Irvine, Calif., --A research team led by UC Irvine neuroscientists has identified how the brain processes and stores emotional experiences as long-term memories. The research, performed on rats, could help neuroscientists better understand why emotionally arousing events are remembered over longer periods than emotionally neutral events, and may ultimately find application in treatments for conditions such as post-traumatic stress disorder. The study shows that emotionally arousing events activate the brain's amygdala, the almond-shaped portion of the brain involved in emotional learning and memory, which then increases a protein called "Arc" in the neurons in the hippocampus, a part of the brain involved in processing and enabling the storage of lasting memories. The researchers believe that Arc helps store these memories by strengthening the synapses, the connections between neurons. The study will appear in today's issue of the Proceedings of the National Academy of Sciences. "Emotionally neutral events generally are not stored as long-term memories," said Christa McIntyre, the first author of the paper. "On the other hand, emotionally arousing events, such as those of September 11, tend to be well-remembered after a single experience because they activate the amygdala."

Keyword: Stress; Emotions
Link ID: 7690 - Posted: 07.27.2005

Happy, sad, angry, scared: Some of us are good at hiding these everyday emotions, while others are unable to disguise them. Whether subtle or intense, facial expressions are the key to how we identify human emotion. Most studies of how we recognize facial expressions have used static models of intense expressions. But new research indicates that facial motion—seeing the range of movement in the arching of an eyebrow or the curve of a smile—is in fact an extremely important part of what makes subtle facial expressions identifiable. A recent study by Zara Ambadar and Jeffrey F. Cohn of the University of Pittsburgh and Jonathan W. Schooler of the University of British Columbia, examined how motion affects people's judgment of subtle facial expressions. Their report, "Deciphering the Enigmatic Face: The Importance of Facial Dynamics in Interpreting Subtle Facial Expressions," is in the May 2005 issue of Psychological Science, a journal of the American Psychological Society. Two experiments demonstrated robust effects of motion in facilitating the perception of subtle facial expressions depicting six emotions, anger, disgust, fear, happiness, sadness and surprise. For the initial experiment, participants viewed a series of subtle facial expressions, displayed by faces on a computer screen. The faces varied in the way they were displayed; in the single static display, only the final expression was shown, while the dynamic displays showed the emergence of a subtle expression through several images, ending at the identical final expression.

Keyword: Emotions
Link ID: 7689 - Posted: 06.24.2010

How alike are you and your husband or wife — or, you and your best friend? Probably more alike than you realize. A study of twins shows that people's spouses and best friends are much more similar to them than was previously recognized — about as close as brothers and sisters. The research also suggested that the preference for partners who are similar to us is partly due to our genes. The research was conducted by J. Philippe Rushton and Trudy Ann Bons of the University of Western Ontario. Their findings are reported in "Mate Choice and Friendship in Twins: Evidence for Genetic Similarity," published in the July 2005 issue of Psychological Science, a journal of the American Psychological Society. Several hundred pairs of identical and fraternal twins, their spouses, and their best friends were sent a 130-item questionnaire that measured social background, personality, and attitudes. Twins turned out to be as similar to their spouses and friends as they were to their fraternal twins, though not as similar as they were to identical twins. The spouses of identical twins (who share 100 percent of their genes) were also more similar to each other than were the spouses of fraternal twins (who only share 50 percent of their genes); the same was true of twins' best friends.

Keyword: Genes & Behavior
Link ID: 7688 - Posted: 06.24.2010

By LAURA TANGLEY These days, it seems, even the moral values of birds are subject to scrutiny. To investigate the spousal fidelity of eastern imperial eagles, large raptors native to central Asia, a team of surreptitious scientists collected feathers the birds had shed near their nests in northern Kazakhstan. Extracting and analyzing DNA from the feathers confirmed that not a single eagle had strayed from its mate during the course of the six-year study - a degree of monogamy unusual among birds. Biologists once believed that most, if not all, bird species were monogamous. But over the past decade, that presumption, based on observations of apparently faithful male-female pairs building nests and raising young together, has been overturned by genetic "paternity tests" of blood samples from the birds. In more than 75 percent of avian species looked at so far, researchers have discovered broods that have two or more fathers. Because obtaining their blood is so difficult, however, large raptors like eagles remain largely untested. Biologists suspect that raptors, unlike smaller songbirds, may indeed be monogamous, in part because they are long-lived species in which males invest considerable energy caring for their offspring and mates. In addition, raptors are "large, ferocious birds of prey equipped with talons and sharp curved beaks," said Andrew DeWoody, an associate professor of genetics at Purdue and a co-author of the eagle study, published online this month in Molecular Ecology. "If a bird gets caught cheating, the repercussions could be severe." Copyright 2005 The New York Times Company

