Helen Pilcher Mothers who think they have longer to live are more likely to give birth to boys than girls, a survey of British women shows. The finding backs up the long-held theory that women may unwittingly be able to influence the sex of their unborn child. Sarah Johns from the University of Kent asked 609 first-time mothers, who had already given birth, to guess when they thought they would die. By subtracting the mother's age, she then calculated the number of years each woman thought she had left to live. The results are reported in the Proceedings of the Royal Society1. As the number of perceived years left rose, so too did the chance that they had had a son. Every extra year on the clock increased the odds of producing a male by 1%. The finding backs up a 30-year-old hypothesis2 that suggests women can bias the sex of their unborn babies, to enhance the chances of their genes being passed on to future generations. Boys need more looking after than girls, the theory says. So when food is scarce and resources are low, females preferentially give birth to girls because they are more likely to live through the hard times. But boys are able to produce more offspring, so when resources are plentiful, mothers should be more likely to give birth to boys, to maximise the number of potential grandchildren. ©2004 Nature Publishing Group

Keyword: Sexual Behavior; Neuroimmunology
Link ID: 5949 - Posted: 06.24.2010

Two related genes that help control signaling between brain cells may be central components of the biological machinery that causes cocaine addiction, researchers have found. Peter Kalivas and his colleagues found that deleting either of two genes in the Homer family in mice produced the same symptoms seen in withdrawal from cocaine. The researchers said that their findings could open a new research pathway to understanding how genetic susceptibility to addiction interacts with environmental factors to cause addiction. Studies by other researchers had suggested that the proteins produced by the Homer genes might play a role in cocaine addiction. Members of the family were known to be activated by cocaine, and reduction of activity in the genes had been linked to cocaine withdrawal. So, to unequivocally test the involvement of the Homer genes in cocaine addiction, Kalivas and his colleagues individually knocked out the genes in mutant mice and tested the behavioral and biological effects. In one behavioral test, they placed the knockout mice in one of two linked chambers after cocaine administration. One was a "comfortable" darkened chamber with nesting material, and the other was an "uncomfortable" bare, white, brightly lit chamber. The researchers found that the mice lacking Homer1 or Homer2 genes showed greater preference for the chamber that they associated with receiving cocaine, compared to normal controls. The knockout mice also showed hyperactivity characteristic of withdrawal.

Keyword: Drug Abuse; Genes & Behavior
Link ID: 5948 - Posted: 08.05.2004

Humans behave like small mammals when tracing the source of a low-pitched sound, according to a study funded by the Medical Research Council at University College London. UCL researchers have devised a new model for how the human brain tracks sound, which could eventually help engineers develop technology for tracking sound sources in noisy environments like crowded bars and restaurants. In the study published in this week's Nature, Dr David McAlpine and Nicol Harper asked volunteers to wander the streets of London wearing microphones in their ears. The microphones measured the time difference between sound arriving at each ear for a range of noises that people typically encounter in the city. While it was already known that animals and humans use small differences in the arrival time of sound at each ear to locate its source, the UCL study found that the human brain adopts a strategy similar to a barn owl's brain for sound pitches above middle-C, and a gerbil's below middle-C. David McAlpine says: "For animals and humans, locating the source of a sound can mean the difference between life and death, such as escaping a pursuer or crossing a busy street. Our study suggests that the brain adopts an efficient strategy for doing this, adapting to different frequencies, or pitches, of sound.

Keyword: Hearing
Link ID: 5947 - Posted: 08.05.2004

Inner ear size may be determinant A University of Toronto researcher has found that differences between men and women in determining spatial orientation may be the result of inner ear size. The study, published online in the journal Perception, examined whether differences in how men and women judge how we orient ourselves in our environment could be attributed to physiological or psychological causes. It found that giving the participants verbal instructions on how to determine their spatial orientation did not eliminate the differences between the sexes. "Since the instructions didn't remove the difference between how men and women judge spatial orientation, we believe it is likely a result of physiological differences," says Luc Tremblay, a professor in U of T's Faculty of Physical Education and Health. For example, says Tremblay, the otoliths – structures found in the inner ear which are sensitive to inertial forces such as gravity – tend to be larger in men than in women, and may allow males to adjust themselves more accurately than females in some environments. In the study, Tremblay asked 24 people (11 males and 13 females) to point a laser straight-ahead (perpendicular to the body orientation) while upright and when tilted 45 degrees backward. To test whether cognitive processes affected spatial orientation, participants – who were tested in the dark – were told to focus on external or internal cues to help them orient the laser. He found that although instructions to pay attention to internal cues helped women to point the laser significantly closer to their straight-ahead, there were still significant differences between the sexes, with women tending to look more towards their feet.

