Female hormones circulating in the brain determine masculine behavior, at least in mice. Estrogen--the quintessential female hormone responsible for regulating the reproductive cycle--turns lady mice into wannabe male mice when it is allowed to penetrate the brain during development, according to new research. Neuroscientist Julie Bakker of the University of Liege in Belgium and her colleagues proved this in the course of solving one of the longstanding riddles of brain development. Although it had long been known that a certain protein--alpha-fetoprotein (AFP)--plays a key role in mouse brain development by binding to estrogen, it was unclear whether AFP facilitates the development of female brains by carrying the hormone or simply by blocking it from entering the brain. The scientists used female mice incapable of producing AFP and set them loose in a Plexiglass aquarium with a sexually active male. To give them extra incentive to mate, they also received injections and capsules of female hormones. But, unlike their wild cousins, the AFP-deficient mice showed little interest in the male's advances and their brains had fewer cells devoted to producing certain chemicals critical to reproduction, just like males. Furthermore, when placed in a cage with a sexually receptive female, the mice without AFP tried to mimic their male counterparts by mounting the female and engaging in pelvic thrusting. © 1996-2006 Scientific American, Inc.

Keyword: Sexual Behavior
Link ID: 8364 - Posted: 06.24.2010

A new device for detecting suspicious odors has an unusual component. Its brain consists of five tiny trained wasps. Their trainer, agricultural engineer Glen Rains, admits the idea may sound far-fetched at first. "I initially thought some people would kind of look at it like uh some kind of like a flea circus type thing," says Rains, associate professor at the University of Georgia. But as he wrote in the journal Biotechnology Progress, the sensor is cheaper to use than trained dogs and more sensitive than some electronic noses. Rains uses parasitic wasps that don't have stingers but do have sensitive sniffers. They've been studied for years for use in biological pest control. "We were trying to come up with ways to improve their efficiency for foraging… it turned out that they use their sense of smell to find food and hosts, filter out all this information they find in the field very, very efficiently," Rains says. Further study showed that the wasps actually learn odors in the field as they get positive or negative reinforcement. © ScienCentral, 2000-2006.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 8363 - Posted: 06.24.2010

A protein that seems to be pivotal in lifting depression has been discovered by a Nobel Laureate researcher funded by the National Institutes of Health's National Institute of Mental Health (NIMH). "Mice deficient in this protein, called p11, display depression-like behaviors, while those with sufficient amounts behave as if they have been treated with antidepressants," explained Paul Greengard, Ph.D., a Rockefeller University neuroscientist who received the 2000 Nobel Prize in Physiology or Medicine for discoveries about the workings of such neuronal signaling systems. He and his colleagues found that p11 appears to help regulate signaling of the brain messenger chemical serotonin, a key target of antidepressants, which has been implicated in psychiatric illnesses such as depression and anxiety disorders. They report on their findings in the January 6, 2005 issue of Science. Brain cells communicate with each other by secreting messengers, such as serotonin, which bind to receptors located on the surface of receiving cells. Serotonin selective reuptake inhibitors (SSRIs), medications commonly prescribed for anxiety and depression, compensate for reduction in serotonin signaling by boosting levels and binding of serotonin to receptors. Previous studies have suggested that serotonin receptors are essential in regulating moods and in mediating the effects of SSRIs, but given the complexity of the serotonin system, exactly how these receptors work remains a mystery.

Keyword: Depression; Genes & Behavior
Link ID: 8362 - Posted: 01.05.2006

RICHMOND, Va. – Virginia Commonwealth University researchers have found that genes contribute more strongly to the risk of depression in women than in men, and that there may be some genetic factors that are operating uniquely in one sex and not in the other. In the January issue of the American Journal of Psychiatry, researchers reported that heritability of depression is higher in women – approximately 42 percent -- than in men, where it is approximately 29 percent. “Our work, together with colleagues at the Karolinska Institute in Sweden, represents the largest epidemiological study of depression in twins done to date. In addition, it broadly replicates what has been shown by our earlier work using the Virginia Twin Registry. In particular, we have shown that depression is a moderately heritable disorder, suggesting that genetic factors are important, but by no means overwhelming,” said Kenneth S. Kendler, M.D., a professor of psychiatry and human genetics in VCU’s School of Medicine and lead author on the study. The research team employed twin study models to evaluate lifetime major depression of approximately 42,000 twins, including 15,000 complete pairs from the Swedish National Twin Registry.

