By NICHOLAS WADE When it comes to the matter of desire, evolution leaves little to chance. Human sexual behavior is not a free-form performance, biologists are finding, but is guided at every turn by genetic programs. Desire between the sexes is not a matter of choice. Straight men, it seems, have neural circuits that prompt them to seek out women; gay men have those prompting them to seek other men. Women’s brains may be organized to select men who seem likely to provide for them and their children. The deal is sealed with other neural programs that induce a burst of romantic love, followed by long-term attachment. So much fuss, so intricate a dance, all to achieve success on the simple scale that is all evolution cares about, that of raisingthe greatest number of children to adulthood. Desire may seem the core of human sexual behavior, but it is just the central act in a long drama whose script is written quite substantially in the genes. In the womb, the body of a developing fetus is female by default and becomes male if the male-determining gene known as SRY is present. This dominant gene, the Y chromosome’s proudest and almost only possession, sidetracks the reproductive tissue from its ovarian fate and switches it into becoming testes. Hormones from the testes, chiefly testosterone, mold the body into male form. In puberty, the reproductive systems are primed for action by the brain. Amazing electrical machine that it may be, the brain can also behave like a humble gland. In the hypothalamus, at the central base of the brain, lie a cluster of about 2,000 neurons that ignite puberty when they start to secrete pulses of gonadotropin-releasing hormone, which sets off a cascade of other hormones. Copyright 2007 The New York Times Company

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 10164 - Posted: 06.24.2010

By NATALIE ANGIER Sexual desire. The phrase alone holds such loaded, voluptuous power that the mere expression of it sounds like a come-on — a little pungent, a little smutty, a little comical and possibly indictable. Everybody with a pair of currently or formerly active gonads knows about sexual desire. It is a near-universal experience, the invisible clause on one’s birth certificate stipulating that one will, upon reaching maturity, feel the urge to engage in activities often associated with the issuance of more birth certificates. Yet universal does not mean uniform, and the definitions of sexual desire can be as quirky and personalized as the very chromosomal combinations that sexual reproduction will yield. Ask an assortment of men and women, “What is sexual desire, and how do you know you’re feeling it?” and after some initial embarrassed mutterings and demands for anonymity, they answer as follows: “There’s a little bit of adrenaline, a puffing of the chest, a bit of anticipatory tongue motion,” said a divorced lawyer in his late 40s. “I feel relaxed, warm and comfortable,” said a designer in her 30s. “A yearning to kiss or grab someone who might respond,” said a male filmmaker, 50. “Or if I’m alone, to call up exes.” Copyright 2007 The New York Times Company

Keyword: Sexual Behavior
Link ID: 10163 - Posted: 06.24.2010

Roxanne Khamsi People with Parkinson's disease are less likely to be smokers and coffee drinkers than their healthy siblings, according to a study of family members. The finding adds to a growing body of evidence that some substance in tobacco might protect the brain against this devastating neurological disorder and sheds new light on coffee's effects on the disease. Researchers say the study provides new evidence that the causes of Parkinson's vary. They also stress that the negative health effects of smoking far outweigh any protective effect the substance might have against this neurodegenerative disease. Parkinson's disease, which generally strikes people over the age of 50, leads to a loss of coordination, dementia and may result in early death. For decades, scientists have found evidence suggesting that smokers are less likely to develop this illness than non-smokers. But experts believe that genes can influence one's risk of developing Parkinson's, and the vast majority of these studies involved participants who were unrelated and therefore genetically dissimilar. To control for this genetic variability, William Scott of the University of Miami in Florida, US, and his colleagues studied the smoking and coffee-drinking habits of Parkinson's patients and their family members. © Copyright Reed Business Information Ltd.

