By YUDHIJIT BHATTACHARJEE In the grand story of evolution that scientists have been reconstructing since Charles Darwin's voyage on H.M.S. Beagle, the chapter on mate selection reads something like this: males compete among themselves to attract females, showing off their antlers, bright plumage or other ornaments that signal good health. Females watch the display from the sidelines, aloof and picky, like wealthy patrons at an art exhibition. When a male meets a female's approval, she agrees to court him and finally grants him permission to impregnate her. That account of mate choice, in which males do all the dancing-to-impress and females sit on the judging panel, is being increasingly viewed by scientists as too simplistic — a broad-brush picture that tells only part of the story. Copyright 2002 The New York Times Company

Keyword: Evolution; Sexual Behavior
Link ID: 2277 - Posted: 06.24.2010

NewScientist.com news service A rapid way to create a 3D map of the brain's genetic activity should help researchers pinpoint the neurological underpinnings of autism, schizophrenia and other brain disorders. Desmond Smith of the University of California, Los Angeles and his colleagues developed the technique called "voxelation" to study Parkinson's disease in a mouse model. "We could see mass migrations of gene activity. It was very dramatic," says Smith. The team found that one group of genes shifted their activity away from the striatum - a region known to be highly disrupted by Parkinson's disease. Their analysis also revealed that genes involved with communication between cells seem to figure prominently in the disease. © Copyright Reed Business Information Ltd.

Keyword: Brain imaging; Genes & Behavior
Link ID: 2276 - Posted: 06.24.2010

WINSTON-SALEM, N.C. – Wake Forest University School of Medicine scientists are closing in on why drinking alcohol before bedtime paradoxically improves sleep that evening, but disrupts sleep during the early morning hours. In a presentation at the Research Society on Alcoholism in San Francisco, Dwayne W. Godwin, Ph.D. explained that a key brain region involved in sleep, the thalamus, is "exquisitely sensitive to alcohol." The cells in the thalamus possess an ion channel that behaves differently depending on the amount of alcohol that has been drunk. "Low doses of alcohol increase activity; high doses shut it down," said Godwin, associate professor of neurobiology and anatomy. Copyright: Wake Forest University School of Medicine

Keyword: Drug Abuse; Sleep
Link ID: 2275 - Posted: 06.24.2010

The skull and jawbone of a small, lightly-built individual, discovered at an archeological site in Dmanisi, Georgia, may call into question the prevailing idea that larger brain size was behind the migration of human ancestors out of Africa. An international research team describes their find in the journal Science, published by the American Association for the Advancement of Science. The scientists found a petite new individual, with a small brain, thin brow ridge, short nose, and huge canine teeth, according to co-author David Lordkipanidze of the Georgian Academy of Sciences, in Tbilisi. This was the third specimen found at the site. By comparison, the other two skulls had room for substantially larger brains. All three specimens are approximately 1.75 million years old, making them the largest collection of individuals from any one site older than around 800,000 years. Lordkipanidze and his colleagues have tentatively concluded that the three belong to the same species, Homo erectus, thought to be the first hominid species to leave Africa. The Dmanisi fossils most closely resemble the African version of Homo erectus, called Homo ergaster.

Keyword: Evolution
Link ID: 2274 - Posted: 07.06.2002

Evidence is mounting that sleep – even a nap – appears to enhance information processing and learning. New experiments by NIMH grantee Alan Hobson, M.D., Robert Stickgold, Ph.D., and colleagues at Harvard University show that a midday snooze reverses information overload and that a 20 percent overnight improvement in learning a motor skill is largely traceable to a late stage of sleep that some early risers might be missing. Overall, their studies suggest that the brain uses a night's sleep to consolidate the memories of habits, actions and skills learned during the day. The bottom line: we should stop feeling guilty about taking that "power nap" at work or catching those extra winks the night before our piano recital. Reporting in the July, 2002 Nature Neuroscience, Sara Mednick, Ph.D., Stickgold and colleagues demonstrate that "burnout" – irritation, frustration and poorer performance on a mental task -- sets in as a day of training wears on. Subjects performed a visual task, reporting the horizontal or vertical orientation of three diagonal bars against a background of horizontal bars in the lower left corner of a computer screen.

