Alison Motluk You don't have to be a scientist to observe that pornographic images lead to erections in men. But you would have to be one to show those images to volunteers while meticulously measuring the volume of response in the brain and penis. Harold Mouras, at University of Picardie Jules Verne in Amiens, France, and his colleagues wanted to understand the cerebral underpinnings of visually-induced erections. They suspected there might be a role for mirror neurons, a special class of brain cell that fires both when people perform an action and when they observe it being performed. The researchers invited eight young men into the lab and asked them to view three types of video clips. Along with late-night fishing documentaries and snippets of Mr Bean, the volunteers got to see erotic videos of men stroking naked women, enjoying fellatio and engaging in intercourse. While the volunteers watched the movies, the researchers watched their brains using functional magnetic resonance imaging (fMRI). They also kept tabs on the tumescence of the other target organ, using a hand-crafted "penile plethysmograph" – essentially an airtight tube in which the enlarging penis causes measurable pressure changes. © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior
Link ID: 11719 - Posted: 06.24.2010

By Gisela Telis Why do we wrinkle our noses in disgust or widen our eyes with fear? A new study shows that doing so might help keep us alive. The idea that facial expressions confer a survival advantage was first posited, perhaps not surprisingly, by Charles Darwin. In 1872, 13 years after he published On the Origin of Species, Darwin wrote a lesser-known tome, The Expression of the Emotions in Man and Animals. In it, he observed that some human expressions occur across cultures and even in some other animals. He cited the wide-eyed gasp of surprise as an example. Darwin speculated that these emotional faces might serve a biological function, such as getting a good look at an enemy. Darwin's hypothesis went untested until 3 years ago, when cognitive neuroscientist Adam Anderson, graduate student Joshua Susskind, and their colleagues at the University of Toronto in Canada decided to apply new technology to the century-old idea. The researchers computer-generated a "classic" fear face: one with raised brows, popping eyes and flaring nostrils. They also mocked up a disgust face: the wrinkled nose, raised lip, and narrowed eyes familiar to anyone who's smelled rotten eggs or stepped in something foul. The team then asked volunteers to mimic these faces while taking vision and breathing tests. Emotional faces weren't just for looks. The team found that a fearful visage improves peripheral vision, speeds up eye movement, and boosts air flow, potentially allowing a person to more quickly sense and respond to danger. Squinty, scrunched-up disgusted faces had the opposite effect, limiting vision and decreasing air flow, ostensibly to keep out substances that might be harmful to the eyes or lungs. © 2008 American Association for the Advancement of Science.

Keyword: Emotions
Link ID: 11718 - Posted: 06.24.2010

The brains of gay men and women look like those found in straight people of the opposite sex, research suggests. The Swedish study, published in the Proceedings of the National Academy of Sciences journal, compared the size of the brain's halves in 90 adults. Gay men and heterosexual women had halves of a similar size, while the right side was bigger in lesbian women and heterosexual men. A UK scientist said this was evidence sexual preference was set in the womb. Scientists have noticed for some time that homosexual people of both sexes have differences in certain cognitive abilities, suggesting there may be subtle differences in their brain structure. This is the first time, however, that scientists have used brain scanners to try to look for the source of those differences. A group of 90 healthy gay and heterosexual adults, men and women, were scanned by the Karolinska Institute scientists to measure the volume of both sides, or hemispheres, of their brain. When these results were collected, it was found that lesbian women and heterosexual men shared a particular "asymmetry" in their hemisphere size, while heterosexual women and gay men had no difference between the size of the different halves of their brain. In other words, structurally, at least, gay men were more like heterosexual women, and gay women more like heterosexual men. A further experiment found that in one particular area of the brain, the amygdala, there were other significant differences. In heterosexual men and lesbian women, there were more nerve "connections" in the right side of the amygdala, compared with the left. The reverse, with more neural connections in the left amygdala, was the case in homosexual men and heterosexual women.

