St. Paul, Minn. – Fragile X-associated tremor/ataxia syndrome can be difficult to diagnose and should have guidelines for diagnostic testing, according to a study in the July 26 issue of Neurology, the scientific journal of the American Academy of Neurology. A second study found chemotherapy aggravated symptoms in one woman’s case. Fragile X syndrome is the most common inherited cause of mental retardation. Fragile X-associated tremor/ataxia syndrome (FXTAS) was recently defined as a disorder that affects carriers of the Fragile X gene, called FMR1. People with FXTAS carry the FMR1 gene and develop symptoms later in life, usually starting in their 60s and 70s. Ataxia is the inability to coordinate voluntary muscle movements. Predominantly occurring in males, FXTAS could affect as many as one in 3,000 men over age 50. Male carriers pass the gene to all daughters but none of their sons. Female carriers have a 50 percent chance of passing the gene to each child. A multi-center study found 56 people had received 98 prior diagnoses, including parkinsonism and essential tremor, before FXTAS was concluded. The researchers believe this was partly due to the recent definition of FXTAS and a lack of familiarity with the disorder. The information about previous diagnoses encouraged them to develop guidelines for diagnostic testing for FXTAS.

Keyword: Development of the Brain; Genes & Behavior
Link ID: 7743 - Posted: 06.24.2010

There's probably not a smoker out there who won't tell you the same thing: Don't try it. That's because despite years of repeated messages in public service campaigns — smoking is a health risk — many who start find it hard to stop. A new study that uses PET scanning and a tracer chemical that binds to an enzyme, called monamine oxidase (MAO), is helping researchers track MAO in smokers and non-smokers. The findings may explain why smokers ramp up their cigarette intake over time and could offer a new tool for those struggling to quit. "The non-smoker clears these tracers, which are actually the tools we use to measure monoamine oxidase… very, very rapidly," explains Brookhaven National Laboratory chemist Joanna Fowler, who led the study. "The smoker clears these tracers much more slowly than the non-smoker." The enzyme is crucial to blood pressure and mood regulation and has two subtypes — MAO A and B. Initially Fowler tracked only MAO B. As reported in Discover Magazine, that study showed that levels of MAO B in smokers' peripheral organs — the heart, kidneys, spleen and lungs — were reduced by 40 to 50 percent compared to non-smokers. "But we do not think that... the degree to which monoamine oxidase is inhibited in peripheral organs will be detrimental to the smoker," says Fowler. © ScienCentral, 2000-2005.

Keyword: Drug Abuse
Link ID: 7742 - Posted: 06.24.2010

Unlike people, fish can regrow damaged nerve fibers in their central nervous systems. Now a study may have found the reason: The creatures lack a protein called Nogo-A that prevents nerve regeneration in mammals. Axons, or nerve fibers, are the transmission lines that conduct electrical signals throughout the body. The fibers are protected by sheaths of myelin, a fatty insulator that speeds the electrical impulses along. Damaged axons in the brain and spinal cord of mammals don't regenerate, and spinal cord injuries can therefore lead to permanent paralysis. Fish are luckier: They can regrow the axons in their central nervous system, but curiously this regeneration stops if their nerve endings come into contact with mammalian myelin. Because a protein in mammalian myelin called Nogo-A is known to inhibit central nervous system axon growth in mammals, a team of researchers led by biologist Claudia Stürmer at the University of Konstanz in Germany wondered if fish might be missing this protein. When the researchers exposed goldfish axons to rat Nogo-A, the nerves stopped growing. Furthermore, a comparison of genomes between ten species of fish, including zebrafish and pufferfish, and humans revealed that fish lack the genetic information to make Nogo-A or a similar inhibitor. The team reports its findings in the August issue of Molecular Biology and Evolution. The paper's careful study of fish phylogeny supports an existing notion that Nogo-A may be a recent evolutionary development that correlates with more complex nervous systems and more complex functions, says Stephen Strittmatter, a neurologist at Yale University in New Haven, Connecticut. "It's an important addition to our growing understanding of the role these inhibitors play," he says. --CAROLYN GRAMLING Copyright © 2005 by the American Association for the Advancement of Science.

