Researchers at the University of Alabama have found a way to mimic epileptic seizures in the tiny roundworm C. elegans. The finding could make the worm a powerful model for unraveling the molecular regulation of epilepsy, a condition that affects two percent of the population. Guy A. Caldwell, coordinator of the Howard Hughes Medical Institute's (HHMI) Undergraduate Research Intern Program and assistant professor of biological sciences at the University of Alabama, led a research team that included Kim A. Caldwell, assistant professor of biological sciences and director of the university's HHMI-sponsored Rural Science Scholars Program; Shelli N. Williams, a Ph.D. student; and two HHMI undergraduate research interns, Cody J. Locke and Andrea L. Braden. They studied worms with a mutation in the LIS1 gene. In its human form, the gene has been linked to a rare birth defect called lissencephaly, which affects one out of every 30,000 children born. In children with lissencephaly, the normally wrinkled surface of the brain's cortex is smooth. They also have mental retardation and severe epilepsy, the causes of which are not well understood. The team traced the mutation's effect on specific neurons in the simple nervous system of the 1-millimeter roundworm and published their findings in the September 15, 2004 issue of the journal Human Molecular Genetics, published online August 31. © 2004 Howard Hughes Medical Institute.

Keyword: Epilepsy
Link ID: 6056 - Posted: 06.24.2010

Using brain imaging, neuroscientists at the NIH’s National Institute of Mental Health (NIMH) have pinpointed the site of a defect in a brain circuit associated with a specific thinking deficit. Their study demonstrates how a rare genetic disorder, Williams Syndrome, can offer clues as to how genetic flaws may translate into cognitive symptoms in more common and complex major mental disorders. Andreas Meyer-Lindenberg, M.D., Karen Berman, M.D., and colleagues, traced the thinking deficit to a circuit at the back of the brain that processes locations of objects in the visual field. The researchers report on their Magnetic Resonance Imaging (MRI) study in the September 2, 2004 Neuron. The study focused on the inability to visualize an object as a set of parts and then construct a replica, as in assembling a puzzle — a key cognitive deficit experienced by people with Williams Syndrome. In addition to this visuospatial construction deficit, people with Williams Syndrome also tend to be overly friendly and anxious and often have mental retardation and learning disabilities. Compared to most mental disorders, which are thought to involve complex interactions between multiple genes and environmental triggers, the genetic basis of Williams Syndrome is remarkably well understood. People with the disorder lack about 21 genes in a particular part of chromosome 7. “Williams Syndrome yields a unique opportunity to study how genes influence our ability to construct our social and spatial worlds,” said NIMH Director Thomas Insel, M.D. “By studying people with this disorder, we can discover how genetic mutations change not only molecular and cellular processes, but lead to differences in the brain circuitry for complex aspects of cognition.”

Keyword: Language; Genes & Behavior
Link ID: 6055 - Posted: 06.24.2010

Helen Pilcher There is no one cause for dyslexia: rather, the causes vary between languages. So conclude researchers who have found that Chinese children with reading difficulties have different brain anomalies to their Western counterparts1. The finding explains why one can be dyslexic in one language but not another. The team also hopes the work will aid the design of culturally specific strategies for learning to read and write that could benefit everyone. People with dyslexia often find it difficult to recognize and understand words. Speakers of alphabetic languages, such as English or Russian, can have a problem converting letters into sounds. Dyslexics in these languages have reduced activity in a brain region called the left temporoparietal cortex. But Chinese readers must learn the meanings of around 5,000 different characters, each corresponding to a word. Instead of letter-to-sound conversion problems, Chinese dyslexics have difficulties extrapolating from a symbol's shape to its sound and meaning. ©2004 Nature Publishing Group

