Janet Raloff and Ben Harder Infant boys who were exposed in the womb to modest concentrations of certain common plasticizers and solvents developed genital changes including smaller-than-normal penises, a new study finds. The results from this study of 85 boys are consistent with what researchers have seen in laboratory animals treated with the chemicals, which are called phthalates. In such tests, the substances impair fetal production of testosterone and other male sex hormones (SN: 4/3/99, p. 213: http://www.sciencenews.org/pages/sn_arc99/4_3_99/fob3.htm). In the current study, mothers with the highest phthalate exposures bore boys with slightly less space between the gonads and anus than did mothers with less phthalate exposure, as gauged by the women's urine concentrations of the chemicals during pregnancy. Moreover, boys with a short anogenital distance tended to have smaller penises and were far more likely to have testes that didn't descend properly into the scrotum. Anogenital distance is typically longer in males than in females. In rodents, prenatal phthalate exposure can erase this difference, says Paul M.D. Foster of the National Institute of Environmental Health Sciences in Research Triangle Park, N.C. He's shown that this shortening in male animals can signal major permanent impairments in reproductive organs (SN: 9/2/00, p. 152: http://www.sciencenews.org/articles/20000902/bob9.asp). Copyright ©2005 Science Service.

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 7442 - Posted: 06.24.2010

The dyslexic brain may have a general problem forming perceptual categories, including the templates for printed letters and speech sounds, say USC neuroscientists. This is reflected in a reduced ability to filter out visual "noise" that can obscure a pattern, the researchers suggest. Their novel hypothesis, published in the current issue of Nature Neuroscience, raises broader questions: Does the dyslexic brain's trouble with patterns and noise extend to other senses? Does poor filtering inhibit the formation of perceptual categories? Or is poor formation of categories the root cause of dyslexics' problem with noise? Dyslexia is the most common and perhaps least understood reading disability. Affecting millions of Americans, it has a history of uncertain explanations. An old, discredited, but persistent view is that dyslexics jumble their letters. In the 1980s, the subtler "magnocellular hypothesis" gained favor with some scientists. Named for a type of neuron, the hypothesis held that dyslexics struggle to process rapid visual signals. Language comprehension also requires rapid processing ability. The Nature Neuroscience study casts doubt on the magnocellular hypothesis. The lead author was Anne Sperling, a graduate of USC's neuroscience program whose Ph.D. thesis was based on the study. The research team, which included Zhong-Lin Lu and Franklin Manis, professors of psychology in the USC College of Letters, Arts and Sciences, and Mark Seidenberg of the University of Wisconsin, Madison, asked dyslexic and non- dyslexic children to identify patterns presented with and without visual noise.

Keyword: Dyslexia
Link ID: 7441 - Posted: 06.04.2005

Palaeontologists think they have found a way to tell whether dinosaur fossils are from males or females. Writing in Science, a US team describe a specialised type of bone layer in fossils from a T. rex which is similar to one found in female birds. In birds, the special tissue is called medullary bone and is laid down in the limbs of females when they lay eggs. The bone tissue found in the dinosaur fossils most closely resembles the medullary bone of emus and ostriches. The scientists behind the discovery say it reinforces the evolutionary links between dinosaurs and birds because it suggests their bodies went through similar processes during egg-laying. "In addition to demonstrating gender, it also links the reproductive physiology of dinosaurs to birds very closely. It indicates that dinosaurs produced and shelled their eggs much more like modern birds than like modern crocodiles," said co-author Dr Mary Schweitzer, of North Carolina State University in Raleigh. Some researchers have proposed that female dinosaurs differed from males in the shapes of their skeletons or in the forms of their head ornamentation. But these theories have been impossible to prove. The medullary bone deposited by female birds when laying eggs is triggered by increasing levels of gonadal hormones produced on ovulation. This tissue is rich in calcium and contains many small blood vessels, providing a ready source of calcium for eggs. (C)BBC

