Washington -- Neuroscientists at Harvard Medical School and its affiliate Mclean Hospital have shown that long-term exposure to stress hormone in mice directly results in the anxiety that often comes with depression. After years of circumstantial evidence linking stress and depression, this evidence may be the "smoking gun" of what, for some, causes some types of mood disorders. The research appears in the April issue of Behavioral Neuroscience, which is published by the American Psychological Association. The findings are important for understanding the causes and improving the treatment of depression. Scientists already knew that many people with depression have high levels of cortisol, a human stress hormone, but it wasn't clear whether that was a cause or effect. Now it appears likely that long-term exposure to cortisol actually contributes to the symptoms of depression. Paul Ardayfio, PhD candidate, and Kwang-Soo Kim, PhD, made their discovery by exposing mice to both short-term and long-term durations of stress hormone, which in rodents is corticosterone. In humans, usually ongoing, chronic stress, such as caring for a spouse with dementia, rather than acute stress, has been associated with depression. Using 58 mice, the researchers gave the hormone in drinking water so as not to confound the results with the stress of injection. Chronic doses were 17 to 18 days of exposure; acute doses were 24 hours of exposure.

Keyword: Stress; Emotions
Link ID: 8785 - Posted: 04.17.2006

Bruce Bower Scientists working in Ethiopia's Middle Awash valley have uncovered fossils of a 4.1-million-year-old human ancestor that bolster the controversial proposition that early members of our evolutionary family evolved one at a time on a single lineage rather than branching out into numerous species. A team led by anthropologist Tim D. White of the University of California, Berkeley unearthed 31 fossils of Australopithecus anamensis, the earliest known species of this ancient hominid genus. The finds, from at least eight individuals, consist primarily of teeth and jaws, but include foot and hand bones and much of an upper right-leg bone. Anatomical similarities indicate that Au. anamensis evolved directly from an earlier hominid, Ardipithecus ramidus (SN: 1/22/05, p. 51: Available to subscribers at http://www.sciencenews.org/articles/20050122/fob2.asp), between 4.4 million and 4.1 million years ago, the researchers assert in the April 13 Nature. By 3.6 million years ago, they add, Au. anamensis had evolved into Australopithecus afarensis, the species that includes the partial skeleton known as Lucy. "There may have been times when one early hominid species evolved into another one without branching off into multiple species," White says. His view contrasts with that of researchers who suspect that hominids branched into many species over the past 6 million to 7 million years (SN: 5/3/03, p. 275: Available to subscribers at http://www.sciencenews.org/articles/20030503/fob1.asp). Copyright ©2006 Science Service.

Keyword: Evolution
Link ID: 8784 - Posted: 06.24.2010

After an article on the topic elicited a strong response from readers, Scientific American Mind magazine conducted a nationwide Zogby Interactive poll that found that 50 percent of Americans believe sexual orientation is not a choice, while only 11 percent said it is a conscious choice. Thirty-four percent believe it's a combination of both. The idea that sexual preference is a hard-wired part of who we are is consistent with a growing body of scientific research that indicates a biological basis for sexual orientation, including studies of identical twins, studies of other species that don't have cultural influences, and the discovery of genes that can change the sexual behavior in flies. But, as psychiatrist Jack Drescher says, "the clinical question has gotten caught up in this whole political argument." At the heart of the controversy is Columbia University psychiatrist Robert Spitzer. In 1973, he helped to get homosexuality removed from psychiatry's official classification manual of mental illnesses, the Diagnostic and Statistical Manual of Mental Disorders. But 30 years later, in 2003, he interviewed 200 people who claimed to have changed from gay to straight, and published the study concluding that such change is possible. © ScienCentral, 2000-2006.