Keyword: Sexual Behavior; Hearing
Link ID: 5946 - Posted: 06.24.2010

A brain imaging study by the NIH's National Institute of Mental Health (NIMH) has found that an emotion-regulating brain circuit is overactive in people prone to depression — even when they are not depressed. Researchers discovered the abnormality in brains of those whose depressions relapsed when a key brain chemical messenger was experimentally reduced. Even when in remission, most subjects with a history of mood disorder experienced a temporary recurrence of symptoms when their brains were experimentally sapped of tryptophan, the chemical precursor of serotonin, the neurotransmitter that is boosted by antidepressants. Neither a placebo procedure in patients nor tryptophan depletion in healthy volunteers triggered the mood and brain activity changes. Brain scans revealed that a key emotion-processing circuit was overactive only in patients in remission — whether or not they had re-experienced symptoms — and not in controls. Since the abnormal activity did not reflect mood state, the finding suggests that tryptophan depletion unmasks an inborn trait associated with depression. Alexander Neumeister, M.D., Dennis Charney, M.D., Wayne Drevets, M.D., NIMH Mood and Anxiety Disorders Program, and colleagues, report on their positron emission tomography (PET) scan study in the August 2004 Archives of General Psychiatry. The NIMH researchers and others had previously shown that omitting tryptophan from a cocktail of several other essential amino acids washes out the precursor chemical from the blood and brain, depleting serotonin and often triggering symptoms in people with a history of depression — and even in healthy people from depression-prone families.

Keyword: Depression; Brain imaging
Link ID: 5945 - Posted: 06.24.2010

When Sydney Brenner gave his Nobel lecture in December 2002, he doffed his cap to the fourth joint-winner of the prize for physiology or medicine that year. In addition to himself and his two colleagues, John Sulston and Robert Horvitz, Brenner said that the honour should also be shared with Caenorhabditis elegans, without whom the others could not have made their groundbreaking discoveries. C. elegans is a barely visible nematode worm that, fully grown, reaches the magnificent length of 1mm. Possessing a fully functioning nervous system that consists of 302 nerve cells, it lives out its brief existence in compost heaps and river banks, sustaining itself on a diet of bacteria. But for Brenner, who in 1963 chose it as a model organism for studying how genes regulate development, the worm was the ultimate lab workhorse. "The animals live in a two-dimensional world feeding on E. coli on the surface of agar plates," he told his audience in Stockholm. "They are easy to grow in bulk, each animal producing about 300 progeny during a cycle." C. elegans quickly became a star, worthy of comparison with the mouse and the fruit fly for services to science. Brenner's early work linking genetic analysis to cell division and organ development laid the foundations for Sulston and Horvitz to identify key genes controlling that development - genes that have their counterparts in man. Among other things, their work has led to a greater understanding of many human diseases. © 2004 Independent Digital (UK) Ltd

Keyword: Development of the Brain
Link ID: 5944 - Posted: 06.24.2010

By DONALD G. McNEIL Jr. The first thing I did after spending 23 hours in a sleep laboratory was to head for a Starbucks and have a mocha-plus-extra-shot. It was truly heady - I hadn't felt so alert in years. But over the next couple of weeks, I became obsessed with my lack of sleep. I thought I could hear myself snore, and I would lie awake at 5 a.m., wondering what had woken me up. The lab, at Downstate Medical Center in Brooklyn, had diagnosed mild obstructive sleep apnea, a condition that blocks breathing and suppresses oxygen levels. In my case, the problem was probably caused by a narrow airway, an oversized uvula, "high normal" weight and drinking alcohol before bed. As a result, I suffered from chronic sleep deprivation leading to daytime grogginess. Dr. Chun Bai, the director of the sleep laboratory, had advised me to practice "better sleep hygiene." I should drink less wine with dinner, he said, go to bed earlier, use two pillows and sleep on my side. He also told me not to gain weight and to watch out when I drove at night. Copyright 2004 The New York Times Company