Keyword: Parkinsons; Drug Abuse
Link ID: 10162 - Posted: 06.24.2010

People with post-traumatic stress disorder (PTSD) may be less sensitive to pain than others who don't have the condition, say Dutch scientists. PTSD patients report panic attacks, flashbacks, anxiety and depression following a traumatic event. The Archives of General Psychiatry study suggests PTSD patients' brains may be wired up differently. A UK expert said it was unknown why some people developed the condition after trauma, while others did not. Researchers used brain scans to compare what happened when volunteers were given hot objects to hold. The PTSD patients generally said the objects felt less hot. Scans confirmed their brains were less active than those of their unaffected counterparts. The researchers do not know why the processing of pain signals should be different in patients with the condition. Many of those diagnosed with PTSD had taken part in conflicts as part of the armed forces, and the project was carried out jointly between the Central Military Hospital in Utrecht and the city's Rudolf Magnus Institute of Neuroscience. A total of 24 military veterans, half with PTSD and half without, were chosen to take part. The research used a functional magnetic resonance imaging (fMRI) scanner, which can show, in real-time, which areas of the brain are most active. The veterans were placed in the scanner, then given objects heated to an uncomfortable temperature to hold. They were asked how painful it was to hold the object. The level of pain reported by the PTSD-diagnosed veterans was significantly less than that reported by the other volunteers. (C)BBC

Keyword: Stress; Pain & Touch
Link ID: 10161 - Posted: 04.09.2007

Waltham, MA —A Brandeis University study published in Cell this week shows for the first time experimentally that the circadian cells in fruit flies function as a network that enables the insects to adapt their behavior according to seasonal changes. This discovery leads the way to understanding how mammals, and presumably humans, adjust physiology and behavior to environmental changes such as short winter days and long summer ones. For years, behavioral geneticists have known that specific brain cells in Drosophila fruit flies regulate the daily rhythmic behavior according to 24-hour endogenous clock machinery. But until now, scientists had offered only mathematical models to explain how fruit flies and other animals, including humans, adapt to seasonal changes such as fluctuating day length and temperature. "In this study we show how the 24-hour intrinsic molecular clock can produce a variable output, so that it fits any seasonal condition," said lead author Dan Stoleru. "This is especially exciting because it gives us an understanding of how animals extract vital information from the environment to drive innate behavior such as reproduction, migration or hibernation." Stoleru, a researcher in the pioneering National Center for Behavioral Genomics lab led by Michael Rosbash, explained that this property is provided by an adaptable brain circuit of oscillating neurons, capable of responding specifically to different environmental cues.

Keyword: Biological Rhythms
Link ID: 10160 - Posted: 06.24.2010

Nathan Seppa Attempts to hide illicit drug use by taking niacin have landed four people in Philadelphia hospitals over the past 2 years, two with life-threatening reactions to high doses of the nutrient, doctors report. Niacin, also known as vitamin B3, plays roles in digestion, hormone production, skin upkeep, and nervous system maintenance. Because the vitamin promotes fat metabolism, doctors sometimes give niacin in large doses to people with high concentrations of cholesterol and triglycerides. That property has led some people to believe that niacin can also cleanse the body of illicit drugs, particularly marijuana. Two of the four Philadelphia patients experienced nausea, rapid heartbeat, dizziness, dehydration, low blood sugar, blood-clotting abnormalities, liver toxicity, and a dangerous drop in blood pH. One patient, a 14-year-old boy, also experienced abdominal pain, a run-up in his white blood cell count, and an irregular heartbeat. The other severely affected patient, a 17-year-old girl, was in a coma when an emergency team found her, says study coauthor Manoj K. Mittal, an emergency physician at Children's Hospital of Philadelphia. He and his colleagues report their findings in an upcoming Annals of Emergency Medicine. ©2007 Science Service.

