Emma Marris Dolphins, when dozing, swim in lazy circles. A new paper uncovers the odd fact that dolphins in the Northern Hemisphere swim in anticlockwise circles, whereas dolphins in the Southern Hemisphere swim in clockwise circles. The marine mammals only sleep with one half of their brains at a time, and continuously swim as they snooze. Wild dolphins, not just captive ones, have been seen to swim in circles when they sleep, and dolphins of various species had previously been shown to move preferentially anticlockwise. That prompted speculation as to why they choose this direction, with explanations relating mainly to the animals' anatomy, perhaps an asymmetry in their brain. But when Paul Manger, a dolphin neuroethologist from Sweden, moved to the University of Witwatersrand in South Africa, he realized that all reports of dolphins swimming anticlockwise round their pools came from the Northern Hemisphere. On a hunch, he went down to the local dolphinarium with a video camera and a Thermos of hot coffee. Four nights of watching the animals produced the surprising result that these Southern dolphins spent 86% of their time swimming clockwise. ©2004 Nature Publishing Group

Keyword: Miscellaneous
Link ID: 6141 - Posted: 06.24.2010

It is well known that obesity has reached epidemic proportions. As waistbands expand, so do the number of health gurus heralding the benefits of portion control and exercise to keep obesity at bay. But with some studies indicating that the rate of obesity is greater in women than in men, could it be that women are at a disadvantage when it comes to these obesity avoidance tactics? Is it possible that females are predisposed to succumb to the temptation to overeat? And could exercise be a less effective method of appetite suppression in women than in men? Researchers at The Florida State University say the answer could be yes. Overeating (hyperphagia) and sedentary behavior are known risk factors for obesity, but research in these areas – especially overeating – has been studied almost exclusively in males. In the new animal study “Diet-induced hyperphagia in the rat is influenced by sex and exercise,” Lisa A. Eckel and Shelley R. Moore (The Florida State University Program in Neuroscience and Department of Psychology) found that female rats are more susceptible than male rats to over consume a palatable, sweetened diet, and that female rats are less likely than male rats to use exercise as a means to control appetite in the presence of such a diet.

Keyword: Obesity
Link ID: 6140 - Posted: 06.24.2010

New studies indicate that a specific type of lipid molecule plays a critical role in controlling the behavior of vesicles that store neurotransmitters within neurons. Neurotransmitters are the chemical messengers that neurons release to communicate with one another. The identification of a regulatory role for the molecule, phosphatidylinositol 4,5 biphosphate, or PtdIns(4,5)P2, provides a new view of the operation of the machinery that produces and recycles synaptic vesicles. Led by Howard Hughes Medical Institute (HHMI) investigator Pietro De Camilli, the researchers published their findings in the September 23, 2004, issue of the journal Nature. De Camilli, HHMI investigator Richard Flavell, Reiko Fitzsimonds, and their colleagues at Yale University School of Medicine collaborated on the studies with Timothy A. Ryan and researchers from the Weill Medical College of Cornell University. Synaptic vesicles are initially loaded with neurotransmitter molecules in the interior of neurons. They then secrete their cargo at synapses — the junctions between neurons. At the synapse, the vesicles undergo a process called exocytosis, in which they fuse with the synaptic plasma membrane and unload their neurotransmitters. Afterward, they are drawn back into the neuron in the process of endocytosis. © 2004 Howard Hughes Medical Institute.

