by Jessica Hamzelou Boosting brain waves can make people move in slow motion. This finding is one of the first to show that brain waves directly influence behaviour, and it could lead to new treatments for Parkinson's disease and other disorders that affect movement. Peter Brown and his colleagues at University College London generated a small electrical current in the brains of 14 healthy volunteers using scalp electrodes. The current increased the activity of normal beta waves – a kind of brain wave that is usually active during sustained muscle activities, such as holding a book. Beta activity usually drops before people begin a movement. The participants then carried out a simple task: they moved a spot on a computer screen as quickly as possible using a joystick. When beta wave activity increased, their fastest times slowed by 10 per cent. "This is the first time that beta wave activity has been shown to slow movement," Brown says. Other studies have found that people with Parkinson's disease have greater beta activity. Brown's research suggests this could be linked to the slowing of movement seen in those with the disease. Electrical stimulation deep in the brain is used to treat people with Parkinson's, although how it works is a subject of debate. © Copyright Reed Business Information Ltd

Keyword: Parkinsons; Sleep
Link ID: 13321 - Posted: 06.24.2010

By Fergus Walsh Babies who are starved of oxygen at birth have a much lower risk of brain damage if they are given mild hypothermia, major research suggests. More than 300 babies were involved in a trial carried out at 33 hospitals in the UK and in five other countries. Researchers found full-term babies who suffered oxygen loss at birth were 57% more likely to survive without brain damage if their bodies were cooled. The findings are published in the New England Journal of Medicine. The babies' body temperature was brought down by about 4C using a fluid-filled mat under their sheet. Doctors are not exactly sure why it helps, but think that slowing their metabolism reduces the after-shocks of the birth trauma, giving the brain time to recover. Dr Denis Azzopardi, from Imperial College London and who led the trial, said: "The study builds on a 20-year body of research but gives, for the first time, irrefutable proof that cooling can be effective in reducing brain damage after birth asphyxia. "Although unfortunately it doesn't work in every case, our study showed the proportion of babies that survived without signs of brain damage went from 28% to 44% with cooling treatments - that's a 57% increase." Carmel Bartley, Family Support Manager from the children's charity Bliss, said: "This is very welcome research into an area which is known to save lives. Cooling of babies with birth asphyxia is an innovative technique already being used in some neonatal centres. "This is a specialist treatment that we would like to see used more widely to ensure the very best outcomes for our most vulnerable babies." (C) BBC

Keyword: Development of the Brain
Link ID: 13320 - Posted: 10.01.2009

By Hal Arkowitz and Scott O. Lilienfeld Obesity is a “global epidemic,” according to the World Health Organization. Two thirds of American adults and one third of school-age children are either overweight or obese (defined as extremely overweight). These proportions have been rising steeply, report the latest surveys. From 1960 to 2002 the population of overweight and obese adults increased by roughly 50 percent, and the corresponding increase for children was 300 percent. Compounding the problem, obesity rates in other countries are rapidly approaching those in the U.S. What is causing this pandemic, and what can we do about it? Researchers have provided some tentative answers that fly in the face of commonly held beliefs. They suggest that the increase in obesity may be a result of environmental changes that tempt us into unhealthy habits and tend to overwhelm our psychological defenses against consuming too much and succumbing to fattening fare. In fact, environmental cues can exacerbate any innate tendency to use food as a balm for jittery nerves or sadness. Thus, many health experts advocate legislation—for instance, a tax on junk food—that promotes healthy eating. Others are trying to help individuals change their immediate eating milieu in ways that discourage overeating. Many people, including health care professionals, believe that obesity can be attributed simply to a lack of self-control or willpower. It is true that obese people are often unable to adequately control their eating. But lack of self-control is merely a description, not an explanation. What remains to be explained is why they cannot exercise self-control. © 1996-2009 Scientific American Inc.