Keyword: Sexual Behavior
Link ID: 8783 - Posted: 06.24.2010

By Greg Miller SAN FRANCISCO--The summer Olympics only come around every four years, and for elite athletes vying for a spot on their national teams, failure to qualify can be crushing. Now, researchers have taken a look at how the brain deals with dashed Olympic dreams. Their findings hint at a possible explanation for why athletes who've suffered tough losses often have a hard time getting back on top of their game. It's a frustrating problem for both athletes and sports psychologists, says Hap Davis, a Canadian psychologist based in Calgary. "You can get people feeling good again, but they don't perform at the level they need to," he says. To get a peek inside his patients' heads, Davis teamed up with cognitive neuroscientists, including Mario Liotti at Simon Fraser University in Burnaby, Canada. The team used functional magnetic resonance imaging to examine the brains of 14 swimmers, 10 women and four men, who didn't make the 2004 Canadian Olympic team. Inside the scanner, the swimmers each watched a video clip of themselves swimming their failed qualification race and another clip featuring a different swimmer. Not surprisingly, the swimmers rated their own videos more wrenching to watch. And their brains showed signs of their emotional pain, with heightened activity in the parahippocampus and other emotion-related areas that have been implicated in depression. (None of the swimmers had a prior history of depression). © 2006 American Association for the Advancement of Science.

Keyword: Emotions
Link ID: 8782 - Posted: 06.24.2010

Johns Hopkins researchers have discovered a gene in fruit flies that helps certain specialized neurons respond more quickly to bright light. The study, published in the April 4 issue of Current Biology, also has implications for understanding sensory perception in mammals. In teasing apart the molecular interactions and physiology underlying light perception, the researchers studied a gene they dubbed “Lazaro” that is expressed 15 times higher in the fly eye than the rest of the fly head. They found that this gene is required for a second biochemical pathway that controls the activity of a protein called the TRP channel. TRP channels are found in fruit fly neurons responsible for sensing light. The fly TRP channel is the founding member of a family of related proteins in mammals that are essential for guiding certain nerves during development and for responding to stimuli including heat, taste and sound. By shining bright light onto and recording electrical changes in single nerve cells in the fly eye, researchers found that neurons carrying a mutation in this gene cannot respond as well to light as compared to neurons carrying normal copies of this gene. In fact, the mutant neurons turn off their response to light four times faster than normal neurons. Because Lazaro helps fly TRP channels work at their maximum, it is possible that a Lazaro-like gene in mammals might also play a role in how well mammalian TRP channels work.

Keyword: Vision
Link ID: 8781 - Posted: 06.24.2010

By NICHOLAS BAKALAR Women can unconsciously detect the smell of fear, new research suggests, and the smell improves their performance on mental tasks. Scientists collected sweat from seven volunteers — four men and three women — who watched horror movies while holding gauze pads in their armpits. Then, their sweat was collected while they watched videos with neutral emotional content. Sixty-eight women next performed a word-association task while smelling the pads. The task involved watching two words flash on a screen one after the other, and then stating whether the two words were related. ("Arms" and "legs" are related; "arms" and "wind" are not.) The subjects were divided into three groups: the first smelled the sweat pads of sweat collected during the frightening video; the second smelled pads collected during the neutral video; and the third, a control group, smelled pads with no sweat on them. Without sacrificing speed, the women smelling the fear pads were more accurate than those in the other two groups when processing meaningful related words. There was no difference in speed or accuracy between the three groups when the words were not related. Copyright 2006 The New York Times Company

Keyword: Chemical Senses (Smell & Taste); Emotions
Link ID: 8780 - Posted: 06.24.2010

By JOHN NOBLE WILFORD In following the fossil tracks of human evolution, scientists have for years searched for links between Australopithecus, the kin of the famous "Lucy" skeleton, and even earlier possible ancestors. Now, they think they have found some connections in Ethiopia. An international team of paleontologists is reporting the discovery of transitional species superimposed in sediments in the neighborhood of a single site. The findings appear today in the journal Nature. Tim D. White, a paleontologist at the University of California, Berkeley, who was a team leader, and his colleagues said the 4.1-million-year-old fossils were anatomically intermediate between the earlier species Ardipithecus ramidus and the later species Australopithecus afarensis, the Lucy family. The newfound bones and teeth are the earliest remains of the most primitive Australopithecus, known as anamensis. "This new discovery closes the gap between the fully blown australopithecines and earlier forms we call Ardipithecus," Dr. White said in a statement. "We now know where Australopithecus came from before four million years ago." Copyright 2006 The New York Times Company

