By Victoria Gill Have you ever failed to notice a friend's radical new haircut? Or missed a road sign showing a change in the speed limit? This failure to notice what should be very apparent is something we unconsciously experience every day as our brains filter the barrage of visual information which we are flooded with. And apparently it has a name; it is called change blindness. Scientists at Queen Mary, University of London, have invented a unique spot-the-difference-style computer game in order to study it. Milan Verma, a scientist at Queen Mary, explains: "It's the phenomenon where seemingly striking or obvious changes are not noticed." He and his colleagues are asking volunteers to play the game - which involves looking at a screen as it flashes between two images of the same scene. "It flicks between a pre-change version and a post-change version of the scene," Dr Verma explains. "The volunteers simply have to press the button and tell us exactly when they spot the change." Trying out the game at Dr Verma's office, my initial reaction was self-satisfaction; I spotted the difference in the first scene - a picture of a butterfly with orange stripes on its wings - almost immediately. BBC © MMX

Keyword: Vision; Attention
Link ID: 14173 - Posted: 06.24.2010

Janet Fang To follow the scent trail left by their prey across the ocean, sharks swim in the direction of the nostril that sniffed the odour first, scientists have found. Their research challenges the classic notion that sharks orient themselves based on the differences between odour concentration received at each nostril. Shark prey — whether living, injured or dead — leaves behind swirling odour plumes that break apart with distance. The latest work, published today in Current Biology1, suggests that when a shark moves into a patch of odour, the smell hits one nostril before the other — and that tells the shark to turn either left or right. By moving from side to side from one patch to another, the animal maintains contact with the odour plume as it tracks its prey, says Jayne Gardiner at the University of South Florida in Tampa, co-author of the study. Ocean odours mix chaotically, so for sharks to steer using odour concentration, they would need to compare the average concentration at the two nostrils over a period of several minutes to determine the prey's direction. They would then have to reposition themselves and start again — a slow process. But by using timing cues, says Gardiner, sharks receive directionality in under a second. The study centred around lab studies of eight smooth dogfish (Mustelus canis), a small grey-brown shark. To recreate prey odour, Gardiner marinated squid — what she calls "junk food for dogfish" — in 50 litres of seawater. She fitted the sharks with headgear consisting of two tubes delivering this squid marinade to one nostril and then the other. She found that for delays between 0.1 and 0.5 seconds, the sharks turned toward the side receiving the first stimulus. If there was no time lag or if the lag was a second or longer, the sharks were equally likely to turn in either direction. © 2010 Nature Publishing Group,

Keyword: Chemical Senses (Smell & Taste)
Link ID: 14172 - Posted: 06.24.2010

Scientists have discovered that a gene linked to Alzheimer’s disease may play a beneficial role in cell survival by enabling neurons to clear away toxic proteins. A study funded by the National Institute on Aging (NIA), part of the National Institutes of Health, shows the presenilin 1 (PS1) gene is essential to the function of lysosomes, the cell component that digests and recycles unwanted proteins. However, mutations in the PS1 gene — a known risk factor for a rare, early onset form of Alzheimer’s disease — disrupt this crucial process. Ralph Nixon, M.D., Ph.D., of the Nathan Kline Institute, Orangeburg, N.Y., and New York University Langone Medical Center, directed the study involving researchers from the United States, Europe, Japan and Canada. Also supported in part by the Alzheimer’s Association, the study appears in the June 10, 2010, online issue of Cell. Researchers have theorized for more than a decade that PS1 mutations linked to early-onset Alzheimer's, a rare form of the disease that usually affects people between ages 30 and 60, may trigger abnormally high levels of beta-amyloid protein to clump together in the brain. Amyloid deposits and tau protein tangles are hallmarks of both early-onset and the sporadic, more common form of the disease found in people aged 60 and older. These new findings, however, suggest PS1 mutations may play a more general role in the development of early-onset Alzheimer's.