Keyword: Obesity
Link ID: 13319 - Posted: 06.24.2010

By Jesse Bering fearful faceBuon giorno from Florence, where I’m presently under the Tuscan sun—sizzling like bacon, I should add—as a hive of awestruck, pale-legged American tourists wearing Nikes, cargo shorts and Polo shirts descend with digital cameras at the ready on the Renaissance city’s signature Duomo in the Piazza Della Signoria. As for me, I’m at an overpriced cafe with a “Coca-Cola Light” in my hand; in the square before me, a bedraggled carriage horse has its great tethered head to the ground, warily inspecting some lime-green gelato spilled moments ago on the cobblestones by a fussy little Australian boy. If I were of a literary rather than a scientific bent, I would find these scenes inspiring; Dante himself couldn’t imagine a stranger hell than his beloved Florence stuffed with such exotic modern characters, pigeons whiffling overhead. Instead, I’m gazing out across this piazza and wondering how many psychopaths there are milling about out there, the cleverest of whom often go unnoticed. What prompts this strange thought is my earlier visit to a lesser-known tourist attraction here in Florence called “The Museum of Serial Killers.” After all, once one is finished marveling over masterpieces like Michaelangelo’s David and Botticelli’s Birth of Venus in the famed Galleria Dell’Accademia and the Uffizi, it’s easy to get fatigued by all the religious iconography in this city. I found myself standing before fantastic, gilded works by the Italian masters and muttering, “Just another Jesus,” and “Oh, it’s only Mary again.” (What a pity so many artists of that age concentrated their talents so heavily on so few subjects.) So, though it's sensational, The Museum of Serial Killers offers respite from these more venerable Florentine sites. Unfortunately, it’s also as tacky inside as its name on the marquee promises, mostly waxworks of notorious psychopaths such as the 15th century French sadist Gilles de Rais, a smiling and unctuous Ted Bundy leaning against a fancy sports car, even a disturbingly realistic reconstruction of John Wayne Gacy’s suburban living room—complete with decomposing corpses beneath the floorboards. © 1996-2009 Scientific American Inc.

Keyword: Aggression; Emotions
Link ID: 13318 - Posted: 06.24.2010

By Michael Torrice For many animals, it pays to have a split mind. A brain with multiple lobes helps humans make more efficient decisions, and it allows birds to spot predators quickly. But a new study in fish uncovers possible hidden costs to a divided brain. Scientists once thought that only humans had a split in brain functions, called lateralization, with some tasks performed on the left side and others on the right. More recently, studies in primates, birds, and fish have suggested that asymmetric brains are common in many vertebrates and that more lateralized brains are more efficient. In a recent experiment, for example, parrots with more brain lateralization were more successful at finding seeds hidden among pebbles. But despite this cognitive boost, scientists have observed a great range of brain lateralization among fish and birds. Some of these animals can have almost completely symmetrical brains. So are there disadvantages to lateralization? To find out, Marco Dadda, a psychobiologist at the University of Padova in Italy, and his colleagues focused on goldbelly topminnows (Girardinus falcatus), a species known for its lateralized brain. For 4 years, the scientists bred three minnow groups to have different dominant sides of their brains. They determined the stronger half by watching which way the fish turned to avoid a predator: Turning right 80% of the time meant the right eye--and thus the left brain hemisphere--was dominant, whereas showing no turn preference pointed to a nonlateralized brain. © 2009 American Association for the Advancement of Science.

Keyword: Laterality
Link ID: 13317 - Posted: 06.24.2010

The drug vorinostat is able to cross the blood-brain barrier and reduce the development of large metastatic tumors in mice brains by 62 percent when compared to mice that did not receive the drug, according to a new study. In humans, the drug has been approved by the U.S. Food and Drug Administration for the treatment of a cancer called cutaneous T-cell lymphoma but can be used experimentally to study its effectiveness against other cancers. This research, by investigators at the National Cancer Institute (NCI), part of the National Institutes of Health, and their collaborators, appears online Sept. 29, 2009, in Clinical Cancer Research. For people, while various therapies are improving the survival of breast cancer patients, the incidence of breast cancer spreading to the brain is increasing. Brain metastases of breast cancer have proven to be largely untreatable because the blood-brain barrier, which arises from the specialized structure of blood capillaries in the brain, severely limits drug access and many drugs are actively transported out of brain at this barrier. Consequently, the one-year survival estimate for breast cancer patients after a diagnosis of brain metastasis is only about 20 percent. Vorinostat has been found to slow the growth of primary tumors of several different types of cancer in mice. Previous studies have suggested that the drug can be taken up by the brain, although little was known about its effects on metastatic tumors. Therefore, to study the effect of vorinostat on the formation of brain metastases, scientists used a mouse model of human breast cancer. Human breast cells were cultured in the laboratory and were injected into mice with compromised immune systems. The breast cancer cells then migrated to the brain, forming metastases.

