By BENEDICT CAREY Scientists studying depression reported yesterday that they had found evidence that a common genetic variation affecting how people manage stress predicts how much benefit they get from taking antidepressants. Psychiatrists have long known that about half the people found to be suffering from depression also show signs of elevated anxiety. Researchers have tried to explain the correlation, as well as why the same drugs can relieve both conditions. In the new study, published in the journal Molecular Psychiatry, doctors from Harvard and the University of California, Los Angeles, treated with drugs a group of 54 Mexican-Americans in Los Angeles who were both depressed and highly anxious. (Limiting the study to one demographic group was a control tool.) They found that 60 percent of the group had a common genetic variant that helps govern the body's response to stress. The researchers found that after being treated with antidepressants, patients with the genetic variation were far less anxious and depressed than when they began the study, said the lead author, Dr. Julio Licinio of the Neuropsychiatric Institute of the University of California. Copyright 2004 The New York Times Company

Keyword: Depression; Genes & Behavior
Link ID: 6605 - Posted: 12.17.2004

SINGAPORE--Fears that escapee zebrafish, genetically engineered to glow in fluorescent color, would interbreed with their drab brethren in the wild, may be unfounded. A study presented at the Biology in Asia conference here last week suggests that the mutant fish don't shine with sex appeal. The zebrafish Danio rerio, native to streams in southern Asia, is normally silvery-grey with dark stripes. But in the 1990s, scientists in Taiwan and Singapore genetically modified strains with genes from jellyfish and anemones, giving the fish a green or red "glow" under UV or even visible light. Originally developed to aid in the detection of water pollutants (with a switch gene added, the fish would glow whenever the target pollutant was in the water), these and similar fish have been popular in the aquarium trade in the U.S. since late last year, with the red variety marketed under the name GloFishTM. But environmentalists have expressed concern that the modified fish will escape and interbreed with wild zebrafish, particularly in their native tropical Asia. Wee-Khee Seah, Zhiyuan Gong, and Daiqin Li of the National University of Singapore made aquariums where a normal or green fluorescent zebrafish female would be confronted with the choice between a normal and a glowing green male behind glass. They found that both types of female spent more than 80% of their time with their noses glued to the glass of the unaltered males' compartments, with the green males jealously courting in vain. Copyright © 2004 by the American Association for the Advancement of Science.

Keyword: Sexual Behavior
Link ID: 6604 - Posted: 06.24.2010

COLUMBUS, Ohio -- New research provides the strongest evidence to date that infants and young children – unlike adults -- are more drawn to sounds than they are to visuals in their environment. In fact, when 4-year-olds are presented with sounds and pictures at the same time and told to pay particular attention to the pictures, they can’t – the sounds dominate their attention. “We found that sounds are dominant over visuals from infancy, and only slowly through childhood do visuals become more important,” said Vladimir Sloutsky, professor in the Center for Cognitive Science at Ohio State University. “The younger the children are, the more dominant their auditory system seems to be.” Earlier work by Sloutsky and his colleagues also showed this preference for sounds over visuals among children. But this new research offers a clearer picture of the nature of this auditory preference and how it changes over time.

Keyword: Hearing; Development of the Brain
Link ID: 6603 - Posted: 06.24.2010

Roxanne Khamsi Mice living in exciting environments still produce reliable and reproducible results when used in scientific experiments, according to a new study. The finding suggests that researchers could offer their lab animals more interesting surroundings. Previous work has shown that mice living in standard, barren cages may suffer greater stress or exhibit abnormal repetitive behaviours1. This uninspired housing has caused concerns over animal welfare, and the validity of experiments. Stress, for example, is known to interfere with learning and memory, as well as the immune system. But regardless of this, scientists have hesitated to add exciting elements to mouse cages for fear that doing so would influence the precision and reproducibility of test results. Although the reluctance is widespread, not everyone believes in this logic. "There have been no data substantiating these fears," says Hanno Würbel, an ethologist at the University of Giessen in Germany. He and a team of researchers decided to investigate whether enriched cage environments compromised experimental outcomes. ©2004 Nature Publishing Group