Keyword: Drug Abuse
Link ID: 10159 - Posted: 06.24.2010

Depression during pregnancy may increase the risk of giving birth early, a UK study suggests. Mothers who were severely depressed gave birth earlier than those without depression, a small study shows. The depressed mothers had significantly higher levels of a stress hormone which is known to initiate birth, an Institute of Psychiatry meeting heard. Experts said depression during pregnancy is common and the findings should be looked at in a bigger study. Dr Veronica O'Keane, perinatal psychiatrist at King's College London, measured amounts of corticotrophin-releasing hormone (CRH), in 25 women who had a diagnosis of major depression (but were not on medication) and 35 women without depression. Levels of CRH - a hormone which is associated with stress but also naturally excreted by the placenta during pregnancy - were found to be higher in those with depression. On average mothers with depression gave birth two days earlier - but three of the mothers in the depressed group had a premature birth (under 37 weeks) compared with none in the control group. In a small subset of the babies at eight weeks, Dr O'Keane also found that those born to mothers who had depression had higher salivary levels of another stress hormone - cortisol - during routine vaccinations. Previous research has shown that children born to mothers who had high levels of anxiety during pregnancy have higher levels of cortisol at 10 years old, indicating the stress gets passed on. Dr O'Keane explained that CRH is needed for normal organ development in the foetus but the higher levels associated with depression could prompt premature delivery. (C)BBC

Keyword: Depression
Link ID: 10158 - Posted: 04.08.2007

By Melinda Wenner People who believe they have lived past lives as, say, Indian princesses or battlefield commanders are more likely to make certain types of memory errors, according to a new study. The propensity to make these mistakes could, in part, explain why people cling to implausible reincarnation claims in the first place. Researchers recruited people who, after undergoing hypnotic therapy, had come to believe that they had past lives. Subjects were asked to read aloud a list of 40 non-famous names, and then, after a two-hour wait, told that they were going to see a list consisting of three types of names: non-famous names they had already seen (from the earlier list), famous names, and names of non-famous people that they had not previously seen. Their task was to identify which names were famous. The researchers found that, compared to control subjects who dismissed the idea of reincarnation, past-life believers were almost twice as likely to misidentify names. In particular, their tendency was to wrongly identify as famous the non-famous names they had seen in the first task. This kind of error, called a source-monitoring error, indicates that a person has difficulty recognizing where a memory came from. © 2007 MSNBC.com © 2007 Microsoft

Keyword: Learning & Memory
Link ID: 10157 - Posted: 06.24.2010

By CARL ZIMMER Humans are born time travelers. We may not be able to send our bodies into the past or the future, at least not yet, but we can send our minds. We can relive events that happened long ago or envision ourselves in the future. New studies suggest that the two directions of temporal travel are intimately entwined in the human brain. A number of psychologists argue that re-experiencing the past evolved in our ancestors as a way to plan for the future and that the rise of mental time travel was crucial to our species’ success. But some experts on animal behavior do not think we are unique in this respect. They point to several recent experiments suggesting that animals can visit the past and future as well. The first clues about the twists and turns of mental time travel came from people with certain brain injuries that caused them to forget autobiographical details without forgetting the information they had picked up along the way. A man known in the scientific literature as K.C., for instance, could play chess with no memory of having ever played it. K.C. could remember sentences psychologists taught him without any memory of the lessons. K.C. had lost what psychologists now call episodic memory. Endel Tulving, a Canadian psychologist, defined episodic memory as the ability to recall the details of personal experiences: what happened, where it happened, when it happened and so on. Copyright 2007 The New York Times Company

Keyword: Learning & Memory
Link ID: 10156 - Posted: 06.24.2010

By John I. Nurnberger, Jr., and Laura Jean Bierut The tendency to become dependent on alcohol has long been known to run in families, which for some only added to the social stigma attached to this complicated condition. But to scientists, that apparent heritability suggested that some genetic component underlying vulnerability to alcohol problems was being transmitted from generation to generation. With rapid advances over the past 10 years in technologies for discovering and analyzing the functions of genes, researchers are now increasingly able to get at the biological roots of complex disorders such as substance abuse and addiction. The power to examine patterns of inheritance in large populations, and to survey hundreds of thousands of tiny variations in the genomes of each of those individuals, enables investigators to pinpoint specific genes that exert strong or subtle influences on a person's physiology and his or her resulting risk for disease. As is true of many other human disorders, alcoholism does not have a single cause, nor is its origin entirely genetic. Genes can play an important role, however, by affecting processes in the body and brain that interact with one another and with an individual's life experiences to produce protection or susceptibility. Teasing these effects apart is challenging, and to date fewer than a dozen genes that influence one's risk for alcoholism have been identified, although more surely exist. © 1996-2007 Scientific American, Inc