Keyword: Miscellaneous
Link ID: 13316 - Posted: 10.01.2009

by Amanda Gefter New Scientist caught up with husband-and-wife writing team David Barash and Judith Eve Lipton to discuss their latest book, Strange Bedfellows: The surprising connection between sex, evolution and monogamy. We ask them what we can learn about monogamy from other species, and how writing a book about monogamy affected their own marriage. Your last book, The Myth of Monogamy (W. H. Freeman, 2001) talked about the rarity of monogamy in nature. What made you decide to write another book on the subject? David: Intellectual honesty or a scientific balancing of the scales if you will. Myth of Monogamy was looking at the glass half empty, at the problems that biology poses for monogamy, but we were aware that monogamy, for all its difficulties, does happen. It happens in animals, it happens in humans. We didn't want to give the impression that it's impossible. Judith: There were both scientific and personal reasons. We thought it was important to point out that the promiscuous behaviour we were describing in ducks, for example, doesn't necessarily hold for people. David and I have been married and monogamous since 1977. There are different kinds of monogamy – for instance, there's a tapeworm that has only one partner until it dies. That's extremely unusual, but there are other forms of monogamy that are more common, like us! We were each married before and have had other sexual partners, but have been monogamous in our own marriage. © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior; Evolution
Link ID: 13315 - Posted: 06.24.2010

by Nic Fleming A diminutive chihuahua and a lumbering Irish wolfhound look completely different, yet most us know they both belong to the concept called "dog". Now the brain regions responsible for our ability to organise the world into separate concepts have been pinpointed. Forming a concept involves selecting the important characteristics of our experiences and categorising them. The degree to which we are able to do this effectively is a defining characteristic of human intelligence. Yet little is known about how conceptual knowledge is created and used in the brain. In an attempt to identify the brain regions responsible, Dharshan Kumaran and colleagues at the Wellcome Trust Centre for Neuroimaging, University College London, showed 25 volunteers pairs of fractal patterns that represented the night sky and asked them to forecast the weather – either rain or sun – based on the patterns. Conceptual rules based on the positions and combinations of the patterns governed whether the resulting outcome would be rain or sun, but the volunteers were not told this. Instead correct predictions were rewarded with cash prizes, encouraging the volunteers to deduce these conceptual rules. In an initial learning phase, the different possible combinations were repeatedly shown to the participants. While they could make their predictions by simply memorising previous outcomes, they could also begin to realise that rules based on the positions and combinations of the patterns governed whether the result would be rain or sun. © Copyright Reed Business Information Ltd

Keyword: Learning & Memory; Attention
Link ID: 13314 - Posted: 06.24.2010

by Peter Aldhous You cannot grow up without leaving your mother's protection and learning to make your own way in the world. Now for rat pups, at least, we have a clear idea of the changes in the brain involved in this vital transition. A team led by Regina Sullivan of New York University's Langone Medical Center previously found that young pups will become attracted to odours – even when those odours are paired with electric shocks. Only when pups reach about 10 days old do they become capable of associating odours with negative stimuli. What enables this transition from blind attraction to the ability to learn about potential danger? Sullivan found previously that odours associated with their mother suppress the release in rat pups of the stress hormone corticosterone. Now her team has shown that corticosterone suppression in turn reduces levels of the neurotransmitter dopamine in the amygdala, a structure that acts as the brain's "fear centre". Smelling a rat The researchers found that in 8-day-old pups exposed to shock-paired odours, genes involved in the release of dopamine were relatively inactive. But these genes were much more active in 12-day-old pups, which learned to avoid the shock-linked odours. What's more, when the team injected 8-day-olds with corticosterone, the activity of the dopamine-associated genes rose, and the pups learned to avoid the shock-paired odours just like older rats. Directly infusing dopamine into the amygdala of the young pups had the same effect on behaviour. "Dopamine was the only thing really correlated with what the pup was learning," says Sullivan. © Copyright Reed Business Information Ltd.

