By Charles Q. Choi Mothers could literally always have their kids on their minds. Researchers find that in mice, cells from fetuses can migrate into a mother's brain and apparently develop into nervous system cells. The discovery comes from Gavin S. Dawe of the National University of Singapore and Zhi-Cheng Xiao of Singapore General Hospital, along with their colleagues from China and Japan. They were looking to design therapies for stroke or diseases such as Alzheimer's. Scientists have known for years that fetal cells can enter a mother's blood; in humans, they may remain there at least 27 years after birth. Like stem cells, they can become many other kinds of cells and in theory might help repair damaged organs. The neurobiologists bred normal female mice with males genetically modified to uniformly express a green fluorescent protein. They found green fetal cells in the mothers' brains. "In some regions of some mothers' brains, there are as many as one in 1,000 to sometimes even 10 in 1,000 cells of fetal origin," Xiao reports. The fetal cells transformed into what seem like neurons, astrocytes (which help to feed neurons), oligodendrocytes (which insulate neurons) and macrophages (which ingest germs and damaged cells). Moreover, after the scientists chemically injured the mouse brains, nearly six times as many fetal cells made their way to damaged areas than elsewhere, suggesting the cells could be responding to molecular distress signals released by the brain. © 1996-2005 Scientific American, Inc.

Keyword: Stem Cells
Link ID: 8163 - Posted: 06.24.2010

Scientists have long known that different parts of the brain are generally responsible for different functions, but only since the development of new, highly sophisticated scanning devices have they been able to watch the brain in action. Using a Magnetic Resonating Imaging scanner or MRI, they can watch portions of the brain "light up" when different things happen. Allan Reiss, director of the Center for Interdisciplinary Brain Science and Research at Stanford University, has been using this device to study how volunteers' brains react to something funny. His goal is to learn more about how we use humor as a way to cope with things like stress. He says, "The way that we do it is we show them black and white cartoons, fairly simple, most of them have captions." By using the MRI, "We can actually see the brain lighting up, specific areas of the brain lighting up in response to the person viewing the cartoon," he explains. In previous research, Reiss found that the brain's reward center was "explicitly involved in perception of humor." But now, writing in the Proceedings of the National Academy of Sciences, Reiss has confirmed that men and women perceive humor differently. Additionally, he's found that personality differences play a role that may be even more important than gender does. © ScienCentral, 2000-2005.

Keyword: Emotions; Sexual Behavior
Link ID: 8162 - Posted: 06.24.2010

By Jennifer Viegas, Discovery News — Squirrels can be very vocal animals, as backyard and park observers know, and now scientists have translated some of their squirrel-speak. The findings, published recently in the journal Animal Behavior, present some of the most detailed information to date on squirrel vocalizations, which the researchers now believe constitute a complex language that is unique to the animals. The team of zoologists focused their analysis on alarm calls of the Richardson's ground squirrel, Spermophilus richardsonii, which is the most common ground squirrel in Canada. Squirrels often communicate with whistles, chirps and chucks, which sound like the word "chuck." Whistles and chirps resemble the sounds that many birds make. "A chuck is a short duration trailing element, which when added to the end of a syllable, harshens the offset of a call so that it punctuates the end of the syllable with a click," explained James Hare, one of the study's authors. Hare, an associate professor of zoology at the University of Manitoba in Winnipeg, added, "The squirrel whistles and chirps are roughly equivalent to those of birds, with a whistle having a more or less constant pitch and a chirp decreasing in pitch over its duration." © 2005 Discovery Communications Inc.

