When evaluating facial attractiveness, participants may fail to notice a radical change to the outcome of their choice, according to a study by researchers at Lund University, Sweden, and New York University. Equally surprising, the study shows that participants may produce confabulatory reports when asked to describe the reasons behind their choices. The findings appear in the October 7 issue of Science. Researchers showed picture-pairs of female faces to the participants and asked them to choose which face in each pair they found most attractive. In addition, immediately after their choice, they were asked to verbally describe the reasons for choosing the way they did. Unknown to the participants, on certain trials, a card magic trick was used to secretly exchange one face for the other. Thus, on these trials, the outcome of the choice became the opposite of what they intended. The researchers measured whether the participants noticed that something went wrong with their choice, both concurrently, during the experimental task, and retrospectively through a post-experimental interview. Less than 10% of all manipulations were detected immediately by the participants, and counting all forms of detection no more than a fifth of all manipulated trials were exposed. The researchers call this effect choice blindness.

Keyword: Sexual Behavior; Vision
Link ID: 8003 - Posted: 10.07.2005

The central nervous system in adult mammals is notoriously bad at healing itself. Once severed, the axons that connect one neuron to another can't regrow. That's why people regain little, if any, movement or sensation after a spinal cord injury. Now, researchers have made a promising discovery. In the 7 October Science, they identify a class of drugs--including one already on the market for treating cancer--that promote axon regeneration in rodents. In the new study, Zhigang He, and Vuk Koprivica at Children's Hospital in Boston along with colleagues tested about 400 small molecules on cultured rodent neurons, hoping to identify ones that promoted the growth of new axonlike extensions. Most of the compounds did nothing, but several compounds that blocked a cell surface protein called the epidermal growth factor receptor (EGFR) had impressive effects. To test the compounds on nerve injuries in live animals, the researchers crushed an optic nerve in adult mice then packed the nerve with foam soaked with one of the EGFR blockers. Two weeks after the injury, the treated mice showed a ninefold increase in axon regeneration compared to untreated animals. Additional work by He's team suggests that the compounds block two kinds of molecular signals: inhibitory molecules embedded in the myelin insulation on axons and inhibitory signals spewed out by support cells that form a scar around the site of injury. "It's a really unexpected finding," says Marie Filbin, a neurobiologist at Hunter College in New York City. She and other experts say they never suspected that EGFR might have a role in thwarting regeneration. The study "identifies a novel target for therapeutic interventions," Filbin says. © 2005 by the American Association for the Advancement of Science.

Keyword: Regeneration; Trophic Factors
Link ID: 8002 - Posted: 06.24.2010

Researchers have discovered a new form of synaptic plasticity, the changes to nerve cells in the brain that underlie learning and memory. The phenomenon, the scientists say, may help govern how a single neuron integrates and processes multiple stimuli. The researchers, led by HHMI investigators Lily Jan and Yuh Nung Jan at the University of California San Francisco, published their findings in the October 7, 2005, issue of the journal Cell. Coauthors on the paper include the Jans' colleagues at UCSF and Robert B. Darnell, an HHMI investigator at The Rockefeller University. Scientists have long known that long-term potentiation (LTP) can strengthen the connections between neurons, so that a nerve cell more readily responds to a signal from its neighbor. This heightened sensitivity can persist for several hours. LTP is best studied in excitatory synapses, where a neurotransmitter molecule is released by one cell and tends to triggers an electrical impulse in the receiving cell. Lily Jan compares the phenomenon to Pavlov's famous experiment in which ringing a bell while feeding a dog causes the dog to associate the two stimuli. LTP, she says, “reminds you of that. If you have two different excitatory inputs and they happen at the same time, it can cause a very long-lasting change.” © 2005 Howard Hughes Medical Institute.