Keyword: Sexual Behavior; Evolution
Link ID: 7440 - Posted: 06.03.2005

By ANDREW POLLACK Shares of Biogen Idec and Elan fell yesterday on news that a fourth patient may have developed the life-threatening brain infection that prompted the companies to halt sales of their multiple sclerosis drug Tysabri earlier this year. If the fourth case of the normally extremely rare infection is confirmed, it would make it more difficult for the drug to return to the market, doctors and analysts said. The new case might indicate the drug is more dangerous than previously thought because it appears the fourth patient might have taken the drug for a substantially shorter time than the other three. Lenore Gelb, a spokeswoman for the Food and Drug Administration, said yesterday that the agency had "been notified by Biogen of a fourth case of symptoms that are suggestive of" the infection. She said the agency was in discussions with Biogen, which is investigating the case. The possibility of a fourth afflicted Tysabri user was first reported yesterday by The Boston Globe, which obtained data on the patient through a freedom of information request to the F.D.A. Tim Hunt, a spokesman for Biogen Idec, said the company would not confirm or deny the report because it was no longer commenting on individual cases. He said the company was evaluating the medical records of all the patients who took Tysabri and hoped to have a complete report by the end of the summer. Copyright 2005 The New York Times Company

Keyword: Multiple Sclerosis
Link ID: 7439 - Posted: 06.03.2005

By NICHOLAS WADE A team of scientists at the University of Utah has proposed that the unusual pattern of genetic diseases seen among Jews of central or northern European origin, or Ashkenazim, is the result of natural selection for enhanced intellectual ability. Intelligence and GeneticsThe selective force was the restriction of Ashkenazim in medieval Europe to occupations that required more than usual mental agility, the researchers say in a paper that has been accepted by the Journal of Biosocial Science, published by Cambridge University Press in England. The hypothesis advanced by the Utah researchers has drawn a mixed reaction among scientists, some of whom dismissed it as extremely implausible, while others said they had made an interesting case, although one liable to raise many hackles. "It would be hard to overstate how politically incorrect this paper is," said Steven Pinker, a cognitive scientist at Harvard, noting that it argues for an inherited difference in intelligence between groups. Still, he said, "it's certainly a thorough and well-argued paper, not one that can easily be dismissed outright." "Absolutely anything in human biology that is interesting is going to be controversial," said one of the report's authors, Dr. Henry Harpending, an anthropologist and a member of the National Academy of Sciences. Copyright 2005 The New York Times Company

Keyword: Intelligence; Genes & Behavior
Link ID: 7438 - Posted: 06.03.2005

By Randy Dotinga Scientists are scanning brain activity in the hopes of catching sight of the physical mechanisms that determine whether you prefer Coke over Pepsi. The nascent research, known as "neuromarketing," could one day lead to new advertising strategies that directly stimulate hard-wired mental reflexes rather than appealing to fuzzy consumer attitudes. "The hope in neuromarketing is that there's some process in the brain that is a better predictor of whether people will actually buy things than what we already have," said Colin Camerer, professor of business economics at the California Institute of Technology. Over the past several years, American and German neuroscientists have been using functional magnetic resonance imaging, or fMRI, brain scans to observe what happens in the brain when people evaluate things like beer, cars and politicians. The latest big finding came from neuroeconomists, who study how people make decisions about everything from buying a lottery ticket to deciding whether to avoid sitting next to a creepy guy on the bus. Earlier this month, Stanford University researchers reported that they've pinpointed the parts of the brain that handle two major parts of a choice -- figuring out how nifty something is and then calculating how likely it is that you'll get it. The study, published in the May 11 issue of The Journal of Neuroscience, was designed to analyze different parts of the decision-making process. Researchers told subjects to press a button quickly when they saw a target on a screen. Before the target appeared, the subjects were told how much they might win during that round, from nothing to $5. © Copyright 2005, Lycos, Inc.