Keyword: Drug Abuse
Link ID: 6139 - Posted: 06.24.2010

By BENEDICT CAREY Last week, a federal advisory panel urged regulators to warn parents that antidepressant drugs not only increase the risk of suicide in some children, but that most have a poor track record in curing their disease. The recommendation came after a yearlong debate over whether the drugs are as safe and effective as advertised. It was based on evidence that a small minority of children show increased signs of suicidal behavior when taking the drugs. Through it all, one of the drugs seemed somehow above the fray: Prozac. Although the warning is recommended for Prozac as well as other drugs, Prozac is still the only one approved by the Food and Drug Administration for the treatment of depression in children and adolescents. A large government-financed trial recently found that it worked better than talk therapy in helping teenagers overcome depression. And when British health officials announced a sweeping ban of antidepressant use in children, which touched off the debate last year, they specifically exempted Prozac. But is it really that different? The short answer is no, experts say. Although chemically distinct from other drugs in the same class, Prozac works on precisely the same principle, they say, and there's no evidence that it is significantly safer or more effective than the others in treating childhood depression. Prozac has shown in several trials that it can relieve depression in youngsters and adolescents significantly better than dummy pills. Such convincing evidence is not available for the other drugs. But, research psychiatrists say, that does not mean the other drugs in the same family do not work in young people, only that they have not been properly tested. Copyright 2004 The New York Times Company

Keyword: Depression
Link ID: 6138 - Posted: 09.22.2004

Monkeys have a lot in common with people, including the ability to procrastinate. Like us, they tend to work harder when the goal is closer, and get lazy when it seems farther away. But researchers at the National Institute of Mental Health (NIMH) have used a genetics trick to turn monkeys into workaholics. "All the animals, including humans, are continually making decisions about the value of a reward and the amount of work or effort it's going to take to get a reward, or desired goal," says Barry Richmond of the NIMH's Laboratory of Neuropsychology. "The cognitive behavior we're studying is this balance between the desire to have the reward and the, if you will, burden of having to work to get it." Richmond and his team taught four monkeys to release a lever to make an onscreen dot change color from red to green. A gray bar on the screen in the background told them how much work remained before they received a reward for their efforts. "Normally when they get a cue that says they have a couple of more trials to do, they tend to work a little more slowly and they tend to make errors," says Richmond. "In trials where they know a reward is coming, they make no errors." © ScienCentral, 2000- 2004.

Keyword: Intelligence; Genes & Behavior
Link ID: 6137 - Posted: 06.24.2010

Now that the human genome has been sequenced, the hunt is on to find the genetic changes that led to the evolution of our own species, Homo sapiens. Researchers have recently found genes that may have endowed humans with larger brains and the ability to speak. Now a research group has uncovered evidence that another gene may have given the brains of apes, including humans, a major cognitive boost millions of years ago. The gene, called GLUD2, encodes glutamate dehydrogenase (GDH)--an enzyme that helps recycle one of the brain's most important neurotransmitters, glutamate. But there are actually two types of GDH: the one coded by GLUD2, which is found mostly in nerve tissues, and a second type, coded by a gene called GLUD1, which is found in many different cells and performs a variety of functions. In a paper published online on 19 September in Nature Genetics, Fabien Burki and Henrik Kaessmann, two genome researchers at the University of Lausanne in Switzerland, report that the brain-specific gene, GLUD2, is found only in apes and humans but not in Old World Monkeys, which only have GLUD1. Moreover, after the ape-human and Old World monkey lineages went their separate evolutionary ways about 23 million years ago, GLUD2 underwent a number of changes that may have enhanced its ability to recycle glutamate. Copyright © 2004 by the American Association for the Advancement of Science.

Keyword: Evolution; Intelligence
Link ID: 6136 - Posted: 06.24.2010

CHARLOTTESVILLE, Va. -- Elderly men who are sedentary or walk less than a quarter of a mile per day are nearly twice as likely to develop dementia and Alzheimer's disease compared to men who walk more than two miles per day, according to a study of over 2,200 Japanese-American men in Hawaii. The study is published in the Sept. 22 issue of the Journal of the American Medical Association. "This is additional evidence that exercise includes health benefits other than just lowering the risk for coronary disease, cancer and other diseases. We now have evidence that regular walking is also associated with benefits that are related to cognitive function later in life," said Robert D. Abbott, Ph.D., professor of biostatistics at the University of Virginia Health System and a co-author of the study. Dementia is a chronic, or persistent, disorder of mental processes due to brain disease. Symptoms may include personality changes, as well as losses in reasoning, orientation, and memory, that interfere with a person's usual activities. So far, it is not clear why walking seems to protect the aging brain from dementia and Alzheimer's disease. "If you've been active throughout your life it could have direct relationships with the same kind of healthy risk factors that are often associated with less obesity, diabetes and heart disease," Abbott said. "People who are active tend to adhere to a healthier life-style and a better diet than those who are inactive. All of these factors could be working together in determining overall vitality and how healthy our brain is. There is also the possibility that people who walk are less likely to get diseases later on in life that could lead to dementia versus people who are inactive."