Keyword: Sleep
Link ID: 5943 - Posted: 08.04.2004

Levels of a particular hormone may influence a person's ability to cope with stress, suggests a study of soldiers put through a prisoner of war camp simulation. Soldiers enduring punishing stints in military survival school performed better and felt more attuned to their environments when they had higher levels of a hormone called dehydroepiandrosterone-S (DHEA-S), report US scientists. The ratio of DHEA-S against levels of another stress hormone, called cortisol, was important in coping with stress, they suggest. The researchers say DHEA-S could one day be given to people before stressful experiences to help them cope better during traumatic events. DHEA-S is secreted by the outer portion of the adrenal gland in response to stress. People aged 20 to 25 have the highest levels of DHEA-S, which then drops by a factor of five by age 80. Previous studies have shown the hormone enhances memory and reduces depression and aggression in mice. It turns up in low levels in people suffering from depression and anxiety, although its role in post-traumatic stress disorder (PTSD) has been unclear. © Copyright Reed Business Information Ltd.

Keyword: Stress; Hormones & Behavior
Link ID: 5942 - Posted: 06.24.2010

Jim Giles The state of suspended animation that astronauts enter during long-haul space flights is a staple of science-fiction movies. But now the European Space Agency (ESA) wants to turn it into reality. Agency staff are planning future research into the possibility of inducing a hibernation-like state in humans. "We are not sure whether it is possible," says Marco Biggiogera, an expert on hibernation mechanisms at the University of Pavia, Italy, who is advising ESA. "But it's not crazy." ESA believes hibernation would help astronauts to cope with the psychological demands of decades-long return journeys to destinations such as Saturn. And because less space and food would be needed on such missions, the spacecraft would be lighter and easier to launch. ©2004 Nature Publishing Group

Keyword: Sleep
Link ID: 5941 - Posted: 06.24.2010

COLUMBUS, Ohio – A new study suggests that wounds on mice that prefer multiple mates heal at the same rate, whether the mice are housed with a mate or live in isolation. But the same doesn't ring true for monogamous mice, said Courtney DeVries, an assistant professor of psychology and neuroscience at Ohio State University. She and Erica Glasper, a doctoral student in psychology at Ohio State, took a closer look at the effects social bonding had on wound healing in monogamous and non-monogamous deer mice. Non-monogamous males mate with more than one female during a breeding season. The researchers especially wanted to see if social interaction, or the lack of it, made a difference in the rate of wound healing in the non-monogamous mice. It didn't. In fact, levels of corticosterone – a stress hormone that rodents secrete – in the non-monogamous mice were the same whether they were paired or alone, and were also significantly lower than the corticosterone levels of paired, monogamous mice.

Keyword: Neuroimmunology; Sexual Behavior
Link ID: 5940 - Posted: 06.24.2010

By Barbara Kantrowitz and Karen Springen NewsweekAug. 9 issue - In the middle of the night, we are all Fellini—the creator of a parade of fleeting images intended for an audience of one. At times, it's an action flick, with a chase scene that seems endless ... until it dissolves and we're falling, falling, falling into ... is it a field of flowers? And who is the gardener waving at us over there? Could it be our old high-school English teacher? No, it's Jon Stewart. He wants us to sit on the couch right next to him. Are those TV cameras? And what happened to our clothes? In the morning, when the alarm rudely arouses us, we might remember none of this—or maybe only a fraction, perhaps the feeling of lying naked in a bed of daisies or an inexplicable urge to watch "The Daily Show." This, then, is the essence of dreaming—reality and unreality in a nonsensical, often mundane but sometimes bizarre mix. Dreams have captivated thinkers since ancient times, but their mystery is now closer than ever to resolution, thanks to new technology that allows scientists to watch the sleeping brain at work. Although there are still many more questions than answers, researchers are now able to see how different parts of the brain work at night, and they're figuring out how that division of labor influences our dreams. In one sense, it's the closest we've come to recording the soul. "If you're going to understand human behavior," says Rosalind Cartwright, a chairman of psychology at Rush University Medical Center in Chicago, "here's a big piece of it. Dreaming is our own storytelling time—to help us know who we are, where we're going and how we're going to get there." © 2004 Newsweek, Inc.

