By DAVID LEONHARDT WHEN you look back on all the attempts to curb teenage drinking, smoking and drug use over the last couple of decades, you start to ask yourself a question that countless parents have asked: Does anybody really know how to change a teenager's behavior? Sometimes the government and advocacy groups have used straight talk, like Nancy Reagan's "Just Say No" campaign. Other times they have tried to play it cool. They drop an egg into a sizzling frying pan and announce, "This is your brain on drugs," or they print mock advertisements that pretend to market cancer. It all feels like a delicate exercise in adolescent psychology. Much of this back and forth is unnecessary. There is in fact a surefire way to get teenagers to consume less beer, tobacco and drugs, according to one study after another: raise the cost, in terms of either dollars or potential punishment. In just about every state that increased beer taxes in recent years, teenage drinking soon dropped. The same happened in the early 1990's when Arizona, Maryland, New Jersey and a handful of other states passed zero-tolerance laws, which suspend the licenses of under-21 drivers who have any trace of alcohol in their blood. In states that waited until the late 90's to adopt zero tolerance, like Colorado, Indiana and South Carolina, the decline generally did not happen until after the law was in place. Teenagers, it turns out, are highly rational creatures in some ways. Budweisers and Marlboros are discretionary items, and their customers treat them as such. Gasoline consumption, by contrast, changes only marginally when the price of a gallon does. Copyright 2005 The New York Times Company

Keyword: Drug Abuse
Link ID: 7680 - Posted: 07.25.2005

Roxanne Khamsi Life is a little less sweet for cats: an analysis of their genes shows that they lack functioning taste receptors for sugar. Throw a dog a bone or a bonbon and he'll enjoy either. Humans too have a taste for sugar. That's because, on most mammalian tongues, specialized taste bud receptors pick up on sweet tastes and send a pleasant signal to the brain. The receptors contain a pair of proteins called T1R2 and T1R3, which are hooked together. When sugar binds to these receptors, they set off a cascade of events within the cell that ultimately signal a sweet sensation. Scientists first documented cats' behavioural distaste for sugar in the 1970s1. But no one could explain why domestic cats (Felis silvestris catus) couldn't care less about candy. Joseph Brand of the Monell Chemical Senses Center in Philadelphia, Pennsylvania, and his colleagues decided to sequence the regions of the domestic cat's DNA that code for the T1R2 and T1R3 proteins. Whatever the cat is eating marshmallows for, it's not the sweetness. Perhaps it likes the texture or it's bored. ©2005 Nature Publishing Group

Keyword: Chemical Senses (Smell & Taste)
Link ID: 7679 - Posted: 06.24.2010

A hormone jab may offer burger lovers and the obese a way of reducing their appetites like the turn of a dial. A team at Imperial College London, UK, have found a natural hormone that boosts the stomach’s “full” signal. The hormone is oxyntomodulin, a peptide produced by the small intestine after a meal. In a trial, a group of 14 obese and overweight subjects self-administered doses of the hormone 30 minutes before breakfast, lunch and dinner. After four weeks they had lost an average 2.3 kilograms compared with a control group. The loss amounted to on average 2.4% of body weight. “By giving the overweight subject oxyntomodulin we are fooling the brain, in a very natural way, into thinking it has just eaten a meal and is no longer hungry,” says Steve Bloom, who led the trials. The researchers also found that the daily energy-intake by the test group was reduced by an average of 170 kilocalories after the first injection, to 250 kcal per day at the end of four weeks. The average recommended intake is 2500 kcal per day for men and 1940 kcal for women. The test subjects’ leptin levels - a hormone responsible for regulating the body's energy expenditure - were also reduced. The researchers also found a reduction in the levels of adipose hormones. These hormones normally encourage the build up of adipose tissues - where fat cells are stored. © Copyright Reed Business Information Ltd.