Keyword: Drug Abuse; Genes & Behavior
Link ID: 10155 - Posted: 06.24.2010

By Marina Krakovsky The day I meet Sonja Lyubomirsky, she keeps getting calls from her Toyota Prius dealer. When she finally picks up, she is excited by the news: she can buy the car she wants in two days. Lyubomirsky wonders if her enthusiasm might come across as materialism, but I understand that she is buying an experience as much as a possession. The hybrid will be gentler on the environment, and a California state law letting some hybrids use the carpool lane promises a faster commute between her coastal Santa Monica home and her job at the University of California, Riverside, some 70 miles inland. Two weeks later, in late January, the 40-year-old Lyubomirsky, who smiles often and seems to approach life with zest and good humor, reports that she is "totally loving the Prius." But will the feeling wear off soon after the new-car smell, or will it last, making a naturally happy person even more so? An experimental psychologist investigating the possibility of lasting happiness, Lyubomirsky understands far better than most of us the folly of pinning our hopes on a new car--or on any good fortune that comes our way. We tend to adapt, quickly returning to our usual level of happiness. The classic example of such "hedonic adaptation" comes from a 1970s study of lottery winners, who a year after their windfall ended up no happier than nonwinners. Hedonic adaptation helps to explain why even changes in major life circumstances--such as income, marriage, physical health and where we live--do so little to boost our overall happiness. Not only that, but studies of twins and adoptees have shown that about 50 percent of each person's happiness is determined from birth. This "genetic set point" alone makes the happiness glass look half empty, because any upward swing in happiness seems doomed to fall back to near your baseline. © 1996-2007 Scientific American, Inc.

Keyword: Emotions
Link ID: 10154 - Posted: 06.24.2010

There's new evidence that the brain plays a role in obesity. A study in mice shows how too much body fat makes the brain resistant to a hormone that normally shuts off appetite when we're full. As this ScienCentral News video reports, the researchers also studied ways to restore sensitivity to the fullness hormone. The fullness hormone "leptin," produced by body fat, normally signals the brain to stop eating. But giving it to obese people doesn't work -- it turned out they do produce plenty of leptin. Now researchers at Oregon Health and Science University say the problem is in the brain. "It was thought that adding leptin back to organisms would help them lose weight," says neuroscientist Michael Cowley at the university's Oregon National Primate Center. "Instead what we found was that obese organisms have very high levels of leptin in their blood and putting more in didn't help them lose weight. And this was termed leptin resistance." Cowley's group studied mice to look for the mechanism behind leptin resistance in the brain. They put groups of mice on either fatty diet or regular chow for 20 weeks -- a quarter of the mouse lifespan. Mice that got obese on the fatty diet produced ten times as much leptin as lean mice, but their brains stopped responding to it. The researchers tested populations of nerve cells known to have receptors for leptin, in the part of the brain that regulates appetite, the hypothalamus. © ScienCentral, 2000-2007.

Keyword: Obesity
Link ID: 10153 - Posted: 06.24.2010

Marilynn Marchione — The most infamous feud in American folklore, the long-running battle between the Hatfields and McCoys, may be partly explained by a rare, inherited disease that can lead to hair-trigger rage and violent outbursts. Dozens of McCoy descendants apparently have the disease, which causes high blood pressure, racing hearts, severe headaches and too much adrenaline and other "fight or flight" stress hormones. No one blames the whole feud on this, but doctors say it could help explain some of the clan's notorious behavior. "This condition can certainly make anybody short-tempered, and if they are prone because of their personality, it can add fuel to the fire," said Dr. Revi Mathew, a Vanderbilt University endocrinologist treating one of the family members. The Hatfields and McCoys have a storied and deadly history dating to Civil War times. Their generations of fighting over land, timber rights and even a pig are the subject of dozens of books, songs and countless jokes. Unfortunately for Appalachia, the feud is one of its greatest sources of fame. Several genetic experts have known about the disease plaguing some of the McCoys for decades, but kept it secret. Several family members revealed their history to Vanderbilt doctors, who are trying to find more McCoy relatives to warn them of the risk. © 2007 Discovery Communications Inc.