Keyword: Alzheimers
Link ID: 6135 - Posted: 09.22.2004

Newsweek - Every evening our eyes tell us that the sun sets, while we know that, in fact, the Earth is turning us away from it. Astronomy taught us centuries ago that common sense is not a reliable guide to reality. Today it is neuroscience that is forcing us to readjust our intuitions. People naturally believe in the Ghost in the Machine: that we have bodies made of matter and spirits made of an ethereal something. Yes, people acknowledge that the brain is involved in mental life. But they still think of it as a pocket PC for the soul, managing information at the behest of a ghostly user. Modern neuroscience has shown that there is no user. "The soul" is, in fact, the information-processing activity of the brain. New imaging techniques have tied every thought and emotion to neural activity. And any change to the brain—from strokes, drugs, electricity or surgery—will literally change your mind. But this understanding hasn't penetrated the conventional wisdom. We tell people to "use their brains," we speculate about brain transplants (which really should be called body transplants) and we express astonishment that meditation, education and psycho-therapy can actually change the brain. How else could they work? This resistance is not surprising. In "Descartes' Baby," psychologist Paul Bloom argues that a mind-body distinction is built into the very way we think. Children easily accept stories in which a person changes from a frog to a prince, or leaves the body to go where the wild things are. And though kids know the brain is useful for thinking, they deny that it makes them feel sad or love their siblings. © 2004 Newsweek, Inc.

Keyword: Development of the Brain
Link ID: 6134 - Posted: 06.24.2010

By Judy Skatssoon, ABC Science Online — A study of how the size of snakes' heads change in response to the size of their prey has cast new light on the nature versus nurture debate. An Australian and French study has showed that adaptability is a combination of genes and life experiences. Research published in the latest issue of the journal Nature described a study of two separate populations of tiger snakes (Notechis scutatus). The mainland population, found at Herdsman Lake in Western Australia, ate frogs and mice, and had small jaws. The second population, on Carnac Island off the coast of Western Australia southwest of Fremantle, preyed on silver-gull chicks and had larger heads. A team including the University of Sydney's Richard Shine tested whether the different head sizes were the result of genetic mutations or a lifetime physical adaptation to the environment, known as adaptive developmental plasticity. "There's been a scarcity of good examples of how these sorts of different ways of adapting to a challenge fit together," Shine said. Copyright © 2004 Discovery Communications Inc.

Keyword: Evolution
Link ID: 6133 - Posted: 06.24.2010

BY JAMIE TALAN Scientists at Brookhaven National Laboratory have identified a biochemical abnormality that might help explain why some people with AIDS develop dementia. For the first time in living AIDS patients with early signs of dementia, scientists detected depletion of the brain chemical dopamine. Not everyone with AIDS develops dementia. It is more common in the late stages of AIDS. Depletion of dopa- mine is most often associated with Parkinson's, not dementia. Brain scan studies suggest that AIDS patients with dementia have lost between 12 to 20 percent of their dopamine cells. By contrast, Parkinson's patients lose 80 to 90 percent of the dopamine cells in a key area of the brain that regulates movement before any symptoms develop. In addition to the tremors and rigidity, many Parkinson's patients can also suffer mild attention and thinking problems and are at high risk for depression. Copyright © 2004, Newsday, Inc.