Keyword: Emotions; Brain imaging
Link ID: 7437 - Posted: 06.24.2010

A male fly's sexual courtship of a female fly is a complicated business of tapping, singing, wing vibration, and licking, but a single gene is all that is needed to produce this complex behavior, according to new research published in this week's issue of the journal Cell. The gene encodes the Fruitless protein. Male and female flies carry different versions of the fruitless protein, as a result of sex-specific splicing of the mRNA. The male form of Fruitless is critical for the male courtship ritual and males' preference for mating with females, as previous studies have shown. Now, Barry J. Dickson and Ebru Demir of the Institute of Molecular Biotechnology of the Austrian Academy of Sciences show just how intimately fruitless is linked to these stereotypically male behaviors. They discovered that female flies with the male version of fruitless behave like males, directing at other females a sexual display nearly identical to their male counterparts. Female flies with the male version of the protein also make amorous advances toward male flies that express female pheromones. In these cases, "we have been able to reverse the sex roles during Drosophila courtship," Dickson and Demir say. Dickson and Demir created male-spliced versions of fruitless in female flies and female-spliced versions in male flies. Males with the female version of fruitless "barely court at all" when paired with virgin female flies in an observation chamber, according to the researchers.

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 7436 - Posted: 06.03.2005

Roxanne Khamsi Male and female fruitflies have been engineered to switch courtship roles, through the manipulation of a single gene. The study, which appears in Cell1, shows how a simple genetic adjustment can cause a dramatic change in sexual behaviour. "It was quite something to see," says Barry Dickson, who is one of the authors and is based at the Austrian Academy of Sciences in Vienna. The mating behaviours of the Drosophila fruitfly are a far cry from intricate Hollywood romance. The male performs a series of tapping and tilting movements, to which the female usually responds if she has not recently mated. Females, in contrast, never court at all. But Dickson and his colleague Ebru Demir reversed this behaviour by designing female flies with the male version of a gene called fruitless. These insects initiated courtship with other females as often as their male counterparts did. The tweaked female flies could only be encouraged to court males if the males were designed to emit female pheromones, a form of natural chemical attractant. When male flies were given the female version of the fruitless gene, they stopped courting and became passive about sex. ©2005 Nature Publishing Group

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 7435 - Posted: 06.24.2010

A single gene which hastens a fruit fly larva’s change into a buzzing sexual adult has been unveiled by researchers. This “maturity gene” could help scientists understand the stormy process of growing up in all animals and maybe even generate ways to manipulate the length of childhood in higher vertebrates, including humans. “It’s metamorphosis in insects and puberty in humans. Either way, it’s just the onset of adult form. Anyone who has watched a child mature knows that they change in very dramatic ways,” says Carl Thummel at the University of Utah in Salt Lake City, US, one of the study authors. The timing of maturity is a complex process, influenced by factors like the availability food and genetics. But the molecular pathways remain similar throughout the animal kingdom. For example, the steroid hormones oestrogen and testosterone play an important role human adolescence, while the steroid ecdysone drives maturation in flies. To better understand the network of signals that control metamorphosis in flies, Thummel and his colleagues reduced the function of a receptor called DHR4 in the fruit fly Drosophila melanogaster. To their surprise, they found that mutant flies with reduced DHR4 activity had a shorter juvenile phase and proceeded to adulthood at a smaller size. The immature larvae had cut short their youthful feeding frenzy by a day. This feeding session - crucial during the maturation process from hatching to pupae - usually lasts about four days. © Copyright Reed Business Information Ltd

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 7434 - Posted: 06.24.2010

By Shankar Vedantam Scientists have found the chemical equivalent of the perfect sales pitch: a hormone that makes us more trusting than we normally are. Volunteers in a study were told they were participating in a decision-making experiment. Those who inhaled the hormone, which occurs naturally in the brain, were more likely to entrust others with large sums of money than were volunteers who inhaled no hormone. The experiment has profound implications about the nature of human trust. Researchers said their finding might lead to cures for people with disorders that prompt them to hold others at arm's length, but they acknowledged that the chemical, which is widely used in medicine, could be misused. The experiment, involving 128 participants, was conducted by scientists at the University of Zurich and other academic centers. Researchers had some volunteers inhale oxytocin and then examined how they and those who inhaled a placebo invested money in a mock transaction. The transaction involved taking a risk: handing over money to a "banker" who had the option of returning the investment with a profit or withholding principal and profit, leaving the investor with nothing. The experiment was a measure of the trust that the investors had in the bankers. Volunteers who inhaled oxytocin were more likely to trust the banker with money and risk larger sums, the researchers said in an article published yesterday in the journal Nature. © 2005 The Washington Post Company