Keyword: Regeneration; Development of the Brain
Link ID: 7741 - Posted: 06.24.2010

Naila Moreira Before it moves, the robot doesn't look like much. A rickety bundle of metal plates and rods standing on two thin legs, it resembles a science fair project more than it does a major advance in technology. Only two small motors, some simple wiring at its hip, and two batteries weigh it down. Then, with a slight push off one heel, the robot steps forward and ambles along with a remarkably human gait. This graceful stride differs radically from the stiff, unnatural motion of traditional two-legged robots. Not only that, says its co-creator Andy Ruina of Cornell University, but the walker uses a small fraction of the energy required by other two-legged machines, and it runs on a control system no more complex than that of a coffee machine. In fact, Ruina says, this slender, 1-meter-tall robot, simple as it looks, introduces a new class of robotics based on the theory known as passive dynamics. The principles of passive-dynamic walking emerged in the late 1980s, pioneered by roboticist Tad McGeer, now with the InSitu Group in Bingen, Wash. While at Simon Fraser University in Burnaby, British Columbia, McGeer showed that a humanlike frame can walk itself down a slope without requiring muscles or motors. Unlike traditional robots, which guzzle energy by using motors to control every motion, McGeer's early passive-dynamic robots relied only on gravity and the natural swinging of their limbs to move forward. Copyright ©2005 Science Service.

Keyword: Robotics
Link ID: 7740 - Posted: 06.24.2010

Review by Rob Loftis, Ph.D. on Aug 2nd 2005 Elizabeth Lloyd's new book has attracted a lot of attention for a technical work of academic philosophy, including profiles in the New York Times and Slate, and an appearance on The View (right between an interview with television doctor Noah Wyle about the health insurance crisis in America and a tribute to Merv Griffin). Lloyd was even the subject of a joke on Saturday Night Live's "Weekend Update," certainly a first for the philosophic community. Lloyd's book is obviously receiving attention because her topic is, quite literally, sexy. But perhaps more importantly for the popular media, her theses are very easy to state in layman's terms. Lloyd believes that the female orgasm is a evolutionary byproduct of the male orgasm, the same way that male nipples are a byproduct of the evolution of female nipples. Furthermore, she believes that biases in the research community have prevented scientists from seeing this obvious truth, including a bias toward adaptive explanations and a nasty tendency to assume female sexuality is like male sexuality. Clearly, she has an interesting and important set of theses. On top of that, her argument has a straightforward, logical structure. She canvasses the 20 adaptive accounts that have been proposed so far and finds obvious gaps in reasoning, while the one nonadaptive account has a lot of prima facie evidence for it. It is nice to see that you can get on television with a clear and important argument. Copyright © CenterSite, LLC, 1995-2005

Keyword: Sexual Behavior; Evolution
Link ID: 7739 - Posted: 06.24.2010

(WebMD) Women who smoke during pregnancy may be twice as likely to give birth to a child with behavioral problems like attention deficit hyperactivity disorder (ADHD). A new study shows that smoking during pregnancy doubled the risk of having a child with ADHD or other behavioral disorders that involve hyperactivity, inattention, and acting impulsively, known as hyperkinetic disorders. Experts have long recommended that women stop smoking during pregnancy in order to reduce the risk of birth defects and other problems. But this study suggests that exposure to nicotine in the womb may also affect the development of the baby's brain and increase the risk of behavioral problems like ADHD. Researchers say ADHD and hyperkinetic disorders are the most common psychological problems diagnosed in children. The two behavioral problems include many of the same symptoms and were treated as one in the study. In the study, Danish researchers examined the association between smoking during pregnancy and ADHD in 170 children with the behavioral problem and more than 3,700 healthy children matched by age, sex, and date of birth. Initially researchers found women who smoked during pregnancy were three times as likely to have a child with ADHD as nonsmokers. ©MMV, CBS Broadcasting Inc.

Keyword: ADHD; Drug Abuse
Link ID: 7738 - Posted: 06.24.2010

As anyone whose nerves have been jangled by a baby's howl or who have been riveted by the sight of an attractive person knows, nature has evolved sensory systems to be exquisitely tuned to relevant input. A major question in neurobiology is how neurons tune the strength of their interconnections to optimally respond to such inputs. Neuronal circuitry consists of a web of neurons, each triggering others by launching bursts of neurotransmitters at targets on receiving neurons to produce nerve impulses in those targets. Neurons adjust the strength of those connections adaptively, to amplify or suppress connections. Some four decades ago, a general principle called the "efficient coding hypothesis" was formulated, holding that sensory systems adjust to efficiently represent the complex, dynamic sounds, sights, and other sensory input from the environment. Writing in the August 4, 2005, issue of Neuron, researchers led by Christian K. Machens of Cold Spring Harbor Laboratory and Andreas Herz of Humboldt-University Berlin describe experiments with grasshopper auditory neurons that reveal new details of such sensory coding. Their findings show that "optimal stimulus ensembles" that trigger the neurons differ from those the grasshopper hears in the natural environment but largely overlap with components of natural sounds found in mating and mate-location calls. In their experiments, the researchers first played various snippets of white noise to isolated grasshopper auditory nerves and measured the electrophysiological signals reflecting the reactions of the auditory neurons to those sounds. These experiments revealed the distribution of stimuli called the "optimal stimulus ensemble" (OSE) that allowed the neurons in the system to perform optimally.

