Yoav Gilad People can smell thousands—perhaps even millions—of different scents. Yet scientists know that in the nose, there are only about 400 different types of odor receptors—proteins that capture scented molecules so that smells can be identified. Thus, there isn’t, obviously, one type of receptor that responds to a rose, while another jumps for jasmine. So how can we smell so much, with so few types of receptors? The answer is that cells mix and match. Each nerve cell in the nose can sense more than one odor, but picks up the smell to a different degree. An odor's unique signature depends on which cells respond to it, and how intensely. What happens when you inhale a rose is that a group of cells is stimulated, and that group sends a combination of signals to the olfactory bulb—the site at the very front of the brain where smell perception takes place. This unique combination of signals tells the brain the odor is the smell of a rose. © 1996-2008 Scientific American Inc.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 11585 - Posted: 06.24.2010

Short on sleep? Besides the bags under your eyes, you may have difficulty remembering names, phone numbers, and other stuff you store in short-term memory. Brain researchers at Columbia University and the New York State Psychiatric Institute can't do much for tired-looking faces, but they're now exploring a method for refreshing your sleep-deprived brain. By using magnetic fields to stimulate certain brain regions of sleep-deprived volunteers, Sarah Lisanby and her team found that they could improve people's performance on a short-term memory test. "We looked to see whether that would help these people become more resilient to sleep deprivation. And our study, our results, suggested just that," Lisanby says. The technique, called Transcranial Magnetic Stimulation or TMS, gives a magnetic wake-up call to specific regions of the brain. TMS delivered to sleepy subjects improved their speed as they tried to recall what letters had flashed on a computer monitor seven seconds earlier. TMS is still experimental, but it's also shown promise in the treatment of depression and is being tested for other conditions including anxiety disorders and schizophrenia. © ScienCentral, 2000-2008.

Keyword: Sleep; Learning & Memory
Link ID: 11584 - Posted: 06.24.2010

Anti-depressants could help people suffering from inflammatory bowel disease, as new research points to a link between the condition and depression. Inflammatory bowel disease describes two medical conditions called Crohn's disease and ulcerative colitis, which affect the digestive system and cause the intestinal tissue to become inflamed, form sores and bleed easily. Symptoms include abdominal pain, cramping, fatigue and diarrhea, according to the Crohn's and Colitis Foundation of Canada. Bouts of IBD can be triggered by certain foods, stress and medications. Researchers at McMaster University have found that depression may have a very detrimental effect on IBD. "The gut is intimately connected to the brain, more than any other organ in the body," Jean-Eric Ghia, lead researcher and a post-doctoral fellow at McMaster University in Hamilton, said in a release. In the study, mice were given medications for symptoms of depression, such as reserpine, which depleted their bodies of noradrenalin, adrenaline, dopamine and serotonin — hormones that influence mood. Colitis, or the inflammation of the colon, was also induced through the administration of two other medications. To combat the depression, the mice were given the anti-depressant desmethylimipramine. The researchers found that this treatment reduced the inflammation in the intestines and restored normal intestinal function. © CBC 2008

Keyword: Depression; Neuroimmunology
Link ID: 11583 - Posted: 06.24.2010

In this nascent age of “neurolaw,” “neuromarketing,” “neuropolicy,” “neuroethics,” “neurophilosophy,” “neuroeconomics,” and even “neurotheology,” it becomes necessary to disentangle the science from the scientism. There is a host of cultural entrepreneurs currently grasping at various forms of authority through appropriations of neuroscience, presented to us in the corresponding dialects of neuro-talk. Such talk is often accompanied by a picture of a brain scan, that fast-acting solvent of critical faculties. Elsewhere in this issue, O. Carter Snead offers a critique of the use of brain scans in the courtroom in which he alludes to, but ultimately brackets, questions about the scientific rigor of such use. For the sake of argument, he proceeds on the assumption that neuroimaging is competent to do what it is often claimed to do, namely, provide a picture of human cognition. But there are some basic conceptual problems hovering about the interpretation of brain scans as pictures of mentation. In parsing these problems, it becomes apparent that the current “neuro” enthusiasm should be understood in the larger context of scientism, a pervasive cultural tendency with its own logic. A prominent feature of this logic is the overextension of some mode of scientific explanation, or model, to domains in which it has little predictive or explanatory power. Such a lack of intrinsic fit is often no barrier to the model nonetheless achieving great authority in those domains, through a kind of histrionics. As Alasdair MacIntyre has shown in another context (that of social science), all that is required is a certain kind of performance by those who foist the model upon us, a dramatic imitation of explanatory competence that wows us and cows us with its self-confidence. At such junctures, the heckler performs an important public service.