Keyword: Dyslexia
Link ID: 6054 - Posted: 06.24.2010

By JOSEPH B. VERRENGIA With 6,000 characters to memorize, Westerners shudder at the idea reading even the most basic street signs and instructions in Chinese. A new set of brain images shows why: Reading English-style alphabets and Chinese characters use very different parts of the brain. The results also suggest that Chinese schoolchildren with reading problems misfire in a different brain region than the one used in reading alphabet-based languages like English. This demonstrates that the learning disorder dyslexia is not the same in every culture and does not have a universal biological cause, researchers said. An image taken from TV shows a soldier rushing a girl away from the school in Beslan, in the region of North Ossetia. The guerrillas attacked on the first day of the school year. (Reuters Television) Neurologists described the results as "very important and innovative." While dyslexia has certain common roots, they said they now have some proof that this kind of functional problem plays out differently according to the unique demands that Western and Eastern languages place on the brain's wiring and processing centers. © 2004 The Associated Press

Keyword: Dyslexia
Link ID: 6053 - Posted: 06.24.2010

Far from opposites attracting, people tend to chose friends who look like them, research suggests. However, psychologist Dr Lisa DeBruine found a facial resemblance is not a turn-on when we are looking for a partner. She believes we may have evolved to prefer the company of people who remind us of family - but have a biological block to prevent incest. The study is published in the Journal of the Royal Society. The researchers showed volunteers male and female faces that had been computer-manipulated to produce a 'family resemblance'. Men liked other men's faces that resembled their own and women liked other women's faces that resembled their own. However, a facial resemblance did not influence attraction to opposite-sex faces. Dr DeBruine, of McMaster University, Canada, said previous research had shown that people were more likely to trust others who looked like them. In one of her previous studies she found people playing a two-person monetary investment game over the internet while viewing a picture of the "second player" were more likely to trust this player if the picture was digitally morphed to resemble them.

Keyword: Emotions
Link ID: 6052 - Posted: 09.01.2004

A team of biochemists from UC Riverside published a paper in the June 11 issue of the Journal of Molecular Biology that gives one explanation for why humans and primates are so closely related genetically, but so clearly different biologically and intellectually. It is an established fact that 98 percent of the DNA, or the code of life, is exactly the same between humans and chimpanzees. So the key to what it means to be human resides in that other 2 percent. According to Achilles Dugaiczyk, professor of Biochemistry at UCR, one important factor resides in something called Alu DNA repeats, sometimes called "junk DNA." These little understood sections of DNA are volatile, and prone to sudden mutations, or genomic rearrangements. At times the results are beneficial in that they give rise to new proteins or an altered gene regulation. Sometimes the mutations result in the growth of a cancer tumor, or some other genetic defect. "The explosive expansion of the DNA repeats and the resulting restructuring of our genetic code may be the clue to what makes us human," Dugaiczyk said. "During the same amount of time, humans accumulated more genetic novelties than chimpanzees, making the human/chimpanzee genetic distance larger than that between the chimpanzee and gorilla."

Keyword: Evolution
Link ID: 6051 - Posted: 09.01.2004

A team of scientists has found that a protein involved in a congenital neurological disorder also plays a role in DNA damage repair and thus cancer prevention. The research appears as the "Paper of the Week" in the August 13 issue of the Journal of Biological Chemistry, an American Society for Biochemistry and Molecular Biology journal. Primary microcephaly is a rare neurological disorder that results in an abnormally small head due to improper brain formation and growth. Children with this condition may be short, have seizures and have normal or mildly retarded intelligence. "Microcephalin is the protein encoded by the MCPH1 gene, which, when mutated, is a major cause of microcephaly. We have now identified an important function for microcephalin, which may eventually help explain the connection of MCPH1 with microcephaly, and which links microcephalin function to DNA damage responses that prevent cancer from developing," said David F. Stern, Ph.D., and Xingzhi Xu, M.D./Ph.D. of the Yale University School of Medicine. Cells incur chronic DNA damage from exposure to normal metabolic byproducts as well as external chemicals and radiation. In order to mitigate this DNA damage, cells must have a mechanism for both detecting damage and for stopping their machinery until the damage is fixed. This feedback mechanism relies on cycle "checkpoint" controls that delay the cell division cycle so that these repair systems have time to work.