Keyword: Depression; Sexual Behavior
Link ID: 8361 - Posted: 06.24.2010

THE US Department of Defense has revealed plans to develop a lie detector that can be used without the subject knowing they are being assessed. The Remote Personnel Assessment (RPA) device will also be used to pinpoint fighters hiding in a combat zone, or even to spot signs of stress that might mark someone out as a terrorist or suicide bomber. In a call for proposals on a DoD website, contractors are being given until 13 January to suggest ways to develop the RPA, which will use microwave or laser beams reflected off a subject's skin to assess various physiological parameters without the need for wires or skin contacts. The device will train a beam on "moving and non-cooperative subjects", the DoD proposal says, and use the reflected signal to calculate their pulse, respiration rate and changes in electrical conductance, known as the "galvanic skin response". "Active combatants will in general have heart, respiratory and galvanic skin responses that are outside the norm," the website says. Because these parameters are the same as those assessed by a polygraph lie detector, the DoD claims the RPA will also indicate the subject's psychological state: if they are agitated or stressed because they are lying, for example. So it will be used as a "remote or concealed lie detector during prisoner interrogation". © Copyright Reed Business Information Ltd.

Keyword: Stress
Link ID: 8360 - Posted: 06.24.2010

The Who guitarist Pete Townshend has warned music fans against potential hearing damage caused by headphones as portable players become more popular. The 60-year-old said studio headphones caused his hearing problems, rather than playing loudly on stage. "I have unwittingly helped to invent and refine a type of music that makes its principal proponents deaf," Townshend wrote on his website. My intuition tells me there is terrible trouble ahead." Townshend, who is preparing to tour with the Who this year, said he discovered he had "badly damaged" his hearing in the 1970s. "My ears are ringing, loudly," he wrote. "My own particular kind of damage was caused by using earphones in the recording studio, not playing loud on stage." He said he must take 36-hour hearing rests while recording a new album with fellow Who member Roger Daltrey, breaks he describes as "frustrating and agonising, but compulsory". (C)BBC

Keyword: Hearing
Link ID: 8359 - Posted: 01.04.2006

Some clinical studies have indicated that marijuana or its active cannabinoid ingredient alleviates symptoms of the inflammatory disease multiple sclerosis (MS). Also, researchers have found that the brain's natural "endocannabinoids" are released after brain injury and are believed to alleviate neuronal damage. However, scientists have not understood how such substances act within the brain's own immune system. Now, experiments by Oliver Ullrich and colleagues have pinpointed how one of the brain's endocannabinoids protects neurons from inflammation after such damage. They say their studies could lead to new drugs to treat the inflammation and brain degeneration from MS or other such disorders. In an article in the January 5, 2006, issue of Neuron, the researchers reported experiments showing how the endocannabinoid anandamide (AEA) protects brain cells from inflammation. Such a role in the brain's immune system is distinct from cannabinoids' effects on neuronal signaling that produce the behavioral effects of marijuana. When Ullrich and colleagues analyzed brain tissue from people with MS, they found elevated levels of AEA, compared to healthy tissue. And in studies with mouse brain slices, they found that inducing damage with a brain-cell-exciting chemical, called NMDA, caused an invasion of the brain's immune cells, called microglia, and an increase in AEA levels.

Keyword: Drug Abuse; Glia
Link ID: 8358 - Posted: 01.04.2006

Researchers from the University of Chicago have uncovered an important mechanism used by the developing brain to pattern nerve connections in the part of the brain that interprets visual signals. In the process, they have provided the first experimental evidence for a decades-old model of how nerve cells establish distant connections in a way that can consistently relay spatial information. In the January 5, 2006, issue of the journal Nature, the researchers show that a gradient of a molecule known as Wnt3 counterbalances another force provided by the EphrinB1-EphB signaling system. The balance between these two signaling systems, they show, is necessary to establish the carefully controlled pattern of nerve connections required to convey spatial information in the correct order from the eye to the brain. "This is the first biological validation of a computational model developed in the early 1980s that suggested that two such forces would be necessary to guide axons as they establish the connections that relay spatial information from one part of the nervous system to another," said study author Yimin Zou, Ph.D., assistant professor of neurobiology at the University of Chicago.