Keyword: Learning & Memory; Stress
Link ID: 13313 - Posted: 06.24.2010

by Ewen Callaway Victorious gamers enjoy a surge of testosterone – but only if their vanquished foe is a stranger. When male gamers beat friends in a shoot-em-up video game, levels of the potent sex hormone plummeted. This suggests that multiplayer video games tap into the same mechanisms as warfare, where testosterone's effect on aggression is advantageous. Against a group of strangers – be it an opposing football team or an opposing army – there is little reason to hold back, so testosterone's effects on aggression offer an advantage. "In a serious out-group competition you can kill all your rivals and you're better for it," says David Geary, an evolutionary psychologist at the University of Missouri in Columbia, who led the study. However, when competing against friends or relatives to establish social hierarchy, annihilation doesn't make sense. "You can't alienate your in-group partners, because you need them," he says. It's his hormones Measuring these effects, however, hasn't been easy. Victors in sporting events are known to experience a burst in testosterone – particularly if they contributed to the win. But physical exertion also boosts testosterone, so it is hard to be sure just what causes an athlete's hormonal surge. © Copyright Reed Business Information Ltd

Keyword: Aggression; Hormones & Behavior
Link ID: 13312 - Posted: 06.24.2010

A warning or mini-stroke occurs before one in every eight strokes, according to an Ontario study. 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. Dr. Daniel Hackam of the University of Western Ontario in London, Ont., and his colleagues analyzed all patients hospitalized with a diagnosis of stroke between July 2003 and September 2007. Of the 16,400 patients reviewed, 2,032, or 12.4 per cent, had a TIA prior to the stroke that landed them in hospital, the team reported in Tuesday's issue of the journal Neurology. "These results illustrate the need for better risk assessment tools for preventing strokes before they occur," Hackam said in a release. "Other studies have shown that up to 80 per cent of strokes after TIA can be prevented when risk factors are managed intensively." Go to emergency for minor stroke People who did not have a TIA were more likely to have a more serious stroke than those who did have a warning stroke. © CBC 2009

Keyword: Stroke
Link ID: 13311 - Posted: 06.24.2010

Alison Abbott Two patients, partially blind because of damage to one side of their brain, were able to sense, and respond to, emotions expressed by people in pictures presented to their blind sides. A study by an international team of researchers found that the patients unconsciously twitched a facial muscle uniquely involved in smiling when a picture showed a happy person, and a muscle involved in frowning when the person depicted looked fearful1. The patients, both from the United Kingdom, have the very rare condition known as partial cortical blindness. Their eyes are intact but they have damage to the visual cortex on one side of their brain. This means that they cannot process information from the visual field on the opposite side of their nose. The scientists, who were led by Marco Tamietto and Beatrice de Gelder at Tilburg University in the Netherlands, say the results show that our spontaneous tendency to synchronize our facial expressions with those of other people in face-to-face situations — known as emotional contagion — occurs even if we cannot consciously see them. "This is interesting evidence that we can recognize the emotions of others without needing to be visually aware of them," says neuroscientist Christian Keysers, an expert in the neurophysiology of emotion at the University of Groningen, the Netherlands, who was not involved in the study. © 2009 Nature Publishing Group,

Keyword: Vision; Emotions
Link ID: 13310 - Posted: 06.24.2010

By Frans de Waal Two young bonobos exhibit the ape equivalent of the human laugh, a “play face,” which is accompanied by laugh-like panting sounds. Just as in humans, if one ape laughs others usually do as well, especially during wrestling and tickling games. Frans de Waal One morning, the principal’s voice sounded over the intercom of my high school with the shocking announcement that a popular teacher of French had just died in front of his class. Everyone fell silent. While the headmaster went on to explain that the teacher had suffered a heart attack, I couldn’t keep myself from a laughing fit. To this day, I feel embarrassed. What is it about laughter that makes it unstoppable even if triggered by inappropriate circumstances? Extreme bouts of laughter are awkward: they involve loss of control, shedding of tears, gasping for air, leaning on others, and even wetting of pants while rolling on the floor! What weird trick has been played on our linguistic species, that we express ourselves with stupid “ha ha ha!” sounds? Why don’t we leave it at a cool “That was funny!”? Philosophers who regard a sense of humor as one of humanity’s finest achievements may find it puzzling that it is expressed with the sort of crude abandon associated with mere animals. But laughter is an inborn, universal human trait, one that we share with our closest relatives, the apes (see “The Laughing Species,” December 2000-January 2001). © 2008–2009 Natural History Magazine, Inc.