Keyword: Alzheimers
Link ID: 6132 - Posted: 06.24.2010

Researchers have combined sophisticated biochemical and imaging techniques to get a glimpse of the stepwise assembly of amyloid fibers in a yeast prion protein. Their findings suggest that these structured fibers form in competition with the amorphous globules that some believe may cause toxicity in amyloid diseases such as Alzheimer's and Parkinson's. The researchers say this may have important implications for those designing drugs to prevent formation of the brain-damaging proteins in those diseases. The researchers reported their findings in the October 2004 issue of the Public Library of Science Biology. They were led by Howard Hughes Medical Institute investigator Jonathan S. Weissman at the University of California, San Francisco. HHMI investigator Ronald D. Vale, also of UCSF, was a co-author of the article. Working in yeast, Weissman and his colleagues investigated the mechanism by which a prion protein assembles individual polypeptides into long amyloid fibers. These fibers are similar to the amyloid plaques that clog the brains of patients with Alzheimer's or Parkinson's disease. © 2004 Howard Hughes Medical Institute.

Keyword: Alzheimers
Link ID: 6131 - Posted: 06.24.2010

Helen Pilcher An unusually powerful magnetic resonance imaging (MRI) machine was unveiled today that should reveal not just the anatomy but also the metabolism of the human brain, say scientists at the University of Illinois at Chicago. If it lives up to its promise, the machine should help researchers to probe how the brain thinks, learns, fights disease and responds to experimental therapies. But it will involve exposing patients to stronger magnetic fields than ever before. MRI uses a combination of magnetism, radio waves and computing power to peer inside the body. Patients lie inside a large circular magnet. When turned on, the magnetic field causes the nuclei of certain atoms, including hydrogen, to line up. A pulse of radio waves is then sent through the magnetic field. The aligned nuclei absorb this radiation and emit it again, producing a signal that reveals the structure of the molecules in which the atoms sit. Most MRI machines use magnets with field strengths of around 3 tesla (equivalent to around 30 fridge magnets). This allows researchers to image water molecules and create pictures of anatomical structures within the body. ©2004 Nature Publishing Group

Keyword: Brain imaging
Link ID: 6130 - Posted: 06.24.2010

St. Paul, Minn. – The popular hypothesis that the hepatitis B vaccine is associated with an increased risk of multiple sclerosis has been scientifically corroborated through a prospective study of patients in the United Kingdom. Results of the study, and a related editorial, are reported in the September 14 issue of Neurology, the scientific journal of the American Academy of Neurology. More than 350 million people worldwide are chronically infected with the hepatitis B virus. Of these, 65 million will die from cirrhosis or liver cancer – approximately 5,000 per year in the United States. The hepatitis B vaccine, considered one of the safest vaccines ever produced, is more than 95 percent effective in preventing chronic hepatitis B infection, and is the first vaccine against a major human cancer. In 1996, about 200 cases of MS (and other central nervous system demyelinating disorders) following hepatitis B vaccination were reported in France, prompting the French government to suspend routine immunization of pre-adolescents in schools. The potential link between vaccination against hepatitis B and an increased risk of MS has since been evaluated in several studies, with limited success.

Keyword: Multiple Sclerosis
Link ID: 6129 - Posted: 06.24.2010

St. Paul, Minn. – People with mild Alzheimer’s disease make more mistakes on a driving test than older people with no cognitive problems, according to a study published in the September 14 issue of Neurology, the scientific journal of the American Academy of Neurology. The study involved an on-road driving test with 32 people with mild Alzheimer’s disease and 136 people with no neurological disorders. The people with Alzheimer’s disease were still driving, although some had reduced their driving due to restrictions imposed by themselves or their families. The 45-minute test included “on-task” time when the drivers were given verbal instructions to follow a route, as well as time when the drivers were not “on task,” or were not asked to remember and follow instructions. The people with Alzheimer’s were more likely to make driving errors during the route-following task than those without Alzheimer’s. For example, more than 70 percent of the people with Alzheimer’s made at least one wrong turn while following the route, while about 20 percent of those without Alzheimer’s made at least one wrong turn. And nearly 70 percent of those with Alzheimer’s made two or more safety errors, such as erratic steering or going onto the shoulder, while following the route, compared to about 20 percent of those without Alzheimer’s.

