Underwater echolocation has built-in dimmer switch. MICHAEL HOPKIN Dolphins adjust the volume of their sonar to target prey, a study has shown1. The system is perfectly tuned to home in on their preferred victims - schools of small fish. A dolphin's clicks quieten as it approaches its target, find Whitlow Au and Kelly Benoit-Bird of the University of Hawaii in Kailua. This isn't a stealth tactic, the researchers say. It seems to result from the way dolphins' nasal system produces sound - they make strings of clicks by expelling pressurized air from their blowholes. The mammals wait until one click bounces back before releasing another, Au and Benoit-Bird explain. As they draw nearer their prey, the echoes arrive sooner, so the click rate is correspondingly faster. "The rate increases as a dolphin closes in on its target," Au says. © Nature News Service / Macmillan Magazines Ltd 2003

Keyword: Hearing
Link ID: 3928 - Posted: 06.24.2010

By MARY DUENWALD More than half of the Americans who suffer from depression now seek treatment, up from one-third 10 years ago, a new survey says. Yet nearly 60 percent of the people in treatment do not receive adequate care, the researchers found. More than 16 percent of Americans — as many as 35 million people — suffer from depression severe enough to warrant treatment at some time in their lives, according to the National Comorbidity Study, sponsored by the National Institutes of Health and published today in a special issue on depression of The Journal of the American Medical Association. In any given one-year period, 13 million to 14 million people, about 6.6 percent of the nation, experience the illness. The numbers are similar to those found in the first survey 10 years ago. At that time, the lifetime prevalence of depression was measured at nearly 15 percent and the one-year figure at 8.6 percent. Copyright 2003 The New York Times Company

Keyword: Depression
Link ID: 3927 - Posted: 06.24.2010

By SANDRA BLAKESLEE People are efficient, rational beings who tirelessly act in their own self-interest. They make financial decisions based on reason, not emotion. And naturally, most save money for that proverbial rainy day. Right? Well, no. In making financial decisions, people are regularly influenced by gut feelings and intuitions. They cooperate with total strangers, gamble away the family paycheck and squander their savings on investments touted by known liars. Such human frailties may seem far too complicated and unpredictable to fold into economic equations. But now many neuroscientists are beginning to argue that it is time to create a new field of study, called neuroeconomics. Copyright 2003 The New York Times Company

Keyword: Brain imaging; Emotions
Link ID: 3926 - Posted: 06.19.2003

By JENNIFER 8. LEE WASHINGTON, — Scientists from the Environmental Protection Agency say there is "sufficient evidence" to conclude that the country's most widely used pesticide, atrazine, causes sexual abnormality in frogs. They are recommending that the agency conduct more research to understand atrazine's mechanisms and its broader impact on frog populations. The scientists noted that there had been six studies involving three species of frogs that show a variety of defects, including frogs with both multiple testes and multiple ovaries, when exposed to the chemical. The scientists cautioned that the results from studies of atrazine had not been consistent and that it was not clear at what levels of exposure those effects occurred or how different frog species were affected. Copyright 2003 The New York Times Company

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 3925 - Posted: 06.24.2010

By NICHOLAS WADE Biologists have made a fundamental discovery about how the human Y chromosome, a genetic package inherited by men, protects itself against evolutionary decay. As part of the work, the scientists have tallied the exact number of genes on the Y chromosome, finding more than they had expected. That and other research has led the researchers to assess the genetic differences between men and women as being considerably greater than thought. Although most men are unaware of the peril, the Y chromosome has been shedding genes furiously over the course of evolutionary time, and it is now a fraction the size of its partner, the X chromosome. Sex in humans is determined by the fact that men have an X and a Y chromosome in each of their body's cells. Women have a pair of X's. Copyright 2003 The New York Times Company

Keyword: Sexual Behavior
Link ID: 3924 - Posted: 06.19.2003

STANFORD, Calif. - Nearly 5 million people in the United States suffer from schizophrenia or manic depression, making antipsychotics the fourth-highest selling class of drugs. But how effectively do the most commonly prescribed medications treat the disorder? And how much better are newer antipsychotics, known as atypicals, compared to their older counterparts? Ira D. Glick, MD, tackled these questions in a sweeping review of medical literature. Glick, professor of psychiatry and behavioral sciences at the Stanford School of Medicine, said 90 percent of antipsychotic prescriptions written in the United States are for atypicals. He and his colleagues found that their effectiveness, widely considered to be superior over conventional medications, varies from drug to drug. The researchers also found that four of the 10 studied atypicals were more effective than the older ones. "Some people consider the new antipsychotics a homogenous group, but there are differences," said Glick, senior author of a paper in the June issue of Archives of General Psychiatry. "Some of the drugs are clearly more effective and have fewer side effects than older medications."