Keyword: Language; Evolution
Link ID: 8161 - Posted: 06.24.2010

KINGSTON, Ont. – A simple test that measures eye movement may help to identify children with Fetal Alcohol Spectrum Disorder (FASD) and ultimately lead to improved treatment for the condition, say Queen's University researchers. At present there are no objective diagnostic tools that can be used to distinguish between children with FASD – which affects approximately one per cent of children in Canada – and those with other developmental disorders such as Attention-Deficit Hyperactivity Disorder (ADHD). Researcher James Reynolds and graduate student Courtney Green, of the Department of Pharmacology and Toxicology and the Centre for Neuroscience Studies, will present their findings next week at the annual meeting of the international Society for Neuroscience in Washington, D.C. "Having a set of tests that can be used as diagnostic tools for fetal alcohol syndrome and all of the other behavioural disorders classified under the broader term fetal alcohol spectrum disorder is tremendously valuable," says Dr. Reynolds, who is part of a $1.25-million Queen's-led team focusing on fetal alcohol syndrome, funded by the Canadian Institutes of Health Research. "Now we can begin to identify specific deficits in these children." Many of the behavioural tests used to assess children with FASD are geared to white, middle-class English-speaking people, notes Ms Green. "The biggest problem [in current tests] is cultural insensitivity," she says. "By measuring eye movement we can cut across cultural barriers and provide objectivity in identifying the disorder."

Keyword: Development of the Brain; Drug Abuse
Link ID: 8160 - Posted: 06.24.2010

Scientists have identified another hormone involved in regulating hunger. Obestatin joins a raft of other hormones which can boost or suppress a person's appetite. The team at Stanford University, US, carried out a computer search of genetic information which led to obestatin, Science magazine reports. A UK expert said that the research would help enable scientists to fully control appetite within the next five to 10 years. The researchers looked at gene sequences in humans and animals, including one which codes for ghrelin, an appetite-boosting hormone. They found another hormone - later dubbed obestatin - was processed from the same protein precursor that produced ghrelin. But obestatin was found to suppress appetite - the opposite effect to ghrelin. When rats were given injections of obestatin in their abdomens and brains, they ate about half as much as animals who were not given the hormone. They also put on less weight. Obestatin also slowed the movement of food from the stomach to the intestines. (C)BBC

Keyword: Obesity; Hormones & Behavior
Link ID: 8159 - Posted: 11.11.2005

By DENISE GRADY Hungry or full, fat or thin: it is mostly a matter of hormones, dozens of them, carrying messages between the digestive tract, the fat cells and the brain. Eat. Don't eat. Burn calories. Store fat. Today, researchers at Stanford University are reporting that they have found a previously unknown member of this chemical cascade, a hormone with a much coveted power: it sharply reduces the desire to eat. The new substance, which the scientists named obestatin (OHB-statin), is made in the stomach and small intestine, and it seems to prompt the brain to send out a signal that says "eat less." Mice given the hormone for eight days ate half as much as usual and lost weight, the researchers are reporting today in the journal Science. The hormone seems to reduce hunger in part by slowing the passage of food through the stomach and small intestine. The study's director, Dr. Aaron Hsueh, said obestatin had not been studied in people and had been tested only in mice. But Stanford issued a statement saying Johnson & Johnson, which sponsored the research, has rights to the discovery. With obesity rates shooting up worldwide, drug companies are scrambling to develop weight-loss drugs, especially appetite suppressants. Copyright 2005 The New York Times Company

Keyword: Obesity; Hormones & Behavior
Link ID: 8158 - Posted: 11.11.2005

STANFORD, Calif. - When the appetite-enhancing hormone ghrelin was discovered a few years ago, researchers thought they had found the last of the major genes that regulate weight. They were wrong. Introducing: obestatin, a newly discovered hormone that suppresses appetite. The finding, to be published in the Nov. 11 issue of Science, offers a key to researchers developing treatments for obesity. In a nation that desperately needs to slim down - the U.S. Centers for Disease Control and Prevention estimates 65 percent of Americans over the age of 20 are either overweight or obese - obestatin is likely to generate interest from scientists and drugmakers alike. The research was sponsored by Johnson & Johnson Pharmaceutical Research & Development, LLC, which has certain license rights to the discovery. Researchers at the Stanford University School of Medicine uncovered obestatin by using the principles of evolution to pick clues from data held in the Human Genome Project, as well as the genome sequencing projects for many other organisms, among them, yeast, fruit flies and mice. "Darwin led us to this new hormone," said senior author Aaron Hsueh, PhD, an endocrinologist and professor of obstetrics and gynecology. Jian V. Zhang, PhD, a postdoctoral scholar in Hsueh's laboratory, is the lead author.