Keyword: Obesity
Link ID: 7678 - Posted: 06.24.2010

WASHINGTON - The government approved a new treatment for insomnia on Friday, the first prescription sleep aid not designated as a controlled substance. Called Rozerem, the drug works differently from its competitors. Rozerem is chemically related to the natural hormone melatonin, which helps regulate the body's sleep-wake cycle, and is thought to work by stimulating melatonin receptors in the brain, explained Dr. Robert Meyer of the Food and Drug Administration. "It's another option" for people with the main form of insomnia, difficulty in falling asleep, Meyer said. "By working through a different pathway, it's entirely possible that this might work for some people in ways that the other drugs do not." Nor do studies show any sign that Rozerem, known chemically as ramelteon, causes dependence, the reason it was not designated as a controlled substance. The main warning: Rozerem is metabolized by the liver, so people with liver problems shouldn't take it, Meyer said Copyright © 2005 The Associated Press. Copyright © 2005 Yahoo! Inc.

Keyword: Sleep
Link ID: 7677 - Posted: 06.24.2010

CHICAGO-Researchers from the Rush Alzheimer's Disease Center found that plaques and tangles in the brain, the changes seen in people with Alzheimer's disease (AD), are more likely to be expressed as dementia in women than in men. In the June 2005 issue of Archives of General Psychiatry, "Sex Differences in the Clinical Manifestations of Alzheimer Disease Pathology," principal investigator Lisa L. Barnes, PhD, sought to determine whether the relation between levels of AD pathology and clinical symptoms of AD differed in men and women. Alzheimer's disease is the leading cause of dementia in older people, she noted. The researchers studied older Catholic nuns, priests, and brothers in the Religious Orders Study, a longitudinal clinicopathologic study of aging and AD. The study involves annual clinical evaluations and brain donation at death. The analyses were conducted on 64 men and 77 women. Women were slightly older at death than men; four cortical regions of the brain were counted, and a global measure of AD was derived. Barnes found women had more global AD pathology than did men due primarily to more neurofibrillary tangles. "On a global measure of AD pathology that ranged from 0 to three, each additional unit of pathology increased the odds of clinical AD nearly three-fold in men compared with more than 20-fold in women. The findings suggest that AD pathology is more likely to be expressed clinically as dementia in women than in men. Our results suggest that the clinical manifestation of AD is stronger in women than in men."

Keyword: Alzheimers; Sexual Behavior
Link ID: 7675 - Posted: 06.24.2010

Bruce Bower When a capuchin monkey looks at its own image in a mirror, something strange happens. The diminutive creature reacts not as if it sees a stranger, as many researchers had assumed. Instead, the reflection gets treated as a special phenomenon, generally eliciting curiosity and friendly overtures from females and a mix of distress and fear from males, a new study finds. Capuchins' reactions signal an intermediate self-awareness that lies somewhere between seeing the mirror image as another individual and recognizing the reflected figure as self, according to a team led by psychologist Frans B.M. de Waal of Emory University in Atlanta. "It's clear that capuchins don't regard their mirror image as that of a stranger," de Waal says. "I'm not sure why they react as they do to mirrors." He suspects that confused capuchins are responding with sex-specific tactics for dealing with ambiguous situations. Investigators typically regard an animal as self-aware if it inspects a paint spot on its face in a mirror. People routinely pass this test by about age 2. Apes and dolphins often do so as adults. Capuchins and other monkeys ignore facial markings in the mirror. Yet capuchins distinguish the sight of their own reflections from the sight of other individuals, much as human babies do at about age 1, de Waal says. He and his colleagues studied eight female and six male monkeys housed at a research facility in Georgia. Copyright ©2005 Science Service