Keyword: Development of the Brain; Genes & Behavior
Link ID: 6050 - Posted: 09.01.2004

The National Sleep Foundation's 2003 Sleep in America poll found that 67 percent of older Americans report trouble sleeping. Sleep for people over 55 often involves waking up several times during the night, not being able to get back to sleep and waking up earlier than desired in the morning. Sleep recordings show that the sleep of older adults is shallower than that in younger adults, with less deep (slow-wave) sleep and frequent awakenings during the night. There are important consequences of disordered sleep in older adults, according to Susan Benloucif, research associate professor of neurology at Northwestern University Feinberg School of Medicine. "Disrupted or unrefreshing sleep frequently leads to fatigue and can have a negative effect on the way you feel, and on social interactions, job performance and other important areas of daytime functioning," Benloucif said. Older adults usually get less sleep than younger adults; however, it is not clear whether the need for sleep diminishes or simply that the ability to sustain sleep declines. Recent research suggests that medical illnesses, or the treatments for those illnesses, are more likely at fault than age itself. The need to urinate is the most common sleep disrupter in late life. The NSF poll reported that nearly two in three adults get up to use the bathroom at least a few nights a week.

Keyword: Sleep
Link ID: 6049 - Posted: 09.01.2004

For decades scientists have believed that people can only remember an ordered list of about seven items at a time--such as seven grocery items or seven digits of a phone number--but new research from the University of Rochester has shown that this magic number varies depending on whether the language used is spoken or signed. The results in the cover story of the latest issue of Nature Neuroscience have important implications for standardized tests, which often employ ordered-list retention as a measure of a person's mental aptitude. "When we hear things, we naturally process them in a series," says Daphne Bavelier, associate professor of brain and cognitive sciences at the University of Rochester. "When we hear music, for instance, it comes to us second by second, so the part of our brains that processes auditory information has evolved to absorb information in sequence. This means hearing a spoken list, such as numbers in an ATM code, corresponds more closely with what the auditory brain does naturally." Conversely, visual information comes to us simultaneously as we might see a sunset, clouds and a skyline all at the same time. While the visual processes in the brain can still remember ordered lists, they tend to be less effective at it, recalling an average of five numbers instead of seven. In the 1960s, cognitive scientists showed that for nearly all speakers of all languages, list retention peaked at around seven items, plus or minus about two. As more languages were tested, a few exceptions were found, such as Chinese, that allows to hold nine items or Welsh that is nearer to five, but in all cases these variations were entirely predictable by the length of time it takes to utter the words in each language.

Keyword: Learning & Memory; Language
Link ID: 6048 - Posted: 09.01.2004

Michael Hopkin A drug that blocks a cellular pathway involved in cravings could help people quit smoking and lose weight. That's the promise of experts who announced the results of a trial at the European Society of Cardiology's annual meeting in Munich, Germany, on 29 August. They say the drug, rimonabant, which could also cut heart-disease risks, may be available in 2006. But is beating cravings really that simple? The results so far are promising. The researchers placed 1,507 overweight trial subjects on a diet and exercise programme designed to help them lose weight. Half also took a single tablet containing 20 milligrams of the drug each day; the remainder took a dummy pill. After a year, those on rimonabant had lost an average of 8.6 kilograms, and 8.5 centimetres off their waistline. Those taking a placebo averaged 3.8 kg and 4.5 cm. "In terms of weight loss the drug is effective - slightly more so than previous drugs," says Nick Finer, an obesity specialist at Addenbrooke's Hospital in Cambridge, UK, who helped to design the trials. "Seventy-five per cent of people achieved 5% weight loss." ©2004 Nature Publishing Group