Keyword: Aggression; Genes & Behavior
Link ID: 10152 - Posted: 06.24.2010

Patients taking medications to treat bipolar disorder are more likely to get well faster and stay well if they receive intensive psychotherapy, according to results from the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD), funded by the National Institutes of Health’s (NIH) National Institute of Mental Health (NIMH). The results are published in the April 2007 issue of the Archives of General Psychiatry. Bipolar disorder is a debilitating illness marked by severe mood swings between depression and mania that affects 2.6 percent of Americans in any given year. “We know that medication is an important component in the treatment of bipolar illness. These new results suggest that adding specific, targeted psychotherapy to medication may help give patients a better shot at lasting recovery,” said NIH Director Dr. Elias A. Zerhouni. “STEP-BD is helping us identify the best tools — both medications and psychosocial treatments — that patients and their clinicians can use to battle the symptoms of this illness,” said NIMH Director Thomas R. Insel, M.D. Psychotherapy is routinely employed as a means to treat bipolar illness in conjunction with medication, but the extent to which psychotherapy is effective has been unclear. In addition, most psychotherapeutic studies have been limited to a single site and compared only one type of treatment to routine care. Thus, in addition to examining the role of medication, STEP-BD set out to compare several types of psychotherapy and pinpoint the most effective treatments and treatment combinations.

Keyword: Schizophrenia; Depression
Link ID: 10151 - Posted: 06.24.2010

Roxanne Khamsi Rich people's brains are less stimulated by small cash rewards than poor people's brains, according to a new imaging study that focused on the brain's "reward centre". The study provides biological and behavioural evidence supporting a basic tenet of economics known as "marginal utility" – that people value the same amount of money less as they become richer, the researchers say. Philippe Tobler at the University of Cambridge in the UK and colleagues recruited 14 students with a wide range of incomes – from their parents or part-time jobs – and bank savings. The students' brains were monitored for activity – using functional magnetic resonance imaging (fMRI), while they viewed abstract images (made of circles and rectangles) on a computer screen. Three of the abstract images would always precede a clear picture of a 20 pence coin, which is worth about US $0.40, while another three abstract images were linked to a scrambled picture of the same coin. When participants correctly predicted that a clear coin picture would follow the abstract image shown on the computer screen, and indicated their guess by pressing a button, they banked a real 20p cash reward. Twenty pence would not be enough to buy a pack of gum in the UK. Each student completed 210 trials of the guessing task. © Copyright Reed Business Information Ltd

Keyword: Emotions
Link ID: 10150 - Posted: 06.24.2010

Michael Hopkin British neuroscientists are planning to investigate whether playing soccer contributes to the development of motor neurone disease. The move comes after three amateur footballers playing in the same league developed the disease, which normally affects less than one person in every 50,000 each year. Experts are now aiming to launch a full epidemiological study of professional footballers and motor neurone disease (MND) patients, to see whether the sport really does raise the incidence of the disease among those who play it at a high level. Details of the patients, all of whom were committed footballers, are published in the journal Amyotrophic Lateral Sclerosis1 — a publication named after the most common form of MND. The patients range in age between 56 and 61 years old, and were all diagnosed with the disease within a decade of each other. "What is unusual about this group is that they are all friends who developed MND at the same time," says Ammar Al-Chalabi of King's College London, one of the experts who described the cases. "A cluster like this could occur by chance, but the odds are quite long." The three have several potential risk factors in common, including having been electrocuted by mains electricity at some point during their lives. But the authors note that the three were very keen at football, playing more than twice a week — almost as much as professional players. ©2007 Nature Publishing Group

