Pediatric researchers at Yale School of Medicine have identified a gene on human chromosome 6 called DCDC2, which is linked to dyslexia, a reading disability affecting millions of children and adults. The researchers also found that a genetic alteration in DCDC2 leads to a disruption in the formation of brain circuits that make it possible to read. This genetic alteration is transmitted within families. "These promising results now have the potential to lead to improved diagnostic methods to identify dyslexia and deepens understanding of how the reading process works on a molecular level," said lead author Jeffrey R. Gruen, M.D., associate professor in the Pediatrics Department at Yale School of Medicine. The study will be published in a special issue of Proceedings of the National Academy of Sciences on October 28. Gruen and first author Haiying Meng will also present the findings that same day at the American Society of Human Genetics (ASHG) meeting in Salt Lake City, Utah. Gruen and co-authors used a statistical approach to study and compare specific DNA markers in 153 dyslexic families. "We now have strong statistical evidence that a large number of dyslexic cases--perhaps as many as 20 percent--are due to the DCDC2 gene," said Gruen. "The genetic alteration on this chromosome is a large deletion of a regulatory region. The gene itself is expressed in reading centers of the brain where it modulates migration of neurons. This very architecture of the brain circuitry is necessary for normal reading."

Keyword: Dyslexia; Genes & Behavior
Link ID: 8083 - Posted: 10.29.2005

The daily routines of one in ten American in Vermont, Alaska, Maine and other northern states will change for the worse on Oct. 30. The alterations start every year around October just after the end of daylight savings time. For most, the clock shift just adds an hour to the weekend -- but for sufferers of seasonal affective disorder, a syndrome involving recurring bouts of depression during fall and winter months, it marks the beginning of a difficult time of year when many forgo an after-work run for a nap, watch television instead of walk the dog, or sleep later in the morning. With this year's turning back of the clock, the 14.5 million Americans susceptible to SAD may begin feeling fatigued, worthless, disinterested, even suicidal. Many will receive treatment involving sitting in front of a light box for an hour or two a day in hopes that the white fluorescent or full-spectrum light will simulate sunlight and make them feel better. The treatment works reasonably well but is hard to stick with, so Kelly Rohan, a SAD expert and assistant professor of psychology at the University of Vermont, views it as more a quick fix than long-term solution.

Keyword: Depression; Biological Rhythms
Link ID: 8082 - Posted: 10.28.2005

By Jennifer Viegas, Discovery News — People pay more attention to body language than to facial expressions, even when observers are trying to focus on faces, according to a new study. The finding, published in this week's Proceedings of the National Academy of Sciences, suggests that interpretation of body language happens without conscious awareness. This instantaneous response also works like a silent alarm system in the brain whenever facial expressions do not match up properly to the individual's body language. The "alarm" is a message in the brain of the onlooker that something is not right with the other person. "The information from body language and its coherence with the facial expression are apprehended rapidly (along with) the assurance that we can trust our gut feeling when we feel somebody 'feels' funny," explained Beatrice de Gelder, one of the study's authors. © 2005 Discovery Communications Inc.

Keyword: Language
Link ID: 8081 - Posted: 06.24.2010

Tom Simonite "It's a small world," we say when a new acquaintance turns out to be linked to several other people we know. It happens surprisingly often. And it seems it happens even more to Scottish dolphins than it does to people. David Lusseau, from the University of Aberdeen, UK, has spent years researching the social world of dolphins, to find out who knows whom and how often they meet. For the 130-strong community living off the east coast of Scotland, he found, it takes an average of just 3.9 steps to link any two dolphins by the shortest possible route through mutual friends. Small-world networks, as mathematicians call them, have the property that any 'node', such as an individual person or dolphin, is connected to every other node through a limited number of steps. This is a result of the way that nodes are organised: most people, for example, have a cluster of close friends but also know a few people from different clusters. This means that connecting any two apparently widely separated people is surprising easy. Researchers have shown it takes about five-and-a-half steps, on average, to get between any two individuals in the world1. This fact is famous for inspiring the play Six Degrees of Separation, by John Guare, and the game 'six degrees of Kevin Bacon', which challenges players to link a given Hollywood actor to the star through a limited number of shared film appearances (see "My friend Flipper"). ©2005 Nature Publishing Group