Keyword: Learning & Memory
Link ID: 8001 - Posted: 06.24.2010

Known as "the cocktail party problem," the ability of the brain's auditory processing centers to sort a babble of different sounds, like cocktail party chatter, into identifiable individual voices has long been a mystery. Now, researchers analyzing how both humans and monkeys perceive sequences of tones have created a model that can predict the central features of this process, offering a new approach to studying its mechanisms. The research team--Christophe Micheyl, Biao Tian, Robert Carlyon, and Josef Rauschecker--published their findings in the October 6, 2005, issue of Neuron. For both the humans and the monkeys, the researchers used an experimental method in which they played repetitive triplet sequences of tones of two alternating frequencies. Researchers know that when the frequencies are close together and alternate slowly, the listener perceives a single stream that sounds like a galloping horse. However when the tones are at widely separated frequencies or played in rapid succession, the listener perceives two separate streams of beeps. Importantly, at intermediate frequency separations or speeds, after a few seconds the listeners' perceptions can shift from the single galloping sounds to the two streams of beeps. The researchers could use this phenomenon to explore the neurobiology of perception of auditory streams, because they could explore how perception altered with the same stimulus.

Keyword: Hearing
Link ID: 8000 - Posted: 10.06.2005

Roxanne Khamsi It may not be considered manly for humans to cry. But when male mice shed a tear, they seem to be trying to prove their masculinity. So say Japanese researchers who have discovered that male mice release pheromones in the fluid that moistens their eyes. "Nobody expected that sex-specific pheromones would exist in tears," says Kazushige Touhara of the University of Tokyo in Chiba. Pheromones, the chemicals that convey messages about everything from fear to sexual desire, are most common in sweat in humans, and in urine in mice. It is not clear whether mice ever cry for the same reasons as humans; in this study, their tears were just the result of a basic physiological response that keeps a mouse's eyes wet and comfortable. Touhara says the pheromones in these secretions are probably picked up by females when they groom the faces of their fellow mice. These sexy cues may help females to work out which of their companions are male and therefore potential mates, Touhara and his team report in Nature1. In most vertebrates, pheromones seem to trigger nerve cells in the vomeronasal organs, which are situated in the hard palate between the nose and mouth. Some studies have found evidence for such an organ in the developing human fetus, but the presence of a functioning one in human adults remains controversial. ©2005 Nature Publishing Group

Keyword: Sexual Behavior; Chemical Senses (Smell & Taste)
Link ID: 7999 - Posted: 06.24.2010

When you jaywalk, your ability to keep track of that oncoming truck despite your constantly changing position can be a lifesaver. But scientists do not understand how such constant updating of depth and distance takes place, suspecting that the brain receives information not just from the eye but also from the motion-detecting vestibular system in the middle ear. In studies with monkeys reported in the October 6, 2005, issue of Neuron, Nuo Li and Dora Angelaki of Washington University School of Medicine in St. Louis have demonstrated how such depth motion is updated and strongly implicated the vestibular system in that process. In their experiments, the researchers trained the monkeys to perform memory-guided eye movements. The animals were first shown a light a fixed distance away from their head. Then the researchers flashed one of eight other, closer "world-fixed" target lights. Next, with the room lights turned off, the monkeys were moved either forward or backward and the fixed-distance light flashed, signaling the monkeys that they should look at where they remembered the world-fixed light had flashed. Finally, the room lights and target light were turned on, so the monkey could make any corrective eye movement to the re-lit target. For comparison, the researchers also conducted experiments in which the monkeys were not moved.

Keyword: Miscellaneous
Link ID: 7998 - Posted: 10.06.2005

New studies in mice have shown that immature stem cells that proliferate to form brain tissues can function for at least a year — most of the life span of a mouse — and give rise to multiple types of neural cells, not just neurons. The discovery may bode well for the use of these neural stem cells to regenerate brain tissue lost to injury or disease. Alexandra L. Joyner, a Howard Hughes Medical Institute investigator at New York University School of Medicine, and her former postdoctoral fellow, Sohyun Ahn, who is now at the National Institute of Child Health and Human Development, published their findings in the October 6, 2005, issue of the journal Nature. They said the technique they used to trace the fate of stem cells could also be used to understand the roles of stem cells in tissue repair and cancer progression. Joyner said that previous studies by her lab and others had shown that a regulatory protein called Sonic hedgehog (Shh) orchestrates the activity of an array of genes during development of the brain. Scientists also knew that Shh played a role in promoting the proliferation of neural stem cells. However, Joyner said the precise role of Shh in regulating stem cell self-renewal — the process whereby stem cells divide and maintain an immature state that enables them to continue to generate new cells — was unknown. In the studies published in Nature, Joyner and Ahn developed genetic techniques that enabled them to label neural stem cells in adult mice that are responding to Shh signaling at any time point so they could study which stem cells respond to Shh. © 2005 Howard Hughes Medical Institute.