Keyword: Sleep
Link ID: 2273 - Posted: 06.24.2010

By Warren King Seattle Times medical reporter Huntington's disease for now has no cure. Treatment focuses on its symptoms — drugs to calm involuntary muscle movements and psychiatric problems. But researchers are homing in on a variety of therapies aimed at the underlying causes of the disease. Much attention has been focused on experiments with transplantation of fetal tissue into the brains of Huntington's patients. Small trials have shown improved cognitive function and muscle coordination in a few patients. The tissue is taken from fetuses aborted in the first trimester and implanted in damaged areas of the brain. It yields healthy brain cells to replace those killed by the disease. And the tissue is not rejected by the body, experiments by University of South Florida and French researchers have shown. Copyright © 2002 The Seattle Times Company

Keyword: Huntingtons; Stem Cells
Link ID: 2271 - Posted: 06.24.2010

Kristin Cobb Women have higher rates of obesity and eating disorders than men do, but scientists don't know why. New findings offer clues to the root of sex differences in eating behaviors. The study showed that men's and women's brains react differently to hunger, as well as to satiation. This is the first research to document sex-specific brain activity related to eating, says study author Angelo Del Parigi of the Phoenix branch of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). The report appears in the June American Journal of Clinical Nutrition. Using positron emission tomography (PET), Del Parigi and his colleagues at NIDDK monitored the brains of 22 men and 22 women. A PET scan identifies areas where there are surges in blood flow that reflect activity. The scientists performed the scans after the participants endured a 36-hour fast and again after they drank a liquid meal to quench their hunger. From Science News, Vol. 162, No. 1, July 6, 2002, p. 4. Copyright ©2002 Science Service. All rights reserved.

Keyword: Obesity; Sexual Behavior
Link ID: 2270 - Posted: 06.24.2010

Embryonic mouse stem cells transformed into neurons in a lab dish and then transplanted into a rat model for Parkinson's disease (PD) form functional connections and reduce disease symptoms, a new study shows. The finding suggests that embryonic stem (ES) cells may ultimately be useful for treating PD and other brain diseases. The study is one of the first to show that ES cells can develop into neurons that function in the brain, according to senior author Ronald McKay, Ph.D., of the National Institute of Neurological Disorders and Stroke (NINDS). The report appears in the June 20, 2002, advance online publication of Nature1. A second study in Nature2 , led by Catherine Verfaillie, M.D., at the University of Minnesota in Minneapolis, shows that bone marrow-derived cells called mesenchymal stem cells have many of the characteristics of ES cells. Dr. McKay and his colleagues added a gene called Nurr1 to cultured mouse ES cells and exposed them to a series of growth factors that caused them to develop into neurons. Nurr1 helps neural precursor cells differentiate, or change, into neurons that produce the neurotransmitter dopamine. The loss of dopamine-producing neurons is a central feature of PD. To see if the ES cell-derived neurons would survive and function in animals, the researchers transplanted the neurons into rats that were missing the dopamine-producing cells on one side of their brains. These rats have parkinsonian symptoms on one side of their bodies. A similar group of rats received transplants of ES cells without the Nurr1 gene, and a third group received sham operations.

Keyword: Parkinsons; Stem Cells
Link ID: 2269 - Posted: 06.22.2002

Women suffering from premenstrual syndrome can alleviate their symptoms with a carbohydrate-rich drink, say scientists. Women were given the drink, PMS Escape, twice daily in the five days before their period. The American researchers found that the women, who had mild to moderate symptoms, had less negative mood swings and food cravings after taking the supplement, which increased the brain chemical serotonin. The drink is fruit-flavoured and contains carbohydrates, vitamins, and minerals. But the data in the study, published in the International Journal of Gynaecology and Obstetrics, has been criticised by Professor of gynaecology John Studd. (C) BBC

Keyword: Hormones & Behavior
Link ID: 2268 - Posted: 06.22.2002

Exclusive from New Scientist Print Edition Therapies that aim to rehabilitate stroke patients may be backfiring. Instead of helping people recover lost speech or movement, they could be making the problems worse. That's the conclusion of researchers who found that people who have had strokes were better able to recall words after they silenced parts of the brain that therapies stimulate. Stroke is caused when a clot forms or a blood vessel ruptures in the brain, cutting off the blood supply and killing neurons within minutes. Although the dead cells are not replaced, people can still recover lost functions such as the ability to recall words. © Copyright Reed Business Information Ltd.