Keyword: Sexual Behavior; Brain imaging
Link ID: 11717 - Posted: 06.17.2008

Hearing loss is about twice as common in adults with diabetes compared to those who do not have the disease, according to a new study funded by the National Institutes of Health (NIH). "Hearing loss may be an under-recognized complication of diabetes. As diabetes becomes more common, the disease may become a more significant contributor to hearing loss," said senior author Catherine Cowie, Ph.D., of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), who suggested that people with diabetes should consider having their hearing tested. "Our study found a strong and consistent link between hearing impairment and diabetes using a number of different outcomes." The researchers discovered the higher rate of hearing loss in those with diabetes after analyzing the results of hearing tests given to a nationally representative sample of adults in the United States. The test measured participants’ ability to hear low, middle, and high frequency sounds in both ears. The link between diabetes and hearing loss was evident across all frequencies, with a stronger association in the high frequency range. Mild or greater hearing impairment of low- or mid-frequency sounds in the worse ear was about 21 percent in 399 adults with diabetes compared to about 9 percent in 4,741 adults without diabetes. For high frequency sounds, mild or greater hearing impairment in the worse ear was 54 percent in those with diabetes compared to 32 percent in those who did not have the disease. Adults with pre-diabetes, whose blood glucose is higher than normal but not high enough for a diabetes diagnosis, had a 30 percent higher rate of hearing loss compared to those with normal blood sugar tested after an overnight fast.

Keyword: Hearing; Obesity
Link ID: 11716 - Posted: 06.24.2010

(HealthDay News) -- People with sleep apnea show tissue loss in brain regions that help store memory, a University of California, Los Angeles (UCLA) study shows. "Our findings demonstrate that impaired breathing during sleep can lead to serious brain injury that disrupts memory and thinking," principal investigator Ronald Harper, a professor of neurobiology at the David Geffen School of Medicine at UCLA, said in a prepared statement. People with sleep apnea stop breathing and awaken repeatedly during the night, leading to chronic daytime fatigue and memory and concentration problems. Research has linked sleep apnea to an increased risk of stroke, heart disease and diabetes. In this study, the UCLA team used MRI to scan the brains of sleep apnea patients. The researchers focused on brain structures called mammillary bodies, located on the underside of the brain. The study found that the mammillary bodies of the 43 sleep apnea patients were almost 20 percent smaller than those in 66 people without sleep apnea. The results will be published in the June 27 issue of Neuroscience Letters. © 2008 U.S. News & World Report

Keyword: Sleep; Learning & Memory
Link ID: 11715 - Posted: 06.24.2010

Researchers may have found a way to predict whether severely brain-damaged patients will regain consciousness. A part of the brain which can stay active even in severely brain-damaged patients could offer a clue about the chances of recovery, they claim. The Belgian team told a conference that activity within a "default network" in the brain appears to match the level of consciousness of the patient. Some believe the default network is associated with daydreaming. The findings were reported in New Scientist magazine. The default network in the brain's cortex appears to be more active when the brain is not actively working on a goal - hence the proposed link with daydreaming. Some evidence suggests that it helps get the brain ready for the next task, although this remains a controversial theory. A number of techniques are used to assess the level of consciousness in people following head injury, and while some are diagnosed as "brain dead", with no sign of any activity in the brain, it can be difficult to make an exact diagnosis when the patient has a higher level of activity, but is still unconscious. Dr Steven Laureys, from the University of Liege in Belgium, believes that activity within the network could help confirm the level of consciousness, and help doctors decide on whether or not to treat them. He measured activity in 13 brain-injured patients with a variety of different levels of consciousness. Some were "minimally conscious", while others were in a coma, or a persistent vegetative state (PVS). A final group were "brain dead". He found that minimally conscious patients had only a 10% fall in normal activity in this area, while in coma and PVS patients, it fell by approximately 35%. There was no activity at all in the brain-dead patients. (C)BBC

Keyword: Stroke; Brain Injury/Concussion
Link ID: 11714 - Posted: 06.14.2008

By DAMIEN CAVE MIAMI — From “Scarface” to “Miami Vice,” Florida’s drug problem has been portrayed as the story of a single narcotic: cocaine. But for Floridians, prescription drugs are increasingly a far more lethal habit. An analysis of autopsies in 2007 released this week by the Florida Medical Examiners Commission found that the rate of deaths caused by prescription drugs was three times the rate of deaths caused by all illicit drugs combined. Law enforcement officials said that the shift toward prescription-drug abuse, which began here about eight years ago, showed no sign of letting up and that the state must do more to control it. “You have health care providers involved, you have doctor shoppers, and then there are crimes like robbing drug shipments,” said Jeff Beasley, a drug intelligence inspector for the Florida Department of Law Enforcement, which co-sponsored the study. “There is a multitude of ways to get these drugs, and that’s what makes things complicated.” The report’s findings track with similar studies by the federal Drug Enforcement Administration, which has found that roughly seven million Americans are abusing prescription drugs. If accurate, that would be an increase of 80 percent in six years and more than the total abusing cocaine, heroin, hallucinogens, Ecstasy and inhalants. Copyright 2008 The New York Times Company