Keyword: Sleep
Link ID: 5939 - Posted: 06.24.2010

By MEL GUSSOW In writing his best-selling first novel, "The Curious Incident of the Dog in the Night-Time," Mark Haddon did not set out to become a spokesman for people with Asperger syndrome, a form of high-functioning autism characterized by obsessive behavior, brilliance in some areas and social ineptitude. The condition is not even mentioned by name in the book, but it is at the heart of the story. Christopher Boone, the 15-year-old protagonist, is an autistic savant. He knows all the countries of the world and their capital cities and every prime number up to 7,057 but has a problem relating to other people, and his inability to lie leads him into a series of quandaries. When a neighbor's dog is killed, Christopher turns amateur detective, using methods of his favorite sleuth, Sherlock Holmes. The title of the book comes from Arthur Conan Doyle's "Silver Blaze." Copyright 2004 The New York Times Company

Keyword: Autism
Link ID: 5938 - Posted: 08.03.2004

By ANAHAD O'CONNOR When Aaron, a 33-year-old writer from New York, decided to get help for his five-year addiction to painkillers, there was really only one option. Every morning, he visited a local clinic for a small cup of methadone, the standard treatment for addiction to heroin and other opiates since the 1960's. But his life soon revolved around the clinic's hours, he said, and the daily routine was humiliating. "I had to stand in line with a bunch of people who were talking about getting high," and take a urine test for illicit drugs each week, said Aaron, who spoke on the condition that his last name be withheld. Then, a year and a half ago, a quiet scientific advance gave Aaron - and 60,000 other Americans - a chance to break their dependence on drugs without shame. Copyright 2004 The New York Times Company

Keyword: Drug Abuse
Link ID: 5937 - Posted: 08.03.2004

By Jennifer Virgas, Discovery News — The world may appear a more colorful place to women, according to a new study that finds many women perceive a greater range of colors — particularly shades of red — than men are able to see. How men and women see the world appears to relate back to evolution and our early ancestors. While men likely were scoping out the landscape for prey to hunt, the researchers theorize that women were gathering fruits, vegetables, insects and other edibles often identified and rated by color. For the study, which will be published in September in The American Journal of Human Genetics, researchers analyzed the DNA of 236 men from a number of populations from Africa, Asia and Europe. The scientists focused on a particular gene, OPN1LW, which codes for a protein, called an opsin protein, involved in the detection of the red light spectrum. This gene also exchanges amino acids — the building blocks of protein — with a nearby gene involved in detecting the green spectrum of light. Copyright © 2004 Discovery Communications

Keyword: Vision
Link ID: 5936 - Posted: 06.24.2010

Software that creates an animated face to match someone talking on the other end of a phone line can help people with hearing difficulties converse, suggests a new study. The animated face provides a realistic impersonation of a person speaking, enabling lip-readers to follow the conversation visually as well as audibly. The prototype system, called Synface, helped 84 percent of participants to recognise words and chat normally over the telephone in recently completed trials by the UK's Royal National Institute for the Deaf (RNID). The RNID trials involved hard-of-hearing volunteers trying to decipher preset sentences and also taking part in real conversations. Synface takes around 200 milliseconds - one fifth of a second - to generate the animated annunciations. But the system incorporates a fractional delay, so that the face is perfectly synchronised with the voice on the end of the line. © Copyright Reed Business Information Ltd.

Keyword: Language; Emotions
Link ID: 5935 - Posted: 06.24.2010

Neurotoxins from blue-green algae present in certain foods or water can accumulate in proteins and might cause brain diseases like Alzheimer’s after many years, suggests a new study. The latest research explains how a devastating neurodegenerative disease common on the remote Pacific island of Guam can still strike people down decades after they have left the island. The disease, called amyotrophic lateral sclerosis/Parkinsonism dementia complex (ALS/PDC), has symptoms resembling those of both Parkinson’s and Alzheimer's disease. The brain damage it causes is similar to that found in Alzheimer’s patients. The latest theory is that the islanders’ taste for flying foxes is to blame. A neurotoxin called BMAA found in the fruit of the cycads on which the flying foxes feed, is thought to become concentrated in the flying foxes' flesh. BMAA, in turn, is made by a blue-green alga, or cyanobacterium, that lives in the roots of the cycads (New Scientist print edition, 10 January). © Copyright Reed Business Information Ltd.