Keyword: Sexual Behavior; Hearing
Link ID: 7737 - Posted: 08.05.2005

As children, we believed that eating carrots could help us see better, but it seems that what makes leafy greens green might keep us healthy and seeing longer. Digging into that spinach salad could help to protect you against the leading cause of blindness worldwide — cataracts — as well as helping your wasteline. "I've always been interested in the role of diet in disease," says nutrition researcher Joshua Bomser. He had a particular interest in the plant pigments that play a critical role in photosynthesis, known as Carotenoids, that are found in many of the everyday fruits and vegetables we eat. "There's been some speculation that they can prevent the development of skin cancer, as well as the development of macular degeneration and age-related cataracts," he explains. "There are about 40 carotenoids that naturally occur in the diet. Of those, only lutein and zeaxanthin accumulate in the lens of the eye." Lutein and zeaxanthin are found in vegetables like kale, spinach and collard greens. So, Bomser and his colleagues at Ohio State University wanted to find out whether these plant pigments, which are found in high concentrations in dark green leafy vegetables, could protect the lens of the eye against the damaging ultraviolet rays of the sun and prevent cataracts. "We were able to show that lutein and zeaxanthin could reduce ultraviolet radiation induced damage in the lens," Bomser says. © ScienCentral, 2000-2005

Keyword: Vision
Link ID: 7736 - Posted: 06.24.2010

Laparoscopic surgeon Butch Rosser had an epiphany several years ago when a reporter sat in on one of his procedures and wrote, "I saw the work of the Nintendo surgeon." "Now that just hit me when I read that," says Rosser, who is now director of minimally invasive surgery at Beth Israel Medical Center in New York City. "And I said, 'Well I am a gamer, all the way back to the days of pong http://en.wikipedia.org/wiki/Pong . Is that why I can do this a little better than the average bear? Is that why this seems so natural to me? Because I navigate in a video game environment?'" Laparoscopic surgeons work by cutting very small holes in a person's skin and inserting what are essentially long joysticks — with a fiber optic camera and surgical tools attached to the end of them — into a person's body to perform "minimally invasive surgery". Without having to cut a person open to look inside, the tiny camera allows them to operate by seeing everything on a video monitor, while making post-surgery recovery much easier. The similarities between this kind of procedure and playing video games struck Rosser so much, he did his own study in 2004 where he compared the surgical skills of surgeons who played video games with those who did not. Skill was measured in a standardized laparoscopic training exercise created by Rosser called "Top Gun." © ScienCentral, 2000-2005.

Keyword: Intelligence
Link ID: 7735 - Posted: 06.24.2010

The levels of cocaine residue in flowing water in Italy suggest that many more people take the drug than official national estimates previously suggested. A study published today in the open access journal Environmental Health reports on a new tool used to measure the levels of a cocaine by-product excreted in urine, and present in rivers and in flowing sewage water. This new method provides evidence that about 40,000 doses of cocaine are consumed every day in the Po valley - according to official estimates for this area, only 15,000 users admit to taking the drug at least once a month. Current official estimates for illegal drug use, including cocaine, are based on population surveys, medical records and crime statistics. These methods are known to be unreliable and to under-estimate the extent of illegal drug use, mainly because they rely on users self-reporting drug use, a socially censured behaviour, which users tend to be elusive about. Ettore Zuccato, from the Mario Negri Institute for Pharmacological Research in Milan, Italy, and colleagues tested a new tool to measure a cocaine residue called benzoylecgonine (BE), present in flowing river and sewage waters because it is excreted in the urine of cocaine users. The residue is a by-product of metabolism in the human body, and cannot be produced by other means. The researchers measured the levels of BE in the river Po and in the sewage water of medium-sized Italian cities. Their results show that the Po, the largest Italian river, with five million people living in its vicinity, steadily carried the equivalent of about 4 kg of cocaine per day. This would imply an average daily use of at least 27 doses of 100 mg of cocaine for every 1,000 young adults of 15 to 34 years of age – the main consumers of cocaine.

