LOVERS know only too well that men usually need a "recovery period" after orgasm, and that sexual intercourse with orgasm is more satisfying than an orgasm from masturbation alone. Now scientists think the two phenomena might be linked. Following orgasm, the hormone prolactin is released into the bloodstream in both men and women. The hormone makes us feel satiated by countering the effect of dopamine, which is released during sexual arousal. Stuart Brody of the University of Paisley, UK, and Tillmann Krüger of the Swiss Federal Institute of Technology in Zurich, measured blood prolactin levels in male and female volunteers who watched erotic films before engaging in masturbation or sexual intercourse to orgasm in the laboratory.

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 8569 - Posted: 02.23.2006

By Rob Stein, Washington Post Staff Writer Medicare endorsed three types of stomach-shrinking surgery yesterday, saying the controversial procedures can offer Americans safe and effective ways to treat obesity. The announcement was seen as a boost for the popular operations, known as bariatric surgery, which had come under a cloud in recent years because of concerns about their safety. "In the right hands, bariatric surgery can benefit patients," said Steve Phurrough of the Centers for Medicare and Medicaid Services, which sets policy for the federal health program. Under the new rules, Medicare will pay for the surgery for obese patients who are suffering from other health problems related to their weight, as long as they undergo the procedure at centers that have been certified as well qualified by the American College of Surgeons or the American Society of Bariatric Surgery. Although some insurers do not cover it, the number of people undergoing the procedures, which cost $25,000 to $40,000, has increased rapidly, jumping from about 16,000 operations in 1992 to an estimated 170,000 in 2005. © 2006 The Washington Post Company

Keyword: Obesity
Link ID: 8568 - Posted: 06.24.2010

By JANE E. BRODY Pregnancy has long been assumed to be a time of expectant joy, at least for women whose pregnancies are planned and who look forward to motherhood. And indeed, it is a happy time for most. But not all. A significant minority — 10 to 20 percent, depending on who is counting — suffer moderate to severe depression during pregnancy, which translates to 80,000 women a year in the United States. All too often the problem goes unrecognized by the women and their doctors. Some depression symptoms — fatigue, change in appetite and lack of energy — overlap normal signs of pregnancy, prompting some women to ignore them. Others are embarrassed to mention their depressed feelings to their doctors since they're supposed to be thrilled to be pregnant. But even when pregnancy-related depression is recognized and acknowledged, women and their doctors can find themselves in a dilemma. After decades of warnings to avoid all manner of drugs, alcohol, nicotine and caffeine, pregnant women are often reluctant to take antidepressants even if their doctors will prescribe them. New studies examining possible effects of antidepressants on the fetus as well as the risks involved in failing to treat depression during pregnancy are likely to make decisions even harder. The decision to treat or not to treat must involve a careful assessment of known risks and benefits based on the best medical information available. Copyright 2006 The New York Times Company

Keyword: Depression; Development of the Brain
Link ID: 8567 - Posted: 06.24.2010

Roger Highfield The reputation that elephants never forget has been given a chilling new twist by experts who believe that a generation of pachyderms may be taking revenge on humans for the breakdown of elephant society. The New Scientist reports that elephants appear to be attacking human settlements as vengeance for years of abuse by people. In Uganda, for example, elephant numbers have never been lower or food more plentiful, yet there are reports of the creatures blocking roads and trampling through villages, apparently without cause or motivation. Scientists suspect that poaching during the 1970s and 1980s marked many of the animals with the effects of stress, perhaps caused by being orphaned or witnessing the death of family members - and produced the equivalent of post- traumatic stress disorder. Many herds lost their matriarch and had to make do with inexperienced "teenage mothers." Combined with a lack of older bulls, this appears to have created a generation of "teenage delinquent" elephants. © 2005 The Standard, Sing Tao Media Corporation.

Keyword: Evolution
Link ID: 8566 - Posted: 06.24.2010

By Rhitu Chatterjee ST. LOUIS, MISSOURI--Gorillas deserve to join the club of "cultured apes." That's the conclusion of the first large-scale study of multiple behaviors in zoo gorillas, reported here yesterday at the annual meeting of the American Association for the Advancement of Science (which publishes ScienceNOW). Culture is defined as a range of behaviors learned from others that varies with the group one belongs to. For example, chimpanzees belonging to one population in Mahale, Tanzania, groom each other with one hand while clasping their free hands together. Another group in the same region has a slightly different tradition: grooming partners touch their free wrists. Yet despite growing evidence for culture in chimpanzees, bonobos, and orangutans, not much is known about gorilla culture or whether it exists at all. The elusive nature of most gorilla species makes it difficult to gather behavioral data in the wild. So a team led by primatologist and conservationist Tara Stoinski of Zoo Atlanta in Georgia decided to monitor the behavior of captive gorillas in 17 American zoos. Earlier observations by her group had shown that gorillas could copy their group members. When one gorilla used sticks to pry apart electric wires around trees to get at the bark, for example, others in the group followed suit. But in order for this behavior to be considered culture, other populations of gorillas would need to react differently. © 2006 American Association for the Advancement of Science.