Keyword: Drug Abuse
Link ID: 11713 - Posted: 06.24.2010

By BENEDICT CAREY The people who suffer from schizophrenia are hardly the only ones confounded by its symptoms. Scientists are baffled, too, and despite years of study they’ve had little success in explaining how the disorder develops, in whom, and why. Yet there’s a restless energy among psychiatric researchers now, and it’s in part because of several recent studies that, paradoxically, reveal how insufficient current theories about schizophrenia are. Schizophrenia is not a single problem with a uniform solution, these results suggest. Rather, the disease most likely comprises a variety of related mental disorders, with an underlying biology and symptoms that can differ from person to person. That shift in thinking has already led to expanded treatment options for some patients, and it is likely to guide research on the disorder for years to come. Perhaps the most striking demonstration of how biologically diverse schizophrenia may be came in a gene study published in March. An analysis of blood samples revealed that rare and previously undetectable genetic mutations were strongly associated with the development of the disorder. Copyright 2008 The New York Times Company

Keyword: Schizophrenia
Link ID: 11712 - Posted: 06.24.2010

By Trisha Gura A recent tabloid captured the common wisdom about anorexia nervosa. In an interview, actor Christina Ricci blamed the pressures of success for her prior struggle with the disease. The headline flashed, “Ricci: Hollywood made me anorexic.” But did it? True, anorexia is characterized by compulsive dieting or exercise to get thin. And the pursuit of thinness in contemporary culture—particularly in Hollywood—has become a seemingly contagious obsession. Yet there is thin, and then there is emaciated. Crossing over that line means a loss of a basic survival instinct—to eat in response to hunger—that culture should not be able to touch. What is more, cultural cues cannot easily explain why the afflicted, who are shockingly skinny, misperceive themselves as fat. Anorexics also say they feel more energetic and alert when starving: starvation boosts their metabolic rate, which is in stark contrast to the slowing of metabolism that occurs in most people during a fast. Such mysteries cry out for a biological explanation. To find one, researchers are probing the brains of anorexics; their work is painting a new picture of anorexia as a multifaceted mental illness whose effects extend far beyond appetite. The illness is accompanied by disturbances in the brain’s reward circuitry that may lead to a general inability to feel delight from life’s pleasures, be they food, sex or winning the lottery. As such, the ailment shares characteristics with drug addiction—the drug in this case being deprivation itself. © 1996-2008 Scientific American Inc

Keyword: Anorexia & Bulimia
Link ID: 11711 - Posted: 06.24.2010

Anrica Deb -- A Dutch woman who was the oldest person in the world when she died at age 115 in 2005 appeared sharp right up to the end, joking that pickled herring was the secret to her longevity. Scientists say that Henrikje van Andel-Schipper's mind was probably as good as it seemed: a post-mortem analysis of her brain revealed few signs of Alzheimer's or other diseases commonly associated with a decline in mental ability in old age. That came as something of a surprise, said Gert Holstege, a professor at Groningen University, whose findings will be published in the August edition of Neurobiology of Aging. "Everybody was thinking that when you have a brain over 100 years, you have a lot of problems," he said in a telephone interview on Friday. He cited a common hardening of arteries and the build up of proteins associated with Alzheimer's disease as examples. "This is the first (extremely old) brain that did not have these problems." Van Andel was the oldest living person in the world at the time of her death in 2005 in the Dutch city of Hoogeveen, according to the Guinness Book of World Records. © 2008 Discovery Communications, LLC

Keyword: Alzheimers; Development of the Brain
Link ID: 11710 - Posted: 06.24.2010