Keyword: Miscellaneous
Link ID: 8080 - Posted: 06.24.2010

Roxanne Khamsi An injection that stimulates the growth of new brain cells can cause mice to lose more than 15% of their body weight, researchers say. Experts hope that the treatment, which lasts for weeks, could eventually be made into weight-loss drugs for humans. The discovery was inspired by the unexpected side effects of a drug that was tested in the 1990s as a treatment for amyotrophic lateral sclerosis (ALS), also called Lou Gehrig's disease. The drug, called Axokine, did not improve muscle control as much as expected, but trial participants did report a loss of appetite. Biologists wondered whether this appetite-suppression effect could be harnessed to fight obesity. "People tried to turn lemons into lemonade and ask what such drugs could do for weight control," explains Jeffrey Flier of the Harvard Medical School in Boston, Massachusetts. The effect with Axokine itself did not yield particularly promising results. Axokine's maker, Regeneron, conducted clinical trials for the drug against obesity in 2003, and then abandoned the idea. But researchers realized that similar drugs might re-wire the brain's desire for food. ©2005 Nature Publishing Grou

Keyword: Obesity
Link ID: 8079 - Posted: 06.24.2010

Scientists are one step closer to unraveling the complex mechanisms in the brain that regulate body weight. Working with mice — whose appetites are controlled by systems very similar to those in humans - they have identified a specific type of neuron that is essential for feeding behavior. Without these neurons, adult mice stop eating and undergo rapid weight loss. Remarkably, the researchers found that absence of these neurons only influenced eating behavior when they were removed from adult mice. If the neurons were eliminated in newborn mice, their developing brains found a way to compensate for the deficiency, and the mice grew up eating normally. The research, conducted by Serge Luquet at the University of Washington in the laboratory of Howard Hughes Medical Institute investigator Richard D. Palmiter, will be published in the October 28, 2005 issue of the journal Science. The task of sorting out the body's diverse and sometimes conflicting signals about hunger and satiety falls to a small cluster of about 5,000 cells in a region of the brain known as the arcuate nucleus. Hormones such as insulin, leptin, and ghrelin deliver information to the arcuate nucleus about whether the body has sufficient calories and nutrients. The brain, in turn, uses this information to decide whether to eat or expend energy. Two types of neurons that recognize and respond to these signals are found in the arcuate nucleus. The first of these, known as POMC (pro-opiomelanocortin) neurons, send signals to other parts of the brain to reduce appetite. Mice with defects in POMC neurons eat excessively and become obese. © 2005 Howard Hughes Medical Institute

Keyword: Obesity
Link ID: 8078 - Posted: 06.24.2010

EVANSTON, Ill. --- French neurologist Jean-Martin Charcot first described amyotrophic lateral sclerosis (ALS) in 1869, but, nearly 140 years later, little is known about the cause of the devastating neurodegenerative disease, and there is no cure. What is known about Lou Gehrig's disease, as it is commonly called, is that misfolded and damaged proteins clump together in cells to form aggregates and motor neurons die. But scientists have long debated whether or not the protein aggregates actually kill the cells. Now a research team at Northwestern University, using mammalian neurons and live-cell time-lapse spectroscopy, has become the first to clearly link the presence of the ALS-associated mutant SOD1 protein aggregates with neuronal cell death. This evidence could help explain the disease process and eventually lead to new therapeutics. In the study, published this month in the Journal of Cell Biology, the scientists looked one at a time at neuronal cells expressing the mutant SOD1 protein and found that in cells where the protein accumulated and aggregates formed, 90 percent of the cells went on to die. (They died between six and 24 hours after aggregates were visually detected.) Cells that did not form aggregates did not die.

Keyword: ALS-Lou Gehrig's Disease
Link ID: 8077 - Posted: 10.27.2005

Is a bird in the hand really worth two in the bush? Depends whom you ask. A new study in monkeys suggests that decision-making in animals is more complex than previously thought. Patience is a puzzle. While it often pays to hold off just a bit longer, most animals will grab a small item of food rather than wait even a few seconds longer for a bigger one. But evolutionary theory predicts that all animals should do the smart thing and get the most out of the long term. So what's the hurry? Ecology can help answer the question. In a study published in April in Biology Letters, a team led by Jeff Stevens, a behavioral biologist at Harvard University in Cambridge, Massachusetts, demonstrated that marmosets will wait longer for a larger food reward than tamarins will. The researchers concluded that the explanation lies in the creatures' lifestyles: Marmosets chew on trees and wait patiently for sap to flow out, while tamarins impulsively grab insects. © 2005 by the American Association for the Advancement of Science.