Keyword: Animal Rights
Link ID: 6602 - Posted: 06.24.2010

WASHINGTON (Reuters) - People's brains react to a photograph of a frightened face, even when it is flashed on a screen too quickly to be consciously recognized, U.S. researchers said on Wednesday. The team at Columbia University in New York found responses in the amygdala, the part of the brain associated with emotional responses, as well as the attention and vision regions of the cerebral cortex. "What we think we've identified is a circuit in the brain that's responsible for enhancing the processing of unconsciously detected threats in anxious people," said Amit Etkin, who led the study. "Our study shows that there's a very important role for unconscious emotions in anxiety," Etkin said. Many studies have shown people register subliminal images -- those flashed on a screen too quickly to be noticed consciously. Writing in the journal Neuron, the researchers said they used high-resolution functional magnetic resonance imaging, a way of scanning brain activity in real time, on 17 undergraduate university students. While the volunteers were looking at a computer, the researchers displayed a fearful face on the monitor for 33 milliseconds, immediately followed by a similar neutral face. Copyright © 2004 Reuters Limited. Copyright © 2004 Yahoo! Inc.

Keyword: Emotions
Link ID: 6601 - Posted: 06.24.2010

Sparrows can piece together a complete song by only hearing parts of it, scientists have found. The findings could help researchers establish how memory works in humans, especially in relation to how we learn languages. Professor Gary Rose, of the University of Utah, US, found that white crown sparrows learned a complete song, in the correct order, despite only ever hearing overlapping segments of it. It is hoped that working in this way with groups of young sparrows will shed light on the mechanisms of memory and learning. "The experiment was set up to determine whether or not birds could produce a normal song, having only heard components of the song - having never heard the whole song," Dr Rose told the BBC World Service. "That was to test something specific with respect to the representation of the memory of the song - is the memory a full account of a song in its normal cadence, or is the memory little bits of snippets?" he said on the Science In Action programme. Dr Rose taught the birds by playing back segments of the song twice a day. He took the original song - recorded from a sparrow in the field - and used a computer to fragment it. When played back, each bird was acoustically isolated from the others. "It wouldn't have been of much interest if they couldn't put it together - but they did," he said. "Our hypothesis was that if we provided information about the linkages between phrases... then the birds could potentially use that information to reconstruct the song." Each segment ended with an overlap to the beginning of the next. This overlap was the information the sparrows needed to piece the song together. (C)BBC

Keyword: Hearing; Language
Link ID: 6600 - Posted: 12.16.2004

By ANDREW POLLACK The Food and Drug Administration has approved a new sleeping pill that some specialists say could pave the way for longer-term use of such medications. The drug, developed by Sepracor, a pharmaceutical company in Marlborough, Mass., will be called Lunesta. It had been called Estorra during its development, but the F.D.A. deemed that name too similar to that of another drug. Spokesmen for the company and the F.D.A. confirmed the approval last night. The F.D.A. now recommends that sleeping pills be used for no longer than 7 to 10 days. That is because there are concerns that the pills can lose effectiveness over time or become addictive. But Sepracor had participants in a clinical trial take Lunesta for six months and found that it did not lose its effectiveness and remained generally safe. David Southwell, Sepracor's chief financial officer, said in an interview yesterday, before the company had received its approval, that the drug's label would not contain the usual language about restricting use to 7 to 10 days. If that were the case, doctors would be more willing to prescribe Lunesta for longer periods, doctors said. Copyright 2004 The New York Times Company

Keyword: Sleep
Link ID: 6599 - Posted: 12.16.2004

Researchers have known that mutations in a key gene called parkin are a major cause of Parkinson's disease (PD). Now they have discovered a new mechanism by which the parkin gene can be compromised, a finding that they say could lead to new drugs for the disorder. Andrea Lozano, Senior Scientist at the Toronto Western Research Institute, of University Health Network and Professor of Surgery at the University of Toronto and colleagues found that the protein produced by a gene called BAG5 inhibits parkin activity and the action of another protein, called Hsp70, a "chaperone" that works with parkin. They found in studies with rats that BAG5 enhances the death of the dopaminergic neurons targeted by Parkinson's and that inhibiting the gene reduces such death. Parkin is part of the cell's "garbage disposal" system that rids the cell of unwanted proteins by degrading them. Mutations of parkin eliminate its ability to chemically "tag" such proteins to designate them for destruction in the cell's proteasome--a process called ubiquitinylation. Loss of such ability causes such protein garbage to aggregate into lethal clumps in neurons--a hallmark of many neurodegenerative diseases. In the brain, the parkin protein works with Hsp70, which helps correct the folding of misfolded proteins.