Alison Abbott Zurich's two largest institutes are appealing to the country's supreme court after a lower court decided to ban two primate experiments studying how the brain adapts to change. They say that the ban is a serious threat to all basic research that uses animals in Switzerland. The University of Zurich and the Federal Institute of Technology Zurich (ETHZ) announced on 4 June that their local administrative court had ruled against the experiments on rhesus monkeys that had been approved in 2006 by the Swiss National Science Foundation, a funding agency and the Zurich canton's veterinary office, which is responsible for controlling animal welfare. The veterinary office decision was challenged by an external advisory committee on animal experimentation, which argued that the proposed experiments would offend the dignity of the animals. The requirement to consider the 'dignity of creatures' was introduced into the Swiss constitution in 2004. The court did not refer to dignity, but agreed that society was unlikely to see the benefits of the research during the three-year funding period approved, and thus the burden on the animals was not justified. Swiss law requires that the benefit to society must be weighed against the burden to animals before any animal experiment can take place. © 2008 Nature Publishing Group

Keyword: Animal Rights
Link ID: 11709 - Posted: 06.24.2010

Dementia could be slowed significantly by treatments which reset the body's natural clock, researchers have said. The Dutch team used brighter daytime lighting - with or without the drug melatonin - to improve patients' sleep, mood and cut aggressive behaviour. It concludes that these can slow deterioration by 5% - which a UK specialist said meant patients living in their own homes for months longer. The study appears in the Journal of the American Medical Association. The disruption to the body's circadian rhythm - the natural cycle that governs sleep and wakefulness - can be one of the most difficult of dementia symptoms for carers to cope with. It can mean that people with the illness can be asleep during the day, but fully awake for periods during the night. Other studies have suggested that the use of bright room lighting and melatonin can help adjust the "clock", and the researchers from the Royal Netherlands Academy of Arts and Sciences in Amsterdam managed to recruit 189 care home residents to take part in an unique trial. Six of the care homes taking part had lighting installed, and this was turned on between 9am and 6pm every day. Some of the patients, most of whom had some form of dementia, received melatonin, a naturally-occurring hormone, and their progress was then monitored for at least the next year. Those who had melatonin, but no extra lighting, had better sleep patterns, but tended to be more withdrawn and have a worse mood. However, patients having melatonin and bright light together managed to avoid these mood problems. (C)BBC

Keyword: Alzheimers; Biological Rhythms
Link ID: 11708 - Posted: 06.12.2008

By Caroline Zink People are incredibly social beings, and we rely heavily on our interactions with others to thrive, and even survive, in the world. To avoid chaos in these interactions, humans create social norms. These rules and regulations establish appropriate and acceptable ways for us to act and respond to each other. For instance, when waiting in line, we expect people also to wait their turn. As a result, we get upset when someone decides to cut in line: they violated a social norm. But how are social norms maintained? And what makes us comply with social norms? Primarily, the answer is that, if we don’t follow the rules, we might get in trouble. Numerous studies demonstrate that, when the threat of punishment is removed, people tend to disregard social norms. The neat and orderly line disintegrates. It remains unclear, however, how the brain processes the threat of punishment when deciding whether or not to comply with a social norm. A recent study conducted by neuroscientist Manfred Spitzer and his colleagues at the University of Ulm in Germany and the University of Zurich in Switzerland tried to shed light on this mystery. The researchers put 24 healthy male students in a functional magnetic resonance imaging (fMRI) scanner to see what parts of the brain were activated during a two-person social exchange with real monetary stakes. © 1996-2008 Scientific American Inc.

Keyword: Emotions
Link ID: 11707 - Posted: 06.24.2010

By Fayana Richards Can't stand today's music? Neither can tune-deaf people. In fact, the disorder makes listening to any music unenjoyable, because the brain can't organize the sounds into a comprehensible melody. New research indicates that the problem lies somewhere in the conscious mind: The brains of tune-deaf individuals know when a sour note has been played, but the people themselves are unaware of it. Two percent to 4% of the U.S. population is tune deaf. People with the disorder, also known as tone deafness, have trouble telling the difference between a good melody and a bad one. Tune deafness is highly heritable, yet biologists know little about what goes wrong in the brain. The normal process of detecting bad notes has been much better described: A device that measures brain activity, called an electroencephalograph, registers two signals, known as mismatch negativity (MMN) and P300. Neuroscientist Allen Braun and colleagues at the U.S. National Institute on Deafness and Other Communication Disorders in Bethesda, Maryland, wondered if the same signals would turn up in the brains of tune-deaf people as they listened to a botched melody. The researchers had seven tune-deaf and 10 non-tune-deaf people listen to a variety of familiar tunes such as "Mary Had a Little Lamb" and "The Star-Spangled Banner" while an electroencephalograph measured their brain activity. As expected, these subjects did not have the typical MMN response to poorly played tunes, the team reports today in PLoS One. But to their surprise, the researchers did detect the P300 response to the incorrect notes. Braun believes these results show that the brain can detect the differences even though tune-deaf people aren't aware. © 2008 American Association for the Advancement of Science.