Keyword: Evolution
Link ID: 8565 - Posted: 06.24.2010

As the prism of our senses, the human brain has ways of refracting sensory input in defiance of reality. This is seen, for example, in the placebo effect, when simple sugar pills or inert salves taken by unwitting subjects are seen to ease pain or have some other beneficial physiological effect. How the brain processes this faked input and prompts the body to respond is largely a mystery of neuroscience. Now, however, scientists have begun to peel back some of the neurological secrets of this remarkable phenomenon and show how the brain can be rewired in anticipation of sensory input to respond in prescribed ways. Writing in the current issue (March 1, 2006) of the journal Brain, Behavior, and Immunity, a team of University of Wisconsin-Madison scientists reports the results of experiments that portray the brain in action as it is duped. The new work, conducted by a team led by UW-Madison assistant professor of psychology and psychiatry Jack B. Nitschke, tested the ability of the human brain to mitigate foul taste through a ruse of anticipation. The work, conducted at the UW-Madison Waisman Center using state-of-the-art brain imaging techniques and distasteful concoctions of quinine on a cohort of college students, reveals in detail how the brain responds to a manipulation intended to mitigate an unpleasant experience.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 8564 - Posted: 02.22.2006

By Jennifer Viegas, Discovery News — Professional dancers are born with at least two special genes that give them a leg up on the rest of us, according to a new study. Recent research also has suggested that intelligence, athletic ability and musical talent are linked to our genes and brain hard-wiring. With dancing added to the list, the evidence indicates that certain individuals are born with a predisposition to specific behaviors and talents, and that at least some of these qualities may represent evolved attributes. "I think that dancing is an evolved trait," said Richard Ebstein, who led the recent study, published in a recent Public Library of Science Genetics journal. "Animals have courtship dances and I think that human dancing represents the further development of a very ancient animal trait." Ebstein, a psychology professor at Hebrew University's Scheinfeld Center for Genetic Studies, said, "Also the fact that dancing is universal and existed in all human societies, even those communities of man separated geographically by tens of thousands of years (native Australians, native Americans, Africans, Eurasians) attests to the very early origin of dance in our evolution as a species." © 2006 Discovery Communications Inc.

Keyword: Genes & Behavior; Sexual Behavior
Link ID: 8563 - Posted: 06.24.2010

Independent research teams from Harvard Medical School and Children's Hospital Boston have identified a master protein that sheds light on one of neurobiology's biggest mysteries--how neurons change as a result of individual experiences. The research, which appears in two papers in the latest issue of Science (Feb 17), identifies a central protein that regulates the growth and pruning of neurons throughout life in response to environmental stimuli. This protein, and the molecular pathway it guides, could help investigators understand the process of learning and memory, as well as lead to new therapies for diseases in which synapses either fail to form or run rampant, such as autism, neurodegenerative diseases, and psychiatric disorders. Though axons and dendrites can be easily spotted waxing and waning under the microscope, the molecular middlemen working inside the cell to shape the neuron's sinewy processes have been much more elusive. The teams found a protein that works in the nucleus of neurons that either pares down or promotes synapses depending on whether or not the neuron is being activated. The protein, myocyte enhancer factor 2 (MEF2), turns on and off genes that control dendritic remodeling. In addition, one of the teams has identified how MEF2 switches from one program to the other, that is, from dendrite-promoting to dendrite-pruning, and the researchers have identified some of MEF2's targets.

Keyword: Learning & Memory
Link ID: 8562 - Posted: 02.22.2006

The discovery of a new role for a sex gene could explain why men are one-and-a-half times more likely to develop Parkinson's disease than women. Scientists at the University of California at Los Angeles (UCLA), US, found that a sex gene responsible for making embryos male and forming testes is also produced by the brain region targeted by the debilitating neurological disease. "Our findings may offer new clues to how the disorder affects men and women differently, and shed light on why men are more susceptible to the disease,” says Eric Vilain, a geneticist at UCLA's David Geffen School of Medicine. In 1990, UK researchers identified the male gender gene, known as SRY. It is located on the male Y sex chromosome and manufactures a protein that is secreted by cells in the testes. The UCLA study unexpectedly showed that the SRY protein also appears to help neurons located in an area of the brain known as the substantia nigra - a motor control centre - secrete the neurochemical dopamine. © Copyright Reed Business Information Ltd.