Keyword: Intelligence
Link ID: 7674 - Posted: 06.24.2010

If you've ever uttered the words, "I'm so hungry I could eat a horse," you know it's not literally possible to chow down on such a huge animal in one sitting. But have you ever considered what stops us from being able to do so (besides the scarcity of horsemeat on most menus)? Scientists say a number of hormones are at work in alerting us that we've had enough to eat. Now there's fresh evidence that one of those hormones—leptin—may alter brain structure in areas associated with craving and addiction in obese individuals born without a gene that produces leptin. The researchers looked at brain scans to see leptin activity in the brain before and after treatment. "There are very few people who have a genetic mutation, that they are just born without it…they tend to eat too much," explains Julio Licinio, a biobehavioral researcher at UCLA who, along with a team of UCLA scientists, studied the only three such people scientists have identified as lacking the leptin gene. Licinio gave them daily leptin replacement while his colleague, brain researcher Edythe London, used MRI brain scans to look at the volunteers' brain structure before they took leptin, and then at three and 18 months into the study. "We found dramatic results in brain structure," says London. "The actual composition of the brain changed, but it wasn't all over the brain. The composition of the brain changed only in regions known to be related to self control behaviors." © ScienCentral, 2000-2005.

Keyword: Obesity; Drug Abuse
Link ID: 7673 - Posted: 06.24.2010

By Jennifer Viegas, Discovery News — Individuals who cope well with stress after trauma usually are described as being "thick skinned," but new research reveals the thickness is in their brains, not in their skin. Scientists determined that resilient people tend to have a thick ventral medial prefrontal cortex (vmPFC), which is near the front of the brain. Conversely, this region tends to be thin for those who experience a lot of anxiety. The discovery will enable doctors to predict who is at risk for stress-related disorders, which could lead to better treatments and may even determine who is best suited for certain careers and activities. "For instance, an individual with a thin vmPFC might wish to avoid high risk professions such as policeman, firefighter or soldier," said Scott Rauch, co-author of the study, which recently appeared in the Proceedings of the National Academy of Sciences. Rauch, who is associate chief of psychiatry for neuroscience research at Massachusetts General Hospital, and his colleagues made the determination after testing 14 healthy volunteers. Volunteers looked at digital photographs of furnished rooms that contained lamps. Whenever the lamps lit up in colors, the test subjects would receive an electrical shock that each participant previously rated as "highly annoying but not painful." Copyright © 2005 Discovery Communications Inc.

Keyword: Stress
Link ID: 7672 - Posted: 06.24.2010

By Rossella Lorenzi, Discovery News — Birds fly south in search of warmer climates because they lack the brains to survive harsh winter conditions, according to a new study. Published in the journal Proceedings of the Royal Society, the research suggests that non-migrating species have bigger brains and are more creative at finding food in the hard winter months. Daniel Sol of the Independent University of Barcelona in Spain and colleagues reanalyzed previous observations of 134 songbird species breeding in the Western Palaearctic region, which includes Europe, North Africa, the Middle East and Central Asia. They divided the songbird species into three groups: long-distance migrants that winter south of Sahara; short-distance migrants that winter south of its breeding range but north of Sahara; and year-round residents. It emerged that species that stayed in one place were more creative in finding food. Copyright © 2005 Discovery Communications Inc.

Keyword: Intelligence; Animal Migration
Link ID: 7671 - Posted: 06.24.2010

All too often we hear of a parent arrested for abusing his or her child. Inevitably, someone asks, "how can this happen?" While the exact reasons for any human behavior are complicated, researchers now have evidence that sometimes such behavior may be passed on from one generation to the next. Because infant abuse is found in animals as well as humans, researchers have been able to study animals like Rhesus Monkeys to see if there are lessons that can be applied to humans. In a study published in the Proceedings of the National Academy of Sciences Dario Maestripieri of the University of Chicago reported that the infant's "early experience" being abused seems to be how the behavior is passed on, adding, "It doesn't seem to be genetically transmitted." He found this by swapping infants "at birth between [the] abusive and non-abusive mothers" eliminating the possibility of a genetic link between mother and any abusive traits the offspring might later show. When the infants grew up and became mothers, Maestripieri found that, "The individuals that had been reared by abusive mother had a high chance of becoming abusive mothers, themselves. Whereas, those that were born to abusive mothers, but were reared by control mothers did not become abusive parents." © ScienCentral, 2000-2005

