By NICHOLAS WADE Two genes involved in determining the size of the human brain have undergone substantial evolution in the last 60,000 years, researchers say, leading to the surprising suggestion that the brain is still undergoing rapid evolution. The discovery adds weight to the view that human evolution is still a work in progress, since previous instances of recent genetic change have come to light in genes that defend against disease and confer the ability to digest milk in adulthood. It had been widely assumed until recently that human evolution more or less stopped 50,000 years ago. The new finding, reported in today's issue of Science by Bruce T. Lahn of the University of Chicago, and colleagues, could raise controversy because of the genes' role in determining brain size. New versions of the genes, or alleles as geneticists call them, appear to have spread because they enhanced brain function in some way, the report suggests, and they are more common in some populations than others. But several experts strongly criticized this aspect of the finding, saying it was far from clear that the new alleles conferred any cognitive advantage or had spread for that reason. Many genes have more than one role in the body, and the new alleles could have been favored for some other reason, these experts said, such as if they increased resistance to disease. Copyright 2005 The New York Times Company

Keyword: Evolution
Link ID: 7880 - Posted: 09.09.2005

BABY chimpanzees express emotion by smiling and pulling faces just like human infants, researchers have found. A study of 37 chimps in their first months of life at a US research centre revealed striking similarities with humans. All smiled to show happiness within the first three weeks of birth, said Dr Kim Bard from the University of Portsmouth. Infants tended to smile when they were placed face-to-face with a human examiner. They also uttered vocal greetings. Like human babies, they imitated carers who opened their mouths and stuck out their tongues. They were also able to imitate a sequence of sounds within the first weeks of life. Chimps who were kept in an environment where carers responded to their emotional needs were more communicative. But they also became angry when the help they came to expect was not forthcoming. ©2005 Scotsman.com

Keyword: Evolution; Development of the Brain
Link ID: 7879 - Posted: 06.24.2010

Like many students, MIT graduate student Gauri Nanda often has a hard time waking up for class. "I've had lots of trouble getting out of bed. Sometimes I'll hit the snooze button for two hours," Nanda says. So as part of a class project, she created an alarm clock — "clocky" — that you have to get out of bed and chase before you can turn it off. "It will fall to the floor and sort of roam around until he finds a place to hide," she explains. "[It] sort of ensures that you wake up in the morning, because you have to use more of your senses before you can actually turn the alarm off." Neuroscientist Masashi Yanagisawa says this approach has scientific merit because getting up wakes you up. "The best way to wake up in the morning is, as soon as you hear the alarm clock goes off, you get up and start to be physically or mentally active, rather than keep pushing the snooze button," explains Yanagisawa, who studies the molecular genetics of our brains at the University of Texas Southwestern Medical Center at Dallas and the Howard Hughes Medical Institute. Our brains have brain cells, or neurons, that produce a protein called orexin. "They are so to speak our 'wake-up neurons,'" Yanagisawa says. "So we need those neurons to be firing very fast in order to maintain wakefulness during day time." Without these brain cells functioning and pumping out orexin people just can't stay awake — they suffer from narcolepsy. "Those patients cannot keep themselves awake during day time in a socially and physically appropriate manner," he says. © ScienCentral, 2000-2005.

Keyword: Sleep
Link ID: 7878 - Posted: 06.24.2010

Male and female fruit flies, like men and women, tend to behave quite differently — particularly during courtship. When trying to find a mate, the male fruit fly performs an elaborate courtship dance packed full of abdomen tapping and wing-beating serenades, while the female looks on. But even though males and females look different (and most of us would say certainly think differently), certainly our eyes, ears, and noses perceive things the same way. Or do they? "Just like in people, we'd always inferred that the male and female fly perceived the world the same," explains Stanford University geneticist Bruce Baker. "But, in fact, we now see, at a molecular level, that those sense organs are not the same, and so it may well be the case that… males and females don't sense the same world." Baker and his research team have been working to try and understand why animals behave as they do, particularly the kinds of innate behaviors that animals just seem to know how to do. "Things like the kind of nest a bird will build; the kind of courtship display that a male peacock might make," he says. "We'd like to understand what happens during development to give an organism the potential to do these often amazing and wonderful sorts of behaviors that they carry out." They discovered a gene that triggers mating behavior in male fruit flies, whose elaborate mating ritual involves all the senses, from smell and taste, to the sound of the courtship song he plays for his beloved. © ScienCentral, 2000-2005.