Keyword: Emotions; Evolution
Link ID: 13309 - Posted: 06.24.2010

Physiologically, why is the sound of fingernails on a blackboard so unnerving? Is this effect particular to human beings, or are other creatures similarly affected? —Rowan Snyder, via e-mail Neuroscientist Josh McDermott of New York University explains: Probably a couple of factors combine to make such sounds unpleasant. The first, perhaps unsurprisingly, is the presence of high frequencies. The range between two and four kilohertz—approximately that covered by the highest octave of a standard piano—seems to contribute the most to the nastiness of the sound. It is unclear why people tend to find these frequencies unpleasant, but we know that noise-induced hearing loss most commonly occurs in roughly this region, so it is conceivable that the aversive reaction partly reflects the ear’s vulnerability. The spectrum of screeching sounds is also much noisier than that of an instrument; that is, there is a strong random component to the sound. The noisiness probably results from the fingernails repeatedly catching on part of the chalkboard surface before sliding forward. This catching and sliding also causes rapid fluctuations in intensity, giving the sound a “rough” character. Roughness is known to be unpleasant—car manufacturers, who aim to produce minimally unpleasant engine noise, for instance, find that smooth sounds with minimal variation in intensity are preferred by listeners over those that are rough. It’s a bit harder to say why sound roughness is considered unpleasant—as far as we know it is not harmful to the ears.

Keyword: Hearing
Link ID: 13308 - Posted: 06.24.2010

By ANAHAD O’CONNOR THE FACTS This familiar claim is the stuff of many a Hollywood story line — like “Daredevil,” in which a lawyer’s sudden blindness heightens his other senses and turns him into a superhero. Studies suggest that the story is more fact than fantasy. In one series of studies, neuroscientists at McGill University tested blind and sighted subjects for pitch perception and their ability to locate sounds. The blind subjects generally scored higher, which came as little surprise — until the scientists discovered that precisely when the subjects had become blind affected their performance. Those who were born blind did best, those who became blind as small children were slightly behind, and those who lost their vision after age 10 did no better than the sighted subjects. The implication was that a young brain could be rewired so that visual-processing areas were used for other purposes. Perhaps the strongest evidence of that was shown in brain-imaging studies, in which scientists found that blind subjects who were best able to locate sound were engaging both the auditory and the visual areas of the cortex. Blind subjects who scored low, as well as sighted subjects, had little or no activity in the visual lobe. Other studies have had similar results with odor discrimination and tactile sensation. THE BOTTOM LINE Research suggests that at least in some circumstances, blindness can heighten other senses. Copyright 2009 The New York Times Company

Keyword: Vision; Hearing
Link ID: 13307 - Posted: 06.24.2010

By Stephen Smith Even now, 11 months, three weeks, and four days since smoking her last, she hears the siren song of the cigarette beckoning. “I still have the craving, it’s true,’’ said Monica Collins, the syndicated newspaper columnist who was so fully under the spell of cigarettes that, by her own reckoning, it took eight attempts before she finally stopped puffing. “There are times I know I’m going to be doing a lot of errands and in my car and going here and there, and I say, ‘Oh, God. I would love to have a cigarette.’ ’’ But she doesn’t. Somehow, this time - maybe it was the nicotine-replacement patch, maybe the counseling - Collins resisted the call of the cigarette. But there is no denying: The stranglehold nicotine places on smokers can sometimes prove insurmountable. Ask Jerry Remy, the Red Sox TV analyst who acknowledged last month that, despite enduring lung cancer, he still falls prey to the occasional impulse to smoke. Ask Barack Obama, who signed a landmark law regulating tobacco in June and, a day later, conceded in a presidential press conference that he has episodically “fallen off the wagon.’’ And then there was Patrick Swayze, stricken with pancreatic cancer and captured in haunting photos with a lit cigarette perched on his lips. The failure to quit, research has shown, has nothing to do with weakness of will. Nicotine, the primary addictive agent in tobacco, steals into the brain, setting on fire circuitry that regulates our sense of pleasure. © 2009 NY Times Co.

Keyword: Drug Abuse
Link ID: 13306 - Posted: 06.24.2010

By Robert Roy Britt The moon holds a mystical place in the history of human culture, so it's no wonder that many myths — from werewolves to induced lunacy to epileptic seizures — have built up regarding its supposed effects on us. "It must be a full moon," is a phrase heard whenever crazy things happen and is said by researchers to be muttered commonly by late-night cops, psychiatry staff and emergency room personnel. It's been a long time since the Big Cheese revealed any new secrets as important as this week's announcement that traces of water exist all across its surface. Coincidentally, a study this week found zero connection between the full moon and surgery outcomes. In fact a host of studies over the years have aimed at teasing out any statistical connection between the moon — particularly the full moon — and human biology or behavior. The majority of sound studies find no connection, while some have proved inconclusive, and many that purported to reveal connections turned out to involve flawed methods or have never been reproduced. Reliable studies comparing the lunar phases to births, heart attacks, deaths, suicides, violence, psychiatric hospital admissions and epileptic seizures, among other things, have over and over again found little or no connection. © 2009 Space.com