Keyword: Alzheimers
Link ID: 6128 - Posted: 06.24.2010

Bruce Bower In southern Asia, where an estimated 75 million children qualify as malnourished, lack of food may only be part of the problem. A prospective study in rural Pakistan finds that mothers who became depressed shortly before or after giving birth had babies far more likely to experience stunted growth and bouts of diarrhea than were babies with psychologically healthy mothers. Maternal depression critically contributes to high rates of malnutrition and failure to thrive among infants in this part of the world, conclude psychologist Atif Rahman of the University of Manchester in England and his colleagues. Most people living in southern Asia now have access to adequate food supplies, the researchers note. In the new study, maternal depression exhibited a stronger link to poor infant health during the first year after birth than did other factors associated with slowed physical growth, including low birth weight and having poor, uneducated parents. This finding raises particular concern, according to the scientists, because several other reports indicate that the depression rate of 10 to 15 percent among expectant and new mothers in Western nations nearly doubles in southern Asia. Copyright ©2004 Science Service.

Keyword: Depression; Development of the Brain
Link ID: 6127 - Posted: 06.24.2010

Pipeline Is Bulging With Diet Pills By Rob Stein, Washington Post Staff Writer Eyeing a potential gold mine in the global obesity epidemic, the pharmaceutical industry has launched a massive drive to develop new diet pills and an intense campaign to persuade the government to make it easier to get weight-loss drugs onto the market. Dozens of companies are testing scores of experimental compounds designed to curb appetite, block weight gain and burn fat. Although most are in the earliest stages, many have moved into preliminary tests in people, and a handful have progressed further. One is generating widespread excitement and could make it onto pharmacy shelves by the end of next year. "It's a hot field," said Donny Wong, an analyst at Decision Resources Inc., a Waltham, Mass., market research firm. "Every large pharmaceutical company has an obesity program, and if they don't have one, they are trying to get one." To encourage and prepare for the flood of drugs that could emerge, the Food and Drug Administration has initiated its first review in nearly a decade of how it assesses new obesity medications. The industry -- joined by some obesity experts and advocates alarmed by the burgeoning health crisis -- is pressing the agency to demand less stringent testing and to speed approval of new agents. © 2004 The Washington Post Company

Keyword: Obesity
Link ID: 6126 - Posted: 06.24.2010

Researchers have uncovered a new culprit behind the brain injury suffered by stroke victims. Their new study, published in the Sept. 17 issue of Cell, links brain cell damage to a rise in brain acidity following the oxygen depletion, or ischemia, characteristic of stroke. The results may lead to new therapies designed to avert the often debilitating effects of stroke, for which successful treatments are currently lacking, the researchers said. A series of experiments in laboratory dishes and in animals implicates a recently described class of membrane ion channels, called acid-sensing ion channels (ASICs), to the influx of calcium in nerve cells starved of oxygen and subjected to acidic conditions. That calcium overload, long attributed to another group of cellular components, is essential for stroke injury as it sets off a cascade of events toxic to cells, said neurophysiologist and lead author of the study (Zhi-Gang Xiong of Robert S. Dow Neurobiology Laboratories in Portland, Oregon). What's more, the team reports, rats injected with agents known to block ASICs--including the venom of a tarantula spider--exhibited a reduction in brain damage from ischemia. Mice lacking a functional copy of the ASIC gene were similarly resistant to stroke damage, they found. "Our study offers multiple lines of evidence that reveal acid-sensing ion channels as major players in the damage suffered by stroke victims," Xiong said. "Furthermore, we found that existing pharmacologic agents that block those channels can dramatically reduce the amount of brain injury."