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 7877 - Posted: 06.24.2010

By Larry O'Hanlon, Discovery News — Bumblebees are a brainy bunch, according to new study showing that the insects watch other bumblebees to learn what flowers to dine on. The ability to learn simply by watching is usually accorded to only certain birds, marine mammals and primates. This new work shows that the old saying "monkey see, monkey do" applies even to some insects. "Bees can learn things on their own or learn from others," said bumblebee researcher Bradley Worden of the University of Arizona. Worden is a co-author of a paper on the matter in an upcoming issue of Biology Letters of the Royal Society. To test the learning skills of bumblebees, Worden and his colleagues set up a glassed-off watching station where bumbles could observe other bees feeding at different flowers. The feeding bees were previously trained to prefer nectar from certain colored artificial flowers. "It's purely observational, without a reward," said Worden, making the distinction between the training commonly used to train dogs and other animals. Afterwards, fresh flowers of the same kinds were made available to the observer bumblebees. The observer bees immediately showed a distinct preference for the kinds of they had seen other bees dining from. Copyright © 2005 Discovery Communications Inc.

Keyword: Learning & Memory; Evolution
Link ID: 7876 - Posted: 06.24.2010

Jennifer Wild Want to keep your wits about you until a ripe old age? Scientists say that aerobics does more than mental exercise to keep your brain fit. Regularly sweating it out on the squash court is like a fertilizer for brain cells, they say. Exercise for the body helps new brain cells to sprout and make more connections, which in turn helps to preserve the frontal lobes, the area of the brain where ageing is most noticeable. To find the most important ingredient in the recipe for mental fitness, Ian Robertson at the University of Dublin reviewed the past ten years of research in the field. He announced his results at this year's British Association for the Advancement of Science meeting in Dublin on 7 September. Robertson found evidence that good nutrition, education, and positive thinking all help to keep your brain young. But the most important factor is aerobics, he concludes. "It has remarkable beneficial effects on the structure and function of the brain." ©2005 Nature Publishing Group

Keyword: Learning & Memory; Alzheimers
Link ID: 7875 - Posted: 06.24.2010

By examining how sounds are registered during the process of learning, UC Irvine neurobiologists have discovered a neural coding mechanism that the brain relies upon to register the intensity of memories based on the importance of the experience. While neurobiologists have long hypothesized this type of neural coding, the study presents the first evidence that a "memory code" of any kind may exist. The UCI researchers believe that this code, as well as similar codes that may be discovered, will not only broaden our understanding of normal learning and memory but also may shed light on learning disorders. It may also one day be possible to manipulate these codes to control what and how we remember – not only basic sounds, but complicated information and events. "This memory code may help explain both good and poor memory," said Norman Weinberger, a professor of neurobiology and behavior in UCI’s Center for the Neurobiology of Learning and Memory. "People tend to remember important experiences better than routine ones." Weinberger and his colleagues found that when the brain uses this coding method, information is stored in a greater number of brain cells, which should result in a stronger memory. However, the researchers believe that if the brain fails to use the code, the resulting memory – even if it is an important one – would be weaker because fewer neurons would be involved. © Copyright 2002-2005 UC Regents

Keyword: Learning & Memory
Link ID: 7874 - Posted: 06.24.2010

Howard Hughes Medical Institute researchers who have analyzed sequence variations in two genes that regulate brain size in human populations have found evidence that the human brain is still evolving. They speculate that if the human species continues to survive, the human brain may continue to evolve, driven by the pressures of natural selection. Their data suggest that major variants in these genes arose at roughly the same times as the origin of culture in human populations as well as the advent of agriculture and written language. The research team, which was led by Bruce T. Lahn, a Howard Hughes Medical Institute investigator at the University of Chicago, published its findings in two articles in the September 9, 2005, issue of the journal Science. Their analyses focused on detecting sequence changes in two genes - Microcephalin and “abnormal spindle-like microcephaly associated” (ASPM) - across different human populations. In humans, mutations in either of these genes can render the gene nonfunctional and cause microcephaly - a clinical syndrome in which the brain develops to a much smaller size than normal. In earlier studies of non-human primates and humans, Lahn and his colleagues determined that both Microcephalin and ASPM showed significant changes under the pressure of natural selection during the making of the human species. “Our earlier studies showed that Microcephalin showed evidence of accelerated evolution along the entire primate lineage leading to humans, for the entire thirty to thirty-five million years that we sampled,” he said. “However, it seemed to have evolved slightly slower later on. By contrast, ASPM has evolved most rapidly in the last six million years of hominid evolution, after the divergence of humans and chimpanzees.” © 2005 Howard Hughes Medical Institute