Keyword: Obesity; Hormones & Behavior
Link ID: 8157 - Posted: 11.11.2005

Juliet Clutton-Brock In Hunters, Herders, and Hamburgers, Richard W. Bulliet divides the history of human-animal relations into four eras: separation, the time when he presumes that humans or pre-human hominids became self-aware as a species; predomestic, the period of hunter-gathering; domestic, lasting from the Neolithic until, say, 1900, when around 40 per cent of US citizens lived on farms and were self-sufficient on their land; post-domestic, our present age of mass production when only about 2 per cent of US citizens live on farms. These divisions are used by Bulliet as a basis for his hypothesis that the changing patterns of how humans perceive animals, both wild and domestic, are a reflection of the development of societies over time. However, the divisions might have been easier to understand if domestic had been named the “age of the home farm” and post-domestic the “age of the factory farm”. In Bulliet’s view, domestic societies lived close to the land, and people took for granted the killing of farm animals and had few moral qualms about consuming animal products. In early domestic societies, the sacrificial killing of animals was common practice, while later, in Europe, blood sports such as bear- and bull- baiting were immensely popular. In post-domestic societies, there has been a great change, and with the divorce from the realities of keeping, breeding and killing livestock, people experience feelings of guilt, shame and disgust when they think about the industrial processes to which domestic animals are subjected. In future, as urbanism spreads, post-domestic people will be separated increasingly from live animals and they will gain their only experiences of them from print and from the electronic media.

Keyword: Animal Rights
Link ID: 8156 - Posted: 06.24.2010

By Jennifer Viegas, Discovery News Genes that favor enhancements to male sexual potency may be exerting a strong influence on human evolution, a recent study suggests. The study determined that at least one new gene has emerged once every million years on the human lineage during the past 63 million years of primate evolution. Most of these new genes appear to be linked to male sexual prowess. Since the new genes evolved from genes that are not directly related to male sexual function, this suggests natural selection aggressively promotes positive changes to male reproductivity. Scientists focused their research on a specific kind of gene, called a retrogene. Retrogenes, which also are called processed genes, can emerge when RNA, or ribonucleic acid, from a parent's gene converts to DNA and makes a copy of itself. These copies are identical, or nearly identical, to the original. The identical, or slightly altered, copy then may give rise to active retrogenes. The overall process is called retroposition, and for some reason it has been happening a lot in primates, including humans, over the last several million years. "The burst of retroposition seems to have generated a number of genes that have contributed to new phenotypes (physical characteristics) to humans and related non-human primates, in particular to male reproduction," said Henrik Kaessmann, one of the authors of the study, which is featured in the November issue of PLoS Biology. © 2005 Discovery Communications Inc.

Keyword: Sexual Behavior; Evolution
Link ID: 8155 - Posted: 06.24.2010

Howard Hughes Medical Institute researchers have discovered that pheromones essential for mating behavior in mice are recognized by the nose and not by the vomeronasal system, as researchers had long suspected. The new studies demonstrate that the main olfactory epithelium, which was presumed to be mostly involved with the sense of smell, plays a critical role in pheromone detection. Howard Hughes Medical Institute investigator Catherine Dulac and colleagues Hayan Yoon, an HHMI predoctoral fellow, and Lynn W. Enquist published their findings in an immediate early publication on November 10, 2005, in the journal Cell. Yoon and Dulac are at Harvard University, and Enquist is at Princeton University. Related studies by HHMI investigator Linda B. Buck are published in the same issue. The pheromone communication system, which is found in a wide range of mammals, involves detection of chemical odorants released by animals. Pheromones are chemicals that are involved in changing behavior or hormone secretion. According to most biology textbooks, detection of pheromones takes place in a specialized structure, called the vomeronasal organ (VNO). Although the VNO resides in the nasal cavity, the pheromone sensory system is distinct from the sense of smell, as are the chemical receptors involved. In animals possessing a pheromone sensory system — including mice, dogs, cats, and elephants — the system governs a range of genetically preprogrammed mating, social ranking, maternal, and territorial defense behaviors. © 2005 Howard Hughes Medical Institute.