Keyword: Alzheimers; Neurotoxins
Link ID: 5934 - Posted: 06.24.2010

Areas of abnormal white matter in the brains of multiple sclerosis (MS) patients appear much larger on diffusion tensor MRI than on T2-weighted MRI, a finding which could impact therapy options, according to a new study by researchers from Duke University Medical Center in Durham, NC. The study analyzed 36 white matter plaques in 20 patients with MS who underwent both T2-weighted and diffusion tensor MRI. By measuring the degree to which water molecules spread in a particular direction--called fractional anisotropy (FA)--which is altered with damage to the nerve axons, the researchers discovered that the average area of focally abnormal white matter on diffusion tensor imaging was 87 mm2, 45% more than the average plaque area seen on T2-weighted images. The researchers believe that besides measuring the degree of diseased white matter more accurately than T2-weighted imaging, diffusion tensor imaging may also show abnormalities earlier than T2-weighted imaging.

Keyword: Multiple Sclerosis; Brain imaging
Link ID: 5933 - Posted: 08.03.2004

An estimated 17.6 million American adults (8.5 percent) meet standard diagnostic criteria for an alcohol use disorder* and approximately 4.2 million (2 percent) meet criteria for a drug use disorder. Overall, about one-tenth (9.4 percent) of American adults, or 19.4 million persons, meet clinical criteria for a substance use disorder — either an alcohol or drug use disorder or both — according to results from the 2001-2002 National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) reported in the current Archives of General Psychiatry, Volume 61, August 2004. Conducted by the National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, the NESARC is a representative survey of the U.S. civilian noninstitutionalized population aged 18 years and older. With more than 43,000 adult Americans participating, the NESARC is the largest study ever conducted of the co-occurrence of psychiatric disorders among U.S. adults. Results from the NESARC show that 19.2 million adults (9.2 percent) meet diagnostic criteria for independent mood disorders (including major depression, dysthymia, manic disorder, and hypomania) and 23 million (11.08 percent) meet criteria for independent anxiety disorders (including panic disorder, generalized anxiety disorder, and specific and social phobias).

Keyword: Emotions; Drug Abuse
Link ID: 5932 - Posted: 06.24.2010

An estimated 30.8 million American adults (14.8 percent) meet standard diagnostic criteria for at least one personality disorder as defined in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition (DSM-IV), according to the results of the 2001-2002 National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) reported in the current issue of the Journal of Clinical Psychiatry [Volume 65:948-958]. Conducted by the National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, the NESARC is a representative survey of the U.S. civilian noninstitutionalized population aged 18 years and older. More than 43,000 American adults participated in the survey. Designed to assess prevalence and comorbidity, or co-occurrence, of multiple mental health disorders, the NESARC is the first national survey conducted in the United States to estimate the prevalence of selected personality disorders — stable patterns of inner experience and behavior that are inflexible and maladaptive that begin in early adulthood and are displayed in a variety of contexts — that often co-occur with other mental health disorders such as substance use disorders and anxiety and mood disorders.

Keyword: Depression; Schizophrenia
Link ID: 5931 - Posted: 06.24.2010

Michael Hopkin A mother on the warpath can be a fearsome foe. Now researchers studying mice believe they have identified the hormone responsible for females' fiercely protective attitudes to their offspring. A maternal mouse will attack any intruder to her nest if she thinks her pups are in danger. This apparently selfless response may be due to low levels of a protein called corticotropin-releasing hormone (CRH), report Stephen Gammie and his colleagues at the University of Wisconsin-Madison. High levels of CRH in the brain are linked to fear and anxiety, Gammie explains. So without it, a mouse is more likely to leap towards an intruder without a thought for herself. "We've known for a while that CRH promotes fear, so we thought it might be important," he adds. To test the idea, the researchers took nursing mothers and put a male mouse in their cage after injecting some of them with CRH. Untreated mice launched a vicious attack on the intruder, attempting to bite vulnerable areas such as the head, neck and back. But, as the researchers report in the journal Behavioral Neuroscience1, mice injected with extra CRH were far less valiant and cowered in fear. ©2004 Nature Publishing Group

Keyword: Aggression; Hormones & Behavior
Link ID: 5930 - Posted: 06.24.2010