Keyword: Stem Cells
Link ID: 7997 - Posted: 06.24.2010

By DONALD G. McNEIL Jr. The Food and Drug Administration proposed new rules yesterday to prevent the spread of mad cow disease by banning brains and spinal cords from older cows in all animal feed. "This reduces a very, very low risk to even lower," said Dr. Stephen F. Sundlof, the agency's director of veterinary medicine, in announcing the changes. But the rules are not as strict as those the agency proposed last year and never adopted, and critics promptly denounced them as inadequate. The new proposal still allows chickens, pigs and other noncattle animals to be fed material that some scientists consider potentially infectious, including the brains and spinal cords of young animals, and the eyes, tonsils, intestines and nerves of older ones. Cows can potentially ingest that material because they can be given chicken feed and droppings swept up from the floors of poultry farms, scrapings from restaurant plates, and a calf milk replacement made from cow blood and fat. In the rules proposed in early 2004, poultry litter and plate waste would have been banned. The F.D.A. and the meat industry are "totally committed to continuing the practice of feeding slaughterhouse waste to cows," said John Stauber, the author of "Mad Cow U.S.A." (1997) and a critic of the meat industry who has called for a ban on feeding all animal protein to livestock. Copyright 2005 The New York Times Company

Keyword: Prions
Link ID: 7996 - Posted: 10.05.2005

While we need maps to navigate long distances, each fall millions of monarch butterflies migrate up to 3,000 miles south to their overwintering grounds in central Mexico without losing their way. "Monarchs absolutely have to be able to see ultraviolet light in order to navigate, and if this is blocked in some way they lose their sense of direction," says ecologist and evolutionary biologist Adriana Briscoe from the University of California, Irvine. Briscoe says what North American migratory monarch butterflies (Danaus plexippus) use as a cue to keep them on track despite clouds, wind and fog along the way has long been a mystery. Previous research showed that monarchs use the sun as one of the celestial cues for deciding which direction to fly in. In particular, they use a type of light that humans can't see called polarized light — produced primarily by the scattering of sunlight through the atmosphere. "We also knew that they had an internal clock which they used to also calibrate their sense of direction," Briscoe explains. But how the butterflies put all this together to navigate was not understood. Now Briscoe, working in collaboration with an international team of researchers, has found that when the skies of certain U.S. states fill each fall with the flitter of up to a hundred million monarchs, these incredible butterflies are using the sun's ultraviolet, or UV, light as a compass to tell them where they are and which direction to fly — the same type of light that cancer-conscious people shy away from. © ScienCentral, 2000-2005.

Keyword: Vision; Animal Migration
Link ID: 7995 - Posted: 06.24.2010

By Jon McClellan, M.D. Consumer, professional, legislative and regulatory organizations are increasingly calling for the development and adoption of evidence-based therapies, based on demands for quality services and expectations that outpouring of dollars and time are rewarded by beneficial outcomes. In child and adolescent mental health, growing public concerns over safety, in particular with psychotropic medications, and the recognition that psychiatric impairment is a major factor within other social service systems has further fueled the demand for empirically based interventions. Randomized, controlled trials (RCTs) with adequate sample sizes and defined study populations are the standard for characterizing an intervention as evidence-based (Cochrane Collaboration, 2002). A listing of all RCTs in child and adolescent psychiatry is beyond the scope of this commentary (for a review, see McClellan and Werry [2003]). This review will outline interventions with the best research support. Fortunately, although the literature remains limited, the number of well-conducted studies is increasing. An estimated 6% of young people under the age of 20 in the United States receive prescriptions for psychotropic medication. This represents approximately a threefold increase since 1987 (Zito et al., 2003), and includes a substantial rise in prescriptions for preschoolers (Zito et al., 2000). The majority of prescriptions are off-label (i.e., not U.S. Food and Drug Administration-approved). Pediatricians and family practice physicians issue the majority of prescriptions for psychotropic drugs, in part due to the scarcity of child psychiatrists (Goodwin et al., 2001). © 2005 Psychiatric Times.