Keyword: Chemical Senses (Smell & Taste); Sexual Behavior
Link ID: 8154 - Posted: 06.24.2010

Howard Hughes Medical Institute researchers have discovered a vast network of neurons in the brain of mice that governs reproduction and controls the effects of reproductive status on other brain functions. In their studies, the researchers found neural circuits that coordinate a complex interplay between neurons that control reproduction and brain areas that carry the neural signals triggered by odorant molecules and those triggered by pheromones, chemical signals produced by animals. The researchers characterize their findings as an initial step in understanding the far-reaching influence that odors and pheromones may have on reproduction and other behaviors. The research team, which was led by HHMI investigator Linda B. Buck at the Fred Hutchinson Cancer Research Center, included first author Ulrich Boehm and Zhihua Zou, who did the work as postdoctoral fellows while in Buck's lab. The researchers published their studies in an immediate early publication on November 10, 2005, in the journal Cell. Related studies by HHMI investigator Catherine Dulac are published in the same issue. The scientists began their studies by focusing on tracing the neural pathways leading to and from neurons that produce gonadotropin releasing hormone (GnRH), which is also known as luteinizing hormone releasing hormone (LHRH). These neurons regulate sexual physiology — including onset of puberty, ovulation, and the menstrual cycle in females and testosterone production in males — by regulating the release of hormones from the pituitary gland. Interestingly, GnRH neurons also appear to be involved in the control of sexual behaviors. © 2005 Howard Hughes Medical Institute

Keyword: Chemical Senses (Smell & Taste); Sexual Behavior
Link ID: 8153 - Posted: 06.24.2010

By Rob Stein Washington Post Staff Writer A first-trimester screening test can reliably identify fetuses likely to be born with Down syndrome, providing expectant women with that information much earlier in a pregnancy than current testing allows, according to a major study being released today. The eagerly awaited study of more than 38,000 U.S. women -- the largest ever conducted -- found that the screening method, which combines a blood test with an ultrasound exam, can pinpoint many fetuses with the common genetic disorder 11 weeks after conception. That allows women to decide sooner whether to undergo the riskier follow-up testing needed to confirm the diagnosis. "This is a big deal for women. It's going to have a big impact on care for women, not just in the United States but throughout the world," said Fergal D. Malone of the Royal College of Surgeons in Dublin, who led the study published in today's issue of the New England Journal of Medicine. Screening women before the second trimester allows those who might opt to terminate a pregnancy to make that decision when doctors say an abortion is safer and less traumatic. It also gives those who want to continue the pregnancy more time to prepare emotionally for their child's condition, and provides earlier reassurance to those whose babies are healthy, avoiding weeks of anxiety, Malone and others said. © 2005 The Washington Post Company

Keyword: Development of the Brain; Genes & Behavior
Link ID: 8152 - Posted: 06.24.2010

Waltham, Mass.- A Brandeis University study published this week in Nature shows for the first time that a molecular signal maintains coherence among brain clock cells that regulate daily activity of Drosophila melanogaster (fruit flies). The two key groups of neurons control morning and evening activity and are maintained in synch even when the flies are plunged into darkness for extended periods of time. This daily resetting signal flows from the morning to the evening cells and maintains a 12-hour difference between the timing of morning and evening activity, without the need for any environmental cues. The Brandeis researchers came to this conclusion by speeding up only the morning cell clock or only the evening cell clock. The results showed clearly that these two clocks always remained coupled in a network that was governed by the morning cell signal. "We think it very likely that something similar is occurring in the brain of mammals, including humans, because their clock neurons also maintain remarkable coherence," said Professor Michael Rosbash, director of the National Center for Behavioral Genomics at Brandeis, and a Howard Hughes Medical Institute investigator. "However, circadian brain anatomy in mammals is much more complicated and the tools much too primitive to allow a similar network approach at this time. Flies are state-of-the art. Fortunately, their circadian clocks and even neural mechanisms are quite conserved with mammals."