Keyword: Evolution; Genes & Behavior
Link ID: 7873 - Posted: 06.24.2010

US experts say they have strong scientific proof that mind over matter works for relieving pain. Positive thinking was as powerful as a shot of morphine for relieving pain and reduced activity in parts of the brain that process pain information. The Wake Forest University researchers say their findings show that by merely expecting pain to be less it will be less. Their work is published in Proceedings of the National Academy of Sciences. Dr Robert Coghill and his team studied 10 normal, healthy volunteers who had a heat simulator applied to their legs while their brains were being scanned using functional magnetic resonance imaging (fMRI). The heat simulator was used to produce pain and fMRI was used to map brain activity. Before subjects underwent brain imaging, they learned to expect mild, moderate, or severe painful heat stimuli following different signals. None of the stimuli were hot enough to cause burns or damage the skin. During brain imaging, a small percentage of the severe stimuli were incorrectly signalled as moderate stimuli to create expectations of decreased pain. All 10 volunteers reported less pain when they expected lower levels of pain. These expectations reduced reports of pain by more than 28% - similar to an analgesic dose of the potent painkiller morphine. (C)BBC

Keyword: Pain & Touch
Link ID: 7872 - Posted: 09.08.2005

CBC News A new and disturbing theory about the possible origin of "mad cow" disease has been published, and a Canadian scientist said it is "plausible." In a report in the British medical journal, The Lancet, Professor Alan Colchester of the University of Kent in England says BSE (bovine spongiform encephalopathy) may have been caused by the tonnes of animal bones and other tissue imported in the '60s and '70s from India for animal feed which also may have contained the remains of humans infected with Creutzfeldt-Jakob disease (CJD). Colchester, and his daughter Nancy, from the college of medicine and veterinary medicine at the University of Edinburgh in Scotland, said the practice may still be taking place elsewhere. They said it is important to discover whether other countries are importing animal byproducts contaminated with human remains that are destined for feed mills. The authors admitted their hypothesis is based on a compilation of circumstantial evidence. They wrote: "We do not claim that our theory is proved, but it unquestionably warrants further investigation." It had previously been thought that the brain-wasting mad cow disease passed to cattle through remains of sheep infected with scrapie -- the sheep equivalent of BSE -- that were added to cattle feed. Copyright © CBC 2005

Keyword: Prions
Link ID: 7871 - Posted: 06.24.2010

When Angelique Tung escaped from the South Tower on September 11th, 2001 she didn't know she was pregnant. Originally from California, she was visiting New York for a business meeting on the 78th floor. Like so many, the images of that day are ingrained in her mind. She remembers her sales manager saying, "You've got to get out of the building." She remembers looking through the giant South Tower windows at smoke, paper, and debris billowing out of the North Tower. And she remembers the impact of the second plane. "Quite frankly I was surprised I was pregnant because I thought this trauma would have caused a miscarriage," Tung says. During her pregnancy she was nervous anytime planes flew too close to her Los Angeles office building. Tung says she also felt anxious and never wanted to travel far from home. Concerned for how her mental state might affect her unborn child, she began to see a psychologist who told her she had symptoms of post-traumatic stress disorder, or PTSD. She is now the mother of two. She says her older son seems like a normal little boy, but notes that he "has fears" and is "definitely more risk-averse" than his younger brother. Though she's no doctor, and can't tell if her son's behavior is just what she would call "first child syndrome" or actually associated with her own trauma, her observation is not unfounded. © ScienCentral, 2000-2005

Keyword: Stress; Development of the Brain
Link ID: 7870 - Posted: 06.24.2010

By Larry O'Hanlon, Discovery News —Hurricane Katrina's rampage didn't stop some deep-sea biologists in her path from making new discoveries before they had to run for their lives. Scientists aboard the Harbor Branch Oceanographic Institution's Seward Johnson announced that they caught a second glimpse of a mysterious new kind of giant squid and reeled up a deep sea crab that can see ultraviolet light. The secret to their success was the innovative Eye-in-the-Sea apparatus, which uses dim red light to watch animals attracted to a pile of bait. This year's big discovery of the ultraviolet-seeing crab raises the question of what the crab sees in UV at 1,700 feet under Gulf of Mexico waves, where no solar UV can reach. "It was totally unexpected," said chief scientist Tammy Frank of the UV-seeing crab. To discover the crab's secret, it had to be carefully brought up from the depths in a cold, dark container. The depressurization was not so much an issue because crabs have no swim bladders, and so are not sensitive to pressure changes as are many fish. Copyright © 2005 Discovery Communications Inc