Keyword: Development of the Brain; Vision
Link ID: 8357 - Posted: 01.04.2006

Most of us assume that a hospital injection must have medicine in it to do any good, but University of Michigan psychiatrist Jon-Kar Zubieta proved that assumption wrong. He found that if he told patients that an injection contained an experimental painkiller--even though it actually contained nothing but salt water--most of them reported a decrease in the pain they felt from a previous shot. We may call it "mind over matter"; doctors call it the placebo effect. "The placebo effect has been known for a long time," Zubieta says. "Specifically in the context of pain, there is a clear effect of reductions of pain ratings by subjects when they believe that they are receiving a substance that is active, even though it is really inactive." In the early days of medicine when anatomy was poorly understood, the placebo effect--which occurs when a "dummy treatment" has positive therapeutic effects because a patient believes it will work--was a crucial component of all medical treatment. As medical knowledge progressed, scientists began to make educated guesses as to how the placebo effect worked, hypothesizing that the human brain could make its own painkilling chemicals and release them under certain high-stress circumstances. But because of technological limitations, no one was able to objectively observe these chemical processes--until now. © ScienCentral, 2000-2006. All

Keyword: Pain & Touch
Link ID: 8356 - Posted: 06.24.2010

One of the puzzling questions in the evolution of bees is how some species developed social behaviors. Arizona State University Life Sciences associate professor Gro Amdam thinks part of the answer can be traced back to bee reproductive traits. A paper describing Amdam's experiments, "Complex social behavior derived from maternal reproductive traits," is the cover story of the current issue (Jan. 5, 2006) of Nature. Additional authors include M. Kim Fondrk and Robert Page from Arizona State University, and Angela Csondes from the University of California, Davis. Honeybees live in highly complex communal societies that include divisions of labor among worker bees. Workers are female bees whose jobs include cleaning, maintaining and defending the hive, raising the young and foraging for nectar and pollen. Other species of bees, like carpenter bees, do not engage in social behavior and instead lead solitary lives. This has prompted researchers to look into how social structures and divisions of labor have arisen in bees from their solitary ancestors. Amdam's research supports the idea that elements of the reproductive behavior of those ancestors evolved to form a basis for social living and divisions of labor.

Keyword: Evolution
Link ID: 8355 - Posted: 01.04.2006

A person’s liking for a particular brand name is wired into a specific part of the brain, a new study reveals. The research may provide an insight into the brain mechanisms that underlie the behavioural preferences that advertisers attempt to hijack. It has long been known that humans and animals can learn to associate an irrelevant stimulus with a positive experience, for example the ringing of a bell with food, as in the case of Pavlov’s dogs. And neuroimaging studies have recently implicated two regions buried deep in the brain – the ventral striatum and the ventral midbrain – as having an important role in this learning. But now work led by John O’Doherty, currently at Caltech in Pasadena, US, shows that the actual level of preference is encoded in these brain regions, and that people access this information to guide their decisions. “The key message of our study is that we are able to make use of neural signals deep in our brain to guide our decisions about what items to choose, say when choosing between particular soups in a supermarket, without actually sampling the foods themselves,” says Doherty, who did the research while at University College London, UK. “This is because we can make use of our prior experiences of the items through which we fashioned subjective preferences – do I like it or not?” he told New Scientist. “The next time we come to make a decision we use those preferences.” © Copyright Reed Business Information Ltd.

Keyword: Emotions
Link ID: 8354 - Posted: 06.24.2010

A new UCLA imaging study shows that age-related breakdown of myelin, the fatty insulation coating the brain's internal wiring, correlates strongly with the presence of a key genetic risk factor for Alzheimer disease. The findings are detailed in the January edition of the peer-reviewed journal Archives of General Psychiatry and add to a growing body of evidence that myelin breakdown is a key contributor to the onset of Alzheimer disease later in life. In addition, the study demonstrates how genetic testing coupled with non-invasive evaluation of myelin breakdown through magnetic resonance imaging (MRI) may prove useful in assessing treatments for preventing the disease. "Myelination, a process uniquely built up in humans, arguably is the most important and most vulnerable process of brain development as we mature and age. These new findings offer, for the first time, compelling genetic evidence that myelin breakdown underlies both the advanced age and the principal genetic risks for Alzheimer disease," said Dr. George Bartzokis, professor of neurology at UCLA's David Geffen School of Medicine.