Keyword: ALS-Lou Gehrig's Disease
Link ID: 10149 - Posted: 06.24.2010

CHAPEL HILL –A study led by scientists from the University of North Carolina at Chapel Hill may have identified a molecular mechanism involved in the development of schizophrenia. In studying the postmortem brain tissue of adults who had been diagnosed with schizophrenia, the researchers found that levels of certain gene-regulating molecules called microRNAs were lower among schizophrenia patients than in persons who were free of psychiatric illness. "In many genetic diseases, such as Huntington's disease or cystic fibrosis, the basis is a gene mutation that leads to a malformed protein. But with other complex genetic disorders – such as schizophrenia, many cancers, and diabetes – we find not mutated proteins, but correctly formed proteins in incorrect amounts," said study lead author and UNC professor of psychiatry Dr. Diana Perkins. The research appears this week in the online edition of the journal Genome Biology. "To our knowledge this study is the first to associate altered expression of microRNAs with schizophrenia," the authors stated. Since the 1950s, scientists have known that the genetic code stored in DNA is first transcribed into messenger RNA (mRNA) which is then the template from which the body's protein building blocks are made. MicroRNAs are a newly discovered class of mRNA that does not carry the code for a protein. Instead, these tiny strands of RNA act by binding to matching pieces of the protein coding mRNA, thus preventing the translation of mRNA to protein.

Keyword: Schizophrenia; Genes & Behavior
Link ID: 10148 - Posted: 06.24.2010

By STEPHANIE SAUL Two weeks after the Food and Drug Administration issued safety warnings about widely used sleeping pills, the drug maker Merck canceled a venture into the shifting market for insomnia medications. Merck and its Danish partner, H. Lundbeck, announced that a safe and effective sleeping pill had eluded their scientists after years of study, and they canceled their joint product, gaboxadol. Unusual side effects — including hallucinations and disorientation — showed up in the studies. The drug also failed a trial of its efficacy. During a conference call yesterday, Lundbeck’s senior vice president for drug development, Anders Gersel Pedersen, said, “We did not want to bring a product to the market with such a shallow risk-benefit ratio.” Merck, based in Whitehouse Station, N.J., had listed gaboxadol as one of three drug applications it planned to file this year, and called the termination “clearly disappointing.” As recently as two years ago, some Merck scientists had viewed the product as a potential blockbuster, possibly safer and as effective as sleeping medications currently on the market. Copyright 2007 The New York Times Company

Keyword: Sleep
Link ID: 10147 - Posted: 06.24.2010

By JANE GROSS Mary Blake Carver gazes from the cover of a neurology magazine this month, under the headline “I’m Still Here!” She often feels like shouting the message to her friends, her children, her husband. Ms. Carver, 55, is among the growing ranks of people in the early stages of Alzheimer’s disease, when short-term memory is patchy, organizational skills fail, attention wanders and initiative comes and goes. But there is still a window of opportunity — maybe one year, maybe five — to reason, communicate and go about her life with a bit of help from those around her. Yet Ms. Carver is often lonely and bored. Her husband leaves her out of many dinner table conversations, both say, because she cannot keep up with the normal patter. He insists on buttoning her coat when she fumbles at the task. She was fired as a massage therapist because she lost track of time. So Ms. Carver fills her days by walking her neighborhood on the Upper West Side of Manhattan, always with her dog, so she looks like “an ordinary person,” she said, not someone with “nothing better to do.” Copyright 2007 The New York Times Company

Keyword: Alzheimers
Link ID: 10146 - Posted: 06.24.2010

Behind every wave of disgust that comes your way may be a biological imperative much greater than the urge to lose your lunch, according to a growing body of research by a UCLA anthropologist. "The reason we experience disgust today is that the response protected our ancestors," said Dan Fessler, associate professor of anthropology and director of UCLA’s Center for Behavior, Evolution, and Culture. "The emotion allowed our ancestors to survive long enough to produce offspring, who in turn passed the same sensitivities on to us." Across a series of subtle and ingenious studies, Fessler has managed to illuminate the ways in which disgust may have served to protect our ancestors during such biologically precarious situations as pregnancy and to maximize the likelihood of our forbears’ reproduction when they were at their most fertile. Fessler’s research also illustrates how the emotional response that helped our ancestors may not serve us as well today and may actually promote xenophobia, sexual prejudices and a range of other irrational reactions. "We often respond to today’s world with yesterday’s adaptations," Fessler said. "That’s why, for instance, we’re more afraid of snakes than cars, even though we’re much more likely to die today as a result of an encounter with a car than a reptile."

Keyword: Emotions; Evolution
Link ID: 10145 - Posted: 06.24.2010