Keyword: Vision; Evolution
Link ID: 7869 - Posted: 06.24.2010

Roxanne Khamsi When it comes to deadly protein clusters in the brain, size matters. The human equivalent of mad cow disease, variant Creutzfeldt-Jakob disease (vCJD) is thought to be caused by misshapen proteins, known as prions, that infect the brain. Research now shows that the most infectious strings of prions are of a middling length; clumps that are longer or shorter are less problematic. The findings, reported in this week's Nature1, could convince medical experts to rethink how they plan to treat illnesses such as vCJD, as well as Alzheimer's and Parkinson's. Researchers have often debated whether longer or shorter chains of prions are more problematic. The molecules seem to multiply by converting the normal proteins that they touch to an irregular form. Long ones form visible tangles in the brain, but short ones might be more capable of spreading the infection. Jay Silveira and his colleagues at the Rocky Mountain Laboratories in Hamilton, Montana, obtained misshapen prion proteins from hamsters, broke them up using a detergent, and sorted them according to size. They then injected strings of known length into other hamsters. ©2005 Nature Publishing Group |

Keyword: Prions
Link ID: 7868 - Posted: 06.24.2010

UPTON, NY - A new set of experiments in mice confirms that a brain receptor associated with the reinforcing effects of marijuana also helps to stimulate the rewarding and pleasurable effects of alcohol. The research, which was conducted at the U.S. Department of Energy’s Brookhaven National Laboratory and was published online September 2, 2005 by the journal Behavioural Brain Research, confirms a genetic basis for susceptibility to alcohol abuse and also suggests that drugs designed to block these receptors could be useful in treatment. “These findings build on our understanding of how various receptors in the brain’s reward circuits contribute to alcohol abuse, help us understand the role of genetic susceptibility, and move us farther along the path toward successful treatments,” said Brookhaven’s Panayotis (Peter) Thanos, lead author of this study and many others on “reward” receptors and drinking (see: this release and , www.bnl.gov/thanoslab). Earlier studies in animals and humans have suggested that so-called cannabinoid receptors known as CB1 — which are directly involved in triggering the reinforcing properties of marijuana — might also stimulate reward pathways in response to drinking alcohol. Thanos’ group investigated this association in two experiments.

Keyword: Drug Abuse
Link ID: 7867 - Posted: 06.24.2010

Smokers are twice as likely as non-smokers to lose their sight in later life, experts warn. The link between age-related macular degeneration (AMD) and smoking is now as robust as that between smoking and lung cancer, they say. Yet many smokers are still unaware that their habit could cost them their sight. AMD Alliance UK and the Royal National Institute of the Blind are calling for specific warnings on cigarette packets. They would also like the government to fund an awareness campaign to alert people to the dangers of smoking, as well as the introduction of a complete ban on smoking in all enclosed public places across the UK. AMD usually develops after a person reaches 50 years and affects the central part of the retina of the eye. It is the UK's leading cause of sight loss - there are around 500,000 people in the UK with AMD. An estimated 54,000 people have the condition as a result of smoking. Yet a report by AMD Alliance UK reveals that only 7% of people know that AMD affects the eyes, based on a survey of 1,023 UK adults. However, seven out of 10 smokers would either stop smoking permanently (41%) or cut down (28%) if they thought it could harm their eyesight. (C)BBC

Keyword: Drug Abuse
Link ID: 7866 - Posted: 09.07.2005

A quick word test may allow simpler, earlier diagnosis of Alzheimer's disease, according to a new study. UK researchers have found that patients in the early stages of the disease consistently forgot words they learned later and used less in life. Word tests which identify this pattern of vocabulary loss may therefore provide a new way to screen patients. Early diagnosis of Alzheimer's is important to maximise the benefit of currently available treatments. The study, conducted by Andy Ellis of the University of York and his collaborators at the Universities of Hull and Aberdeen, characterised shrinking vocabulary in the early stages of the disease. The researchers asked 96 Alzheimer's patients and 40 healthy people of similar age to list all the animals they could in one minute. In a second minute, the test subjects were asked to list types of fruit. While the healthy subjects were able to list 20-25 words, on average, those suffering from Alzheimer's could list only 10-15, indicating a constriction of their active vocabulary. The lost words tended to be those learned later in childhood and encountered less frequently in everyday life. (C)BBC