Keyword: Aggression; Sexual Behavior
Link ID: 7670 - Posted: 06.24.2010

Like the rest of the 18 million people worldwide, everyday Lola Crosswhite strives to live a normal life while battling the effects of Alzheimer's disease. Today she fights the disease with the help of medications, notes and her daughter Diana Shaw. "We have a planner, we call it mom's paper brain," says Shaw. But she also tried fighting it with gene therapy. In 2002, Crosswhite was one of eight early-stage Alzheimer's patients who volunteered for a clinical trial to test the safety of the first gene therapy for the disease. Researchers led by University of California, San Diego Mark Tuszynski reported in the journal Nature Medicine that the safety trial showed promise. They took skin cells from patients, grew them up in a culture dish and genetically engineered them to make human nerve growth factor (NGF). The cells were then injected into the area of the brain where cells were dying due to Alzheimer's. In this way, the implanted cells act as biological pumps for the local delivery of the growth factors in the brain. "The growth factor released by these genetically engineered cells will bath the other cells in the growth factor, slow down the degeneration and thereby improve, or slow the decline in Alzheimer's disease," Tuszynski explains. "Establishing clearly that degenerating human cells can respond to growth factors." © ScienCentral, 2000-2005.

Keyword: Alzheimers
Link ID: 7669 - Posted: 06.24.2010

The odds of having a son or daughter aren't always even. Many kinds of animals will preferentially bear more males, or females, to increase the chances of passing on their genes. Female fruit flies, for example, bear more sons after mating with younger males than with older ones. Why? The reason, researchers have learned, is that the sons of young lovers are much more likely to turn out to be virile studs. To solve the puzzle, evolutionary biologists Tristan Long, now at the University of California in Santa Barbara, and Alison Pischedda, at Queen's University in Kingston, Canada, mated virgin female Drosophila to males of various ages. The team found that the sons of young (1-day old) males produced more offspring than sons of old (13-day old) males; whereas there was no difference in numbers of offspring produced by daughters of young and old males. This indicates that it pays to produce more sons when mated to a high quality (in this case, young) male, the researchers report online 20 July in Proceedings of the Royal Society B. Older males may give rise to poorer quality sons because they've accumulated harmful mutations during their lives, and these will have a bigger effect on sons than daughters because males experience more intense selection pressure when it comes to mating, the team speculates. But the researchers don't know how fruit flies skew their progeny's sex ratio towards sons or daughters. Copyright © 2005 by the American Association for the Advancement of Science.

Keyword: Sexual Behavior
Link ID: 7668 - Posted: 06.24.2010

CAMBRIDGE, Mass., –- Scientists working with salmon have found that gene expression in the brain can differ significantly among members of a species with different life histories. Their study indicates that roughly 15 percent of Atlantic salmon genes show differential expression in males who migrate from their freshwater birthplaces to mature in oceans versus those who do not leave the freshwater environment to mature. The researchers, at Harvard University, the University of Massachusetts and the US Geological Survey, report the finding in the current issue of Proceedings of the Royal Society B. They compared female salmon, male salmon that will eventually undertake the well-known journey from their river birthplaces to oceans –- and then migrate heroically back upstream one to three years later to spawn –- and males of the same age known as "sneakers" that mature at greatly reduced size without leaving freshwater. "The finding that hundreds of the nearly 3,000 genes we studied were expressed differently in the brains of sneakers and other male salmon came as a surprise," says Nadia Aubin-Horth, a postdoctoral researcher in the Bauer Center for Genomics Research in Harvard's Faculty of Arts and Sciences. "Since these males of the same species in the same wild environment differed only in their life history, we did not expect the expression of so many of their genes to differ." Aubin-Horth and her colleagues were also surprised by some of the 17 separate classes of genes demonstrating differing activity levels.

Keyword: Genes & Behavior; Sexual Behavior
Link ID: 7667 - Posted: 06.24.2010

By Jennifer Viegas, Discovery News — Humans attempt to do many things at the same time, such as driving and chatting on the phone, or working and listening to music, and now research suggests why such multitasking may be possible: the brain appears to have its own control center. Studies indicate that the physical "center" of the brain is located in the prefrontal cortex, on the left-hand front side, just above the temple. This is the first time that a "mastermind," which could control both visual and auditory activity, has been identified. Before the new research, most scientists thought the brain processed sight and sound in different areas. Now it is believed that sight and sound influence each other. "Many others have studied how matched audio-visual events, such as watching lips move and hearing speech sounds, are processed in the brain, but we wanted to draw attention to all of the audio-visual events humans are exposed to that are completely unrelated, like driving and talking on a cell phone or cleaning your apartment and listening to music," said Jennifer Johnson, lead author of the study and a researcher in the experimental psychology program at McGill University. Copyright © 2005 Discovery Communications Inc.