Keyword: Sexual Behavior
Link ID: 7687 - Posted: 07.26.2005

Durham, N.C. – Plant toxins in the diets of early humans drove the evolution of a bitter taste receptor better able to detect them, suggests new genetic research by scientists at University College London, Duke University Medical Center, and the German Institute of Human Nutrition. The ability to discern bitter flavors likely offered a survival advantage by protecting ancient people from poisonous fare, the researchers concluded. Today, however, the same sensory sensitivity may have adverse consequences for human health, they added, by causing an aversion to bitter-tasting nutrients, some of which might lower the risk of cancer and heart disease. In their study, the researchers examined the sequence of one gene encoding the bitter taste receptor TAS2R16 in 60 human populations from all over the world. By reconstructing the history of the gene, the researchers found evidence of evolutionary selection. Specifically, they found that particular derived variants of the taste receptor rapidly rose to high frequency many thousands of years ago, before the expansion of early humans out of Africa. Through further analyses they showed that one of the selected gene variants confers an increased sensitivity to particular toxins, including five that release cyanide when digested. The receptor variant also is more sensitive to certain beneficial compounds, they showed. The team reported its findings in the July 26, 2005, issue of Current Biology. The researchers included senior author David Goldstein, Ph.D., of the Duke Institute for Genome Sciences & Policy (IGSP) and lead author Nicole Soranzo, Ph.D., of the University College London. © 2001-2005 Duke University Medical Center.

Keyword: Chemical Senses (Smell & Taste); Evolution
Link ID: 7686 - Posted: 06.24.2010

The brain is bombarded by information about the physical proportions of our bodies. The most familiar sensations, such as a puff of wind or the brush of our own shirt sleeve, serve to constantly remind the brain of the body's outer bounds, creating a sense of what is known as proprioception. In a new study, researchers report this week that the brain's ability to interpret external signals and update its sense of bodily self is more dynamic than had been previously thought and that such updates can happen very quickly, altering within a matter of seconds how body parts and individual touch sensations are perceived. The information that is integrated in the course of proprioception comes from several different senses, including touch, pain, vision, information from muscles, and so on. The brain must combine all these information inputs to accurately perceive the external world through our body's interaction with it and also to produce a coherent sense of self. Because all these signals carry such different kinds of information, the brain must perform a constant juggling act in order to make sense of the body and the world. In the new study, the research team used a method called tendon vibration to induce a distortion of healthy volunteers' sense of their own bodies. When the biceps tendon of the right arm was vibrated, the subjects in the experiments felt within seconds that their right elbow was rotating away from the body, even though the arm was actually quite still. If subjects held their left index finger with their right hand while this happened, they felt their left index finger getting longer as they felt their arm move.

Keyword: Pain & Touch
Link ID: 7685 - Posted: 07.26.2005

CHICAGO – A testosterone patch may produce modest increases in sexual desire and frequency of satisfying sexual experiences in women who develop distressful, low sexual desire following hysterectomy and removal of the fallopian tubes and ovaries, according to a study in the July 25 issue of Archives of Internal Medicine, one of the JAMA/Archives journals. Diminished sexual desire has been reported by 30 to 50 percent of women who undergo surgical menopause (menopause induced by the surgical removal of both ovaries), according to background information in the article. In one form of female sexual dysfunction, hypoactive sexual desire disorder, a chronic absence of desire for sexual activity results in personal distress. When the ovaries are removed (oophorectomy), blood levels of sex hormones, including testosterone, drop. Although some women see improvements in sexual functioning with estrogen therapy alone, previous studies suggest that the combination of estrogen and testosterone is more effective in preserving sexual desire. Glenn D. Braunstein, M.D., of Cedars-Sinai Medical Center, Los Angeles, and colleagues conducted a 24-week, randomized, double blind, multicenter clinical trial in women who developed distressful low sexual desire after surgical menopause and were receiving oral estrogen therapy. The 447 women (aged 24 to 70 years) were randomized to receive placebo or testosterone patches twice weekly in one of three progressively higher doses. Testosterone levels were checked at baseline, 12 and 24 weeks. Changes in sexual desire and frequency of satisfying sexual activity were determined on the basis of a woman's reports on standardized questionnaire and sexual function activity log.