Keyword: ADHD; Depression
Link ID: 7994 - Posted: 06.24.2010

By Arline Kaplan Repetitive transcranial magnetic stimulation (rTMS), which allows for direct activation of neurons, will play an ever-expanding role in depression and schizophrenia treatment, according to recent reports from Mark S. George, M.D., and Alan L. Schneider, M.D. George, who is distinguished professor of psychiatry, radiology and neurology, and director of the Brain Stimulation Laboratory at the Medical University of South Carolina College of Medicine, provided updates on rTMS research at the 2005 American Psychiatric Association annual meeting. "We call this electrodeless electrical stimulation," George said at a symposium. "Electrical energy in a coil induces a magnetic field, and the field passes unimpeded through the skin and skull and induces an electrical current in the brain." The physiological effects of TMS depend upon the site and frequency of stimulation (Ontario Ministry of Health and Long-Term Care, 2004). The frequency of cortical stimulation varies. Rapid-rate or repetitive TMS usually refers to the application of TMS for a train of minutes at frequencies >1 Hz and is commonly used in treatment studies. Transcranial magnetic stimulation at ≤1 Hz is referred to as slow or low-frequency TMS. The ability to stimulate the brain at either high or low frequency is important, because high-frequency rTMS (e.g., 20 Hz) may increase cerebral blood flow and neuronal excitability in the region of the cortex under the coil, but low-frequency rTMS (≤1 Hz) may have the opposite effect. © 2005 Psychiatric Times

Keyword: Schizophrenia; Depression
Link ID: 7993 - Posted: 06.24.2010

By David W. Loring, Ph.D. Epilepsy is a major public health concern, with prevalence estimated to be slightly less than 1% (Annegers, 1996). Each year, 25,000 to 40,000 children in the United States alone experience their first unprovoked seizure (Hirtz et al., 2003). Depending on the type of seizure (e.g., generalized versus focal) or specific epilepsy syndrome (e.g., juvenile myoclonic epilepsy, benign rolandic epilepsy), there are several recommended medications with demonstrated clinical efficacy from which to choose (Hirtz et al., 2003). Selection of a specific medication, however, is often based upon clinical experience due to the absence of adequate antiepileptic drug (AED) pediatric clinical trials. Antiepileptic drugs decrease membrane excitability, increase postsynaptic inhibition or alter synchronization of neural networks to decrease excessive neuronal excitability associated with seizure development. Common side effects of decreasing neuronal excitability, however, are slowed motor and psychomotor speed, poorer attention and mild memory impairment (Meador, 2005). Unlike adults, cognitive side effects in children occur against the backdrop of normal cognitive and psychosocial development, and treatment decisions made in childhood may have lifelong implications. Adults who developed epilepsy during their childhood tend to have less education, decreased rates of employment and employment at lower job levels, lower rates of marriage, poorer physical health, and increased incidence of psychiatric disorders (Jalava and Sillanpaa 1997a, 1997b; Jalava et al., 1997; Sillanpaa et al., 1998). Importantly, these long-term effects are also present in adults who are no longer taking medications. © 2005 Psychiatric Times.

Keyword: Epilepsy
Link ID: 7992 - Posted: 06.24.2010

Five years ago Karen Reed, from East Yorkshire, was slimmer of the year - but she had a secret. For the past 28 years she has been bulimic. Her daily life revolves around bingeing on vast amounts of food and then making herself sick. The condition has taken a terrible toll on Karen's health. The acid from her stomach has burnt a hole in her oesophagus and dissolved away most of her teeth. "I was 15 when I first made myself sick, I'm 43 now," said Karen. "I can't remember what it feels like to be normal, this is normal for me, throwing up two, three times a day is normal." But it is not just Karen who is suffering. Her eldest daughter Jess, who is 17 and a part time model, is also bulimic. "For me it was always a need to lose weight and it was a very effective way I found," she said. "The first time I threw up I saw on the scales it made me lose a few pounds so I kept it going. It was something that progressed and got worse and now it has such a detrimental effect on my life." Bulimia is treated as a psychological disorder in the UK but Karen and Jess say they have had therapy without success. A BBC documentary team has followed them as they try and get hold of an experimental drug which they believe could cure them of their eating disorder. (C)BBC

