neuron went head to head as a person saw a hybrid mashup of the two stars’ pictures. Each time the Monroe neuron fired, her image would get brighter, and when the Brolin neuron fired, his image would get brighter. Researchers told the participant which person was the target, and watched as the neurons duked it out. In most trials, subjects quickly became experts at causing neurons to fire with their thoughts alone, even when faced with a “distractor” image, says Cerf, who conducted the research while at Caltech but is now at New York University. © Society for Science & the Public 2000 - 2010

Keyword: Attention
Link ID: 14594 - Posted: 10.28.2010

Scans appear to show differences in brain functioning in women with persistently low sex drives, claim researchers. The US scientists behind the study suggest it provides solid evidence that the problem can have a physical origin. They measured brain activity as the women watched erotic videos. But a spokesman for the charity Relate said the study simply demonstrated low libido at work in the brain, rather than exposing its cause. In recent years, a diagnosis of "hypoactive sexual desire disorder" (HSDD) in women has become more accepted by science. However, there remains controversy about whether the term can or should be used to describe a lack of sexual desire, which may be caused by a variety of psychological, emotional and physical factors. The latest study, carried out at Wayne State University in Detroit and presented to the American Society for Reproductive Medicine conference in Denver, highlights differences in mental processing in women who have low sex drives. Its author, Dr Michael Diamond, said it suggested that HSDD was a genuine physical problem. BBC © MMX

Keyword: Sexual Behavior
Link ID: 14593 - Posted: 10.26.2010

By Steve Connor, Science Editor People who are able to sleep for just a few hours each night without nodding off at their desks the following day owe their apparently superhuman ability to stay awake to variations in their genes, a study has suggested. Winston Churchill, Margaret Thatcher and Bill Clinton were all famous for managing on just five or six hours' sleep a night, rather than the customary eight. Napoleon Bonaparte, Michelangelo and Florence Nightingale apparently got by on four hours, as does Madonna and the American chat-show host Jay Leno. Sleep researchers have known that different people have different sleep patterns, with some individuals – known as "owls" – being more active and alert in the evenings, while others – known as "larks" – are early risers. It is also known that as people get older they tend to develop more disturbed sleep patterns. Studies suggest that older people need as much sleep as younger people, but sleep in bouts rather than as a single, long snooze. Trying to understand why people vary in the amount of sleep they need led to a study of 37 healthy adults who carry a variant in their DNA that has already been linked with sleep disturbances. The study compared them against 92 equally healthy people who did not carry the genetic variant, known as DQB1*0602. All took part in tests in a sleep laboratory at the University of Pennsylvania School of Medicine in Philadelphia. For the first two nights they spent 10 hours in bed and were fully rested. For the next five nights they were subjected to chronic partial sleep deprivation where they were only allowed to sleep for four hours a night. The rest of the time they were kept awake with the lights on. ©independent.co.uk

Keyword: Sleep; Genes & Behavior
Link ID: 14592 - Posted: 10.26.2010

People who smoke heavily in middle age seem to more than double their risk of Alzheimer's disease and other forms of dementia late in life, research suggests. Smoking is a well-established risk factor for stroke, but the link between smoking and risk of Alzheimer's and other types of dementia has been less clear since heavy smokers often die from other ailments before smoking's toll on the brain is evident. To find out more, Dr. Minna Rusanen of the University of Eastern Finland in Kuopio and colleagues analyzed data from 21,123 people in California who participated in a survey between 1978 and 1985. When the study began, the participants were between 50 and 60 years old, and they were tracked for an average of 23 years of followup. During that time, 5,367 participants or 25 per cent were diagnosed with dementia, including 1,136 with Alzheimer's disease and 416 with vascular dementia, the researchers found. Compared with non-smokers, those smoking more than two packs a day had 2.14 times higher risk of dementia 2.57 times higher risk of Alzheimer's, and 2.57 times higher risk of vascular dementia — another common and sometimes overlapping cause of progressive deterioration of memory and thinking. "This study shows that the brain is not immune to the long-term consequences of heavy smoking," said the study's principal investigator, Rachel Whitmer, a research scientist with the Kaiser Permanente Division of Research in Oakland, Calif. © CBC 2010

Keyword: Alzheimers; Drug Abuse
Link ID: 14591 - Posted: 10.26.2010

By Sandra G. Boodman Right away, Lori White knew that something was very wrong. The 44-year-old legal assistant at a Northern Virginia law firm had been working out with a personal trainer at her gym, executing a demanding and unfamiliar move. As she pulled down on a bar equipped with weights while simultaneously lunging forward, she felt an explosive pop in her head, immediately followed by a headache more crushing than any she had previously experienced. For the next 10 minutes, White recalled, she sat on the floor, clutching her head and fearing she would throw up or pass out. To her relief, the pain receded within a few hours. "I figured I'd just strained something," she recalled. But within weeks of the 2005 episode, an alarming new problem surfaced: stabbing pains lasting five to 30 seconds in the front of her head, similar to the "brain freeze" that people sometimes experience while eating ice cream. It took White three years to discover what had happened that day in the gym and two more to sort out what should be done about it - a confusing and sometimes contradictory process that involved specialists in the Washington area as well as Baltimore and Charlottesville. Two weeks ago at Georgetown University Hospital, White underwent treatment that doctors hope will cure her problem. © 2010 The Washington Post Company

Keyword: Pain & Touch
Link ID: 14588 - Posted: 10.26.2010