Keyword: Attention
Link ID: 7666 - Posted: 06.24.2010

Roxanne Khamsi A hormone that regulates appetite may also influence memory formation, researchers say. Recent findings, and the worldwide trend toward larger waistlines, have convinced them that we need to take a closer look at how obesity affects learning. In the past decade, a hormone known as leptin has received enormous attention for its role in regulating appetite and metabolism. Fat tissues produce significant quantities of this natural compound, which in turn reduces a person's desire to eat. At first, researchers were surprised to discover that obese individuals often over-express this hormone, as this would be expected to reduce their appetite. But many now believe that these people are simply desensitized to leptin. At the same time, studies have begun to link memory deficits with metabolic diseases such as obesity and diabetes. Jenni Harvey of the University of Dundee, UK, says patients with diabetes can experience "anything from short-term memory loss to Alzheimer's-like symptoms". And she says leptin is the key. An increasing number of reports show that abnormal levels of leptin can significantly alter brain cell function, Harvey told an audience at the annual meeting of the Biochemical Society in Glasgow, UK, this week. ©2005 Nature Publishing Group

Keyword: Learning & Memory; Obesity
Link ID: 7665 - Posted: 06.24.2010

New research suggests that accumulation of amyloid-â peptides in cerebral blood vessels, as opposed to the brain itself, may be a more important pathological mediator of Alzheimer's disease. Two independent yet related articles describe such findings in the August issue of The American Journal of Pathology. Both articles are highlighted on the Journal's cover. Alzheimer's disease, the most common form of progressive dementia, affects an estimated 4.5 million Americans according to the Alzheimer's Association. Amyloid-â (Aâ) deposition is a hallmark of Alzheimer's disease and other cerebral amyloid angiopathies. However, exactly how Aâ accumulates and causes damage is not fully understood. In the first article, "Cerebral microvascular Aâ deposition induces vascular degeneration and neuroinflammation in transgenic mice expressing human vasculotropic mutant AâPP," Miao et al. describe early-onset Aâ deposition in Tg-SwDI mice. These mice express Aâ protein with mutations that are found in human early-onset cerebral amyloid angiopathy, causing specific accumulation of Aâ in cerebral blood vessels. The Aâ peptides accumulated because they could not adequately cross the blood-brain barrier to be cleared from the brain. Over time, Aâ accumulation increased in the cerebral microvessels of the thalamus and subiculum of the brain. This resulted in degeneration of blood vessels as evidenced by reduced vessel density and increased apoptosis.

Keyword: Alzheimers
Link ID: 7664 - Posted: 07.21.2005

Cocaine may keep users from adapting to new situations by disrupting connections between key brain regions, suggests a new study in rats. The finding may shed light on the impulsive behaviour seen in cocaine addicts, researchers say. A team looked at the connections between two regions of the brain: one involved with learning, memory and processing information - the prefrontal cortex and hippocampus - and one involved with pleasure seeking, emotion and reward behaviour - the nucleus accumbens in the limbic system. Normally, these two regions are held in balance with connections between the two sending information in both directions and allowing “plasticity” of thought, so that behaviour can be modified and adapted to different situations. Neuroscientists Yuriori Goto and Anthony Grace at the University of Pittsburgh, US, believe that cocaine disrupts these connections and causes the limbic system to become over stimulated. “It may explain why cocaine addicts are oriented towards pleasure rather than other goals, and have an impaired ability to make decisions. It could be why addicts go back to taking more of the drug and ex-addicts often become addicted again faster than those who have never taken it,” says Grace. © Copyright Reed Business Information Ltd.