Keyword: Evolution
Link ID: 8779 - Posted: 04.14.2006

By Michael Shermer Amyotrophic lateral sclerosis (ALS) is a neuromuscular disease that attacks motor neurons until muscle weakness, atrophy and paralysis lead inexorably to death. Victims of this monstrous malady could be forgiven for feeling unlucky. How, then, can we explain the attitude of the disease's namesake, baseball great Lou Gehrig? He told a sellout crowd at Yankee Stadium: "For the past two weeks you have been reading about the bad break I got. Today I consider myself the luckiest man on the face of this earth." The Iron Horse then recounted his many blessings and fortunes, a list twice punctuated with "I'm lucky" and "That's something." Clearly, luck is a state of mind. Is it more than that? To explore this question scientifically, experimental psychologist Richard Wiseman created a "luck lab" at the University of Hertfordshire in England. Wiseman began by testing whether those who believe they are lucky are actually more likely to win the lottery. He recruited 700 subjects who had intended to purchase lottery tickets to complete his luck questionnaire, which is a self-report scale that measures whether people consider themselves to be lucky or unlucky. Although lucky people were twice as confident as the unlucky ones that they would win the lottery, there was no difference in winnings. © 1996-2006 Scientific American, Inc.

Keyword: Emotions
Link ID: 8778 - Posted: 06.24.2010

New Haven, Conn. -- Yale scientists have systematically plotted the responses of the entire Drosophila (fruit fly) olfactory system, providing the first multi-dimensional map of the range of odorants sensed and the regions of the brain that are stimulated. John Carlson, the Eugene Higgins Professor of Molecular, Cellular and Developmental Biology and Elissa Hallem, his former graduate student in the Interdepartmental Neuroscience Program, published the comprehensive study in the journal Cell. "The results of our analysis allow us to make predictions about which odors smell alike to an animal, and which smell different," said Carlson. "These predictions can now be tested in behavioral experiments and may help point us to insect attractants and repellants that are highly effective." This paper provides particular insight into the understanding of how animals perceive environmental smells that are often complex mixtures of molecular structures. The study identifies compounds that both stimulate and inhibit response in odor neurons, and the differences in response that are due to concentration and duration of exposure to a compound.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 8777 - Posted: 04.14.2006

Comparative studies have studied testosterone levels and related them to mating systems and aggression, but very few studies have attempted to relate testosterone to fitness, that is, the combination of lifetime reproductive success and survival, in the wild or experimentally. Over nine breeding seasons, Wendy Reed (North Dakota State University) and her colleagues followed a group of dark-eyed juncos, small mountain songbirds found throughout North America. They injected males with elevated levels of testosterone and found that they had shorter lives but that they were very successful at siring more offspring – even with females who were mated with other males. "The surprising result was that testosterone-treated males had a higher overall fitness than control males," write the authors in a study in the May issue of American Naturalist. This led to the question of why don't juncos naturally have higher levels of testosterone? Testosterone-treated males produced more offspring, but they were smaller, and smaller offspring had lower postfledging survival. Older, more experienced females preferred to mate with older males and realized higher reproductive success when they did so. While young males treated with testosterone increased their ability to attract older females, it resulted in poor reproductive performance.