Keyword: Miscellaneous
Link ID: 11582 - Posted: 06.24.2010

By Siri Carpenter "There is nothing more painful to me at this stage in my life,” Jesse Jackson once told an audience, “than to walk down the street and hear footsteps and start thinking about robbery—then look around and see somebody white and feel relieved.” Jackson’s remark illustrates a basic fact of our social existence, one that even a committed black civil-rights leader cannot escape: ideas that we may not endorse—for example, that a black stranger might harm us but a white one probably would not—can nonetheless lodge themselves in our minds and, without our permission or awareness, color our perceptions, expectations and judgments. Using a variety of sophisticated methods, psychologists have established that people unwittingly hold an astounding assortment of stereotypical beliefs and attitudes about social groups: black and white, female and male, elderly and young, gay and straight, fat and thin. Although these implicit biases inhabit us all, we vary in the particulars, depending on our own group membership, our conscious desire to avoid bias and the contours of our everyday environments. For instance, about two thirds of whites have an implicit preference for whites over blacks, whereas blacks show no average preference for one race over the other. Such bias is far more prevalent than the more overt, or explicit, prejudice that we associate with, say, the Ku Klux Klan or the Nazis. That is emphatically not to say that explicit prejudice and discrimination have evaporated nor that they are of lesser importance than implicit bias. According to a 2005 federal report, almost 200,000 hate crimes—84 percent of them violent—occur in the U.S. every year. © 1996-2008 Scientific American Inc.

Keyword: Emotions
Link ID: 11581 - Posted: 06.24.2010

By Steve Mitchell For people, ultraviolet B (UVB) is an invisible, cancer-causing ray to be blocked with sunscreen and dark glasses, but for a species of jumping spider, the light sets a romantic mood. In the first evidence of an animal having the ability to see UVB, researchers have found that the ornate jumping spider uses the light in mating displays. The finding raises the possibility that other animals can see this wavelength, which researchers have long assumed no creature could detect. Several insects, crustaceans, birds, fish, and mammals can see ultraviolet A light, but researchers took it for granted that no animal could perceive UVB because their eyes do not appear capable of detecting this slightly shorter wavelength, which packs more energy and can cause skin cancer and eye damage. However, while working last year on a species of jumping spider that uses UVA in mating displays (Science, 26 January 2007), a team led by Daiqin Li, an arachnologist at the National University of Singapore, made the surprising discovery that males of another jumping spider species (Phintella vittata) in China have patches on their abdomens that reflect UVB light and are used in mating displays. Could these spiders see the light, so to speak? To put this notion to the test, Li’s team placed 20 male spiders in glass cages lined with light filters. Female spiders in cages next to the males spent more time ogling the guys’ mating displays when UVB light was allowed in than when the wavelength was blocked. In a separate experiment, the researchers took 14 pairs in which the females had responded positively to the male’s courtship display under normal lighting conditions and placed them in cages separated by the UVB-blocking filter. Eleven of the 14 females now no longer showed an interest in the males’ come-hither dance, confirming that seeing UVB light--and not the male’s particular display--was essential, the researchers report online today in Current Biology. Li’s team doesn’t yet know how the spiders see UVB or whether their eyes are somehow protected from the damaging effects of the light. © 2008 American Association for the Advancement of Science.