Keyword: Parkinsons
Link ID: 6598 - Posted: 12.16.2004

Ranitidine, a widely used substance used as an antihistaminic drug against gastric ulcers, may become a new treatment for cerebral ischemia caused by craneoencephalic infarcts or traumatisms, the third leading cause of deaths in industrialised countries. In experiments with a model of cerebral ischemia using rats, a team from the Institute of Neurosciences of the Universitat Autònoma de Barcelona (Spain) has observed how the presence of ranitidine reduces neuronal death by a quarter. The substance reaches its maximum effect six hours after the lesion has occurred, which will facilitate treatment in real cases with humans. The scientists of the Institute of Neurosciences at the UAB have studied ranitidine's effects on an experimental model using neurons from rats' brains. The cells underwent a lack of oxygen and glucose analogous to that which they suffer, within the brain, when there is a lack of blood flow (what happens when there is a cerebral ischemia) caused by an infarct or a traumatism. When a lesion of this type occurs, the cells either die directly or, in many cases, they becomes victims of a slow programmed death called apoptosis, a kind of "suicide" at a cellular level.

Keyword: Stroke; Apoptosis
Link ID: 6597 - Posted: 12.16.2004

In experiments with fruit flies, Johns Hopkins researchers have found that blindness induced by constant light results directly from the loss of a key light-detecting protein, rather than from the overall death of cells in the retina, which in humans is a light-sensitive tissue at the back of the eye. The research, reported in the Dec. 14 issue of Current Biology, overturns the long-standing belief that blindness from chronic light exposure is a direct result of overall retinal degeneration and cell death. Although many animals, and presumably humans, lose both their retinal cells and vision after exposure to low levels of light for long periods, the relationship between exposure and blindness had been poorly understood. In the Hopkins experiments, flies whose light-detecting protein rhodopsin was engineered to resist destruction retained their vision twice as long as normal flies, although over time they developed blindness due to delayed decay of rhodopsin. The researchers measured vision damage indirectly by measuring loss of the electrical signals normally initiated by rhodopsin when exposed to light. "Everyone assumed that the blindness caused by chronic light exposure was an effect of the degeneration and loss of the retinal cells, but our experiments show these are two distinct events caused by two distinct processes," says Craig Montell, Ph.D., professor of biological chemistry in Hopkins' Institute for Basic Biomedical Sciences. "Understanding how degradation of rhodopsin and other visual proteins contributes to vision loss may help us in the future to reduce the severity of blindness in rare people susceptible to chronic exposure to light."

Keyword: Vision
Link ID: 6596 - Posted: 12.16.2004

Perhaps the Beanie Baby craze wasn't so weird after all. Most people have a collection of some kind at some point in their lives. Indeed, historical studies show that acquiring and retaining objects, even when they are not necessary for survival, is not only nearly universal, but also has been part of human behavior since the earliest human societies. Yet despite the ubiquitous nature of this trait, very little is known about what drives humans to collect. By studying patients who developed abnormal hoarding behavior following brain injury, neurology researchers in the University of Iowa Roy J. and Lucille A Carver College of Medicine have identified an area in the prefrontal cortex that appears to control collecting behavior. The findings suggest that damage to the right mesial prefrontal cortex causes abnormal hoarding behavior by releasing the primitive hoarding urge from its normal restraints. The study was published online in the Nov. 17 Advance Access issue of the journal Brain. Hoarding behavior is common among animals; around 70 species hoard and mostly they hoard food, which makes sense from a survival standpoint. Studies of hoarding behavior in rodents have shown that collecting is driven by certain primitive structures deep in the brain and most mammals, including humans, share these subcortical regions.

Keyword: OCD - Obsessive Compulsive Disorder
Link ID: 6595 - Posted: 12.16.2004

ATLANTA -- Scientists with the Center for Behavioral Neuroscience, a research consortium based at Georgia State University, have for the first time used a form of magnetic resonance imaging to reveal anatomical features of the nervous system in a live crayfish, a crustacean whose brain measures only 3 millimeters wide. The technique, which is reported and highlighted in an accompanying commentary in the Dec. 15 issue of The Journal of Experimental Biology, provides a powerful new tool for understanding the neurobiology of behavior in invertebrate animal models. Conventional MRI technology employs high-intensity magnetic fields to excite protons in the water molecules of soft tissue. Scanners detect the excitation and image cross-sectional slices of an organ, such as the brain. To image a live crayfish, whose physiology does not normally respond to magnetic fields, CBN researchers injected manganese, a contrast-enhancing agent that crayfish cells absorb, through a long tube into its circulatory system. The infusion took place while the animal was positioned inside the MRI scanner.