Keyword: Hearing
Link ID: 11706 - Posted: 06.24.2010

In a classic “Seinfeld” dilemma, Jerry draws a blank on his new girlfriend’s name, and the relationship has become too intimate for him just to ask. Throughout the half hour episode, Jerry’s various ploys to jog his memory bear no fruit, and the denouement comes too late to salvage the nascent romance. By the end of the show, the girlfriend has discovered his predicament, become irate, and stormed out of his apartment. And that’s when it hits him: Dolores. Now, two psychologists from McMaster University are shedding light on the cause of Jerry’s mental block. According to a new study by Amy Beth Warriner and Karin Humphreys, the longer you try to come up with the word that’s on the tip of your tongue, the more likely you’ll be to get stuck on that word in the future. For years, Humphreys herself endured a Seinfeld-like struggle with the word 'obsidian,' the term for black, shiny volcanic glass. Instead of saying 'obsidian,' Humphreys would think, “It’s like oblong, but no, it’s not oblong. I know that it’s not oblong but that’s the only word coming to mind,” she says. But out of this protracted mental battle came an idea: maybe by straining her memory on that stubborn vocabulary word, she was making it even harder to remember the answer later on. To test out this hypothesis, she and Warriner brought 30 undergraduates into the psychology laboratory. Through their experiment, they found that “by actually getting into a tip of the tongue state, I’ve actually dug myself into a hole, and I’ve made this wrong learning. And the next time I go to do that, I’m going to get into this wrong state again,” says Humphreys. © ScienCentral, 2000-2008.

Keyword: Learning & Memory
Link ID: 11705 - Posted: 06.24.2010

Ewen Callaway You might call it our circadian eye. A handful of retina cells sense light, not for vision, but instead to reset our body clocks each day. Killing off these cells in mice leaves their sight unharmed, but throws their clocks out of whack, two new studies show. Jolting these cells back into action might offer salvation to insomniacs, whose circadian cycles are slightly off, says Satchidananda Panda, a molecular biologist at the Salk Institute in San Diego, who led one study. Natural degeneration of these cells could also explain why insomnia often strikes the elderly. "Maybe we can develop an eye drug to reset your clock," he says. Alternatively, triggering the cells with extra-pale blue light – the wavelengths they're most sensitive to – could do the same trick, says Samer Hattar, a neuroscientist at Johns Hopkins University in Baltimore. Hattar's team identified the same role for the cells, which produce a recently-discovered light sensor called melanopsin. The first evidence for our circadian eye came in the 1920s, when an American physician noticed that congenitally blind mice can still dilate their pupils – a sign of light detection – despite lacking rods and cones, the photosensors that transform light to vision. © Copyright Reed Business Information Ltd.

Keyword: Biological Rhythms; Vision
Link ID: 11703 - Posted: 06.24.2010

Katharine Sanderson Have you ever felt your heart wrench when selling your beaten-up old car, or offered up a formerly prized possession to the voracious hordes on eBay with a hint of sadness? If so, you have experienced the 'endowment effect' – in which people value a something more once they possess it. Exactly why this happens is not known. It could be because humans overvalue the positive and ignore the negative associations, or it could be that the thought of losing something is just too much to bear. Now, psychologists led by Brian Knutson at Stanford University in Palo Alto, California, have imaged the brain as it struggles with this effect — and have shown that parting with our possessions really does hurt1. "Selling something you like is painful,” says Scott Rick, who studies emotional responses at the University of Pennsylvania, Philadelphia, and is co-author of the paper, published in the journal Neuron. Their findings suggest that the endowment effect is due to simple anxiety over losing our possessions, rather than any tendency to overvalue it. © 2008 Nature Publishing Group