Keyword: Schizophrenia
Link ID: 3923 - Posted: 06.19.2003

Researchers at the University of Illinois at Chicago are studying subtle abnormalities in eye movements that may one day be used to diagnose psychiatric disease. Irregularities in how the eyes track a moving object reflect defects in the neural circuitry of the brain and appear to correspond with particular types of mental disorders. Schizophrenic patients, for example, have difficulty keeping their eyes focused on slow-moving objects. With new technology, these abnormalities can be measured precisely and compared with normal patterns. "Psychiatric illnesses are not well understood neurologically," said John Sweeney, director of the Center for Cognitive Medicine in UIC's department of psychiatry. "Eye movement tests offer a way to investigate abnormalities in the brain that are causing these disturbances." The goal, Sweeney said, is to develop eye movement tests as a simple, noninvasive tool for diagnosing brain disorders, including schizophrenia, depression and developmental illnesses such as autism. "At present, however, the field is still in its infancy," he said.

Keyword: Schizophrenia
Link ID: 3922 - Posted: 06.19.2003

A medication used to treat the symptoms of mild-to-moderate Alzheimer disease may actually do more - it may be able to delay progression of the disorder, according to a study conducted at the Indiana University School of Medicine. The study, which appears in the June issue of Archives of Neurology, enabled researchers to evaluate a change in cognition observed in patients who prematurely discontinued treatment with placebo or Exelon ® (rivastigmine tartrate), a medication prescribed for many patients. "If Exelon only had an effect on the symptoms of the disease, we would have expected rapid deterioration in patients' cognition to the level observed in the placebo group after treatment withdrawal, but that was not the case with this study," notes Martin Farlow, M.D., professor of medicine at the IU School of Medicine and director of the Alzheimer Clinic at Indiana University Hospital.

Keyword: Alzheimers
Link ID: 3921 - Posted: 06.19.2003

New Haven, Conn. -- Adolescents are more vulnerable than any other age group to developing nicotine, alcohol and other drug addictions because the regions of the brain that govern impulse and motivation are not yet fully formed, Yale researchers have found. After conducting an analysis of more than 140 research studies from across the basic and clinical neurosciences, including many conducted at Yale, the researchers concluded that substance use disorders in fact constitute neurodevelopmental disorders. "Several lines of evidence suggest that sociocultural aspects particular to adolescent life alone do not fully account for greater drug intake," said Andrew Chambers, M.D., assistant professor of psychiatry at Yale School of Medicine and lead author of the study published this month in the American Journal of Psychiatry. "And while we strongly suspect that genetic factors in individuals can lower the threshold of drug exposure required for 'tripping the switch' from experimental to addictive drug use, here we have a phenomena where a neurodevelopmental stage common to virtually everyone regardless of genetic make-up confers enhanced neurobiological vulnerability to addiction."

Keyword: Drug Abuse; Development of the Brain
Link ID: 3920 - Posted: 06.19.2003

Why do some of us find it hard to control our diet or exercise? Neuroscientists writing in this month’s journal Nature Medicine say the reason could be all in our head. As this ScienCentral News video reports, the findings throw new light on a major epidemic in this country—obesity. How do you know when you’ve eaten enough and it’s time to work it off? Your brain tells you. Neuroscientists are now investigating whether some people overeat because of an imbalance in this brain mechanism. When we eat, nutrients in the food stimulate the secretion of the hormones leptin and insulin, which send signals to a part of the brain called the hypothalamus. When we eat too much, “the hormones working through the brain decrease the food intake, increase our energy expenditure, and even decrease the production of nutrients by other organs in the body,” explains Dr. Luciano Rossetti, professor of medicine and molecular pharmacology and director of the Diabetes Research and Training Center at the Albert Einstein College of Medicine. © ScienCentral, 2000-2003.