Keyword: Stroke
Link ID: 2267 - Posted: 06.24.2010

Bruce Bower In 1992, Karen Wynn's numbers came in big. The numbers in question were tiny in an absolute sense, but they counted for a lot among investigators of child development. The reason: Wynn claimed to have exposed intuitive arithmetic skills of 5-month-old babies. The young psychologist, having received her doctorate in psychology just 2 years earlier, reported that infants show a facility for adding and subtracting small numbers of items, on the order of 1 + 1 = 2 and 2 – 1 = 1. Her results appeared in a major scientific journal, attracted worldwide media coverage (SN: 8/29/92, p. 132), and inspired a wave of research into what she regards as infants' seemingly innate "number sense." Now at Yale University, Wynn is more convinced than ever that babies, along with many nonhuman animals, carry an evolutionary legacy of basic number skills. She's also aware, however, that a spirited debate has emerged about whether the line of research that she's championed really taps into an inborn counting mechanism in the human brain. Some scientists argue that babies use non-numerical visual cues, such as the area and length of the border around visible items, to make quantitative judgments. These handy perceptual features, which vary along with changes in item number, may eventually serve as building blocks when youngsters really learn to count, between ages 2 and 4, in these researchers' view. From Science News, Vol. 161, No. 25, June 22, 2002, p. 392. Copyright ©2002 Science Service. All rights reserved.

Keyword: Development of the Brain; Intelligence
Link ID: 2265 - Posted: 06.24.2010

Kristin Cobb A protein that links gluttony and weight gain may be a novel target for antiobesity drugs. Mice lacking this protein can indulge in fatty food but remain as slim as mice on a lower-fat diet, a new study reports. The finding suggests a new avenue to help morbidly obese people lose weight. When food is scarce, stockpiling energy in fat cells is a survival advantage. But when food is plentiful, as in industrialized countries, genes that promote fat storage lead to obesity (SN: 4/14/01, p. 238: Available to subscribers at http://www.sciencenews.org/20010414/bob17.asp). The molecular mechanisms that translate extra calories into fat deposition are largely unknown. Now, researchers at Kyoto University in Japan have identified a key pathway in the process. Scientists have long known that the hormone called gastric inhibitory polypeptide (GIP) is secreted into the bloodstream by the small intestine in response to ingested foods, particularly fatty ones. GIP binds to cell-surface receptors on distant fat cells, signaling food intake. From Science News, Vol. 161, No. 25, June 22, 2002, p. 387. Copyright ©2002 Science Service. All rights reserved.

Keyword: Obesity
Link ID: 2264 - Posted: 06.24.2010

SAN FRANCISCO, June 21 – Increased levels of the stress hormone cortisol are clearly elevated in child-bearing-aged women who have stopped menstruating – not only in the bloodstream, but also in the cerebrospinal fluid, a senior researcher at the Magee-Womens Research Institute has found. The study is significant because it shows a definitive link between cortisol levels in circulating blood and those in the fluid that surrounds and bathes the brain and spinal cord. "In fact, cortisol levels in the cerebrospinal fluid are even higher than in the circulating bloodstream," said Sarah Berga, M.D., a professor in the departments of obstetrics, gynecology and reproductive sciences and psychiatry at the University of Pittsburgh School of Medicine and a senior investigator at Magee-Womens Research Institute. "This is really important because cortisol is neurotoxic."

Keyword: Hormones & Behavior; Stress
Link ID: 2263 - Posted: 06.24.2010

Seek glimpse into why amputees 'feel' what isn't there By Randy Dotinga HealthScoutNews Reporter HealthScoutNews) -- Scientists are getting a glimpse into how the brain creates a phantom limb, potentially helping them develop new ways to treat amputees who feel pain in body parts that aren't there. In a very unusual case involving a stroke victim's perception of a third arm, researchers at the University of California at San Francisco found activity in a part of the brain that sends signals to the body, not the other way around. That suggests the brain's mental image of the body may play a key role in the development of phantom limbs, says Dave McGonigle, a radiology researcher and co-author of a study that appears in the current issue of Brain. Copyright © 2002 ScoutNews, LLC. All rights reserved.