Keyword: Parkinsons; Sexual Behavior
Link ID: 8561 - Posted: 06.24.2010

Researchers from The University of Texas at Austin studying electric fish have gained new insight into how memory is stored at the level of neurons. Their finding, published in the Feb. 16 issue of Neuron, could help researchers better understand memory formation and neural disorders like epilepsy in humans. Dr. Harold Zakon, Dr. Jörg Oestreich and colleagues show that when electric fish zap each other in dark waters, their neurons store a memory of the sizzling communiqué by turning on special cell membrane channels. The channels give the fish neurons the ability to retain a memory long after its original stimulus is gone. "There is short-term stimulation that results in long-term changes in excitability," says Zakon, professor of neurobiology. "Essentially, it is memory." The electric fish studied by Zakon and Oestreich discharge electrical signals to survey their environment and communicate with each other. "Every time they discharge, it's kind of like they are opening their eyes and closing them," says Zakon. "Each pulse of electricity is a snapshot of the environment. These guys are swimming around and discharging at a very regular frequency. They're digitizing their environment."

Keyword: Pain & Touch; Learning & Memory
Link ID: 8560 - Posted: 06.24.2010

Sean Mackey, associate Director for the Pain Management Division of Stanford University School of Medicine, found that if people could watch a certain part of their brains in action in real time, they could use that feedback to learn how to manage pain. He calls it a case of, "Brain over pain." "What's unique about this specific experiment," says Mackey, "is that this experiment, for the first time, studied a group of people and taught them to learn how to control their own brain, a specific region in their own brain. And by doing so, it changed their behavior… that's never been done before." The specific part of the brain that is involved in pain perception and regulation is deep inside the brain. It's called the Rostral Anterior Cingulate Cortex (rACC). It was that part Mackey and his team wanted people to watch. People were put in an MRI scanner similar to those used to scan parts of the body for injuries. However this was a functional real-time MRI scanner, which allowed people, according to Mackey, "To then see their own brain activity on a moment by moment basis." Some of the people Mackey observed were patients who suffered chronic pain. Others were volunteers who agreed to endure a moderately painful hot probe touching them. While the volunteers were watching their own brains in action, the team then gave them various strategies on how to manage the pain. © ScienCentral, 2000-2006.

Keyword: Pain & Touch
Link ID: 8559 - Posted: 06.24.2010

By Mary Beckman ST. LOUIS, MISSOURI--Scientists hoping to find a simple set of genes that dictates a predisposition to addiction are likely to be frustrated, according to new research, which reinforces the notion that not only are addictions genetically complex, but they also overlap with each other to some extent. Studies with twins indicate that addiction to nicotine, alcohol, and other drugs is partly inherited. Health professionals would love to understand the genes responsible, but the handful identified so far likely represent only a small portion of those at work. To see if a general set of addiction genes can explain most bad habits, geneticist Kirk Wilhelmsen of the University of North Carolina, Chapel Hill, examined how smoking and other addictive behaviors were passed down in two different populations of people. The first included almost 400 California families in which at least three people smoked. People who scored highest on a standard nicotine addiction test or who had high numbers of smoking withdrawal symptoms sported a particular genetic sequence on chromosome 6, the researchers reported here today at the annual meeting for the American Association for the Advancement of Science (which publishes ScienceNOW). In contrast, those for whom cigarettes were particularly relaxing shared sequences on chromosome 15. This group also had a unique region on chromosome 4 that appears to be linked to the amount of time people take in the morning to light up. This same region is known to harbor many genes involved in alcohol metabolism. © 2006 American Association for the Advancement of Science.