Keyword: Brain imaging
Link ID: 6594 - Posted: 12.16.2004

Pharaoh ants use an appreciation of geometry to find their way home. Worker pharaoh ants travel to and from their colony along a series of branching paths scented with pheromones. But until now it was unclear how the ants knew which branch would lead them home. Duncan Jackson and his colleagues at the University of Sheffield, UK, noticed that various species of leafcutter and pharaoh ants - Monomorium pharaonis - lay trails radiating out from the nest that fork at an angle of 50° to 60°. When a returning ant reaches a fork in the trail, it usually takes the path which deviates least. In other words, it will change direction slightly to the right or left but will not make an acute turn back on itself. This means it always takes the path that leads back to the colony.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 6593 - Posted: 12.16.2004

Helen Pearson The infectious proteins called prions that cause the human form of mad cow disease may hitch into the body on the back of another meat protein, US researchers have shown. The finding may help to explain how the rogue prions jump between species. Disease-causing prions are thought to have passed into people when they ate beef from infected cattle, triggering the brain wasting condition called new-variant Creutzfeldt-Jakob disease, or vCJD. But researchers have not been sure exactly how prions enter the body. To find out, Neena Singh and her team at Case Western Reserve University in Cleveland, Ohio, mimicked the process of eating and digesting infected meat. They mashed up brain tissue that contained prions from patients who had a form of Creutzfeldt-Jakob disease. They then exposed it to a range of harsh digestive enzymes from the mouth, stomach and intestine, which normally break proteins into pieces. Prions, which are known to be enormously tough, escape this attack almost unscathed, they showed, as does a second type of protein called ferritin, which stores iron and is abundant in meat. The two proteins seem to stick together, they report in the Journal of Neuroscience1. ©2004 Nature Publishing Group

Keyword: Prions
Link ID: 6592 - Posted: 06.24.2010

Using a precisely targeted laser, researchers have snipped apart a single neuron in the roundworm C. elegans — an achievement that opens a new avenue for studying nerve regeneration in this genetically manipulable animal. Indeed, their initial studies have demonstrated that the severed nerves of worms are capable of regenerating and regaining full function. According to the researchers, studying nerve regeneration in the worm could provide answers to questions that are not accessible currently by doing experiments in more complex animals, including mice and zebrafish. “Until now there has been little study of nerve regeneration using genetic methodology, because most studies have been done on higher vertebrate organisms.” Yishi Jin A research team that included Yishi Jin, a Howard Hughes Medical Institute investigator at the University of California, Santa Cruz (UCSC), Andrew Chisholm, also of UCSC, and Adela Ben-Yakar, who was at Stanford University and is now at the University of Texas at Austin, reported its achievement in the December 16, 2004, issue of the journal Nature. Other co-authors are from Stanford University and UCSC. © 2004 Howard Hughes Medical Institute

Keyword: Regeneration
Link ID: 6591 - Posted: 06.24.2010

Marine biologists have confirmed sharks can detect changes in magnetic fields. This ability has long been suspected by researchers who have observed the fish migrating huge distances in the ocean along straight lines. A Hawaii University team has trained captive sharks to swim over targets in their tank whenever an artificial magnetic field is activated. The new study, by Dr Carl Meyer and colleagues, is reported in Interface, a journal of the UK's Royal Society. "This significant advance in demonstrating the existence of a 'compass' sense should now make it possible to investigate exactly how this sense works and how sensitive sharks are to the Earth's magnetic field," the team tells Interface. The Hawaii group used six sandbar sharks and one scalloped hammerhead in their research. They kept the animals in a 7m-diameter tank. The fish were trained to associate the presence of food in a 1.5m by 1.5m target area on the enclosure floor with the switching on of a magnetic field, derived from a copper coil surrounding the tank In a series of trials, the field was then activated at random times and the fish were seen to move on the feeding zone even when there was no food present, proving the existence of their "compass". "Activating the artificial field produced an immediate response in the conditioned sharks," the team says. "They changed from swimming steadily around the perimeter of the tank to swimming faster, turning rapidly and converging on the target in anticipation of a food reward." Tiger sharks, blue sharks and scalloped hammerhead sharks are all known to swim in straight lines for long periods across hundreds of kilometres of open ocean, and then later orient themselves to underwater mountains, or seamounts, where geomagnetic anomalies exist. Scientists want to understand how sharks are able to detect magnetic fields. Other animals that do it, such as trout and pigeons, possess the iron mineral magnetite in their bodies. (C)BBC