Keyword: Learning & Memory; Drug Abuse
Link ID: 8076 - Posted: 06.24.2010

CHAMPAIGN, Ill. -- When it comes to focusing on a task amid distractions, some folks more than 60 years old are as mentally sharp as 22-year-olds. Others struggle. Researchers at the Beckman Institute for Advanced Science and Technology at the University of Illinois at Urbana-Champaign have shed some light on why that is. Reporting in the current issue (September) of the quarterly journal Psychology and Aging, the scientists say there is less white matter in the frontal lobes of those who struggle with focusing. The differences became apparent through the use of functional magnetic resonance (fMRI) imaging of the brains of 40 individuals ranging in age from 19 to 87. "We found that both performance and brain-activation differences of older good performers and the older poor performers are predicted by changes in brain structure, specifically by the volume of white matter connecting the right and left hemispheres of the frontal lobes," said Arthur F. Kramer, a professor of psychology. Participants took part in a "flanker" experiment in which they viewed a line of five keyboard arrows on a computer screen and reacted by pushing one of four buttons that corresponded with the direction the center arrow was pointing. Sometimes the participants would be distracted by changes in direction by arrows not in the center.

Keyword: Attention
Link ID: 8075 - Posted: 10.27.2005

Michael Hopkin You can tell a lot about someone from how they treat their friends. As the results of a study of captive chimpanzees seem to show, our ape cousins are only in it for themselves. The study, led by Joan Silk of the University of California, Los Angeles, looked for evidence that chimpanzees (Pan troglodytes) will help other members of their group. But the apes seem to be indifferent at best to the welfare of their fellows. Silk and her colleagues presented captive chimps with an apparatus that allowed them to get food by pulling on one of two ropes. Choosing one of the ropes meant that the chimp could haul in a tasty titbit. Selecting the other yielded exactly the same reward, but another chimp in an adjacent cage also received a morsel to eat. Given that the chimp in charge got the same food reward regardless of which rope was selected, one might expect them to have shown some compassion and chosen the one that gave food to their companion too. "All they had to do was be nice," Silk says. ©2005 Nature Publishing Group

Keyword: Evolution
Link ID: 8074 - Posted: 06.24.2010

For captive chimpanzees, friendship appears to run shallow. In a new behavioural study, chimps failed to lend a helping hand to unrelated animals from their own social group – even though they would have suffered no inconvenience by doing so. Researchers led by Joan Silk of the University California, Los Angeles, US, set captive chimps tests in which they obtained a food reward. They could choose either to gain a food reward for themselves, or for both themselves and another animal from their own group. In similar circumstances, people will help both friends and strangers – and may do so even if they incur a cost as a result. Behavioural scientists believe this is because people who are seen as being altruistic tend to get helped out more often themselves. When such tests are run with other people watching, experimental volunteers are especially generous. © Copyright Reed Business Information Ltd.

Keyword: Evolution
Link ID: 8073 - Posted: 06.24.2010

By Shankar Vedantam, Washington Post Staff Writer The government will back down from a plan to require long-term studies of new psychiatric drugs before allowing them on the market, regulators said yesterday. The reversal of the recently adopted policy came after a panel of experts unanimously recommended against requiring such studies as a condition of approval. While such studies are needed, the experts said, delaying decisions on new medications would hurt patients. The panel's vote came after it heard a barrage of complaints from industry executives, academic researchers and patient advocates. All the critics predicted that the policy would lead to delays in bringing new drugs to market while providing little new information that may not apply to most patients. They also warned that the policy would cause drug companies to scale back on developing new drugs because of the potential increase in expense and risk. The new plan, which the Food and Drug Administration had begun to implement over the past six months, called for companies to conduct studies for as long as half a year before seeking approval of new drugs. Like many other medications, psychiatric drugs are typically approved on the basis of positive results from two short-term studies, each of which may last only eight weeks. © 2005 The Washington Post Company

Keyword: Schizophrenia; Depression
Link ID: 8072 - Posted: 06.24.2010

First-ever images of living human retinas have yielded a surprise about how we perceive our world. Researchers at the University of Rochester have found that the number of color-sensitive cones in the human retina differs dramatically among people—by up to 40 times—yet people appear to perceive colors the same way. The findings, on the cover of this week's journal Neuroscience, strongly suggest that our perception of color is controlled much more by our brains than by our eyes. "We were able to precisely image and count the color-receptive cones in a living human eye for the first time, and we were astonished at the results," says David Williams, Allyn Professor of Medical Optics and director of the Center for Visual Science. "We've shown that color perception goes far beyond the hardware of the eye, and that leads to a lot of interesting questions about how and why we perceive color." Williams and his research team, led by postdoctoral student Heidi Hofer, now an assistant professor at the University of Houston, used a laser-based system developed by Williams that maps out the topography of the inner eye in exquisite detail. The technology, known as adaptive optics, was originally used by astronomers in telescopes to compensate for the blurring of starlight caused by the atmosphere.