Keyword: Biological Rhythms; Genes & Behavior
Link ID: 8151 - Posted: 11.10.2005

A deep-voiced black-capped chickadee may wonder why other birds ignore it, but there may be a good reason behind the snub, says a University of Alberta study that looked into how the bird responds to calls. Dr. Isabelle Charrier and Dr. Chris Sturdy modified the black- capped chickadee calls, played those sounds back to the bird and observed how they reacted. They found that the chickadee relies on several acoustic features including pitch, order of the notes and rhythm of the call. They also rejected the calls of the control bird, the gray-crowned rosy finch, in favour of their own species. This research is published in the current edition of the journal, "Behavioural Processes." The chickadees two most well-known vocalizations are the "chick-a-dee" call and the "fee-bee" song. The song is produced mainly by males and is used to attract a mate and to defend a territory during the breeding season. The learned call is produced by both sexes throughout the year and is believed to serve a variety of functions such as raising mild alarm, maintaining contact between mates and co-ordinating flock activities. They even go through stages of learning this "language," which explains why juvenile birds can be heard frantically practicing to perfect the call.

Keyword: Sexual Behavior; Language
Link ID: 8150 - Posted: 11.10.2005

People in early stages of Alzheimer's disease have greater difficulty shifting attention back and forth between competing sources of information, a finding that offers new support for theories that contend breakdowns in attention play an important role in the onset of the disease. Routine tasks that require the shifting of attention, such as driving a car while conversing with a passenger, may become more challenging for people in very early stages of Alzheimer's disease, suggests a new study from Washington University in St. Louis. Published in a recent issue of the journal Neuropsychology, the study suggests that subtle breakdowns in attention may offer a reliable clue that a patient is grappling with early symptoms of Alzheimer's-related dementia. The findings are important because they offer clinicians and researchers another tool by which to better predict and understand dementia of the Alzheimer's type early in its history. Psychologists focus on early detection in part because current medications are useful only when given very early in the course of the disease.

Keyword: Alzheimers; Attention
Link ID: 8149 - Posted: 11.10.2005

Infants begin pulling off an amazing feat sometime in the final three months of their first year of life. They learn an important social interaction by following the gaze of an adult, a step that scientists believe gives babies a leg up on understanding language. University of Washington psychologists Rechele Brooks and Andrew Meltzoff have pinpointed this developmental step as beginning somewhere in the 10th or 11th month of life, and have found that infants who are advanced in gaze-following behavior before their first birthday understand nearly twice as many words when they are 18 months old. Writing in the current issue of the journal Developmental Science, Brooks and Meltzoff provide further evidence for the importance of eyes in human social interactions and trace how gaze-following develops in infants. Three years ago they reported that 12- 14- and 18-month-old infants are much more likely to look at an object when a person turns toward it with open eyes rather than closed eyes. "Our work shows that babies can look where an adult is looking but that it isn't easy, particularly at home where there are a lot of distractions," said Brooks, who is a research associate at the UW's Institute for Learning and Brain Sciences.

Keyword: Language; Development of the Brain
Link ID: 8148 - Posted: 11.10.2005

Roxanne Khamsi Researchers have finally pinned down a physical difference between male flies that are engineered to behave homosexually and those that are not: the tweaked variety is missing a small cluster of nerve cells in the brain. Genetically altered flies that are designed to court members of their own sex, or no one at all, have made headlines in recent months (see 'Fruitflies tap in to their gay side '). But no one knew exactly what those genes were doing, or how the flies differed physically from heterosexual ones. Now Japanese researchers have pinpointed one difference in the brain. Scientists caution that fly mating behaviour is very different from that of humans, as are our brains, so these results cannot be extrapolated to people. "No homologue of the fruitless gene is found in mammals and humans," points out Ken-Ichi Kimura of the Hokkaido University of Education in Iwamizawa, Japan. But such work does help researchers to work out the complex genetic and environmental factors that help animals to choose their mates. "This finding will provide insight for understanding how a sexual behaviour is constructed in the circuitry of the brain through a function of single gene," adds Kimura. ©2005 Nature Publishing Group