Keyword: Alzheimers; Genes & Behavior
Link ID: 8353 - Posted: 01.03.2006

By Elizabeth Agnvall Special to The Washington Post Just as we're taking down the tree, organizing the new toys and stepping onto the scale comes a study finding that may make us wonder why we do it all: Parents are more likely to be depressed than people who do not have children. Published last month in the Journal of Health and Social Behavior, the study of 13,000 U.S. adults found that parents, from those with young children to empty nesters, reported being more miserable than non-parents. The researchers analyzed data from a national survey of families and households that asked respondents how many times in the past week, for example, they felt sad, distracted or depressed. Unlike earlier studies, this one found moms and dads equally unhappy. So: After all the sleepless nights and drowsy mornings, the cycles of feeding and throwing up, the American Girl doll accessories bought on credit, the toothpick models of the solar system and the algebra tutors . . . we would have been happier without it all? In a word, says study author Robin Simon, an associate professor of sociology at Florida State University, yes. © 2006 The Washington Post Company

Keyword: Emotions; Sexual Behavior
Link ID: 8352 - Posted: 06.24.2010

By ANAHAD O'CONNOR THE FACTS Some old bromides - like the one that holds that chocolate causes acne - were just plain wrong. But when it comes to one piece of dietary advice that many of us were brought up on, the old wisdom prevails: fish is apparently food for the brain. Like many old wives' tales about food and eating, how this claim got started is not entirely clear. Some believe that it may have grown out of a theory that humans evolved in coastal areas because certain nutrients in fish, particularly omega-3 fatty acids, were necessary for brain development. But whatever the origin of the claim, multiple studies have provided some evidence to support it. One study this year at Harvard, which looked at 135 mothers and their infants, found that the more fish the mothers ate during their second trimesters, the better their infants did on tests when they were 6 months old. But the researchers urged mothers to stick to canned light tuna or salmon while steering clear of shark, swordfish and other types of fish with high mercury levels. Copyright 2006 The New York Times Company

Keyword: Development of the Brain
Link ID: 8351 - Posted: 01.03.2006

By NICHOLAS BAKALAR They may not have hot flashes or experience drastic mood swings. But a new study of captive female gorillas suggests that like human females the animals go through physiological changes when their reproductive days are ending. Sylvia Atsalis, a co-author of the study and a primatologist at the Brookfield Zoo in Chicago, said, "Like humans, gorillas seem to go not only through menopause, but also through perimenopause, during which we have documented some hormonal changes and during which there is reduced likelihood of conception." Some scientists theorize that menopause is evolutionarily adaptive, giving grandmothers an opportunity to help with child care or leave mothers more time to care for existing offspring. Others see it as merely an artifact of the increased life span of animals in captivity, having no survival value for a species. In the study, researchers monitored the menstrual patterns of 30 gorillas in 11 zoos by measuring daily fecal samples for progesterone, the hormone whose levels increase sharply just after ovulation. Of the animals, 22 were older than 30, the age at which gorillas begin to have reduced pregnancy rates and poor survival of offspring. Of the 22, five had clearly passed through menopause and seven were in perimenopause. The oldest, a menopausal 51-year-old, last gave birth at age 11, but mated with her partner until she was 49. Copyright 2006 The New York Times Company

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 8350 - Posted: 01.03.2006

By NATALIE ANGIER WASHINGTON, - If the mere sight of Tai Shan, the roly-poly, goofily gamboling masked bandit of a panda cub now on view at the National Zoo isn't enough to make you melt, then maybe the crush of his human onlookers, the furious flashing of their cameras and the heated gasps of their mass rapture will do the trick. Cute cues are those that indicate extreme youth, vulnerability, harmlessness and need, scientists say. "Omigosh, look at him! He is too cute!" "How adorable! I wish I could just reach in there and give him a big squeeze!" "He's so fuzzy! I've never seen anything so cute in my life!" A guard's sonorous voice rises above the burble. "OK, folks, five oohs and aahs per person, then it's time to let someone else step up front." The 6-month-old, 25-pound Tai Shan - whose name is pronounced tie-SHON and means, for no obvious reason, "peaceful mountain" - is the first surviving giant panda cub ever born at the Smithsonian's zoo. And though the zoo's adult pandas have long been among Washington's top tourist attractions, the public debut of the baby in December has unleashed an almost bestial frenzy here. Some 13,000 timed tickets to see the cub were snapped up within two hours of being released, and almost immediately began trading on eBay for up to $200 a pair. Copyright 2006 The New York Times Company