Keyword: Alzheimers; Apoptosis
Link ID: 14171 - Posted: 06.24.2010

by Adam Hadhazy Nerve cells in our sweat glands and blood vessels may constitute an important, previously unrecognized source of sensory info. You are more sensitive than you realize, neuroscientist Frank Rice of Albany Medical College has discovered. His study of patients whose skin lacks normal nerve fibers has revealed a previously unknown source of perception that contributes to the familiar ability to feel texture, temperature, pressure, and pain: the nerve endings surrounding blood vessels and sweat glands in human skin. Rice, neurologist David Bowsher of the University of Liverpool, and their colleagues were studying two patients who were unable to feel pain, yet somehow retained a rudimentary ability to distinguish hot from cold and rough from smooth. On examining skin samples and other biopsies, the researchers found that all of the usual nerve endings associated with skin sensation were missing. The only possible sources of feeling were the nerves of the blood vessels and glands. Scientists knew that such nerves existed but thought they simply regulated blood flow and perspiration. The evidence from the patients examined by Rice and Bowsher suggests that the nerve cells also act as an additional sensory system. “It is very likely that these nerve endings contribute to conscious perception in all of us,” Rice says. If he is correct, problems with this previously unknown system could contribute to poorly understood pain conditions, such as migraines and fibromyalgia. Rice and a group of collaborators are gearing up to investigate this potential link by searching for malformations of the blood-vessel nerves that could affect their function.

Keyword: Pain & Touch
Link ID: 14170 - Posted: 06.24.2010

by John Travis More than 3 years after initially passing peer review and being accepted, a controversial paper addressing how to diagnose psychopathy and whether past criminal behavior is central to the condition has been published in the June issue of Psychological Assessment. The paper has privately circulated among forensic psychologists since 2007, but some of the explanation behind its publishing delay became evident last month when a commentary in International Journal of Forensic Mental Health made it a matter of public knowledge that forensic psychologist Robert Hare of the University of British Columbia,Vancouver, had threatened to file a defamation lawsuit against the authors and the journal's publisher. The Psychological Assessment article, by Jennifer Skeem, a forensic psychologist at the University of California, Irvine, and psychologist David Cooke of Glasgow Caledonian University, is critical of a widely used diagnostic tool developed by Hare called Psychopathy Checklist-Revised (PCL-R) and what the article labels as Hare's construct of psychopathy. Hare, however, saw a copy of the paper prepublication and took exception to Skeem and Cooke's portrayal of PCL-R, his work, and his writings. On 8 November 2007, lawyers representing Hare sent an e-mail to the American Psychological Association (APA), Skeem, and Cooke threatening a defamation lawsuit. "In 40 years, I've engaged in some heated academic debates, but in the journals. This time was different because it had little to do with scientific/academic discourse and everything with taking unwarranted shots at me as a straw man," Hare says. © 2010 American Association for the Advancement of Science.

Keyword: Aggression
Link ID: 14169 - Posted: 06.24.2010

By THE NEW YORK TIMES Dozens of readers had questions about Tourette’s syndrome, the odd and poorly understand disorder that causes uncontrollable tics and vocalizations, after the disorder was profiled in a recent Patient Voices series. Here, Dr. Robert A. King and Dr. James F. Leckman of Yale School of Medicine respond to readers wondering whether Tourette’s is inherited and how common the disorder is. Is Tourette’s Inherited? My daughter is engaged to someone with Tourette’s. I worry about their children inheriting Tourette’s. What is the likelihood of that occurring? Anonymous, San Francisco Dr. King and Dr. Leckman respond: Tourette’s likely has genetic determinants, but they may vary from family to family. When a parent has Tourette’s, sons have a higher risk of inheriting the condition than daughters. On average, about 20 percent of male offspring will have Tourette’s, compared to only about 5 percent of female offspring. The rates for a chronic motor tic disorder are a bit higher: 30 percent of the sons and about 9 percent of the daughters will have such a condition. In contrast, the rates are reversed for obsessive-compulsive disorder, or O.C.D., which sometimes accompanies Tourette’s, with 7 percent of sons and 15 percent of daughters developing symptoms of O.C.D. These are all approximate figures. Copyright 2010 The New York Times Company