Keyword: Sexual Behavior
Link ID: 8776 - Posted: 06.24.2010

With swelling prison populations, researchers are trying to understand the biology behind aggressive behavior. National Institute of Mental Health scientist Andreas Meyer-Lindenberg is looking for clues to how genes wire our brains early in life. He's focusing on a specific gene that was previously linked to impulsive violence in certain populations of people. A study in 2002 found that subjects with a particular form of a gene had a significantly higher risk of violence only if they were abused as children. While this gene-environment interaction is important in understanding this behavior, Meyer-Lindenberg wanted to focus on the genetic facets of violence. The study also found that a variation in this gene, called MAOAG, disproportionately affects men, because this gene is located on the X chromosome, which determines sex. Since men only have one X chromosome, they are more prone to the effects of the gene. Women have two X chromosomes, but the chances of having the gene variation on both chromosomes is very rare. "One of the most fascinating things," Meyer-Lindenberg says, about this field of science called psychiatric genetics, "is how it is possible that genes [can] encode for molecules that affect something as complex as behavior, even psychiatric illness such as depression and social behavior." © ScienCentral, 2000-2006.

Keyword: Aggression; Genes & Behavior
Link ID: 8775 - Posted: 06.24.2010

When 8 year-old Andrew Kilbarger of Lancaster, Ohio received three injections in his right arm, he became one of six boys participating in the first U.S. gene therapy trial for muscular dystrophy. Andrew has Duchenne Muscular Dystrophy (DMD). DMD patients lack the gene that controls production of a protein called dystrophin, which helps keep muscle cells intact. Patients with DMD usually die by the age of 25, often because of the failure of the heart and breathing muscles. The start of any new gene therapy trial is an exciting time. But for the Muscular Dystrophy Association (which funded the trial), and the participants and doctors involved at Columbus Children's Hospital, this is a particularly exciting event because for this disease, it has been a long, hard road. Researchers discovered the gene for dystrophin 20 years ago but since it is one of the largest genes known, it was too big to work with. In 2000, geneticist Xiao Xiao found a way to miniaturize the gene. His team at the University of Pittsburgh tested the "mini-dystrophin" gene in a strain of mice with muscular dystrophy. The improvement seen in the muscle tissue of the mice was dramatic, and led to the human trial that just began. "The limitation of that is the gene vehicle will not be widespread. It will… be localized around the injection site. However, diseases like muscular dystrophy affect almost every skeletal muscle cell," he says." So you cannot, in theory, inject the genes into every muscle cell directly. So we have to figure out a novel or innovative way to deliver or disseminate [the gene]." © ScienCentral, 2000-2006.

Keyword: Muscles
Link ID: 8774 - Posted: 06.24.2010

Everyone is familiar with the sinking feeling you get after deleting a computer file by mistake or leaving the house without your keys. But such events also cause their own unique reactions in the brain. US scientists writing in the Journal of Neuroscience found one area becomes more active after "costly" mistakes. They say it may help explain obsessive compulsive disorder, where minor events appear to be enough to triger an over-reaction in the same area. In the study, the brains of 12 healthy adults were examined using a functional MRI (fMRI) scanner while they were undertook 360 computer tests, such as spotting the odd one out or picking pairs of letters. Succeeding at some carried a small financial reward, while failing at others incurred penalties. Others carried no reward or penalty. People were told they had a $10 (£5.70) "credit" to begin, and that they would receive real cash depending on their balance at the end. The response to a mistake that cost them money was seen to be greater than the response to other mistakes and involved a part of the brain called the rostral anterior cingulate cortex (rACC). That part of the brain did not show the same level of activity when the mistake did not carry a penalty, or had a neutral consequence. The researchers had already found in previous research that the rACC area did become more active when there was no cost in people with OCD. (C)BBC