Keyword: Miscellaneous
Link ID: 6590 - Posted: 12.15.2004

The development of a laboratory model for a rare, inherited form of blindness holds promise that scientists might one day be able to test new treatments to prevent or cure this devastating disease of the retina. This finding, from investigators at St. Jude Children's Research Hospital and Columbia University, will be published in the Dec. 20 issue of Molecular Brain Research (MBR). The model for this disease, called Leber congenital amaurosis (LCA), is especially important because no treatments are currently available to prevent it. There are not enough patients to enroll in large clinical trials to test new prevention treatments; therefore, any potential new therapy must have a high probability of working. This is especially the case with LCA. Diseases with such a limited patient population discourage the expensive commercial research and development needed to find an effective treatment for it, according to Michael A. Dyer, Ph.D., assistant member of St. Jude Developmental Neurobiology. Dyer is first author of the MBR report. The investigators are now using the model to develop a gene therapy to prevent this form of blindness. "The development of this model reflects an important goal at St. Jude of finding cures for rare devastating childhood diseases beyond cancer," Dyer said.

Keyword: Vision; Genes & Behavior
Link ID: 6589 - Posted: 12.15.2004

By Kelly Hearn, AlterNet. For Gene Haislip, a former official of the U.S. Drug Enforcement Agency, the perennial debate over Ritalin, the stimulant commonly prescribed for children with "attention deficit hyperactivity disorder (ADHD)," is an aching reminder of a moral battle he fought – and lost – to big drug companies. For 17 years, the now retired director of the DEA´s Office of Diversion Control set production quotas for controlled substances like methylphenidate (MPH), the federally restricted stimulant commonly known as Ritalin. During that time, he fought hard to raise public awareness about over-prescribing of stimulants to children, about the drug's high rate of street diversion, and about its long-term health impact on young patients. "This affects the most sensitive part of our population," says Haislip, now a consultant for drug companies on issues of compliance to federal law. "When I was at the DEA, we created awareness about this issue. But the bottom line is we didn't succeed in changing the situation because this – prescribing methylphenidate, for example – is spiraling. "A few individuals in government expressing concern can't equal the marketing power of large companies," he adds. "I have doubts that the truth is driving this issue. It seems that market forces and money is behind it." © 2004 Independent Media Institute.

Keyword: ADHD; Drug Abuse
Link ID: 6588 - Posted: 06.24.2010

A mutant gene that starves the brain of serotonin, a mood-regulating chemical messenger, has been discovered and found to be 10 times more prevalent in depressed patients than in control subjects, report researchers funded by the National Institutes of Health's National Institute of Mental Health (NIMH) and National Heart Lung and Blood Institute (NHLBI). Patients with the mutation failed to respond well to the most commonly prescribed class of antidepressant medications, which work via serotonin, suggesting that the mutation may underlie a treatment-resistant subtype of the illness. The mutant gene codes for the brain enzyme, tryptophan hydroxylase-2, that makes serotonin, and results in 80 percent less of the neurotransmitter. It was carried by nine of 87 depressed patients, three of 219 healthy controls and none of 60 bipolar disorder patients. Drs. Marc Caron, Xiaodong Zhang and colleagues at Duke Unversity announced their findings in the January 2005 Neuron, published online in mid-December. "If confirmed, this discovery could lead to a genetic test for vulnerability to depression and a way to predict which patients might respond best to serotonin-selective antidepressants," noted NIMH Director Thomas Insel, M.D.

Keyword: Depression; Genes & Behavior
Link ID: 6587 - Posted: 12.15.2004

Galanin is one of several neuropeptides known to increase food intake. Previous findings have suggested that galanin may also be involved in alcohol consumption and/or the motivation to drink alcohol beverages. Most recently, researchers have discovered that giving galanin microinjections to rodents can increase their voluntary alcohol intake. Their findings are published in the December issue of Alcoholism: Clinical & Experimental Research. "Galanin's well-known effects of increasing food intake, especially the intake of fat-rich diets, was one of the early reasons we investigated it," said Michael J. Lewis, a senior fellow working with Dr. Bart Hoebel in his laboratory in the Department of Psychology at Princeton University and Sarah Leibowitz at Rockefeller University, and corresponding author for the study. "Alcohol is the only drug of abuse that can also qualify as a calorie-rich food, and it undoubtedly has important interactions with systems that control food intake and nutrition." Lewis added that alcohol, galanin and food intake have another area of commonality: all are stimulants of the neurotransmitter dopamine, which has been linked by numerous studies to the rewarding effects and "high" produced by potent drugs of abuse such as nicotine, cocaine and heroin.

Keyword: Drug Abuse; Obesity
Link ID: 6586 - Posted: 12.15.2004