Keyword: Drug Abuse; Obesity
Link ID: 6047 - Posted: 06.24.2010

Significant structural differences in the brains of males and females may result from selective cell death orchestrated by just a single gene during early development, according to a new study. Researchers at the University of Massachusetts Amherst in the US examined the brains of mice lacking a gene called Bax and found that some sex differences that are obvious in normal mice were completely absent. It has been known since the late 1970s that certain well-defined clusters of brain cells known as nuclei differ markedly in males and females, either in overall size or in the total number of cells present. For example, in adult rodents, the bed nucleus of the stria terminalis, or BNST, is 75% larger and contains many more cells in males than in females. The opposite pattern is seen in a region known as the anteroventral periventricular nucleus, or AVPV, which is both larger and richer in cells in females than in males. © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior; Apoptosis
Link ID: 6046 - Posted: 06.24.2010

(Santa Barbara, Calif.) –– Our biological clock, or circadian rhythm, is upset by travelling across time zones, but very soon the body adjusts to the new day/night cycle. New studies of the computational models of the circadian rhythm of fruit flies show that the internal clock is robust, that is, not easily perturbed. These studies may eventually lead to greater understanding of human jet lag as well as human disease states. Engineers at the University of California, Santa Barbara's new Institute for Collaborative Biotechnologies and the Max Planck Institute (MPI) for Dynamics of Complex Technical Systems, in Magdeburg, Germany have analyzed the mechanism of genetic circuits by which the fruit fly regulates its circadian rhythm. The results are published in the August 30 Proceedings of the National Academies of Science. The mechanism controlling the biological clock generates a complicated dynamic behavior, oscillating back and forth and making it difficult to study, but also making it a good prototypical dynamic cellular system. The circadian rhythm of the fruit fly is a regulatory system that takes its cues from the sun. When the sun rises it affects the light-sensitive neurons of the brain of the fruit fly, setting off reactions of proteins at a certain rate depending on the amount of light. The reactions set the clock. There are key proteins and two key feedback loops involved, making the system a hierarchical control scheme, a design tool often used in engineering.

Keyword: Biological Rhythms
Link ID: 6045 - Posted: 06.24.2010

DALLAS – Mice with specific genetic mutations exhibit behavior similar to human psychosis, report UT Southwestern Medical Center at Dallas researchers, providing further support to the notion of a genetic link to schizophrenia. The researchers genetically engineered mice with a mutation in the gene NPAS3, a mutation in the gene NPAS1 or a mutation in both genes. Both genes encode proteins that switch other genes on and off in brain cells. "These mice display certain deficits that are potentially consistent with schizophrenia," said Dr. Steven McKnight, chairman of biochemistry at UT Southwestern and senior author of the study that will appear in an upcoming issue of the Proceedings of the National Academy of Sciences and is to be posted online this week. "It's too early to tell whether the abnormal behavior we observed in these mutated mice can be directly connected with human disease. On the other hand, we find it intriguing that members of a Canadian family carrying a mutation in the human NPAS3 gene have been reported to suffer from schizophrenia." Normal mice in a pen will climb over each other and interact, but the mice with the genetic mutations fail to socialize in this way. Instead, the mutants dart about wildly, avoiding interaction with their normal siblings.

Keyword: Schizophrenia; Genes & Behavior
Link ID: 6044 - Posted: 06.24.2010

By JANE E. BRODY Sam's parents began to suspect something was not quite right when at age 2, their son still was not walking and he said nothing that made any sense. Laboratory and neurological tests showed no abnormalities. But a genetic test revealed that Sam's cells contained an extra copy of the X chromosome. Instead of having 46 chromosomes, including one copy of each of the sex chromosomes, X and Y, the normal complement for a boy, each of Sam's cells had 47 chromosomes, with two X's and one Y, a genetic abnormality commonly called Klinefelter's syndrome. A doubling of the X chromosome, according to a government study of 40,000 infants in the 1970's, occurs once in every 500 to 1,000 male births, making it one of the most common genetic abnormalities. It is a leading genetic cause of male infertility. Yet nearly two-thirds of boys and men who have Klinefelter's do not know it, and many live out their lives never suspecting that they have an extra chromosome. As Sam's mother noted in an interview, doctors, too, are often in the dark. "None of our doctors had ever heard of it," she said. "We did a lot of research on our own." Copyright 2004 The New York Times Company