Keyword: Stroke
Link ID: 6125 - Posted: 09.17.2004

The origin of language stemmed from relationships, not genes By Ruth Walker Here is a book that gives new meaning to the old saying, "The hand that rocks the cradle rules the world." Its authors, one a psychiatrist and the other a psychologist and philosopher, have teamed up to tackle the momentous question of how humans developed language. Fearing not to challenge some of the heavyweights of modern science, from Jean Piaget to Noam Chomsky and Steven Pinker, they present their own theory: The development of language is connected primarily with affect rather than cognition, with the emotional learning that occurs in infants in the arms of those who love them. That is, language is rooted not in genes, not in the wiring of brains, but in behaviors we have learned over millenniums. Phrases like "emotional intelligence" and "the feeling brain" sound less oxymoronic today than they did before they appeared in the titles of groundbreaking works by Daniel Goleman and, more recently, Antonio Damasio. But in "The First Idea," Stanley Greenspan and Stuart Shanker contend that "emotional intelligence," as it is coming to be understood, is only one of the "roots and branches" of intelligence itself. "The trunk," they argue, is a set of abilities they refer to as the "functional-emotional developmental capacities." The critical concept in "The First Idea" is what the authors call "co-regulated emotional signaling." By this they mean the affectionate back-and-forth between baby and caregiver. Mom and Baby make eye contact, and when Mom smiles at Baby, Baby smiles back. Copyright © 2004 The Christian Science Monitor.

Keyword: Language; Development of the Brain
Link ID: 6124 - Posted: 06.24.2010

With cars blurring past to her left and right, Judy Niosi pried her fingers around the steering wheel as she drove along a major highway, struggling to come to grips with what she thought was a heart attack. "I was feeling was that my heart started pounding—forcefully—to the point where I thought my chest was going to explode," recalls the 37-year-old graphic artist. "My hands became sweaty and I had the constant thoughts that I was going to die." Niosi gulped down air, talked to herself in a soothing tone and somehow rumbled up her driveway a short while later. By then, her symptoms had disappeared. "I immediately got on the Internet looking for things, you know, heart attack symptoms to make sure that I wasn't having a heart attack," she says. "And I came across panic attacks and then I realized it must've been a panic attack." Her physician confirmed her suspicions. Doctors have long suspected that panic attacks like Niosi's—characterized by repeated bouts of intense fear that seem to come out of nowhere—could be hereditary and may result from the way our brains are wired. Piling up is new evidence that this may be the case. Psychiatrist Alexander Neumeister, an assistant professor at Yale University, reported in the Journal of Neuroscience that key brain receptors that receive chemical signals from other cells are deficient in those who suffer from panic attacks. The receptors help move the brain chemical serotonin—it regulates emotion—around the brain. © ScienCentral, 2000- 2004.

Keyword: Emotions
Link ID: 6123 - Posted: 06.24.2010

Helen Pearson A group of deaf Nicaraguan children who have created their own way of signing are giving linguists a precious glimpse of a language in its infancy. The kids are revealing how our brains are wired for learning language. It has long been debated to what extent our brains are a 'blank slate', able to learn any structure of language to which we are exposed, or whether they are hard-wired with grammatical rules. Existing languages do share fundamental rules. But this may simply be because different languages have influenced each other as they evolved. Linguists have attempted to answer the question by examining languages as they arise. For example, when people who speak different languages are pulled together, as they were by immigration or slavery, they rapidly evolve a pidgin language that can be polished over the years into a more sophisticated creole. But in these cases the communications are based on pre-existing languages. The Nicaraguan children are special because they have created a language from scratch. Deaf kids in the country lived in effective isolation until they were brought together in specialist schools in the late 1970s and 80s. Once the deaf children started to mingle, they began to communicate in their free time using gestures. They tend to stick with the signs they have acquired by the time they reach adolescence, so oldest set of children uses a relatively crude set of gestures. But younger generations have continued to refine them, forming a completely new language with its own grammatical rules. ©2004 Nature Publishing Group

Keyword: Language
Link ID: 6122 - Posted: 06.24.2010