Keyword: Tourettes
Link ID: 14168 - Posted: 06.24.2010

By Ferris Jabr NEW YORK—When it comes to brain power, we humans like to think we're the animal kingdom's undisputed champions. But in the past few decades we've had to make a lot of room on our mantle place for shared trophies. Problem-solving? Sorry, but crows and octopuses do that too. Tool use? Primates, birds and even fish have learned that trick. It turns out our human cognitive abilities are just not as unique as we once thought. The collapsing divisions between animal and human minds is exactly what a group of scientists gathered to discuss on Saturday, June 5, at a World Science Festival panel, "All Creatures Great and Smart." WNYC radio host Jad Abumrad mediated the talk. The first topic of conversation was a behavior known as altruism: selflessly helping a stranger. Brian Hare, who studies ape psychology at Duke University, described a recent experiment on this kind of cooperation in bonobos—primates that are in the same genus as chimpanzees. "We wanted to challenge that notion that humans are unique and test whether one of our closest relatives is capable of voluntarily sharing," Hare said. In the study, published earlier this year in Current Biology, researchers showed a bonobo into a room with some food inside. Instead of hogging all the grub, the bonobo consistently chose to unlock the door of an adjacent room and share the food with an unfamiliar bonobo. © 2010 Scientific American,

Keyword: Evolution
Link ID: 14167 - Posted: 06.24.2010

By Katherine Harmon When the body does not properly manage insulin levels, diabetes and other metabolic disorders are familiar outcomes. That hormonal imbalance, however, has also been linked to a higher risk for psychiatric disorders, such as schizophrenia. And a new study has uncovered a potential pathway by which this metabolic hormone can upset the balance of a key neurotransmitter. "We know that people with diabetes have an increased incidence of mood and other psychiatric disorders," Kevin Niswender, an endocrinologist at Vanderbilt University Medical Center and coauthor of the study, said in a prepared statement. Previous researchers, including Aurelio Galli, a neurobiologist at Vanderbilt, had found that insulin was affecting more than blood sugar levels. "Something goes wrong in the brain because insulin isn't signaling the way that it normally does," Galli, a coauthor of the new paper, published online June 8 in the journal PLoS Biology, said in a prepared statement. Although schizophrenia is a complex disease that is thought to have a variety of individual genetic and epigenetic causes, these researchers and others have proposed that a common thread is too little dopamine, a neurotransmitter that is involved in movement, reward and motivation. But just how, molecularly, insulin and dopamine dysfunctions might be linked has yet to be settled. © 2010 Scientific American,

Keyword: Schizophrenia
Link ID: 14166 - Posted: 06.24.2010

By Katherine Harmon Premature infants have a known higher risk for poor neurological development, often leading to developmental and educational issues. However, these babies, born before 37 weeks, make up a small number of any generation, and new research shows that the 40 percent of babies born any more than a week before a full 40-week term are also at higher risk for having special education needs during childhood. By analyzing the 2005 Scottish school census of 407,503 children and national birth records, researchers found that risk for special education needs steadily decreased with gestation duration all the way to 40 and 41 weeks—even though babies born between 37 weeks and 41 weeks are considered "at term." For the survey, special education needs included learning disabilities (such as autism, attention deficit hyperactivity disorder, dyslexia and others) and physical disabilities that can impair learning. The findings were published online June 8 in PLoS Medicine. "The tendency of most previous studies to treat gestation as a binary factor (preterm versus term) has masked a dose-effect across the whole range of gestation," noted the researchers, led by Daniel MacKay, of the University of Glasgow's Section of Public Health. And the sheer number of children who were born before 40 weeks (but after 37 weeks) mean that they constitute a greater percentage of special education children. Whereas preterm births accounted for about 5 percent of deliveries, they made up 3.5 percent of children needing special education. After adjusting for other factors, such as maternal demographics and mode of delivery, early term infants (delivered between 37 weeks and 39 weeks), had a 5.3 percent higher risk (than full term babies) for needing special education later. © 2010 Scientific American,