Keyword: Drug Abuse
Link ID: 7734 - Posted: 06.24.2010

Scientists have developed a more effective way to rid surgical instruments of the infectious agents that cause CJD in humans. The twisted prion proteins are remarkably difficult to remove by standard decontamination processes. The new technique can remove prions to levels a thousand times lower than those achieved by existing methods. Details of the University of Edinburgh work are published in the Journal of General Virology. The prion responsible for vCJD is widely distributed in the tissues of the body's lymphatic and central nervous systems. The pre-symptomatic gestation period for CJD can be from a few years to decades. This has raised concerns that surgical instruments used on lymphoid tissues - such as the spleen and tonsils - could harbour the prion, and pass it on to patients on which they are subsequently used. Other forms of CJD have occasionally been transmitted by contaminated neurosurgical instruments. Studies have shown that the standards of surgical instrument cleaning and sterilisation in British hospitals vary considerably. Although the Department of Health has drawn up decontamination procedures for instruments that may have been exposed to the CJD prion, it is recognised that the guidelines are unlikely to remove all traces of infectivity. (C)BBC

Keyword: Prions
Link ID: 7733 - Posted: 08.03.2005

Recent suicide attempters treated with cognitive therapy were 50 percent less likely to try to kill themselves again within 18 months than those who did not receive the therapy, report researchers supported by the National Institutes of Health’s (NIH) National Institute of Mental Health (NIMH) and the Center for Disease Control and Prevention (CDC). A targeted form of cognitive therapy designed to prevent suicide proved better at lifting depression and feelings of hopelessness than the usual care available in the community, according to Gregory Brown, Ph.D., Aaron Beck, M.D., University of Pennsylvania, and colleagues, who published their findings in the August 3, 2005 Journal of the American Medical Association (JAMA). “Since even one previous attempt multiplies suicide risk by 38-40 times and suicide is the fourth leading cause of death for adults under 65, a proven way to prevent repeat attempts has important public health implications,” said NIMH Director Thomas Insel, M.D. To achieve a large enough sample to reliably detect differences in the effectiveness of interventions, the researchers first screened hundreds of potential suicide attempters admitted to the emergency room of the Hospital of the University of Pennsylvania in Philadelphia, ultimately recruiting 120 patients into the study. Averaging in their mid-thirties, 61 percent of the participants were female, 60 percent black, 35 percent white, and 5 percent Hispanic and other ethnicities. Most had attempted to kill themselves by drug overdosing (58 percent), with 17 percent by stabbing, 7 percent by jumping and 4 percent by hanging, shooting or drowning. Seventy-seven percent had major depression and 68 percent a substance use disorder.

Keyword: Depression
Link ID: 7732 - Posted: 06.24.2010

More than two decades after they fled the Khmer Rouge reign of terror, most Cambodian refugees who resettled in the United States remain traumatized, a study funded by the National Institutes of Health’s (NIH) National Institute of Mental Health (NIMH) and National Institute on Alcohol Abuse and Alcoholism (NIAAA) has found. Sixty-two percent suffered from Post Traumatic Stress Disorder (PTSD) and 51 percent from depression in the past year — six-to-seventeen times the national average for adults. The more trauma they endured, the worse their symptoms. In the August 3, 2005 edition of the Journal of the American Medical Association (JAMA), the RAND Corporation’s Grant Marshall, Ph.D., and colleagues report on their survey in the nation’s largest Cambodian community. An estimated three million of Cambodia’s seven million people died during the repression and civil wars of the l970s and most of those who survived suffered multiple traumas. Moreover, even after two decades in the U.S., the majority of the refugee community speak little or no English, are at income levels below poverty, and rely on public assistance. Since previous studies of such refugee populations have been criticized for possibly overestimating rates of mental disorders, Marshall and colleagues set out to allay such concerns by employing a more conservative approach. Native Khmer speakers conducted highly structured two-hour interviews with 490 randomly-selected former refugees, ages 35-75, in their Long Beach, CA homes, beginning in 2003. They used standardized questionnaires for gauging levels of violence exposure and alcohol use disorder and standardized diagnostic interviews to determine the prevalence of PTSD and depression.