Keyword: Obesity
Link ID: 3919 - Posted: 06.24.2010

By RICHARD M. COHEN The sharp pain in my right knee has shot me over the falls. I have a new respect for the camel that invented the cumulative burden. Pain associated with multiple sclerosis — the upper back jolts in cervical disks, joint pain and endless muscle knots and spasms — are a part of life, filed away under "Routine." Grinding intestinal pain has receded to the muted timpani of the dull ache, a few years into post-colon-cancer, after-the-ileostomyitis. The grimace is fixed, built onto my face. Copyright 2003 The New York Times Company

Keyword: Pain & Touch
Link ID: 3918 - Posted: 06.24.2010

Junior coral-reef fish navigate using sound. JOHN WHITFIELD Trying to find Nemo? Follow your ears. That's what young fish do to relocate their home reefs. UK researchers have found that the hubbub of adult fish guides fry in the deep ocean. The discovery could help conservation. Recorded reef racket might attract youngsters to overfished or artificial reefs or to marine reserves. It also suggests that man-made noise may be confusing fish and damaging reef ecosystems. "Boat engines and power plants could be contributing to reductions in recruitment to reefs," comments fish biologist Su Sponaugle of the University of Miami. © Nature News Service / Macmillan Magazines Ltd 2003

Keyword: Hearing; Animal Migration
Link ID: 3917 - Posted: 06.24.2010

International research team discovers potential link between ultraviolet vision and urine scent marks in rodents Humans and most other mammals cannot see ultraviolet (UV) light, whereas some rodents can. A Chilean-German research team has now reported UV vision in the South-American degu, a distant relative of the guinea pig. In a search for behaviourally relevant UV signals in the habitat of these rodents, the researchers found that fresh degu urine reflects the UV parts of the spectrum most strongly, while dry old urine has only marginal UV reflectance. The socially active degus use urine extensively to scent mark their communal trails and wallowing places. The researchers postulate that such scent marks represent visual as well as olfactory cues for the UV-sensitive degus (Investigative Ophthalmology & Visual Science, vol. 44, pp. 2290-2296, May 2003). For humans and most other mammals, the visible spectrum extends from short-wave blue to long-wave red, ultraviolet (UV) is invisible to them. In contrast, many fish, reptiles and birds can see UV and use it in the identification of conspecifics: In some birds, e.g. blue tits, males and females have different UV patterns in their plumage. UV vision is also important for bird foraging: the waxy cover of many berries has a high UV reflectance. UV vision is part of the sensory equipment of many vertebrates and invertebrates (e. g., honeybees), but has been lost in the evolution of mammals. Not completely, however, as some rodents like mice and rats have retained UV vision. The adaptive reasons for this specialization are largely unknown.

Keyword: Vision; Animal Communication
Link ID: 3916 - Posted: 06.11.2003

Youngsters who watch films in which actors are seen smoking are three times as likely to take up the habit, according to research. Research in health journal The Lancet said smoking in movies can actually encourage non-smokers to follow their screen idols. The findings have been both welcomed and rubbished, with some experts saying there are too many other factors which influence whether teenagers do go on to smoke. The US study has also led anti-smoking group Glantz to call for films where actors are seen smoking to be given an adult R-rating. Bollywood stars have already launched their own campaign to persuade film-makers to avoid using smoking in films. The latest research, which was conducted at Dartmouth Medical School, New Hampshire, studied 2,063 children between the ages of 10 and 14 who had never touched a cigarette. (C) BBC

Keyword: Drug Abuse
Link ID: 3915 - Posted: 06.10.2003

Cathy Burgess, a Nottinghamshire woman with motor neurone disease (ALS), wanted more people to know about the illness. She spoke to BBC News about the disease a few weeks before her death. "It was like someone had crept up on me and an icy hand grabbed my heart while I wasn't looking and stole my future." Cathy, who was 48, only discovered she had motor neurone disease two years ago. "I promised myself to learn a new skill every year and I did - skiing, sailing, ballroom dancing, scuba diving and sky-diving. "One of the things I always say is that my family and support network are my parachute." (C) BBC

Keyword: ALS-Lou Gehrig's Disease
Link ID: 3914 - Posted: 06.10.2003

Got GABA? Why do some elderly people have difficulty with vision, speech, and mobility? Some neuroscientists have turned to monkeys for the answer, and believe it might be because of a brain chemical called GABA. “Our subjects were literally the world’s oldest rhesus monkeys,” says Audie Leventhal, professor of neurobiology and anatomy and adjunct professor of physiology at the University of Utah School of Medicine. “We chose rhesus monkeys because they are, with the exception of the great apes, the animal species that has brains that are closest to ours.” The brain of a thirty-year-old rhesus monkey works a lot like the brain of a ninety-year-old human. “The very old monkeys we studied exhibit behaviors very similar to what very old people do,” Leventhal says. “In addition to looking like old people, having grey hair, wrinkles, and so on, they have cognitive declines. They don’t move as quickly. They have more difficulty doing complex tasks as they get older.” © ScienCentral, 2000-2003.