Keyword: Anorexia & Bulimia
Link ID: 7991 - Posted: 10.04.2005

By Terri Sapienza After the sores broke open and I got a pain in my chest -- not on my chest, but deep inside my chest -- I knew it was time to call the doctor. The episode had started a week earlier, as seven bumps appeared on the right side of my chest running in a crooked, vertical row. I assumed I'd been bitten by something. A few days later the bumps sprouted white tops and then multiplied -- another patch of bumps emerged under my right arm. The itching got worse. Poison ivy, I figured. I used cortisone cream and willed myself not to scratch. But chest pain has a way of getting your attention, as did the headaches and a burning sensation under my arm. I headed for the doctor. My physician, Peter J. Ouellette of Georgetown University, took one look, asked a few questions and announced his diagnosis: shingles. I repeated it, to make sure I had heard correctly. Shingles. I had heard of shingles, but had no idea what it was or what it meant. "It's one of the adult forms of chickenpox," Ouellette said, reassuringly. "You'll be fine." © 2005 The Washington Post Company

Keyword: Miscellaneous
Link ID: 7990 - Posted: 06.24.2010

Researchers at the University of Illinois at Chicago have discovered that a protein found in the brain is genetically linked to alcoholism and anxiety. Results of the study are published in the October issue of the Journal of Clinical Investigation. The researchers studied rats selectively bred for high alcohol preference (P rats), which were found to have high anxiety levels and consume greater amounts of alcohol than alcohol non-preferring (NP) rats. The researchers focused on a molecule called CREB, or cyclic AMP responsive element binding protein, which is thought to be involved in a variety of brain functions. When CREB is activated, it regulates the production of another brain protein called neuropeptide Y. The higher-imbibing P rats were found to have lower levels of CREB and neuropeptide Y in certain regions of the amygdala -- an area of the brain associated with emotion, fear and anxiety -- than their teetotaling NP cousins. "This is the first direct evidence that a hereditary deficiency of CREB protein in the central amygdala is associated with high anxiety and alcohol-drinking behaviors," said lead researcher Subhash Pandey, associate professor of psychiatry and director of neuroscience alcoholism research at the UIC College of Medicine.

Keyword: Drug Abuse; Learning & Memory
Link ID: 7989 - Posted: 10.04.2005

By Larry O'Hanlon, Discovery News — Researchers studying the pigments that color flowers have stumbled onto a natural combination that creates subtle green fluorescent patterns on petals. The patterns might be to be visible to bees, bats and other evening pollinators with eyes especially sensitive to green light. It is the first known case of a plant possibly using fluorescence to attract pollinators. "Fluorescence can be an important signal in mate choice for budgerigars and possibly in mantis shrimp, and it may be that in flowers it attracts pollinators," reported Fernando Gandía-Herrero and his colleagues at the University of Murcia in Spain, in a brief article in a recent issue of Nature. Gandía-Herrero and his colleagues extracted pigments from the petals of Mirabilis jalapa flowers, commonly known as four o'clocks, and found that when one pigment chemical, betaxanthin, is activated by the blue light contained in sunlight, it fluoresces green light that contributes to the yellow color of some of its petals. On other petal parts, however, green fluorescence is efficiently sucked up before it can escape by another pigment — violet betacyanin — the team reports. The result is an internal light-filtering system that controls the amounts and locations of green fluorescence escaping the petals, and therefore controls the pattern of green light seen by pollinators. © 2005 Discovery Communications Inc

Keyword: Vision
Link ID: 7988 - Posted: 06.24.2010

By Jennifer Viegas, Discovery News — Chimpanzees have a reputation for being noisy, rambunctious animals, but new research from The Jane Goodall Institute indicates that wild chimps possess an enormous amount of self-control, especially in terms of their vocalizations. The research found that chimps not only know when to be quiet, but also tell each other to shut up when danger lurks. Findings will be presented at the joint meeting of the Acoustical Society of America and NOISE-CON 2005, which runs from Oct. 17-21 in Minneapolis, Minn. "The pant-hoot means something like 'Hey! This is me! I'm here!,'" said Michael Wilson, lead author of the study. "It's a way to keep track of allies and associates." Wilson, director of field research at Goodall's Gombe Stream Research Centre in Tanzania, added, "People studying chimpanzees use a rather similar call to find one another in the dense forest — a sort of loud 'hoo' that can be heard over a few hundred yards. © 2005 Discovery Communications Inc.