Keyword: Hormones & Behavior; Emotions
Link ID: 7433 - Posted: 06.24.2010

By BENEDICT CAREY In a finding that may someday benefit the socially manipulative as well as the socially awkward, Swiss researchers are reporting that doses of a natural hormone significantly increased the level of trust that people placed in strangers who were handling their money. Scientists have long known that the hormone used in the study - oxytocin, which circulates widely in the body during childbirth and lactation - prompts warm relations and mating in other mammals. But they say the Swiss study, which appears in today's issue of the journal Nature, is the first to show that a simple administration of a hormone in humans can consistently alter something as socially sensitive as trust. The new finding could help researchers not only understand the biological system underlying social judgments but also perhaps correct it when it goes awry, as in conditions like social phobia or autism, scientists say. In the study, the participants played an investment game with anonymous partners. Those who were given oxytocin invested more money with the partners than did those who did not receive the hormone, the researchers found. Copyright 2005 The New York Times Company

Keyword: Hormones & Behavior; Emotions
Link ID: 7432 - Posted: 06.02.2005

ANN ARBOR, Mich. – Remember how it felt the last time you burned your finger on a hot stove? Imagine what it's like to have that burning pain in your hands or feet all the time and know there's virtually nothing you can do about it. It's called neuropathic pain, and it's a common complication of many diseases and medical conditions, especially diabetes. Drugs have little effect on this type of pain, which is caused by damage to sensory neurons that transmit pain, temperature and touch signals to and from the brain. Now, scientists at the VA Ann Arbor Healthcare System and the University of Michigan Medical School have developed a way to block the signals responsible for neuropathic pain. The secret to their success is based on a virus called herpes simplex or HSV – the same virus that causes cold sores and genital herpes. The scientists use a disabled form of the virus, called a vector, to deliver genes to the nucleus of neural cells. A study published today in the June, 2005 of the Annals of Neurology describes how laboratory rats with nerve damage showed much less pain-related behavior after receiving injections of the HSV-based vector, which contained a gene called GAD, or glutamic acid decarboxylase. The treatment's pain-killing effect lasted up to six weeks, and even longer in rats that received additional injections.

Keyword: Pain & Touch
Link ID: 7431 - Posted: 06.24.2010

When Ellen Bramble was 49 she stepped off a flight of stairs into thin air. She tumbled down, her laundry flying "every which way" and her limbs relaxed, as if she didn't even know she was falling. "I just kind of rolled and bounced on the concrete stairs…and I didn't get hurt, just a couple of bruises," says Bramble, a photographer from Portland, Oregon. This was the first of three falls that later led doctors to diagnose Bramble with multiple sclerosis (MS). MS is a disease in which the body's own white blood cells attack and erode the protective insulation around nerve fibers in the brain, spinal cord, and optical nerves, causing patients' bodies to go numb and lose track of what they're doing. As her disease progressed, Bramble, who is now 59, learned to deal with her physical limitations. But what's been most frustrating is that she's often felt lost in a "fog." Bramble has "cognitive dysfunction," a symptom shared by half of America's 400,000 multiple sclerosis patients, which makes it difficult for her to think clearly and to do simple things many people take for granted — remembering words, reading, keeping track of her daily chores, or even knowing where she's going when she pulls out of her driveway. (C) ScienCentral, 2000-2005.