Keyword: Vision; Sexual Behavior
Link ID: 11580 - Posted: 06.24.2010

Ewen Callaway Baby talk might be more than the mutterings of child who hasn't yet grasped language. A study of zebra finches finds that their brains use babbling to polish their calls into the perfect tune. Bird songs aren't so different from human speech, says Dmitriy Aronov, a neuroscientist at Massachusetts Institute of Technology in Cambridge, US, who led the study. "We have this magnificent transformation from highly imperfect infant behaviour to highly complex adult behaviour," he says. Young zebra finches learn their complex tunes by copying their fathers. After a month of doing little more than squawking for food, young zebra finches spend the next 2 months experimenting with song. It sounds awful at first – a 9-year old's first clarinet lesson would be the human equivalent. But gradually the birds sculpt their random chirps into a perfect copy of their father's tune. Neuroscientists mapped out the brain area responsible for the adult song, which controls muscles in the zebra finch mouth. Most researchers assumed that young birds babbled because they were still learning to develop the nerves of the "motor pathway" that controls these muscles. © Copyright Reed Business Information Ltd.

Keyword: Language; Development of the Brain
Link ID: 11579 - Posted: 06.24.2010

A woman's voice becomes more alluring when she is at her most fertile, according to US research. Recordings of women taken at different points in their menstrual cycle were played to people of both sexes. New Scientist magazine reports that the voices rated as most attractive belonged to women at peak fertility. The study suggests sex hormones can alter the workings of the voice box, but the change may be too subtle to pick up in many situations. Human reproduction differs from reproduction in other mammals in that there are no obvious signs that a woman is at her fertile phase. However, scientists have suggested that very subtle changes caused by the rise and fall of different sex hormones can be detected by men, who then perhaps find a woman more attractive without necessarily even realising why. The latest research, from the State University of New York at Albany and originally published in the journal Human Evolution and Behavior, involved taking recordings of women counting from one to 10 at four points during the menstrual cycle and then played them back to male and female students. The missing link here is finding out how this works in plain conversation - in a bar, for example. (C)BBC

Keyword: Sexual Behavior; Language
Link ID: 11578 - Posted: 05.01.2008

Administering a hormone contained in contraceptive pills can treat brain injuries, suggests new research out of two Chinese universities. Researchers at Hangzhou Normal University and Zhejiang University have found that giving the hormone progesterone to people with severe brain injuries seems to improve their cognitive function. Previous studies have shown that progesterone can reduce inflammation and have a protective effect on the brain when injured. The Chinese researchers studied 159 patients with acute brain injury, half of whom were given progesterone and the other half placebo for five days following their injury. Patients were classified as having favourable outcomes (good recovery or moderate disability), or unfavourable outcomes (severe disability, vegetative state or death). The randomized double-blind trial revealed that significantly more patients who received progesterone had favourable outcomes at three and six-month intervals than those who received placebo. Forty-seven per cent of the patients who received progesterone and 31 per cent of the placebo group had favourable outcomes and 53 per cent of the progesterone and 70 per cent of the placebo patients had unfavourable outcomes. Copyright © CBC 2008

Keyword: Brain Injury/Concussion; Hormones & Behavior
Link ID: 11577 - Posted: 06.24.2010

By Jasmin Aline Persch Female canaries adore a good old-fashioned love song that abides by rigid musical rules. Mature males always follow the rules. Curiously, young males will go against convention — and rock out to tunes that would not impress the ladies. But the feathery punks will shape up when it counts. In a study by scientists at Rockefeller University in New York City, young male canaries isolated in soundproof cages learned to imitate computer-generated compositions in the first half of their youth. Come spring mating season, they changed their tune to the good old-fashioned canary love song — even though they’d never heard it before. The Rockefeller University researchers were surprised the young male canaries broke steadfast tradition. But the quick turnaround to the conventional emphasizes how crucial the recognizeable canary love song is to coupling. It encourages females to build nests, produce eggs and find a soul mate. Scientists continue to decipher birdsong. They're also studying the musical talents of apes, humpback whales, bats and mice. Listen (above) and learn (below) about these up-and-coming mammal musicians. © 2008 MSNBC Interactive