Keyword: Development of the Brain
Link ID: 14165 - Posted: 06.24.2010

by Ewen Callaway You spend more time window shopping than you may realise. Whether someone intends to buy a product or not can be predicted from their brain activity – even when they are not consciously pondering their choices. The ability to predict from brain scans alone what a person intends to buy, while leaving the potential buyer none the wiser, could bring much-needed rigour to efforts to meld marketing and neuroscience, says Brian Knutson, a neuroscientist at Stanford University in California who was not involved in the research. NeuromarketingMovie Camera, as this field is known, has been employed by drug firms, Hollywood studios and even the Campbell Soup Company to sell their wares, despite little published proof of its effectiveness. Rather than soup, John-Dylan Haynes at the Bernstein Center for Computational Neuroscience in Berlin, Germany, attempted to predict which cars people might unconsciously favour. To do so, he and colleague Anita Tusche used functional MRI to scan the brains of two groups of male volunteers, aged 24 to 32, while they were presented with images of a variety of cars. One group was asked to rate their impressions of the vehicles, while the second performed a distracting visual task while cars were presented in the background. Each volunteer was then shown three cars and asked which they would prefer to buy. © Copyright Reed Business Information Ltd.

Keyword: Emotions; Brain imaging
Link ID: 14164 - Posted: 06.24.2010

by Carlin Flora; Depression is a chemical imbalance, most people think. Researchers, drug manufacturers, and even the Food and Drug Administration assert that antidepressants work by “normalizing” levels of brain neurotransmitters—chemical messengers such as serotonin. And yet hard science supporting this idea is quite poor, says Irving Kirsch, professor of psychology at the University of Hull in the U.K. An expert on the placebo effect, Kirsch has unearthed evidence that antidepressants do not correct brain chemistry gone awry. More important, the drugs are not much more effective against depression than are sugar pills, he says. To support these controversial claims, Kirsch conducted a meta-analysis, digging up data from unpublished clinical trials. When all the evidence is weighed together, Prozac, Paxil, and other such popular pills seem to be at best weakly effective against depression—an argument Kirsch presses in his new book, The Emperor’s New Drugs. Some other research backs up his claims. A study published this winter in the Journal of the American Medical Association found that psychoactive drugs are no better than placebos for people suffering from mild to moderate depression. Where did the idea of depression as a chemical imbalance come from?
 The initial two drugs, imipramine and iproniazid, that were discovered and promoted as effective antidepressants both seemed to increase the amount of serotonin in the brain. It was discovered afterward that one of them seemed to block the reabsorption of serotonin, leaving it to linger longer at cell receptors, and the other blocked the destruction of the serotonin neurotransmitters in the synapses in the brain.

Keyword: Depression
Link ID: 14163 - Posted: 06.24.2010

by Jennifer Couzin-Frankel A new study of nearly 1000 people with autism has confirmed that the genetics of the disease are much more idiosyncratic than some had thought. Rather than a few genes that raise the risk of autism throughout the population, scientists are finding dozens of genes that spur disease, many of them in just one or two people. It appears that these variants do share certain characteristics, however: Many play a role in cell proliferation and cell signaling in the brain. Although scientists are heartened by this new map of autism genetics, they also say that they have a long road ahead in discerning how these genetic changes cause this particular disease. Over the past few years, researchers studying autism and schizophrenia have found that the genomes of patients with one or the other are riddled with so-called copy-number variants: deletions or duplications of stretches of DNA that can encompass many genes. Indeed, the most dramatic of these copy-number variants are even visible with a microscope, as abnormalities in the chromosomes of children afflicted with undiagnosed intellectual disabilities. Some of these disease-causing changes happen spontaneously during embryonic development, whereas others are inherited. The latest study, published online today in Nature, is the second phase of the Autism Genome Project consortium, which comprises more than 120 scientists in 11 countries in North America and Europe. (The first, published in 2007 in Nature Genetics, was a broad analysis of gene changes and copy-number variation, with fewer families and less detailed analysis of rare copy-number variants.) Here the scientists scanned the genomes of 996 children with autism-spectrum disorders, a group of conditions that affect social and communication skills, at high resolution and compared them with the genomes of the children's parents and to 1287 people without the disease. © 2010 American Association for the Advancement of Science.