Keyword: Development of the Brain
Link ID: 6043 - Posted: 08.31.2004

By BENEDICT CAREY If only that very first bite of asparagus had inspired delight, and the first taste of jelly doughnut caused a stomachache. If children's happiest food memories were baked and not fried, leafy green rather than beefy, think of the difference in what people might eat. Now, think of what it might mean to change those memories - as an adult. Psychologists in California and Washington were studying false memories when they stumbled on a surprisingly easy target for manipulation: foods. In a study accepted for publication in the journal Social Cognition, the researchers describe how they fooled college students into thinking that as children they had become sick when eating certain foods. The students answered questions about their early eating memories. A week later, they were presented with a bogus food history profile that embedded a single falsehood - that they had gotten sick when eating pickles or hard-boiled eggs - among real memories. "This is called the false feedback technique, where you gather data from the subjects and use it to lend credibility to this false profile," said Dr. Elizabeth Loftus, a psychologist at the University of California at Irvine who led the research. Copyright 2004 The New York Times Company

Keyword: Learning & Memory
Link ID: 6042 - Posted: 08.31.2004

Sex hormones influence brain development, establishing differences between male and female brains. The hormones may do this by telling neurons in certain brain regions whether to kill themselves, according to a new study that finds that male and female brains are much more similar than usual in mice missing a cell-suicide gene. During mammalian development, testosterone and its chemical cousins give males more neurons in some brain regions and leave females with more in others. Previous work hinted that testosterone does this by triggering programmed cell death, or apoptosis, in certain regions but repressing it in others. However, other mechanisms--such as rates of cell birth, migration, or maturation--had not been ruled out. To investigate the role of apoptosis, neurobiologist Nancy Forger of the University of Massachusetts, Amherst, and her colleagues examined the brains of mice missing a gene called Bax. Previous studies had found that knocking out Bax eradicates cell death completely. The team counted cells in two forebrain regions that normally differ in male and female mice: the principal nucleus of the bed nucleus of the stria terminalis, where males normally have more neurons, and the anteroventral periventricular nucleus (AVPV), where females have more neurons. Bax deletion completely eliminated these differences, even though hormone levels in the mice were normal, the researchers report this week in the Proceedings of the National Academy of Sciences. Each of these areas must have a different molecular "switch," Forger says, so that testosterone activates apoptosis in the AVPV but represses death in the bed nucleus. Removing Bax didn't eradicate all differences between the sexes, however: Bax-less females, like their genetically normal counterparts, still had a greater proportion of dopamine-releasing neurons in the AVPV than did males. Copyright © 2004 by the American Association for the Advancement of Science.

Keyword: Sexual Behavior; Apoptosis
Link ID: 6041 - Posted: 06.24.2010

For the first time, researchers have shown a biological basis for autism IT MIGHT take only the touch of peach fuzz to make an autistic child howl in pain. The odour of the fruit could be so overpowering that he gags. For reasons that are not well understood, people with autism do not integrate all of their senses in ways that help them understand properly what they are experiencing. By the age of three, the signs of autism—infrequent eye contact, over-sensitivity or under-sensitivity to the environment, difficulty mixing with others—are in full force. There is no cure; intense behavioural therapies serve only to lessen the symptoms. The origins of autism are obscure. But a paper in Brain, a specialist journal, casts some light. A team headed by Marcel Just, of Carnegie Mellon University, and Nancy Minshew, of the University of Pittsburgh, has found evidence of how the brains of people with autism function differently from those without the disorder. Using a brain-scanning technique called functional magnetic-resonance imaging (fMRI), Dr Just, Dr Minshew and their team compared the brain activity of young adults who had “high-functioning” autism (in which an autist's IQ score is normal) with that of non-autistic participants. The experiment was designed to examine two regions of the brain known to be associated with language—Broca's area and Wernicke's area—when the participants were reading. Copyright © The Economist Newspaper Limited 2004. All