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 8147 - Posted: 06.24.2010

For most people, a whiff of food that made them sick in the past is enough to trigger a wave of nausea - and to prevent them from eating that food again. It's a response that's instantaneous, involuntary, and so fundamental to basic biology that it occurs in a broad range of species. Even worms, researchers have now shown, quickly learn to avoid smells associated with foods that have made them ill. The new study, led by Howard Hughes Medical Institute investigator Cornelia I. Bargmann and Yun Zhang, a postdoctoral fellow in Bargmann's laboratory at The Rockefeller University, demonstrates a clear capacity for learning in the laboratory animal C. elegans, a microscopic worm with only 302 neurons. The work suggests that the cellular mechanisms underlying this type of learning have been maintained through evolution, and opens the way for more in depth studies of how learning occurs. The study will be published in the November 10, 2005, issue of the journal Nature. One of C. elegans' fundamental behaviors is movement toward food based on its sense of smell. In the laboratory, this often means wriggling across a plate full of agar toward a cluster of E. coli. But in its natural environment, the soil, C. elegans encounters an astounding variety of bacteria. As it writhes through its world, the worm might meet up with hundreds of different species of bacteria in as little as five minutes. But while some bacteria make ideal worm food, others are toxic. © 2005 Howard Hughes Medical Institute

Keyword: Chemical Senses (Smell & Taste); Learning & Memory
Link ID: 8146 - Posted: 06.24.2010

Childhood sex abuse increases the risk of women developing eating disorders - and can even impact on their children, a study says. Researchers found girls abused before the age of 16 were twice as likely to develop eating disorders later in life. The University of Bristol team also said these women were likely to have weight concerns while pregnant and that had a knock-on effect on the child. The findings were published in the British Journal of Psychiatry. The team studied 10,000 women - one in five of whom had being abused. Researchers involved in the university's Children of the 90s project found 79% of the women recalled happy childhoods. The report said these women were less likely to worry about their weight or develop conditions such as bulimia and anorexia later in life. But of those who were sexually abused, 15% showed symptoms of an eating disorder and 30% showed concern about their weight during pregnancy. The researchers said this was a cause for concern, as maternal eating problems after childbirth interfered with parenting and child growth. Women with excessive fears about weight and shape are less likely to breast feed. But the report accepted other distressful experiences during childhood could also trigger problems. Previous research has shown that eating disorders may be connected to a wide range of unhappy childhood influences including parental alcohol misuse, physical or emotional cruelty and other family problems. (C)BBC

Keyword: Anorexia & Bulimia; Sexual Behavior
Link ID: 8145 - Posted: 11.09.2005

Diana Lutz The Velocity of Honey's 24 chapters are short meditations on questions that are probably never going to make the cover of Science or Nature, such as why toast falls butter side down and why time seems to speed up as we grow older. You might call them crossword puzzles for the scientifically minded—they offer a mental workout for its own sake but also soothe and amuse. In fact, author Jay Ingram calls The Velocity of Honey "a self-help book." Its essays "reduce stress," he says, and offer "a brief interruption in the ridiculous rush of life." Ingram, who hosts the Discovery Channel's science program Daily Planet, says he picked the topics for their appeal—adding with characteristic self-irony that this means their appeal to him. Somehow, he says, that turned out to mean there is a lot of physics and psychology and not much in between. (Ingram himself has a master's degree in microbiology from the University of Toronto.) The physics chapters include, in addition to tumbling toast, essays on the way paper crumples and crackles when it is squeezed, the aerodynamics of the maple key (the thin fibrous "wing" that encases the maple seed), the tricky behavior of stones thrown slantwise across water or sand, and the motion across ice of the 20-kilo granite "rocks" used in the sport of curling. © Sigma Xi, The Scientific Research Society

Keyword: Biological Rhythms; Attention
Link ID: 8144 - Posted: 06.24.2010