Keyword: Drug Abuse; Genes & Behavior
Link ID: 8558 - Posted: 06.24.2010

Bruce Bower Among elderly people, a spouse's hospitalization for certain ailments substantially raises his or her partner's likelihood of dying, according to the largest study ever to quantify such effects. The risk is especially great within the first month after the spouse enters the hospital. Partners died most frequently following their spouses' hospitalizations for particularly disabling conditions, such as dementia, psychiatric illness, and hip or other bone fractures, say medical sociologist Nicholas A. Christakis of Harvard Medical School in Boston and sociologist Paul D. Allison of the University of Pennsylvania in Philadelphia. "Our study shows that your chances of dying increase not just when your partner dies, but when your partner becomes seriously ill," Christakis says. After climbing rapidly in the first weeks after a spouse's hospitalization, a partner's risk of death declines to slightly above normal for a few months before rising again for the rest of the time examined, the scientists report in the Feb. 16 New England Journal of Medicine. The length of the spouse's hospitalization didn't affect the death risk. Copyright ©2006 Science Service.

Keyword: Stress; Neuroimmunology
Link ID: 8557 - Posted: 06.24.2010

By Rossella Lorenzi, Discovery News — The huge, ferocious North American Tyrannosaurus rex was a rigid and stiff beast with razor-sharp sensory skills, according to new research presented Friday at the meeting of the American Association for the Advancement of Science in St. Louis. CT scans allowed Lawrence Witmer, from Ohio University College of Osteopathic Medicine, to explore the inside of a four-foot-long T. rex skull and look for regions that were unusually developed. Several 3-D visualizations of the brain cavity, nerve and vascular trunks, and the labyrinth of the inner ear, revealed that the beast had surprisingly well-developed smell, hearing and balance, normally features typical of smaller and more agile animals. Large olfactory lobes in the brain indicated that T. rex had a keen sense of smell, while the inner ear structures linked to hearing showed that the creature was good at discriminating different kinds of sound. The organ used for balance indicated that the ferocious killer had excellent equilibrium. "The inner-ear structure is consistent with a dynamic lifestyle involving rapid tracking movements of the eyes and head," Witmer concluded. © 2006 Discovery Communications Inc.

Keyword: Evolution
Link ID: 8556 - Posted: 06.24.2010

Jim Giles Do the faint traces of anaesthetics that waft around operating rooms somehow prime physicians to become drug addicts? It's not as unlikely a proposal as it sounds. US researchers who have promoted the theory have released their latest findings, and the results strengthen fears that exposure to aerosolized drugs puts anaesthetists and surgeons at risk. The new data comes from a trawl of records on health problems among medics working in Florida. Trainee surgeon Priscilla McAuliffe and colleagues at the University of Florida in Gainesville found that although anaesthetists make up less than 5% of the state's licensed physicians, they accounted for 12% of the 150 physicians who began treatment for substance abuse in 20021. Surgeons also made up a good chunk of the physicians being treated for addiction. And these surgeons disproportionately took the opiates used in anaesthetics as their drug of choice, the team has found. Whereas around 25% of all physicians treated for addiction were abusing opiates, among surgeons this figure was 40%. The data is particularly striking for a very common anaesthetic called fentanyl. Reporting their results in June last year at a meeting of the College on Problems of Drug Dependence in Orlanda, Florida, McAuliffe's colleagues have found that 94% of physicians reporting addiction to fentanyl were anaesthetists or surgeons. ©2006 Nature Publishing Group

Keyword: Pain & Touch; Drug Abuse
Link ID: 8555 - Posted: 06.24.2010

Roxanne Khamsi, St Louis Growing up in an orphanage can substantially stunt early cognitive and physical development – but being placed in foster care may reverse this to some degree, a study of abandoned Romanian children suggests. However, the researchers observing the youngsters found that boys do not show the same initial improvements as girls when placed in foster care: "The girls placed in foster care do much better in terms of their IQ scores compared with boys," says Nathan Fox of the University of Maryland, US, one of the team. The study involved comprehensive assessments of 136 children placed in institutional care as part of the Bucharest Early Intervention Project. Sixty-nine of the originally institutionalised children were selected at random and placed in foster care, while the remaining 67 youngsters stayed in the orphanage. There are not enough resources in Bucharest to place all of the children in foster care, the researchers say. At about 4.5 years of age, girls in foster care scored an average of 82 on the IQ test given to them, while those who remained in institutional care scored an average of 70. But the mean score of boys in both groups was in the 60s. Even with foster care intervention, most of the children still scored in the low IQ range. Average IQ scores are around 100. © Copyright Reed Business Information Ltd.