Keyword: Depression; Stress
Link ID: 7731 - Posted: 06.24.2010

Durham, N.C. – Using a novel analysis of the interactions among related genes, Duke University Medical Center researchers have uncovered some of the first evidence that complex genetic interactions account for autism risk. The Duke team found that the brain mechanism that normally stops or slows nerve impulses contributes to the disease. The team's findings implicate the so-called GABA receptor genes, which are genes that code for key components of "off switches" in the brain's neurons. GABA, or gamma aminobutyric acid, is a neurotransmitter – a chemical that one neuron fires at receptors on another neuron to trigger a response – in this case an inhibitory response. GABA receptors are protein switches nestled in nerve cell membranes that are triggered by GABA to cause such inhibition. Importantly, the study found that the GABA brain system most likely exerts its influence via complex gene-gene interactions. The current findings, and others that might result from the team's new approach, may ultimately point to methods for early diagnosis of autism, and perhaps new autism therapies, according to the researchers. "Identifying the genes that contribute to cause autism has been challenging," said Margaret Pericak-Vance, Ph.D., director of the Duke Center for Human Genetics. "One explanation is that many genes are involved, none of which individually may have a major effect." At least ten genes – and possibly as many as a 100 – are hypothesized to be involved in autism, she said. © 2001-2005 Duke University Medical Center

Keyword: Autism
Link ID: 7730 - Posted: 06.24.2010

Babies born during famine have more than double the risk of developing schizophrenia later in life, according to a study based on the 1959-1961 famine in China. The findings show that starvation experienced during the critical stages of early gestation alters brain development, producing mental health consequences years later in adulthood, the researchers say. Schizophrenia occurs worldwide in about 1% of the population. But in individuals who received inadequate fetal nutrition, the risk may be as much as 2.3%, say researchers. David St Clair at Aberdeen University and colleagues at Shanghai Jiao Tong University in China, looked at the incidence of schizophrenia among those born before, during and after the 1959-1961 period of extreme famine in the badly affected Chinese province of Anhui. Although birth rates during the period plummeted by 80%, the death-adjusted risk of schizophrenia for those born in 1960 was 2.3 times higher than for those born before or two years after the famine. The findings are consistent with those of a small Dutch study, which found a two-fold increase in schizophrenia for those born during a war-imposed famine in Holland during 1944 to1945, called the Hunger Winter. But since this study featured just 20-25 cases of the condition, those findings were only of modest statistical significance. © Copyright Reed Business Information Ltd.

Keyword: Schizophrenia
Link ID: 7729 - Posted: 06.24.2010

By SANDRA BLAKESLEE Dr. Anna Berti sits facing a patient whose paralyzed left arm rests in her lap next to her good right arm. "Can you raise your left arm?" Dr. Berti asks. "Yes," the patient says. The arm remains motionless. Dr. Berti tries again. "Are you raising your left arm?" she asks. "Yes," the patient says. But the arm still does not move. Dr. Berti, a neuroscientist at University of Turin in Italy, has had many such conversations with stroke patients who suffer from denial syndrome, a strange disorder in which paralyzed patients vehemently insist that they are not paralyzed. This denial, Dr. Berti said, was long thought to be purely a psychological problem. "It was a reaction to a stroke: I am paralyzed, it is so horrible, I will deny it," she said. But in a new study, Dr. Berti and her colleagues have shown that denial is not a problem of the mind. Rather, it is a neurological condition that occurs when specific brain regions are knocked out by a stroke. Patients deny the paralysis because a closely related region of the brain that is still intact appears to tell them that their bodies are responding normally. The study, published in the July 15 issue of Science, may also shed new light on the nature of consciousness. Self-awareness, the researchers say, is not located in a unique brain structure or mechanism, but instead is distributed in many parts of the brain. As a result, there are different kinds of awareness for functions like movement, vision, awareness of the body and the space around the body. Copyright 2005 The New York Times Company

Keyword: Stroke
Link ID: 7728 - Posted: 08.02.2005

Psychology researchers Elizabeth Loftus of the University of California, Irvine and Daniel Bernstein of the University of Washington found that if they could convince volunteers that, as a child, a certain food had made them sick, about 30 percent of the volunteers were likely to indicate they'd avoid that food in the future. Loftus says, "It looks like we can sometimes make people, using this suggestive manipulation, avoid certain foods or embrace other foods that might be healthy for them." Loftus has studied false memories for 25 years. She says she and other researchers have long known they could, "change memory for a detail of an event." For example, she notes how someone remembering a car accident where a car goes through a stop sign could be convinced to remember details differently. She said, "We would, through a suggestive and leading question, make people believe it was a yield and not a stop sign." She and other researchers are now working on planting entire false events in people's memories, what she calls, "rich false memories." Loftus says early research into rich false memories included events like where, "we made people believe that they were lost in a shopping mall for an extended time." She adds other researchers tried to convince people, "that they had an accident at a family wedding or that they were a victim of a vicious animal attack." Loftus says, "Because they're very complete, they're detailed and sometimes people are very confident about them." © ScienCentral, 2000-2005.