Keyword: Autism
Link ID: 6040 - Posted: 06.24.2010

By Sarah Webb Since the 19th century, neuroscientists have speculated that human emotion might be a kind of secondary sensory response: The brain translates sense data (the sight of an oncoming bus) into a physical reaction (elevated heart rate), which then triggers an emotional one (fear that bus is going to hit). Testing the theory directly is not ethically possible, but new, indirect experiments support the link between sensation and emotion. Hugo Critchley of University College London looked for signs that emotional awareness is tied to heartbeat perception in the brain. If physical reactions trigger emotion, he reasoned, people who are highly attuned to bodily processes should also be unusually sensitive. He and his collaborators tested the ability of 17 subjects to perceive whether a series of tones was synchronized with their hearts. The researches also scanned the subjects’ brain activity and later asked them to fill out a questionnaire. Subjects who more accurately judged their heartbeats tended to have greater activity in the right anterior insula, a region deep in the brain. They also reported feeling negative emotions, such as fear or anger, more deeply than the other subjects did. Stefan Wiens of Karolinska Institute in Stockholm, who helped run the study, notes that people who think they are viscerally aware often aren’t, and that those who are often do not realize it. So far, trying to teach people to recognize the timing of their heartbeats has not exactly lead to greater sensitivity. Attempts to learn, Wiens says, have tended to frustrate subjects or make them more anxious. © 2004 The Walt Disney Company.

Keyword: Emotions; Brain imaging
Link ID: 6039 - Posted: 06.24.2010

A cannabis-like substance produced by the brain may dampen delusional or psychotic experiences, rather than trigger them. Heavy cannabis use has been linked to psychosis in the past, leading researchers to look for a connection between the brain's natural cannabinoid system and schizophrenia. Sure enough, when Markus Leweke of the University of Cologne, Germany, and Andrea Giuffrida and Danielle Piomelli of the University of California, Irvine, looked at levels of the natural cannabis-like substance anandamide, they were higher in people with schizophrenia than in healthy controls. The team measured levels of anandamide in the cerebrospinal fluid (CSF) of 47 people suffering their first bout of schizophrenia, but who had not yet taken any drugs for it, and 26 people who had symptoms of psychosis and have a high risk of schizophrenia. Compared with 84 healthy volunteers, levels were six times as high in people with symptoms of psychosis and eight times as high in those with schizophrenia. "This is a massive increase in anandamide levels," Leweke told the National Cannabis and Mental Illness Conference in Melbourne, Australia, last week. And that is just in the CSF. Levels could be a hundred times higher in the synapses, where nerve signalling is taking place, he says. © Copyright Reed Business Information Ltd.

Keyword: Schizophrenia; Drug Abuse
Link ID: 6038 - Posted: 06.24.2010

By ANDREW POLLACK Eyetech Pharmaceuticals' drug to treat the leading cause of blindness in the elderly appeared to move closer to a broad government approval yesterday after an advisory panel to the Food and Drug Administration spoke favorably about it. The advisory panel was not asked to vote on whether the drug, Macugen, should be approved as a treatment for age-related macular degeneration. But committee members ruled unanimously that Eyetech had provided the F.D.A. with enough information to evaluate the drug. The panel members also did not seem to raise any serious new issues that would block approval. "It appears to me very efficacious and safe,'' Jose S. Pulido, a panel member and an ophthalmologist at the Mayo Clinic, said during the meeting, held in Rockville, Md. Copyright 2004 The New York Times Company

Keyword: Vision
Link ID: 6037 - Posted: 08.28.2004