Keyword: Autism; Genes & Behavior
Link ID: 14162 - Posted: 06.24.2010

By NICHOLAS WADE The glue that binds a human society together is trust. But people who trust others too much are likely to get taken for a ride. Both trust and distrust, it now seems, are influenced by hormones that can induce people to ratchet their feeling of trust up or down. The trust side of the equation is mediated by a brain hormone known as oxytocin. A soft touch or caress will send a pulse of oxytocin into a person’s bloodstream. Swiss researchers found in 2005 that a squirt of oxytocin would make players in an investment game more willing to hand over their money to strangers. It may seem strange that there is a hormonal influence in such a delicate calculation as to whether or not to trust someone. But perhaps trust is so important to a society’s survival that natural selection has generated a hormonal basis for it. In any event, trust has a downside — one may hand over too much money to a Mr. Madoff who promises to generate steady returns in both up and down markets. There needs to be an antidote to oxytocin that makes a person keep those warm, fuzzy feelings suppressed in the appropriate circumstances. Researchers at Utrecht University in Holland now report that they have identified this antidote: it is testosterone. They gave young women a dose of the hormone in the form of a drop of liquid placed under the tongue, then asked them to judge the trustworthiness of a series of men’s faces shown in photographs. The women were significantly less inclined to trust a face when given testosterone than when they had taken a placebo, the Dutch team reported last month in The Proceedings of the National Academy of Sciences. Copyright 2010 The New York Times Company

Keyword: Hormones & Behavior
Link ID: 14161 - Posted: 06.24.2010

By Katherine Harmon Veterans of war have been known to suffer from high incidence of post-traumatic stress disorder (PTSD), depression and traumatic brain injury in addition to any physical wounds. And a new study of thousands of U.S. Army soldiers returning from combat duty in Iraq found up to 31 percent reported symptoms of PTSD or depression as long as a year after returning from the battlefield. Between 2004 and 2007, 18,305 soldiers returning from Active Component and National Guard infantry brigade combat teams completed surveys that screened for PTSD, depression and other trends, such as alcohol abuse, aggression and general difficulties getting along in civilian life, three months and a year after the soldiers returned from deployment in Iraq. Based on general definitions of the disorders, the researchers found that 20.7 percent to 30.5 percent of soldiers met the criteria for PTSD, and 11.5 percent to 16 percent met the criteria for depression. And "using the strictest definitions with high symptom rates and serious functional impairment," the authors found up to 11.3 percent of soldiers had PTSD and up to 8.5 percent suffered from depression. Between 8.5 percent and 14 percent of soldiers reported "serious functional impairment" due to their symptoms, the authors noted in their study, which was led by Jeffrey Thomas, of the Division of Psychiatry and Neuroscience at Walter Reed Army Institute of Research, and published online June 7 in Archives of General Psychiatry. © 2010 Scientific American,