Keyword: Obesity; Learning & Memory
Link ID: 7727 - Posted: 06.24.2010

CAMBRIDGE, Mass. -- Researchers have found that the two primary areas of the human brain appear to age in radically different ways: The cortex used in higher-level thought undergoes more extensive changes with age than the cerebellum, which regulates basic processes such as heartbeat, breathing and balance. Their work, based on an analysis of gene expression in various areas of human and chimpanzee brains, also shows that the two species' brains age very differently, despite their close evolutionary relationship. The research, by scientists at Harvard University, the University of California, Berkeley, Lawrence Berkeley National Laboratory, and the Max-Planck-Institute for Evolutionary Anthropology, will be reported this week in the open-access journal PLoS Biology. "We were surprised both by the homogeneity of aging within the cortex and by the dramatic differences in aging between cortex and cerebellum," says Joshua B. Plotkin, a junior fellow in the Harvard Society of Fellows. "The fact that gene activity levels in the cerebellum remain more stable as a person ages suggests that this region of the brain experiences less oxidative stress and damage as part of normal aging." "Much remains to be learned about how the brain ages and how changes in gene expression over time are related to brain activity," says Michael B. Eisen, assistant professor of molecular and cell biology at UC Berkeley. "Our analyses suggest that the different functions of different regions of the brain influence how they age, and that we can learn about functional variation and evolution by studying gene expression changes with age."

Keyword: Genes & Behavior; Evolution
Link ID: 7726 - Posted: 08.02.2005

CHICAGO – Home videos of first and second year birthday parties provide support for parents' reports of children whose behavior seemed normal when they were one-year-olds but then display symptoms of autism at the age of two years, according to a study in the August issue of Archives of General Psychiatry, one of the JAMA/Archives journals. Although symptoms of autism have been observed in children as young as eight to 12 months, some parents report that their child had normal or near-normal development and then experienced a regression, as their communication and/or social skills worsened, according to background information in the article. Estimates of the prevalence of this "regressive pattern" vary widely and depend for the most part on parental memories that may be biased by later events, the authors suggest. Emily Werner, Ph.D., and Geraldine Dawson, Ph.D., of the University of Washington, Seattle, analyzed home videotapes of first and second year birthday parties for children without autism and for children who have been diagnosed with autism spectrum disorder (ASD). Of the 56 children included in the study, 15 were children diagnosed with ASD whose parents reported a worsening in social and/or communication skills during the second year of life, 21 were children with ASD whose parents reported that they had had impairments before age one year (early onset) and 20 were typically developing children. All the children in the study were younger than seven and all but three were younger than four years old.

Keyword: Autism
Link ID: 7725 - Posted: 06.24.2010

By Jennifer Viegas, Discovery News — The human brain processes male and female voices differently, according to a recent study that looked at how the human brain reacts to male and female voices. The research explains why most of us hear female voices more clearly, as well as that we form mental images of people based only on the sound of their voices. The findings, published in the current journal NeuroImage, also might give insight into why many men tire of hearing women speak: the "complexity" of female voices requires a lot of brain activity. "It is females' increased use of prosody, or the natural 'melody' of speech, that makes their voices more complex," said Michael Hunter, one of the study's authors. Hunter, professor of medicine and biomedical sciences at the University of Sheffield's Cognition and Neuroimaging Laboratory, explained to Discovery News that these qualities are not related to pitch, but rather to the vibration and number of sound waves. For the study, Hunter and his colleagues played recordings of male and female voices to 12 men while they underwent MRI brain imaging scans. Test subjects assigned a gender to the voices they heard while the scans took place. These identifications were 98-99 percent accurate. Researchers monitored the areas of the brain that showed activity during the scans. Copyright © 2005 Discovery Communications Inc.

Keyword: Hearing
Link ID: 7724 - Posted: 06.24.2010