Keyword: Evolution; Vision
Link ID: 8349 - Posted: 01.03.2006

Reduced volume, or atrophy, in parts of the brain known as the amygdala and hippocampus may predict which cognitively healthy elderly people will develop dementia over a six-year period, according to a study in the January issue of Archives of General Psychiatry, one of the JAMA/Archives journals. New strategies may be able to prevent or delay the onset of Alzheimer's disease (AD), the most common cause of dementia among older adults, according to background information in the article. Accurate methods of identifying which people are at high risk for dementia in old age would help physicians determine who could benefit from these interventions. There is evidence that adults with AD and mild cognitive impairment, a less severe condition that is considered a risk factor for AD, have reduced hippocampal and amygdalar volumes. However, previous research has not addressed whether measuring atrophy using magnetic resonance imaging (MRI) can predict the onset of AD at an earlier stage, before cognitive symptoms appear. Tom den Heijer, M.D., Ph.D., of the Erasmus Medical Center, Rotterdam, the Netherlands, and colleagues used MRI to assess the brain volumes of 511 dementia-free elderly people who were part of the Rotterdam Study, a large population-based cohort study that began in 1990. They screened the participants for dementia at initial visits in 1995 and 1996 and then in follow-up visits between 1997 and 2003, during which they asked about memory problems and performed extensive neuropsychological testing. The authors also monitored the medical records of all participants. During the follow-up, 35 participants developed dementia and 26 were diagnosed with AD.

Keyword: Alzheimers
Link ID: 8348 - Posted: 01.03.2006

By David Brown, Washington Post Staff Writer In medical research, nobody is convinced by a single experiment. A finding has to be reproducible to be believable. Only if different scientists in different places do the same study and get the same outcomes can physicians have confidence the finding is actually true. Only then is it ready to be put into clinical practice. Nevertheless, one of medicine's most overlooked problems is the fact that some questions keep being asked over and over. Repeated tests of the same diagnostic study or treatment are a waste -- of time and money, and of volunteers' trust and self-sacrifice. Unnecessary clinical trials may also cost lives. All this is leading some experts to ask a new question: "What part of 'yes' don't doctors understand?" Two papers dramatically illustrated this problem last year and may have helped nudge the medical establishment toward doing something about it. One article examined 18 years of research on aprotinin, a drug used to reduce bleeding during heart surgery. The other looked at studies on the relationship between a baby's sleeping position and sudden infant death syndrome. Both concluded that research on these subjects went on long after the answers were known -- namely, that aprotinin worked and that babies sleeping on their backs were less likely to die of SIDS. © 2006 The Washington Post Company

Keyword: Sleep
Link ID: 8347 - Posted: 06.24.2010

Researchers have developed a new tool to help them study endangered whales – autonomous hydrophones that can be deployed in the ocean to record the unique clicks, pulses and calls of different whale species. Those efforts are leading to some surprising findings, including the discovery by a team of researchers of rare right whales swimming in the Gulf of Alaska. "There has been only one confirmed sighting of a right whale in the Gulf of Alaska since 1980, so discovering them is not only surprising, it is fairly significant," said David K. Mellinger, an assistant professor at Oregon State University's Hatfield Marine Science Center in Newport. "We picked up the sounds of one whale off Kodiak Island, and several others in deep water, which is also something of a surprise, since most right whale sightings have been near-shore." Results of these and five years of studies have been published in the January 2006 issue of the journal BioScience. Mellinger said scientists have been able to use the hydrophones to distinguish sounds made by different whale species. And some species, he added, have different "dialects" depending on where they are from. Blue whales off the Pacific Northwest sound different than populations of blue whales that live in the western Pacific Ocean, and those sound different from populations of blue whales off Antarctica. And they all sound different than the blue whales off Chile.

Keyword: Hearing; Animal Communication
Link ID: 8346 - Posted: 06.24.2010

Initial results of the nation's largest clinical trial for depression have helped clinicians to track "real world" patients who became symptom-free and to identify those who were resistant to the initial treatment. Participants treated in both medical and specialty mental health care settings experienced a remission of symptoms in 12 to 14 weeks during well-monitored treatment with an antidepressant medication. The study, funded by the National Institutes of Health's (NIH) National Institute of Mental Health (NIMH), used flexible adjustment of dosages based on quick and easy-to-use clinician ratings of symptoms and patient self-ratings of side effects. About a third of participants reached a remission or virtual absence of symptoms during the initial phase of the study, with an additional 10 to 15 percent experiencing some improvement. Subsequent phases of the trials will help determine successful treatments for the nearly two thirds of those patients who were identified as treatment-resistant to a first medication in phase one. The trial, known as the STAR*D study -- Sequenced Treatment Alternatives to Relieve Depression -- included 2,876 participants and was conducted over six years at a cost of $35 million. (For more information on STAR*D, go to: http://www.clinicaltrials.gov/ct/show/NCT00021528?order=1).

Keyword: Depression
Link ID: 8345 - Posted: 01.02.2006