Keyword: Stress
Link ID: 14160 - Posted: 06.24.2010

By Ferris Jabr Our eyes swivel restlessly in their sockets during rapid eye movement (REM) sleep, an aptly named period of intense dreaming that makes up 20 to 25 percent of total sleep time. Whether this fidgeting is random or serves a function has never been clear, but a new study suggests that our eyes shift their gaze to fixate on the imagined people, places and actions in our sleep dreamscape. In other words, the movements of dreaming eyes mimic those of waking eyes. For more than 50 years neuroscientists have debated the reasons for REM during sleep, proposing all kinds of ideas: the eyes roll around to lubricate the inside of the eyelids; jiggling eyes warm the brain; eyes twitch randomly in response to stimulation from the brain stem. According to a study in the June issue of Brain, the most likely explanation is the "scanning hypothesis," which says that throughout REM sleep our eyes orient their gaze to scan the imagery of our dreams—just as eyes change their gaze in response to our environment when we're awake and moving around. But how do researchers know where someone is looking while they dream? And how do they test whether that has anything to do with what someone is dreaming about? In the study neuroscientists at Pitié-Salpêtrière Hospital in Paris turned to a unique group of subjects: individuals with REM sleep behavior disorder (RBD). During REM sleep, the limb muscles of most people enter a state of temporary paralysis that prevents any flailing about. People with RBD do not go into sleep paralysis and physically act out their dreams—often with dramatic and violent actions: They kick, scream, grab, reach, climb and jump, both in their dreams and in reality, allowing researchers to observe what normally remains inside a dreamer's head. © 2010 Scientific American,

Keyword: Sleep; Vision
Link ID: 14159 - Posted: 06.24.2010

By Bruce Bower Where there’s secondhand cigarette smoke, there’s emotional fire. As exposure to cigarette fumes increases among nonsmokers, so does their risk of developing serious psychological distress and of being hospitalized for mental ailments, a new study finds. Cigarette smokers have been shown to have more psychological problems than nonsmokers do, and new evidence suggests that nonsmokers who inhale high levels of secondhand smoke may experience nearly as much psychological distress as smokers, say epidemiologist Mark Hamer of University College London and his colleagues. Overall, these findings support the view, largely based on animal studies, that nicotine administered in large enough doses can induce sadness and other negative moods, the researchers propose in the August Archives of General Psychiatry. “Our data are preliminary, but there is a strong possibility that the observed association reflects a causal link,” Hamer says. Previous research suggests that nicotine alters mood by disrupting immune responses, stress-hormone regulation and the transmission of dopamine, a chemical messenger in the brain. But little is known about nicotine’s possible relationship to specific psychiatric disorders. The link between nicotine exposure and mood held up after statistically accounting for participants’ social status, alcohol use, physical activity level, body mass index, chronic physical illness, level of psychological distress upon entering the study and previous hospitalizations for mental illness. © Society for Science & the Public 2000 - 2010

Keyword: Drug Abuse; Stress
Link ID: 14158 - Posted: 06.24.2010

by Linda Geddes Children with autism appear to have a characteristic chemical signature in their urine which might form the basis of an early diagnostic test for the condition. The finding also adds weight the hypothesis that substances released by gut bacteria are contributing to the onset of the condition. Autism has previously been linked to metabolic abnormalities and gastrointestinal problems such as gut pain and diarrhoea. Several studies have also hinted at changes in gut bacteria in the faeces of children with autism. To investigate whether signs of these metabolic changes might be detectable in children's urine, Jeremy Nicholson and colleagues at Imperial College London investigated 39 children with autism, 28 of their non-autistic siblings and 34 unrelated children. Using nuclear magnetic resonance (NMR) spectroscopy to analyse the children's urine, they found that each of these groups had a distinct chemical fingerprint, with clear and significant differences between children with autism and unrelated controls. "The signature that comes up is related to gut bacteria," says Nicholson. It is not yet clear whether the bacteria's metabolic products contribute to the development of autism, but it is a possibility worth investigating, he adds. A large proportion of autistic children have severe gastrointestinal problems that tend to appear at about the same time as the behavioural symptoms. © Copyright Reed Business Information Ltd.