Keyword: Language; Evolution
Link ID: 7987 - Posted: 06.24.2010

Findings from the largest survey ever mounted on the co-occurrence of psychiatric disorders among U.S. adults afford a sharper picture than previously available of major depressive disorder* (MDD) in specific population subgroups and of MDD’s relationship to alcohol use disorders (AUDs)** and other mental health conditions. The new analysis of data from the 2001-2002 National Epidemiologic Survey of Alcohol and Related Conditions (NESARC) shows for the first time that middle age and Native American race increase the likelihood of current or lifetime MDD, along with female gender, low income, and separation, divorce, or widowhood. Asian, Hispanic, and black race-ethnicity reduce that risk. Conducted by the NIH’s National Institute on Alcohol Abuse and Alcoholism (NIAAA), the analysis appears in the Monday, October 3, 2005 Archives of General Psychiatry. The NESARC involved face-to-face interviews with more than 43,000 non-institutionalized individuals aged 18 years and older and questions that reflect diagnostic criteria established by the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). Its principal foci were alcohol dependence (alcoholism) and alcohol abuse and the psychiatric conditions that most frequently co-occur with those AUDs. Because of its size and scrutiny of multiple sociodemographic factors, the NESARC provides more precise information than previously available on between-group differences that influence risk.

Keyword: Depression
Link ID: 7986 - Posted: 06.24.2010

BETHESDA, Md. – It's often said that the key to Bill Bradley's basketball success was summed up in the title of the 1965 book by John McPhee, "A sense of where you are." Bradley always seemed to know where all nine other players were, where Bradley himself was in relation to the basket – and where the open spot was to be found for his stylized jump shot. "Navigation is a very interesting problem: It's very abstract and involves a high level of higher integrative, cognitive skills," noted Patricia E. Sharp, of Bowling Green State University. "And it turns out that the humble laboratory rat probably solves navigational problems about as well as we do," she adds. Sharp and her collaborator Shawnda Turner-Williams measured the electrical firing of 51 individual cells in the medial mammillary nucleus of five rats' brains – "to our knowledge…the first recordings from medial mammillary body cells in awake animals," according to their research paper. The paper "Movement-related correlates of single cell activity in the medial mammillary nucleus of the rat during a pellet-chasing task," appears in the Journal of Neurophysiology, published by the American Physiological Society. Cell firing rates indicate "unambiguous" left-right turning, correlate to speed

Keyword: Learning & Memory
Link ID: 7985 - Posted: 06.24.2010

Two Australian scientists have been awarded the Nobel prize for medicine for their discovery that stomach ulcers can be caused by a bacterial infection. Robin Warren and Barry Marshall showed the bacterium Helicobacter pylori plays a key role in the development of both stomach and intestinal ulcers. Thanks to their work these ulcers are often no longer a long-term, frequently disabling problem. They can now be cured with a short-term course of drugs and antibiotics. In 1982, when H. pylori was discovered by Marshall and Warren, stress and lifestyle were considered the major causes of stomach and intestinal ulcers. It is now firmly established that the bacterium causes more than 90% of duodenal (intestinal) ulcers and up to 80% of gastric (stomach) ulcers. Dr Warren, a pathologist from Perth, paved the way for the breakthrough when he discovered that small curved bacteria colonised the lower part of the stomach in about 50% of patients from which biopsies had been taken. He also made the crucial observation that signs of inflammation were always present in the stomach lining close to where the bacteria were seen. (C)BBC

Keyword: Stress
Link ID: 7984 - Posted: 10.03.2005