Keyword: Sexual Behavior; Animal Communication
Link ID: 11576 - Posted: 06.24.2010

Catherine Brahic It has been debated for nearly four decades but no one has yet been able to prove it is chemically possible. Now good evidence suggests that birds can actually "see" the lines of the Earth's magnetic field. Klaus Schulten of the University of Illinois, proposed forty years ago that some animals – including migratory birds – must have molecules in their eyes or brains which respond to magnetism. The problem has been that no one has been able to find a chemical sensitive enough to be influenced by Earth's weak geomagnetic field. Now Peter Hore and colleagues at the University of Oxford have found one. Cryptochromes are a class of light-sensitive proteins found in plants and animals, and are thought to play a role in the circadian clock, in regulating plant growth, and timing coral sex. A few years ago, Henrik Mouritsen of the University of Oldenburg in Germany showed that they were present in the retinal neurons of migratory garden warblers, and that these cells were active at dusk, when the warblers were performing magnetic orientation. Cryptochromes have not yet been made in the lab and obtaining them is difficult, but Hore's team has now shown that a related molecule – a carotenoid-porphyrin-fullerene triad – with similar chemical properties to cryptochromes is sensitive to weak magnetism. © Copyright Reed Business Information Ltd.

Keyword: Vision; Animal Migration
Link ID: 11575 - Posted: 06.24.2010

By CRAIG S. SMITH PARIS — Albert Hofmann, the mystical Swiss chemist who gave the world LSD, the most powerful psychotropic substance known, died Tuesday at his hilltop home near Basel, Switzerland. He was 102. The cause was a heart attack, said Rick Doblin, founder and president of the Multidisciplinary Association for Psychedelic Studies, a California-based group that in 2005 republished Dr. Hofmann’s 1979 book “LSD: My Problem Child.” Dr. Hofmann first synthesized the compound lysergic acid diethylamide in 1938 but did not discover its psychopharmacological effects until five years later, when he accidentally ingested the substance that became known to the 1960s counterculture as acid. He then took LSD hundreds of times, but regarded it as a powerful and potentially dangerous psychotropic drug that demanded respect. More important to him than the pleasures of the psychedelic experience was the drug’s value as a revelatory aid for contemplating and understanding what he saw as humanity’s oneness with nature. That perception, of union, which came to Dr. Hofmann as almost a religious epiphany while still a child, directed much of his personal and professional life. Copyright 2008 The New York Times Company

Keyword: Drug Abuse
Link ID: 11574 - Posted: 06.24.2010

By Charles Q. Choi An analysis of century-old bottles of absinthe — the kind once quaffed by the likes of van Gogh and Picasso to enhance their creativity — may end the controversy over what ingredient caused the green liqueur's supposed mind-altering effects. The culprit seems plain and simple: The century-old absinthe contained about 70 percent alcohol, giving it a 140-proof kick. In comparison, most gins, vodkas and whiskeys are just 80- to 100-proof. In recent years, the psychedelic nature of absinthe has been hotly debated. Absinthe was notorious among 19th-century and early 20th-century bohemian artists as "the Green Fairy" that expanded the mind. After it became infamous for madness and toxic side effects among drinkers, it was widely banned. The modern scientific consensus is that absinthe's reputation could simply be traced back to alcoholism, or perhaps toxic compounds that leaked in during faulty distillation. Still, others have pointed at a chemical named thujone in wormwood, one of the herbs used to prepare absinthe and the one that gives the drink its green color. Thujone was blamed for "absinthe madness" and "absinthism," a collection of symptoms including hallucinations, facial tics, numbness and dementia. © 2008 LiveScience.com.