Keyword: Alzheimers
Link ID: 7865 - Posted: 09.07.2005

In findings that support a relationship between agricultural chemicals and Parkinson's disease, two groups of researchers have found new evidence that loss of DJ-1, a gene known to be linked to inherited Parkinson's disease, leads to striking sensitivity to the herbicide paraquat and the insecticide rotenone. The two studies were performed with the fruit fly Drosophila, a widely used model organism for studies of human disease, and shed new light on biological connections between inherited and sporadic forms of Parkinson's disease. The work is reported in Current Biology by two independent groups, one led by Nancy Bonini of the University of Pennsylvania and the Howard Hughes Medical Institute, and the other led by Kyung-Tai Min of the NINDS branch of the U.S. National Institutes of Health. Parkinson's disease occurs both sporadically and as a result of inheritance of single gene mutations. One of the most common neurodegenerative disorders, it is associated with the progressive and selective loss of a specific population of neurons in the brain, the dopaminergic neurons of the substantia nigra pars compacta . Exposure to several common environmental toxins, thought to injure neurons through oxidative damage, has been shown to be associated with sporadic forms of Parkinson's disease. During the past decade, researchers have also made remarkable progress in identifying genes responsible for inherited forms of Parkinson's disease, with the expectation that understanding the function of these genes will elucidate mechanisms behind sporadic Parkinson's disease. Past work had shown that one form of familial Parkinson's disease results from a loss of function of a gene called DJ-1.

Keyword: Parkinsons; Neurotoxins
Link ID: 7864 - Posted: 09.07.2005

Evolution of Brain, Cognition, and General Intelligence by David C. Geary Review by Keith Harris, Ph.D. Why and how have humans developed a type of consciousness unlike that of other creatures? Although targeted at readers already knowledgeable in this area, this book does a very good job of developing and extending evolutionary theory to explain our cognitive faculties. The author's background in developmental psychology (in which he holds a doctorate) serves as a solid platform for this overview of the history of the human brain, including the evolution of our type of intelligence and the intricate social functioning for which it serves so well. Having previously published over a hundred professional articles and several books, in this work, Geary gets at what are among the most interesting -- and largely unresolved -- issues about being human: why are we conscious and why do we have such a well-developed sense of self? The first chapter is a concise integration of the facts, themes and arguments that make up the book. The second chapter covers the basic processes that underlie the evolution of species, and does so in a thorough but concise manner. Readers are advised to pay close attention to the first two of the books' nine chapters, as a good grasp of these are needed well for an understanding the later chapters. © CenterSite, LLC, 1995-2005

Keyword: Evolution
Link ID: 7863 - Posted: 06.24.2010

New York - Doctors commonly view excessive daytime sleepiness as a cardinal sign of disturbed or inadequate sleep. But a new study suggests it could also signal depression or even diabetes, regardless of whether an individual doesn't sleep well. Among a random sample of 16,500 men and women ranging in age from 20 to 100 years old from central Pennsylvania, 8.7 percent had excessive daytime sleepiness. Researchers, who considered a wide range of possible reasons for why these individuals were excessively sleepy during the daytime, found that excessive daytime sleepiness was more strongly associated with depression and obesity or metabolic factors than with sleep-disordered breathing or sleep disruption. Depression was by far the most significant risk factor for excessive daytime sleepiness, they report in the Journal of Clinical Endocrinology and Metabolism. The likelihood of being excessively sleepy during the daytime was more than three times higher in those who reported they were being treated for depression. The investigators also observed strong ties between excessive daytime sleepiness and diabetes. Individuals reporting treatment for diabetes were close to two times more likely to report excessive daytime sleepiness than those who were not being treated for diabetes. © 2005 Independent Online.

Keyword: Sleep; Depression
Link ID: 7862 - Posted: 06.24.2010

Working long hours is considered a hallmark of a medical residency. But in recent years, concerns have risen about how shifts that can last days affect a doctor's ability to function. The results of a new study quantify the negative effects and show that the performance of fatigued residents is comparable to how they would act after imbibing three or four cocktails. An 80-hour limit for a resident's workweek was introduced in July 2003 in response to concerns about overwork. In the new study, J. Todd Arnedt of the University of Michigan and his colleagues measured the performance of 34 doctors on an attention test and in a driving simulator after being on call. The volunteers took part in the tests on four different occasions, both after working mostly day shifts with only a few overnight calls, and after working intense overnight shifts that added up to about 80 hours in a week. For some of the tests, the doctors were also given alcoholic drinks or nonalcoholic placebos. After a month of difficult work schedules, the doctors exhibited reaction times that were seven percent slower than their responses after working a lighter schedule. In the driving simulator, doctors coming off a month of working nights displayed comparable skills to the subjects who had an easier schedule but had a blood-alcohol level just below the legal driving limit. What is more, the post-call doctors were 30 percent more likely to not maintain a steady speed in the driving simulator compared to well-rested doctors who had been drinking. © 1996-2005 Scientific American, Inc

Keyword: Sleep
Link ID: 7861 - Posted: 06.24.2010