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 7684 - Posted: 06.24.2010

Two recent studies suggest that multiple rare mutations within a single gene may increase risk for autism, according to investigators with the Vanderbilt Center for Molecular Neuroscience and the Vanderbilt Kennedy Center for Research on Human Development While debate still rages over the 'cause' of autism, mounting evidence suggests that genetic factors play a major role in the disease. Two recent studies suggest that multiple rare mutations within a single gene may increase risk for autism. Their findings also may point to new therapeutic options for this devastating disorder. In this pair of studies, the researchers identify and characterize a number of mutations in the gene that regulate brain levels of serotonin, a neurotransmitter involved in many biological processes including breathing, digestion, sleep, appetite, blood vessel constriction, mood and impulsivity. About 25 percent of people with autism have elevated levels of serotonin in their blood. Selective serotonin reuptake inhibitors (SSRIs), drugs used to treat depression, anxiety and obsessive-compulsive disorders, also improve some of the symptoms of the disorder. These findings have led scientists to propose that serotonin plays an important role in autism. In the August issue of the American Journal of Human Genetics, Sutcliffe, Blakely and colleagues report that several mutations within the serotonin transporter (SERT) gene, which regulates serotonin levels in the brain, may be risk factors for autism.

Keyword: Autism
Link ID: 7683 - Posted: 07.26.2005

Jim Giles Why doesn't the world go dark when we blink? Because a critical part of the brain switches off and fails to detect the blackness behind closed eyes, says a team of neuroscientists. We blink about ten times a minute without noticing any change in what we see. Researchers had suspected that this is because the visual system is inactivated during blinking, but were not able to prove this. A team at University College London have cracked the problem by inserting an optical fibre into the mouths of people wearing black-out goggles. The fibre illuminated the back of the subjects' retinas, so that they saw a light at all times, even when they blinked. This allowed the researchers, who publish their results in Current Biology1, to distinguish between the effects of the act of blinking and the darkness that it causes. Using magnetic resonance imaging (fMRI) brains scans, Davina Bristow and colleagues revealed that activity in a part of the visual system known as V3 was suppressed in subjects when they blinked. V3 is one of a series of brain areas that handle signals sent from the eyes. With it out of action, the blink goes unnoticed. "It's not that the visual gap is filled in," says Bristow. "It's that you're not aware of it." ©2005 Nature Publishing Group

Keyword: Vision
Link ID: 7682 - Posted: 06.24.2010

Scientists say they have discovered a protein that could be injected to repair damaged nerves and brain cells. The protein, KDI tripeptide, works by blocking the harmful effects of a substance present in degenerative brain diseases and spinal cord injuries. By blocking this substance, called glutamate, KDI prevents permanent cell death and helps the body heal itself. The Finnish work from the University of Helsinki will be published online by the Journal of Neuroscience Research. So far the researchers have tested KDI in the lab on animals and nerve cells from humans. The findings have been promising and they hope to be able to begin treating people with nerve and degenerative brain diseases, such as Alzheimer's and Parkinson's disease, using KDI injections within a year. Since KDI occurs naturally in some form in the body, researchers do not believe it will have major toxic side effects. None have been noted during their work to date. Lead researcher Dr Päivi Liesi said: "We have had such good results with animals that I think it is totally feasible we would be ready to start human clinical trials within a year." Currently, KDI has to be injected as a solution directly to the damaged area. However, in the future it might be possible to make the treatment as an oral drug or an intravenous injection, said Dr Liesi. Her work builds on that of Dr George Martin from the National Institute on Ageing, at the US National Institutes of Health, who first discovered the molecule that KDI is derived from. Dr Martin said: "This represents a new approach and one with considerable promise. (C)BBC

Keyword: Regeneration
Link ID: 7681 - Posted: 07.25.2005

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