Keyword: Drug Abuse
Link ID: 11573 - Posted: 06.24.2010

Colin Barras Here's a possible explanation for why rock star Ozzy Osbourne infamously bit the head off a bat: he couldn't stand the competition. Bat calls, it turns out, can reach up to a deafening 140 dB – that's 20 dB louder than a rock concert and 15 dB above the human pain threshold. Bats use high-pitched calls to echolocate because only at those ultrasonic frequencies can they detect their small, swiftly moving insect prey. But high-frequency calls don't travel far through the air, leaving bats unable to detect prey beyond a few metres. Annemarie Surlykke at the University of Southern Denmark in Odense and Elisabeth Kalko of the University of Ulm, Germany, reasoned that bats with the highest frequency calls would compensate for the small detection distance with louder cries, because a louder call travels further. To test this they recorded the calls of 11 bat species living on Barro Colorado Island in Panama. They found that the call of one species – the lesser bulldog bat (Noctilio albiventris) – reached an ear-shattering 137 dB, an estimate they think is likely to be on the conservative side because of the high directionality of the calls. Even so, N. albiventris now holds the record as the loudest winged animal yet recorded. © Copyright Reed Business Information Ltd.

Keyword: Hearing
Link ID: 11572 - Posted: 06.24.2010

By NICHOLAS BAKALAR A new study has found that it may be possible to train people to be more intelligent, increasing the brainpower they had at birth. Until now, it had been widely assumed that the kind of mental ability that allows us to solve new problems without having any relevant previous experience — what psychologists call fluid intelligence — is innate and cannot be taught (though people can raise their grades on tests of it by practicing). But in the new study, researchers describe a method for improving this skill, along with experiments to prove it works. The key, researchers found, was carefully structured training in working memory — the kind that allows memorization of a telephone number just long enough to dial it. This type of memory is closely related to fluid intelligence, according to background information in the article, and appears to rely on the same brain circuitry. So the researchers reasoned that improving it might lead to improvements in fluid intelligence. First they measured the fluid intelligence of four groups of volunteers using standard tests. Then they trained each in a complicated memory task, an elaborate variation on Concentration, the child’s card game, in which they memorized simultaneously presented auditory and visual stimuli that they had to recall later. Copyright 2008 The New York Times Company

Keyword: Learning & Memory
Link ID: 11571 - Posted: 06.24.2010

By Nikhil Swaminathan It is well established that the brain uses more energy than any other human organ, accounting for up to 20 percent of the body's total haul. Until now, most scientists believed that it used the bulk of that energy to fuel electrical impulses that neurons employ to communicate with one another. Turns out, though, that is only part of the story. A new study in Proceedings of the National Academy of Sciences USA indicates that two thirds of the brain's energy budget is used to help neurons or nerve cells "fire'' or send signals. The remaining third, however, is used for what study co-author Wei Chen, a radiologist at the University of Minnesota Medical School, refers to as "housekeeping," or cell-health maintenance. Researchers reached their conclusions after imaging the brain with magnetic resonance spectroscopy (MRS) to measure its energy production during activity shifts. Chen says the technology, which has been around for three decades and is used to track the products of metabolism in different tissues, could prove instrumental one day in detecting brain defects or to diagnose tumors or precursors of neurodegenerative diseases (such as Alzheimer's and Parkinson's) early. © 1996-2008 Scientific American Inc.

Keyword: Brain imaging
Link ID: 11570 - Posted: 06.24.2010

Nick Bryant Australian scientists believe they may have discovered how to help people lose weight without cutting back on food. Researchers in Melbourne found that by manipulating fat cells in mice they were able to speed up metabolism. After removing a particular enzyme, scientists found the mice were able to eat the same amount as others but burn more calories and gain less weight. The breakthrough could pave the way for fat-burning drugs and also help to combat diabetes. The research found that mice in which the angiotensin converting enzyme (ACE) had been removed were, on average, 20% lighter than normal mice and had up to 60% less body fat. Because of their faster metabolisms, it also appeared they had less chance of developing diabetes because they processed sugar more quickly. Drugs which impair the action of ACE in humans already exist, and are used to combat high blood pressure. The latest research could help the development of weight loss pills. The question is whether they will have the same slimming effect on people as they have done on mice. Dr Ian Campbell, medical director of the charity Weight Concern, said the study was "interesting", but stressed the work had only been carried out in mice. (C)BBC