Keyword: Emotions
Link ID: 11702 - Posted: 06.24.2010

Smoking and obesity could both cause permanent hearing damage, say scientists. Either could threaten blood flow to the ear, they say, with damage levels clearly linked to the level of obesity or the length of a smoking habit. However, the Antwerp University-led study found that high levels of work noise remained the biggest risk. In a separate study, smoking in middle age was linked to worse memory, which could hasten the arrival of dementia. A link between smoking and hearing problems has been suggested by others, but the conclusions of the latest research, involving more than 4,000 men and women aged between 53 and 67, offer the most convincing evidence to date. All the study participants were given a hearing test, then asked about their lifestyle and where they worked. Dr Erik Fransen, of the University of Antwerp in Belgium, one of the lead researchers, said that the ability to pick out high frequency sounds was damaged in smokers and the obese, although to not as great an extent as those exposed to very loud noise in the workplace. He said: "The hearing loss is proportional to how much you smoke and your body mass index (BMI). "It starts getting worse once you have smoked regularly for more than one year." He said that, unlike some parts of the body, once damage had occurred, there was no prospect of recovery. "Once the damage is done, it's done. It does not repair." The theory behind the hearing damage is similar to the reason smoking and obesity can harm other organs. Both can disrupt the flow of blood around the body, and Dr Fransen suggested that the resulting lack of oxygen, coupled with the failure to remove toxic waste from the ear, can be damaging. (C)BBC

Keyword: Drug Abuse; Hearing
Link ID: 11701 - Posted: 06.10.2008

By Lisa Conti Splenda is not satisfying—at least according to the brain. A new study found that even when the palate cannot distinguish between the artificial sweetener and sugar, our brain knows the difference. At the University of California, San Diego, 12 women underwent functional MRI while sipping water sweetened with either real sugar (sucrose) or Splenda (sucralose). Sweeteners, real or artificial, bind to and stimulate receptors on the taste buds, which then signal the brain via the cranial nerve. Although both sugar and Splenda initiate the same taste and pleasure pathways in the brain—and the subjects could not tell the solutions apart—the sugar activated pleasure-related brain regions more extensively than the Splenda did. In particular, “the real thing, the sugar, elicits a much greater response in the insula,” says the study’s lead author, psych­ia­trist Guido Frank, now at the Univer­sity of Colorado at Denver. The insula, involved with taste, also plays a role in enjoyment by connecting regions in the reward system that encode the sens­a­tion of pleasantness. Although Splenda elicits less overall activity within the brain, the researchers were surprised to find that the artificial sweetener seems to inspire more communication between these regions. “Looking at the connection between the taste areas, Splenda is stronger,” Frank says. He suggests that when we taste Splenda, the reward system becomes activated but not satiated. “Our hypoth­esis is that Splenda has less of a feedback mechanism to stop the craving, to get satisfied.” © 1996-2008 Scientific American Inc.

Keyword: Obesity
Link ID: 11700 - Posted: 06.24.2010

By Nikhil Swaminathan Stacey Gayle used to love music. Listening to it and performing it was a big part of her life. She had stacks of CDs in her car, went to concerts of artists like Sean Paul, and would go to parties where hot songs would blare. She was also an active member of the choir at her church: Solid Rock Church of the Nazarene. Then she started having seizures. The first one happened while she slept in her bedroom in Rosedale, Queens in New York City on the night of March 3, 2005. She had just turned 22. Her mother rushed her to the emergency room, where doctors stabilized her. Several brain scans and blood tests gave no clue as to why she seized. Soon after, she had another, this time at a friend's barbecue. She blacked out, fell down and started to shake like crazy as her brain cells went out of whack, firing electrical signals without pause. At first, the seizures seemed to occur randomly. In the spring of 2006, however, she noticed a pattern. At the time, Sean Paul's "Temperature" was sitting at the top of the Billboard Hot 100 singles chart, continually being played on urban radio stations. It was playing at nearly every barbecue and party she went to. That was a problem: "Every time it would go on, I would pass out and go into a seizure," she recalls. © 1996-2008 Scientific American Inc.

Keyword: Epilepsy; Hearing
Link ID: 11699 - Posted: 06.24.2010