Keyword: Drug Abuse
Link ID: 7663 - Posted: 06.24.2010

Scientists who have discovered a gene linked to autism believe they can use the new knowledge to work out an individual's risk of the condition. The French team from IntegraGen SA hope to have a working risk assessment test on the market by the end of 2006. The gene sits on chromosome 16 and holds the DNA code for a protein that plays a central role in brain function. Experts said the Molecular Psychiatry study was promising but that it was premature to talk about an autism test. For their study, the French authors looked at 116 families where at least one member had autism. By analysing the DNA from these individuals they found a region on chromosome 16 - PRKCB1 - appeared to be linked with autism. PRKCB1 is expressed in granule cells in the cerebellum of the brain. Its associated protein is involved in transmitting signals from the granule cells to the Purkinje cells. Both these cells help relay messages in and out of the brain. Researchers have already found a decreased number of both granule and Purkinje cells in the brains of people with autism. Lead researcher Dr Jorg Hager said: "This is the first time that the protein PRKCB1, and the brain functions that it is involved with, have been associated with autism. The test they are devising will check for the presence of four genes, including PRKCB1, linked to autism. They envisage that families who already have a child with autism would be able to have their other children tested at an early age - around 18 months. If the cheek swab sample is positive, it means the infant is at increased risk of developing autism and early interventions such as behavioural educational programmes, can be started, said Dr Hager. Around 535,000 people in the UK have an autism spectrum disorder. (C)BBC

Keyword: Autism; Genes & Behavior
Link ID: 7662 - Posted: 07.20.2005

By GARDINER HARRIS WASHINGTON, - Top officials from three of the nation's premier public health agencies held an unusual news conference on Tuesday to say that childhood vaccines are life-saving medicines with no proven link to autism. "The science says very clearly that vaccines save lives and protect our children," said one of the officials, Dr. Julie L. Gerberding, director of the Centers for Disease Control and Prevention. To many, that declaration might have seemed akin to an announcement so basic as that high cholesterol readings are linked with heart disease. But the officials felt a need to make a forceful defense of vaccines because a growing number of parents contend that a mercury-containing vaccine preservative called thimerosal caused their children to become autistic. Indeed, several parents held a vigil outside the news conference, with one holding a large sign blaming vaccines for her child's disorder. Representative Dave Weldon, a Florida Republican who champions the notion that thimerosal has caused an explosion of autism cases around the world, attended the news conference and, after it ended, gave his own press briefing criticizing the public health officials. Copyright 2005 The New York Times Company

Keyword: Autism; Neurotoxins
Link ID: 7661 - Posted: 07.20.2005

Seeing is something most of us take for granted, so a loss of vision can be frightening. "I was going to my college reunion and I was watching television the night before the reunion started. And all of a sudden I couldn't see anything on the television," recalls New Yorker Robert Burch, 71, who lost his sight in his right eye ten years ago due to age-related macular degeneration, or AMD. "All of a sudden that eye was finished, and it happens like that. And it's the scariest thing in the world because now you're afraid, 'My God, what happens if the second eye goes?'" Sadly, AMD, the leading cause of untreatable vision loss and legal blindness in the U.S. for people over the age of 60, has robbed more than 10 million Americans of some or all of their vision. Treatments have helped to keep people like Burch seeing longer, but there is no cure. Now, a team of researchers looking for the genetic causes of AMD has found that when a commonly inherited gene mutation is triggered, most likely by an infection, it can result in AMD. But at the same time they saw that certain other mutations in that gene actually protect against the chance of developing AMD. "The results were quite amazing," says geneticist Rando Allikmets, Acquavella Associate Professor in opthamology and Research Director at the Edward S. Harkness Eye Institute at Columbia University Medical Center. "Genetically speaking, I never believed there was a major gene that was involved in AMD… however it is the case. Now we know that at least half of the entire disease is caused by variants, common variants in Factor H." © ScienCentral, 2000-2005.

Keyword: Vision; Genes & Behavior
Link ID: 7660 - Posted: 06.24.2010