Keyword: Alzheimers
Link ID: 3913 - Posted: 06.24.2010

by Steven H. Hyler, M.D. Psychiatric Times Negative stereotypes of patients with mental illness have a long history in Hollywood. Inaccurate portrayals have an important and underestimated negative effect on the perception of people with mental disorders--by the public, legislators, families and patients themselves. In this update of a 1991 presentation given by Glenn Gabbard, M.D., Irving Schneider, M.D., and myself, I will review some of the common stereotypes seen in film and television and discuss several recent films that perpetuate such myths. This stereotype dates back to early one-reel films. Several years before his famous Birth of a Nation (1915), D. W. Griffith gave the American public The Maniac Cook (1909). In this film, Griffith introduced the stereotype of the "deranged" mental patient who is dangerously violent and requires incarceration lest he or she wreak havoc upon society. Later versions of this stereotype can be found in the genre of horror films that first appeared in the 1960s, such as Psycho (1960), Halloween (1978) and the Friday the 13th series (1980 and later), and continue to the present. Recently, several popular films that reinforce this stereotype have appeared. Silence of the Lambs (1991) brought to the screen the character of Hannibal Lecter, the homicidal psychiatrist who killed his victims and, in one case, ate his liver "with some fava beans and a nice Chianti." Other recent films of this genre include American Psycho (2000), adapted from the controversial book of the same name by Bret Easton Ellis. Christian Bale plays Patrick Bateman, the ultimate yuppie homicidal maniac. © 2003 Psychiatric Times. All rights reserved.

Keyword: Schizophrenia
Link ID: 3912 - Posted: 06.24.2010

by H. Michael Zal, D.O. Psychiatric Times The successful treatment of social phobia requires an individualized treatment plan combining reassurance and education found in psychotherapy; relearning, possible through cognitive-behavioral therapy (CBT); and neurotransmitter adjustment, possible through psychopharmacology. Adequate treatment is best administered in the milieu of a solid therapeutic relationship. Following are some of the specific nonpharmacologic treatment choices that physicians can use in treating social phobia (Table 1). Individual psychotherapy. This treatment offers an opportunity to confirm an appropriate diagnosis, which in itself has a therapeutic effect. Once the condition has a name, the clinician and patient can work together to address it. Psychotherapy also allows therapists to reassure patients that their symptoms are real and not an indication that they are crazy or losing control. It allows for the establishment of a rapport that can reduce anxiety and enhance compliance. It provides education about the interplay of psychological, behavioral and biological forces in social phobia. Associated issues of patients' low self-esteem, lack of assertiveness or feelings of inferiority that often accompany social phobia also can be addressed. © 2003 Psychiatric Times. All rights reserved.

Keyword: Depression
Link ID: 3911 - Posted: 06.24.2010

In a new book, "The Ride Together: A Brother and Sister's Memoir of Autism in the Family," Paul and Judy Karasik tell the story of growing up in a tall Victorian house in Chevy Chase, Md., with their parents and two brothers, Michael and David. David, the oldest, is autistic and mildly retarded, and the book follows him as he grows from infancy to middle age. (He is now in his 50's and lives in a group home near Washington.) Excerpts follow; the first is set in 1960, the second in 1966. Judy Karasik narrates; the cartoons are by Paul Karasik. "How come David never has to clean up his room?" I asked. Copyright 2003 The New York Times Company

Keyword: Autism
Link ID: 3910 - Posted: 06.10.2003

By CLAUDIA DREIFUS CAMBRIDGE, Mass. — Dr. Cynthia L. Breazeal of the Massachusetts Institute of Technology is famous for her robots, not just because they they are programmed to perform specific tasks, but because they seem to have emotional as well as physical reactions to the world around them. They are "embodied," she says, even "sociable" robots — experimental machines that act like living creatures. As part of its design triennial, the Cooper-Hewitt National Design Museum in New York is exhibiting a "cyberfloral installation," by Dr. Breazeal, which features robotic flowers that sway when a human hand is near and glow in beautiful bright colors. "The installation," said Dr. Breazeal, 35, "communicates my future vision of robot design that is intellectually intriguing and remains true to its technological heritage, but is able to touch us emotionally in the quality of interaction and their responsiveness to us — more like a dance, rather than pushing buttons." Copyright 2003 The New York Times Company

Keyword: Robotics; Emotions
Link ID: 3909 - Posted: 06.24.2010