Keyword: Obesity
Link ID: 11569 - Posted: 04.29.2008

By ABIGAIL ZUGER, M.D. Marya Hornbacher is a virtuoso writer: humorous, articulate and self-aware. She is also, as she has now documented in two books, incurably mentally ill. Even on the best possible treatment, Ms. Hornbacher tiptoes along the same high wire as Plath, Lowell, Woolf and the rest of the unbalanced artistes. Off medication, she reliably falls into a turmoil of confused self-destruction, which, as she would be the first to acknowledge, means heartbreak and worry for her friends and relatives, challenges for her doctors, and, in the age-old contradiction, new fodder for her muse. For scientists trying to parse the mystery of brain and mind, she is one more case of the possible link between mental illness and artistic creativity. With all our scans and neurotransmitters, we are not much closer to figuring out that relationship than was Lord Byron, who announced that poets are “all crazy” and left it at that. But effective drugs make the question more urgent now: would Virginia Woolf, medicated, have survived to write her final masterpiece, or would she have spent her extra years happily shopping? Copyright 2008 The New York Times Company

Keyword: Anorexia & Bulimia; Schizophrenia
Link ID: 11568 - Posted: 06.24.2010

By Dennis Drabelle I never used to be a napper. In fact, daytime slumber was virtually beyond a congenitally wired type like me. My buddies would catch 40 winks on the long bus ride home from our high school, but for me that was out of the question. With age, however, my metabolism has changed. After the double whammy of a late-morning run and lunch, I'm pretty much a goner. I lie down and nod off in much the same way that Marlene Dietrich fell in love in that old song of hers: because I can't help it. While it lasted, though, my nap resistance put me in sync with the American way of sleep: Do it all at once and strictly at night. Traditionally, we've begrudged ourselves naps. They may be forced on toddlers, recommended for pregnant women and tolerated among senior citizens with nothing better to do, but they've been frowned upon for worker bees in their prime. Recently, however, sleep scientists have discovered advantages to napping, which they view not just as solace but also as something akin to brain food. No longer written off as a cop-out for the weak and the bored, the nap is coming into its own as an element of a healthy life. When you take a look at American history, we might seem to be a nap-friendly people. After all, some of our most productive figures napped shamelessly during the day, among them Benjamin Franklin and Thomas Edison. But they probably did so because, like Dietrich, they couldn't help it. Consider the daily schedule Franklin drew up for "The Art of Virtue," a treatise he worked on for 50 years but never finished: Over a 24-hour period, sleep gets allotted a mere five hours. Or take the contemptuous words of Edison: "Sleep is an acquired habit. Cells don't sleep. Fish swim in the water all night. Even a horse doesn't sleep. A man doesn't need any sleep." © Copyright 1996-2008 The Washington Post Company

Keyword: Sleep
Link ID: 11567 - Posted: 06.24.2010

Heidi Ledford Can training one aspect of the mind, such as memory, improve overall mental sharpness? Researchers conducting a study on healthy college students suggest that such mental cross-training does work. The notion that a few daily puzzles and quizzes sharpens the intellect and staves off cognitive decline is controversial (see Brain craze). Most research has shown that such brain games do little more than allow the participant to develop strategies for improving performance on that particular task. The improvement does not typically extend beyond the game itself. But a new study published this week in Proceedings of the National Academy of Sciences reports that a group of college students improved their performance on a pattern-recognition test — a commonly used intelligence test — after training their working memory1. Susanne Jaeggi and Martin Buschkuehl, both now at the University of Michigan in Ann Arbor, and their colleagues recruited 70 participants from the University of Bern in Switzerland, and trained them on a rigorous memory test. The test consisted of a string of events: every three seconds, a small white box would appear on the screen in varying locations while at the same time a letter of the alphabet was read aloud. © 2008 Nature Publishing Group

Keyword: Learning & Memory
Link ID: 11566 - Posted: 06.24.2010