Keyword: Vision
Link ID: 8071 - Posted: 06.24.2010

As we continue to live longer we are becoming more and more prone to age-related diseases such as the so-called big four: heart disease, cancer, diabetes and Alzheimer's disease or AD. Although an estimated 4.5 million Americans are believed to have AD, the only way to know for sure is with an autopsy. "Alzheimer's disease is a very difficult disorder to diagnose even in the late stages," explains Alzheimer's researcher Lee E. Goldstein from the Brigham and Women's Hospital and Harvard Medical School in Boston. "If were going to intervene early were going to have diagnose it early right now there is no good way to do that." Although we know a great deal about this disease, primarily from what genetics research has told us over the last ten years, what is needed is a biomarker or a "biological fingerprint" to help doctors spot the disease early. "We don't have good biomarkers for Alzheimer's disease: used not only for prediction and diagnosis, but also used for drug testing. If you want a way to screen to see how well the patient's doing beyond cognitive testing, if you want some kind of measure of whether the brain is being helped — using some kind of representative marker — we don't really have much in that way in Alzheimer's disease," says Goldstein's colleague from Massachusetts General Hospital and Harvard, Rudolph Tanzi, who was one of the geneticists to find the first disease-related genes. © ScienCentral, 2000-2005.

Keyword: Alzheimers; Vision
Link ID: 8070 - Posted: 06.24.2010

The hunt for genes implicated in schizophrenia has proven to be one of the most frustrating quests in psychiatry. But scientists are zeroing in on some important players, including a gene involved in breaking down the neurotransmitter dopamine. Now, a study of children missing a copy of that gene indicates that precise levels of dopamine are required for proper cognitive function. The COMT gene, originally identified in 1957, has become perhaps the most intensively studied of any in psychiatric genetics. The gene exists in two forms--a high-active and a low-active version, which causes less and more dopamine to accumulate in synapses, respectively. Individuals can have either two high-active or two low-active copies of the gene, or one of each. Studies have shown that people with a low-active pair, and thus relatively high levels of dopamine in the brain, are a little more efficient cognitively than people with two high-active versions. But if the levels are too far afield, the brain can be impaired. A team led by psychiatrist Doron Gothelf, a postdoctoral researcher at Stanford University in California, investigated this by studying individuals missing one copy of the COMT gene, a deletion that occurs in one out of every 4000 births. They followed 24 children with the deletion--called velo-cardial-facial syndrome, which impairs health and mental development. © 2005 by the American Association for the Advancement of Science.

Keyword: Schizophrenia; Genes & Behavior
Link ID: 8069 - Posted: 06.24.2010

ST. LOUIS -- Saint Louis University research shows a new class of drugs may hold promise in treating brain chemical problems such as Alzheimer's disease, says the principal investigator of research published in an early on-line version of Peptides. "We found that we can develop antisense – which is a molecular compound – to cross the blood brain barrier enough to alter brain function. This can have a profound effect on treating diseases that occur because there is too much or too little of a certain kind of protein in the brain," says William A. Banks, M.D., professor of geriatrics and pharmacological and physiological sciences at Saint Louis University and principal investigator. "The blood brain barrier is the Holy Grail – it's the most difficult tissue to pass through." The article will run in the April print issue of Peptides. Antisense molecules are very specific compounds that scientists can create to plug into genetic pathways and block certain genes from producing harmful proteins. Many scientists believe that overproduction of the amyloid beta protein in the brain causes Alzheimer's disease. Previous Saint Louis University research has found that scientists can develop antisense to cross the blood brain barrier and lower levels of amyloid beta protein in mice.