Keyword: Development of the Brain; Sexual Behavior
Link ID: 8554 - Posted: 06.24.2010

By GARDINER HARRIS WASHINGTON, — A top federal medical official overruled the unanimous opinion of his scientific staff when he decided last year to approve a pacemaker-like device to treat persistent depression, a Senate committee reported Thursday. The device, the surgically implanted vagus nerve stimulator, had not proved effective against depression in its only clinical trial for treatment of that illness. As a result, scientists at the Food and Drug Administration repeatedly and unanimously recommended rejecting the application of its maker, Cyberonics Inc., to sell it as such a treatment, said the report, written by the staff of the Senate Finance Committee. But Dr. Daniel G. Schultz, director of the Center for Devices and Radiological Health at the agency, kept moving the application along and eventually decided to approve it, the report said. That approval did follow the backing of a divided F.D.A. advisory committee. Still, the Senate committee, which for two years has been investigating the decision-making processes at the F.D.A., could find no previous instance in which the director of the center had approved a device in the face of unanimous opposition from staff scientists and administrators beneath him, the report said. Copyright 2006 The New York Times Company

Keyword: Depression
Link ID: 8553 - Posted: 06.24.2010

Researchers at the University of Pennsylvania School of Medicine discovered that a key receptor protein is a critical component of the internal molecular clock in mammals. What's more, this molecule –called Rev-erb– is sensitive to lithium and may help shed light on circadian rhythm disorders, including bipolar disorder. The findings, which also provide insight into clock-controlled aspects of metabolism, are reported in this week's issue of Science. "We're interested in the internal control of metabolism because feeding behavior is on a daily cycle, and hormonal activities that regulate this are circadian," says senior author Mitch Lazar, MD, PhD, Director of the Institute for Diabetes, Obesity, and Metabolism at Penn. "Many studies, including those here at Penn, suggest a relationship between the human circadian clock and metabolism. Proteins are the gears of the clock, and not much is known about what regulates protein levels within the cell." Rev-erb was known to be a key component of the clock that exists in most cells of the body. Rev-erb inhibits clock genes called bmal and clock, but within a normal 24-hour circadian cycle the Rev-erb protein is destroyed within the cell, allowing bmal and other clock proteins to increase. Among other actions, these clock genes cause Rev-erb to increase, which again inhibits bmal and clock. "The time it takes for that to happen determines the length of the cycle–roughly 24 hours–and keeps the clock going," explains Lazar.

Keyword: Schizophrenia; Biological Rhythms
Link ID: 8552 - Posted: 06.24.2010

By John Bohannon One thing that seems to set humans apart from all other animals is our ability to reason. When the barometer falls, for example, we expect bad weather, but we don't think the barometer causes the weather. Scientists have assumed that such an understanding is beyond other animals. But a study of the reasoning abilities of rats now shows that we may not be so unique after all. Even young children have a deep understanding of cause and effect--they are not surprised when a toy train derails at a break in the tracks--but the rest of the animal world seems to be limited to learning by association. In a classic experiment by the Russian physiologist Ivan Pavlov, dogs learned to associate dinner with the sound of a bell. The dogs would salivate whenever a bell rang even if no dinner was around, indicating a simple association between events that happen closely in time. The new experiment started out much the same way. First, the researchers trained rats to associate a tone with the appearance of sugar snack inside a small niche in the wall. Then, instead of just observing events, the rats were given an opportunity to cause them. A lever was introduced which, when pressed, sounded the tone. The question was: Would the rats expect food to follow the tone even though they had caused it? If they had learned by association, the rats should expect a treat. © 2006 American Association for the Advancement of Science.

Keyword: Learning & Memory
Link ID: 8551 - Posted: 06.24.2010

When sexual species reproduce asexually, they accumulate bad mutations at an increased rate, report two Indiana University Bloomington evolutionary biologists in this week's Science. The researchers used the model species Daphnia pulex, or water flea, for their studies. The finding supports a hypothesis that sex is an evolutionary housekeeper that adeptly reorders genes and efficiently removes deleterious gene mutations. The study also suggests sexual reproduction maintains its own existence by punishing, in a sense, individuals of a species that meander into asexuality. "It is known that sex is common in plants and animals, and that asexual species are typically short-lived, but why this should hold throughout evolutionary time is a great mystery," said Susanne Paland, who led the study. "Our results show that asexual deviants are burdened by an ever-increasing number of genetic changes that negatively affect the function of their proteins. It appears sex is important because it rids genomes of harmful mutations." Coauthor Michael Lynch added, "Although there has been solid theory on the matter for quite some time, these results provide the first definitive proof at the molecular level that sexual reproduction magnifies the efficiency of natural selection in eliminating deleterious mutations from populations."

Keyword: Sexual Behavior; Evolution
Link ID: 8550 - Posted: 02.17.2006