Keyword: OCD - Obsessive Compulsive Disorder
Link ID: 8773 - Posted: 04.14.2006

Roxanne Khamsi The first common genetic variant that substantially increases a person’s risk of obesity has been identified, researchers claim. They hope that their discovery will open doors to new treatments for the condition. The team identified a small genetic change in a region of DNA near a gene known as INSIG2 as being linked to obesity. DNA code is made up of four bases, or "letters". A single change in this particular region, from a G to a C, makes a person more prone to obesity, according to the study. They believe this change somehow affects the regulation of the gene INSIG2, which has a role in fat production. The US researchers, led by Albert Herbert at the Boston University Medical School, found that an individual with two copies of the C variant is 22% more likely to have a body mass index (BMI) greater than 30 – the point where people move from being "overweight" to "obese". This is the first study to strongly identify a genetic component in obesity in a number of populations, comments Carol Shoulders at Imperial College London, UK. © Copyright Reed Business Information Ltd

Keyword: Obesity; Genes & Behavior
Link ID: 8772 - Posted: 06.24.2010

By Shankar Vedantam Pharmaceutical giant Eli Lilly and Co. recently funded five studies that compared its antipsychotic drug Zyprexa with Risperdal, a competing drug made by Janssen. All five showed Zyprexa was superior in treating schizophrenia. But when Janssen sponsored its own studies comparing the two drugs, Risperdal came out ahead in three out of four. In fact, when psychiatrist John Davis analyzed every publicly available trial funded by the pharmaceutical industry pitting five new antipsychotic drugs against one another, nine in 10 showed that the best drug was the one made by the company funding the study. "On the basis of these contrasting findings in head-to-head trials, it appears that whichever company sponsors the trial produces the better antipsychotic drug," Davis and others wrote in the American Journal of Psychiatry. Such studies make up the bulk of the evidence that American doctors rely on to prescribe $10 billion worth of antipsychotic medications each year. Davis pointed out the potential biases in design and interpretation that produced such contradictory results. Other experts note that industry studies invariably seek to boost the image of expensive drugs that are still under patent. Moreover, they say, the trials are relatively brief and test drugs on patients with simpler problems than doctors typically encounter in daily practice. © 2006 The Washington Post Company

Keyword: Schizophrenia
Link ID: 8771 - Posted: 06.24.2010

DURHAM, N.H. -- In a former cowshed on the edge of the University of New Hampshire campus, David Berlinsky, assistant professor of zoology, peers into a big blue plastic tub. Inside, black sea bass circle slowly in the dim light. The converted barn is now an aquaculture research facility for the College of Life Sciences and Agriculture, and home to Berlinsky’s latest research. Black sea bass feature prominently on many menus, but wild populations of the fish are in decline and their availability is limited. Because of the high demand, they’re a good candidate for aquaculture on the east coast. Except, that is, for one problem: they have a tendency to change sex unpredictably in captivity. “In the wild, black sea bass are born as females and turn into males at around two to five years old,” Berlinsky explains. “When you bring them into captivity, they change into males more quickly.” Some captive-born fish emerge as males even before reaching adulthood, devoting energy toward reproductive development and away from growth. Such problems make breeding and growing the fish in captivity a tricky proposition. “Black sea bass is a wonderful fish to culture and to eat,” says George Nardi, vice president and director of GreatBay Aquaculture, a commercial fish farm in Newington, NH. But the sex change problem must be tackled if fish farmers are to bring a high-quality fish to market. “We invest in our brood stocks, the parents of the young fish, much as a thoroughbred horse farm invests in mares and stallions,” he says. “It doesn’t do us much good if we always have to go out and get new females.”

Keyword: Sexual Behavior
Link ID: 8770 - Posted: 06.24.2010

Boston, MA – Researchers from the Harvard School of Public Health, Kaiser Permanente, and a team of collaborators have found further evidence implicating the Epstein-Barr virus (EBV) as a possible contributory cause to multiple sclerosis (MS). The study appears in the advance online edition of the June 2006 issue of Archives of Neurology. MS is a chronic degenerative disease of the central nervous system. Women are more likely than men to get the disease and it is the most common neurologically disabling disease in young adults. Although genetic predisposition plays an important role in determining susceptibility, past studies have shown that environmental factors are equally important. EBV is a herpes virus and one of the most common human viruses worldwide. Infection in early childhood is common and usually asymptomatic. Late age at infection, however, often causes infectious mononucleosis. In the U.S., upwards of 95% of adults are infected with the virus, but free of symptoms. EBV has been associated with some types of cancer and can cause serious complications when the immune system is suppressed, for example, in transplant recipients. There is no effective treatment for EBV. The study population was made up of more than 100,000 members of the Kaiser Permanente Northern California (KPNC) health plan, who provided blood specimens as part of medical examinations between 1965 and 1974.