Keyword: Multiple Sclerosis
Link ID: 7430 - Posted: 06.24.2010

By studying in detail the ability of patients with selective brain damage to recall events in their past, researchers, led by Larry R. Squire of the University of California San Diego and Veterans Affairs Medical Center, have helped settle a long-standing controversy about where the long-term memory of one's personal experiences are stored. The research is published in the June 2 issue of Neuron. The controversy has revolved around whether long-term memory continues to depend on the region called the medial temporal lobe, which contains the brain's memory-processing center, the hippocampus. According to this view, such "autobiographical" memories depend on specific contextual information that would require the continued involvement of the brain's central memory structures. The other view is that autobiographical memories, like other types of shorter-term memories, gradually become independent of the medial temporal lobe as time passes. Memory studies of brain-damaged patients have not yielded a clear winner, because of the complexity of such damage and the difficulty in accurately documenting the quality of such memories. Now, Squire and his colleagues have presented evidence that "the ability to recollect remote autobiographical events depends not on the medial temporal lobe but on widely distributed neocortical areas."

Keyword: Learning & Memory
Link ID: 7429 - Posted: 06.02.2005

EVANSTON, Ill. --- Using a newly released method to analyze functional magnetic resonance imaging (fMRI), Northwestern University researchers have demonstrated that the interconnections between different parts of the brain are dynamic and not static. This and other findings answer longstanding debates about how brain networks operate to solve different cognitive tasks. They are presented in the current (June 1) issue of the Journal of Neuroscience. Equally important, the researchers discovered that the brain region that performed the integration of information shifted depending on the task their subjects performed. In this study, the subjects were assigned two language tasks. In both, subjects were asked to read individual words and then make a spelling or rhyming judgment. "We found that one network takes different configurations depending on the goal of the task," said Tali Bitan, primary author of "Shifts of Effective Connectivity Within a Language Network during Rhyming and Spelling." Bitan worked with Associate Professor James Booth of the same department and M-Marsel Mesulam, director of the Cognitive Neurology and Alzheimer's Disease Center in Northwestern's Feinberg School of Medicine. Mesulam, who was among the first scientists to predict the existence of convergence zones within interconnected brain networks, said the study presents "the clearest and most convincing evidence to date" of the dynamics in effective connectivity.

Keyword: Miscellaneous
Link ID: 7428 - Posted: 06.02.2005

Giving people a whiff of a key chemical can make them more inclined to trust strangers with their cash, a new study reveals. Just three puffs of a nasal spray containing a hormone called oxytocin increased the chance that people would part with their money. The research centred around a game in which an “investor” player gives part or all of his money on blind trust to an anonymous “trustee” player who earns interest on the combination of his own money and the invested sum. But the investor is told there is no obligation for the “trustee” to give any money back at all - they risk losing any money they choose to invest. Michael Kosfeld at the University of Zurich, Switzerland, who led the study found that investors gave away their money far more willingly if they had sniffed oxytocin than if they had sniffed a placebo. But this extra willingness disappeared when the trustee’s role was computerised, rather than carried out by another human, confirming that the effect was interpersonal, and not simply a general willingness to gamble. Kosfeld speculates that the hormone reduces people’s aversion to betrayal, overcoming an unwillingness to initiate interaction with strangers. This matches observations in animal studies. “It helps animals to approach one another, which is a parallel with trust in our game,” he says. © Copyright Reed Business Information Ltd.

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 7427 - Posted: 06.24.2010

Cancer survivors are twice as likely to develop cognitive problems as individuals who have never been treated for cancer, according to an article in the June 1 Journal of the National Cancer Institute. Previous research has raised concerns about a possible link among cancer, cancer therapies and cognitive dysfunction. This study found that long-term cancer survivors were at increased risk of cognitive impairment. An accompanying editorial urged a cautious interpretation of the results pending further research. In the study, USC psychologists studied 702 cancer survivors and their cancer-free twins in the Swedish Twin Registry. Studying twins removes statistical influences from genetic or early childhood causes of both cancer and cognitive deficits. Working with colleagues at the Karolinska Institute and Gothenberg University in Sweden, the researchers evaluated the survivors through a standardized mental status interview. Participants were scored on a scale from zero to three. Anyone who scored a three, defined as having verbal, orientation or recall problems that interfere with daily life, was considered to have cognitive dysfunction.