Keyword: Autism
Link ID: 14157 - Posted: 06.24.2010

by Jim Giles The children of lesbian parents outscore their peers on academic and social tests, according to results from the longest-running study of same-sex families. The researchers behind the National Longitudinal Lesbian Family Study say the results should change attitudes to adoption of children by gay and lesbian couples, which is prohibited in some parts of the US. The finding is based on 78 children who were all born to lesbian couples who used donor insemination to become pregnant and were interviewed and tested at age 17. The new tests have left no doubt as to the success of these couples as parents, says Nanette Gartrell at the University of California, San Francisco, who has worked on the study since it began in 1986. Compared with a group of control adolescents born to heterosexual parents with similar educational and financial backgrounds, the children of lesbian couples scored better on academic and social tests and lower on measures of rule-breaking and aggression. A previous study of same-sex parenting, based on long-term health data, also found no difference in the health of children in either group. "This confirms what most developmental scientists have suspected," says Stephen Russell, a sociologist at the University of Arizona in Tucson. "Kids growing up with same-sex parents fare just as well as other kids." © Copyright Reed Business Information Ltd.

Keyword: Development of the Brain; Sexual Behavior
Link ID: 14156 - Posted: 06.24.2010

Answered by: Professor Andrew Smith Caffeine – 1,3,7-trimethylxanthine, to give it its chemical name – is a member of a group of naturally occurring substances called methylxanthines. These compounds are similar in structure to adenosines, naturally occurring molecules in our bodies which aid the onset of sleep. In its natural context, which is in tea and coffee plants, caffeine can kill or paralyse insects and is thus an effective natural pesticide. The earliest recorded caffeine consumers were in China in the 10th century BC, when philosophers believed tea-drinking was "an indispensable ingredient to the elixir of life". Coffee-quaffing originated in Yemen in the 15th century. The exact amount of caffeine present in a drink depends on its growing conditions and preparation. While tea naturally has more caffeine gramme for gramme than coffee, there is less tea per cubic centimetre of cup, leading to its weaker stimulant properties. For the record, in a 5oz cup of filter coffee, there is between 100mg and 150mg of caffeine. The same sized serving of tea holds 35-45mg. Meanwhile, a 12oz serving of cola contains just 40mg. Doctors say at least 100mg is necessary to properly increase our alertness. (A study published by Bristol University last week argued that caffeine can't make irregular users more alert; a cup of coffee in the morning, the research suggested, only counteracts the effects of withdrawal that have built up overnight.) How does it work? Adenosine bonds to receptor cells in the brain to calm the activity of the central nervous system, thus triggering tiredness. There is also evidence to suggest that it decreases blood flow in the brain. Caffeine molecules bind to these receptor cells but have no active effect on the nervous system. However by doing so they take the place of adenosine molecules that could make a difference. This process is known as "competitive inhibition" and effectively delays the onset of fatigue, increases alertness and improves people's ability to sustain attention. ©independent.co.uk

Keyword: Attention; Drug Abuse
Link ID: 14155 - Posted: 06.24.2010

Amy Maxmen A leading antipsychotic drug temporarily reduces the size of a brain region that controls movement and coordination, causing distressing side effects such as shaking, drooling and restless leg syndrome. Just two hours after injection with haloperidol, an antipsychotic commonly prescribed to treat schizophrenia, healthy volunteers experienced impaired motor abilities that coincided with diminished grey-matter volume in the striatum — a brain region that mediates movement. "We've seen changes in the brain before, but to see significant remodelling of the striatum within a couple of hours is staggering," says Clare Parish at the Howard Florey Institute for brain research in Melbourne, Australia, who was not involved in the study. "Our viewpoint was that only chemical changes would happen in such a short time." In functional magnetic resolution imaging (fMRI) scans the authors observed the participants' striatal volume diminishing and changes to the structure of the motor circuitry in their brains. Further, their reaction times slowed in a computer test taken after the treatment, indicating the onset of lapses in motor control that affect many patients on antipsychotics. © 2010 Nature Publishing Group,

Keyword: Schizophrenia; Brain imaging
Link ID: 14154 - Posted: 06.24.2010