Keyword: Pain & Touch; Stroke
Link ID: 2262 - Posted: 06.24.2010

SHARON BEGLEY, The Wall Street Journal It wasn't the kind of passage you usually encounter in a strait-laced science journal: "I have had to spend periods of several weeks on a remote island in comparative isolation," Anonymous wrote in Nature. Curiously, he continued, the day before he was due for shore leave his beard grew noticeably: "I have come to the conclusion that the stimulus for (this) growth is related to the resumption of sexual activity." Neither Anonymous nor his fellow scientists were surprised that the aforementioned activity would loose a flood of testosterone, which affects beards the way Miracle-Gro affects tomato plants. No, the weird part is that merely anticipating female companionship did the trick. Just as stress in the med students I wrote about last week altered the expression of genes in their immune systems, so libidinous thoughts seem to affect gene expression, says developmental psychologist David Moore of Pitzer College in Claremont, Calif. Thoughts can cause the release of hormones that can bind to DNA, "turning genes `on' or `off.' " ©2002 Associated Press

Keyword: Genes & Behavior
Link ID: 2261 - Posted: 06.24.2010

By Helen Briggs BBC News Online science reporter Professional musicians have more grey matter in a part of the brain involved in processing music, scientists have found. The discovery could explain why musical virtuosos tend to be born not made. But it is unlikely to resolve the long-running debate about what makes a potential Mozart. Repeated flexing of the brain by practising a musical instrument could account for the extra grey matter in the auditory cortex. The latest twist in the search for a scientific basis of musical ability was made by a team at the University of Heidelberg in Germany. Neurologists played tones of varying frequencies to professional musicians, amateur musicians and non-musicians, and then recorded their brain responses. (C) BBC

Keyword: Hearing
Link ID: 2260 - Posted: 06.22.2002

Almost one in three people with Parkinson's disease suffer from sleep attacks causing them to fall asleep suddenly. A study by doctors in Austria has concluded that the attacks, which have been the subject of controversy, actually do exist. They concluded that the attacks which can happen at any time are caused by the medication taken by patients to alleviate symptoms of the disease. As yet, there is no way of predicting, preventing or treating the attacks. Dr Carl Nikolaus Homann and colleagues at the Karl Franzens University Hospital in Graz, Austria, reviewed studies of 124 patients with Parkinson's disease. They found that 30% had suffered at least one sleep attack. (C) BBC

Keyword: Parkinsons; Sleep
Link ID: 2259 - Posted: 06.21.2002

Exclusive from New Scientist Print Edition The sweet scent of roses or almonds could take some of the pain out of your stay in hospital. But only if you're a woman. Serge Marchand and Pierre Arsenault at the University of Québec in Abitibi-Témiscamingue asked 20 men and 20 women to keep their hand immersed in painfully hot water for as long as they could while smelling various odours. When given pleasant aromas such as almond extract to sniff, the women experienced significantly less pain. Foul smells such as vinegar seemed to slightly intensify their pain. However, the pain felt by the men was not affected by the smells. Both sexes reported feeling happier in the presence of good smells, while bad smells put them in a worse mood. But this effect on the emotions can't be what changed the women's perception of pain. If it was, the men should have responded in the same way. © Copyright Reed Business Information Ltd.

Keyword: Chemical Senses (Smell & Taste); Pain & Touch
Link ID: 2258 - Posted: 06.24.2010

By Eric Haseltine If a stroke robbed you of your visual cerebral cortex (the back of your brain), you'd no longer be able to see. But you wouldn't be blind, strictly speaking, because you'd still be able to unconsciously orient yourself toward visual stimuli and even make your way across a cluttered room without bumping into anything. Such blindsight is made possible by a primitive visual pathway (sometime called the "where" pathway) that controls behavior without conscious vision. You've experienced blindsight if you've ever reflexively reached for a ball suddenly thrown at you. Open your hand as if you were about to pick up one of these silver dollars to experience another example of this mysterious ability. Notice that you automatically opened your fingers wider than if you had reached for one of the dimes. © Copyright 2002 The Walt Disney Company.

Keyword: Vision; Pain & Touch
Link ID: 2257 - Posted: 06.24.2010

By NICHOLAS WADE Scientists working with human embryonic stem cells have converted them into the type of brain cell that is lost in Parkinson's disease, and have shown that the equivalent cells in mice alleviate Parkinson-like symptoms in rodents. "What we are showing here is that we absolutely, definitely have the right cell," said Dr. Ron McKay, a stem cell biologist who works at the National Institutes of Health. The cells produce a neuron-to-neuron signalling chemical called dopamine. The loss of dopamine is believed to cause many of the symptoms of Parkinson's disease. Dr. McKay hopes that the cells he has developed will one day be used to treat the disease, after he has spent two years testing how they work in monkeys. Indeed a surgeon could put them in patients quite quickly "but they wouldn't know what they have done," Dr. McKay said. Copyright 2002 The New York Times Company

Keyword: Parkinsons; Stem Cells
Link ID: 2256 - Posted: 06.21.2002