Keyword: Miscellaneous
Link ID: 7426 - Posted: 06.01.2005

The following tests were developed by Simon Baron-Cohen, director of the Autism Research Centre at the University of Cambridge. Baron-Cohen's theory is that the female brain is predominantly hard-wired for empathy, and that the male brain is predominantly hard-wired for understanding and building systems. He calls it the empathising-systemising (E-S) theory. Empathising is the drive to identify another person's emotions and thoughts, and to respond to these with an appropriate emotion. The empathiser intuitively figures out how people are feeling, and how to treat people with care and sensitivity. Systemising is the drive to analyse and explore a system, to extract underlying rules that govern the behaviour of a system; and the drive to construct systems. The tests work out your empathising quotient (EQ) and systemising quotient (SQ). The interactive version, which will calculate your results for you, requires Flash (version 5). Alternatively, the plain HTML version allows you to print off the questionnaire and calculate your own scores. In either case, do both the SQ and EQ questionnaires then click on the link at the end for "your brain type". This will tell you whether you have a male brain, a female brain or if you're perfectly balanced. You can post your results or comments on the tests on the Essential Difference talkboard. Or you can send us an email at life@guardian.co.uk © Guardian Newspapers Limited 2004

Keyword: Sexual Behavior; Autism
Link ID: 7425 - Posted: 06.24.2010

Christen Brownlee Researchers decades ago mapped out the brain's sense of touch, with patches of neurons corresponding to body parts, such as a hand, a lip, or the torso. A new study suggests that the sense of smell may have its own brain atlas. The finding adds to a growing body of research on smell, which scientists haven't studied as much as touch, hearing, or sight. Last year, Linda Buck of the Fred Hutchinson Cancer Research Center in Seattle and Richard Axel of Columbia University shared the Nobel Prize in Physiology or Medicine for their work in deciphering the mechanisms behind smell (SN: 10/9/04, p. 229: Available to subscribers at http://www.sciencenews.org/articles/20041009/fob5.asp). Over the past 15 years, the two scientists have independently worked out how scents are perceived by olfactory neurons in the nose. Their work has also detailed how these neurons transmit signals to the olfactory bulb, a structure at the front of the brain. However, researchers still knew little about how the brain processes odor information in the olfactory cortex, a region in the temporal lobe, which extends along the sides of the brain. "We know quite a bit about the mechanisms used to encode touch and sight, but we knew nothing about how different odorants are encoded in the olfactory cortex," says Zhihua Zou of the Fred Hutchinson center. Copyright ©2005 Science Service.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 7424 - Posted: 06.24.2010

By Jennifer Viegas, Discovery News — Three newly discovered primate species that lived 30 million years ago suggest that our first ancestors originated in Asia and not in Africa, challenging the well-known "Out of Africa" theory about human evolution. The actuality could be something a bit more complicated, such as "Out of Asia into Africa and Back to Asia," since some researchers now think Asian primates journeyed to Africa, where they evolved into humans, who then traveled both in and out of Africa. According to a study published in this week's Proceedings of the National Academy of Sciences, numerous fossil teeth for the three new anthropoids were found in the Bugti Hills of central Pakistan. Scientists believe our world-traveling animal cousins were anthropoids, which means "apes" and refers to the group of primates from which humans evolved. "The Oligocene period (30-25 million years ago) in South Asia was so far totally undocumented paleontologically," said Laurent Marivaux, lead author of the paper. "So, it is not surprising that the discovery of fossilized animals from this period is totally new for science, and that they (may) change or modify substantially our previous view on mammal evolution, notably here, the evolutionary history of anthropoid primates." Copyright © 2005 Discovery Communications Inc.

Keyword: Evolution
Link ID: 7423 - Posted: 06.24.2010