Keyword: Multiple Sclerosis; Neuroimmunology
Link ID: 8769 - Posted: 06.24.2010

Adam Keiper Every so often, when some new scientific paper is published or new experiment revealed, the press pronounces the creation of the first bionic man—part human, part machine. Science fiction, they say, has become scientific reality; the age of cyborgs is finally here. Many of these stories are gross exaggerations. But something more is also afoot: There is legitimate scientific interest in the possibility of connecting brains and computers—from producing robotic limbs controlled directly by brain activity to altering memory and mood with implanted electrodes to the far-out prospect of becoming immortal by “uploading” our minds into machines. This area of inquiry has seen remarkable advances in recent years, many of them aimed at helping the severely disabled to replace lost functions. Yet public understanding of this research is shaped by sensationalistic and misleading coverage in the press; it is colored by decades of fantastical science fiction portrayals; and it is distorted by the utopian hopes of a small but vocal band of enthusiasts who desire to eliminate the boundaries between brains and machines as part of a larger “transhumanist” project. It is also an area of inquiry with a scientific past that reaches further back in history than we usually remember. To see the future of neuroelectronics, it makes sense to reconsider how the modern scientific understanding of the mind emerged.

Keyword: Robotics; Parkinsons
Link ID: 8768 - Posted: 06.24.2010

ANN ARBOR, Mich. -- It happens to all of us, no matter how hard we try. Whether it's deleting a computer file and realizing a split-second later that we can't get it back, or dropping a bag of groceries, or realizing that our gas tank is nearly empty on a lonely stretch of highway, we all make mistakes that aren't just annoying, but potentially costly. Now, a team of University of Michigan researchers has looked inside the human brain and captured the instant when someone makes a costly mistake. What they've found is interesting by itself, but may also help scientists understand mental health problems such as obsessive-compulsive disorder, or OCD. In general, the U-M scientists found that a particular part of the brain called the rostral anterior cingulate cortex, or rACC, becomes much more active when a person realizes he or she has made an error that carries consequences – for instance, losing money. By contrast, the same area of the brain doesn't show the same level of activity when the mistake doesn't carry a penalty, or even when a correct action carries a reward. The rACC is thought to be involved with emotional responses, and scientists had suspected it might also be involved in response to costly errors. But this is the first brain-imaging study to test that idea.

Keyword: Emotions; Brain imaging
Link ID: 8767 - Posted: 06.24.2010

By Jennifer Viegas, Discovery News — Labradors and dachshunds appear to waddle, while greyhounds seem to march by with a fast clip, but new research has determined that the basic mechanics behind dog walking are the same for all canines. The discovery could lead to a better understanding of health issues related to walking in dogs, such as hip problems. It could also result in improvements to four-legged, dog-like robots, which the U.S. military already is investigating. "The big benefit would be to show how robot dogs should walk more efficiently," said lead scientist Jim Usherwood, a researcher at the University of London's Royal Veterinary College Structure and Motion Laboratory. Usherwood added, "Almost all robots require a large amount of power — much higher than an animal would use — partly because they tend to use bent legs. I show what would happen with stiff legs." Inspired by stiff-legged mechanical toys that can walk down hills, Usherwood and his team designed several different computer models for dog walking. The researchers then compared these models with observations of actual dogs on a treadmill. © 2006 Discovery Communications Inc.

Keyword: Miscellaneous
Link ID: 8766 - Posted: 06.24.2010