Keyword: Alzheimers
Link ID: 8068 - Posted: 06.24.2010

Zapping the brain with an electrical current could one day control high blood pressure in people, a new study suggests. UK researchers have shown for the first time that stimulating a certain part of the brain with implanted electrodes can influence arterial blood pressure in a predictable way in patients. Short bursts of electrical stimulation were applied in an area in the midbrain called the periaqueductal grey matter (PAG) in 15 awake patients. The patients had already had the deep brain electrodes fitted as a treatment for chronic pain. The stimulation lowered blood pressure in patients who had the electrodes near the front (or ventral) part of the PAG. In patients where the electrodes were near the back (or dorsal) part, blood pressure could be increased. “It’s very early days yet, but this is an exciting preliminary finding,” says Alexander Green, at the department of neurosurgery, Oxford University, UK, who believes the technique has great potential. But he cautions that the surgery to place the electrodes in the brain carries a one in 300 risk of stroke. For patients receiving the implants to treat severe conditions such as Parkinson’s disease, the risk may be acceptable. But that is currently far from the case for patients with blood pressure problems. © Copyright Reed Business Information Ltd.

Keyword: Stress
Link ID: 8067 - Posted: 06.24.2010

By JANE E. BRODY Helen's friend was alarmed. She had called Helen at 9 in the morning and found her speech slow and slurred. So the friend asked a neighbor to go immediately to Helen's apartment in Brooklyn to check on her. It took a long time for Helen to respond to the doorbell. When she finally opened the door, the neighbor, too, was alarmed: Helen was getting dressed but she had left the shower running. Her movements were awkward, as if half her body was not functioning properly. The neighbor called Helen's doctor, who said she should be taken to the hospital without delay. Helen remembers none of this. After testing her from head to toe, the doctors concluded that Helen had had a T.I.A. - a transient ischemic attack, commonly called a mini-stroke, in which the blood supply to part of the brain is cut off for a brief period, in Helen's case, her friends estimate, for about 20 minutes. Though T.I.A.'s leave no residual effects detectable by the patient or by sophisticated medical tests, they can portend a major stroke. As a result, it is critically important for someone with such an attack to get prompt medical attention and treatment - often something as simple as a daily aspirin - to prevent a far more serious blockage to the brain. Copyright 2005 The New York Times Company

Keyword: Stroke
Link ID: 8066 - Posted: 10.25.2005

By LAURIE TARKAN When Sara Martinez noticed her memory slipping, it seemed an especially cruel turn of events. "I've always had an excellent memory. It was my claim to fame," said Ms. Martinez, 57. "Now, I forget people's names, I forget appointments, I forget scenes from the opera." A readout of an electroencephalograph, which monitors brain waves, and is being tested as a way to look for signs of Alzheimer's disease. Ms. Martinez, who lives in New York, said she was also worried about her future. Her father died of a dementia that she believes was Alzheimer's disease; her mother, still living, has lost her memory to a disorder called vascular dementia. So when a friend told her about a study at New York University that uses an electroencephalograph to monitor brain waves and predict who will get Alzheimer's, Ms. Martinez enrolled. Buoyed by preliminary reports of early detection tests for Alzheimer's, an increasing number of people, worried about their family history or their own forgetfulness, are seeking clues about their mental fate. A wide variety of detection methods are being studied, including the EEG, sophisticated brain-scanning techniques, paper-and-pencil neuropsychological tests, genetic tests and even scratch-and-sniff tests. Copyright 2005 The New York Times Company

Keyword: Alzheimers
Link ID: 8065 - Posted: 10.25.2005

Scientists have discovered that schizophrenia sufferers are not fooled by a visual illusion and are able to judge it more accurately than non-schizophrenic observers. The study by UCL (University College London) and King's College London suggests that in everyday life, schizophrenics take less account of visual context. If this is part of a more general failure to deal appropriately with context, it could explain why some sufferers might misattribute people's actions or feel persecuted. The study, published in the journal Current Biology, used an illusion where an object's contrast appears reduced by its surroundings. A medium-contrast patterned disc was shown to volunteers, who had to judge its appearance in the presence of a high-contrast background. Of the 15 participants with chronic schizophrenia, 12 were found to make more accurate judgments than the most accurate person in a control group of 33 non-schizophrenic volunteers. Dr Steven Dakin, of the UCL Institute of Ophthalmology, says: "We often think of people with schizophrenia as not seeing the world the way it really is – for example, during hallucinations – but we have shown that sometimes their vision can be more accurate than non-sufferers.

Keyword: Schizophrenia; Vision
Link ID: 8064 - Posted: 06.24.2010