Keyword: Biological Rhythms
Link ID: 13305 - Posted: 06.24.2010

By PAM BELLUCK Blindness first began creeping up on Barbara Campbell when she was a teenager, and by her late 30s, her eye disease had stolen what was left of her sight. Reliant on a talking computer for reading and a cane for navigating New York City, where she lives and works, Ms. Campbell, now 56, would have been thrilled to see something. Anything. Now, as part of a striking experiment, she can. So far, she can detect burners on her stove when making a grilled cheese, her mirror frame, and whether her computer monitor is on. She is beginning an intensive three-year research project involving electrodes surgically implanted in her eye, a camera on the bridge of her nose and a video processor strapped to her waist. The project, involving patients in the United States, Mexico and Europe, is part of a burst of recent research aimed at one of science’s most-sought-after holy grails: making the blind see. Some of the 37 other participants further along in the project can differentiate plates from cups, tell grass from sidewalk, sort white socks from dark, distinguish doors and windows, identify large letters of the alphabet, and see where people are, albeit not details about them. Copyright 2009 The New York Times Company

Keyword: Vision; Robotics
Link ID: 13304 - Posted: 06.24.2010

By BENOIT DENIZET-LEWIS Austin didn’t know what to wear to his first gay dance last spring. It was bad enough that the gangly 13-year-old from Sand Springs, Okla., had to go without his boyfriend at the time, a 14-year-old star athlete at another middle school, but there were also laundry issues. “I don’t have any clean clothes!” he complained to me by text message, his favored method of communication. When I met up with him an hour later, he had weathered his wardrobe crisis (he was in jeans and a beige T-shirt with musical instruments on it) but was still a nervous wreck. “I’m kind of scared,” he confessed. “Who am I going to talk to? I wish my boyfriend could come.” But his boyfriend couldn’t find anyone to give him a ride nor, Austin explained, could his boyfriend ask his father for one. “His dad would give him up for adoption if he knew he was gay,” Austin told me. “I’m serious. He has the strictest, scariest dad ever. He has to date girls and act all tough so that people won’t suspect.” Austin doesn’t have to play “the pretend game,” as he calls it, anymore. At his middle school, he has come out to his close friends, who have been supportive. A few of his female friends responded that they were bisexual. “Half the girls I know are bisexual,” he said. He hadn’t planned on coming out to his mom yet, but she found out a week before the dance. “I told my cousin, my cousin told this other girl, she told her mother, her mother told my mom and then my mom told me,” Austin explained. “The only person who really has a problem with it is my older sister, who keeps saying: ‘It’s just a phase! It’s just a phase!’ ” Copyright 2009 The New York Times Company

Keyword: Sexual Behavior; Development of the Brain
Link ID: 13303 - Posted: 06.24.2010

The brain never sits idle. Whether we are awake or asleep, watch TV or close our eyes, waves of spontaneous nerve signals wash through our brains. Researchers at the Salk Institute for Biological Studies studying visual attention have discovered a novel mechanism that explains how incoming sensory signals make themselves heard amidst the constant background rumblings so they can be reliably processed and passed on. "We live with the illusion that our visual system processes all the information that is available in the visual scene in a single glimpse," says John H. Reynolds, Ph.D., an associate professor in the Systems Neurobiology Laboratory at the Salk Institute and senior author of the current study. "In reality, there is far too much detail in a typical scene for the visual system to take it in all at once. So our perception of the world around us is in a sense pieced together from what we pay attention to." Researchers had known for some time that paying attention to visual details increases the firing rate of neurons tuned for attended stimulus. Until now, it was assumed that these attention-dependent increases in neural activity were the primary cause of the improvement in perceptual discrimination that we experience when we focus a sensory stimulus. The findings of the Salk researchers, published in the September 24, 2009 issue of the journal Neuron, reveal that the uptick in the firing rate is only a small part of the story. "What we found is that attention also reduces background activity," says postdoctoral researcher and first author Jude Mitchell, Ph.D. "We estimate that this noise reduction increases the fidelity of the neural signal by a factor that is as much as four times as large as the improvement caused by attention-dependent increases in firing rate. This reduction in noise may account for as much as 80% of the attention story." © 2009 Eureka! Science News

Keyword: Attention
Link ID: 13302 - Posted: 06.24.2010