BACKGROUND: Alcohol interferes with how brain cells communicate with one another, coordination, grogginess, impaired memory and loss of inhibitions associated with drunkenness. Yet researchers have been unable to pinpoint how alcohol causes this disruption in the brain. FINDINGS: Now scientists at the David Geffen School of Medicine at UCLA have deciphered how a naturally occurring gene mutation in rats' brains lowers the animals' tolerance to alcohol, leading to rapid and acute intoxication after the equivalent of one drink. The UCLA study is the first to identify how the gene variation alters GABA receptors -- specific sites targeted by chemicals from the brain cells -- making them more responsive to very low levels of alcohol. Alcohol enhances the GABA receptors' influence on brain cells, slowing the cells' activity and ability to communicate. IMPACT: The fact that the gene mutation arises naturally suggests that tolerance levels to alcohol may be genetically wired in people, too. If so, the findings could eventually help identify children and adults at higher risk of developing alcohol dependency, so these individuals can make an informed decision about whether to drink. The study results may also speed the development of new drugs that target alcohol-sensitive GABA receptors, leading to better treatments for alcohol poisoning and addiction.

Keyword: Drug Abuse; Genes & Behavior
Link ID: 6822 - Posted: 02.07.2005

WASHINGTON — Underscoring the value of good prenatal care, new research suggests that early infection may create a cognitive vulnerability that appears later during stress on the immune system. Researchers at the University of Colorado at Boulder have reported that rats who experienced a one-time infection as newborns didn’t learn as well as adult rats who were not infected as pups, after their immunity was challenged. The research is in February’s Behavioral Neuroscience, published by the American Psychological Association (APA). The findings fit into a growing body of evidence that even a one-time infection can potentially permanently change physiological systems, a phenomenon called “perinatal programming.” Understanding how infection in newborns can disrupt memory in immune-challenged adults may help scientists to understand how exposure to germs or environmental stressors before or just after birth may foster susceptibility to neuropsychiatric and neurodegenerative diseases. For example, prenatal viral infection has been implicated in schizophrenia, autism and cerebral palsy; bacterial infection is a risk factor for Parkinson’s disease. Up to 20 percent of pregnancies have complications involving infections of the uterus and its contents, a number that will rise as more children are born premature. © 2005 American Psychological Association

Keyword: Neuroimmunology; Learning & Memory
Link ID: 6821 - Posted: 06.24.2010

Stroke survivors who stop taking their daily prescription of aspirin triple the risk of another stroke within a month, research suggests. Aspirin has been shown to cut the risk of recurrent stroke by about 25%. But Swiss research suggests the protective effect is rapidly lost when aspirin is no longer taken. If confirmed, the findings may prompt a rethink of the current advice that patients stop taking aspirin in the days before undergoing minor surgery. Each year in England and Wales, more than 130,000 people have a stroke and, of these, more than 53,000 are recurrent strokes. The researchers say their work underlines the importance of complying with therapy. The Swiss researchers focused on 309 patients who had a stroke or a mini-stroke - known as a transient ischemic attack (TIA) - and later went on to suffer a further episode. All of this group had at least inititally been put on long-term aspirin therapy. The researchers said they found that in 13 cases the patients had stopped taking their aspirin in the four weeks leading up to their latest stroke. To find out how significant this was, the researchers found another group of 309 stroke patients, who had also been prescribed aspirin but this time had not suffered a recurrent stroke. In this group, just four patients admitted they had stopped taking their pills during the four weeks surveyed. From this the researchers, who presented their findings at a conference of the American Stroke Association, calculated that stopping aspirin therapy increased the short term risk of a recurrent stroke by more than three times. However, they admit more work is needed to firm up their conclusions. (C)BBC

Keyword: Stroke
Link ID: 6820 - Posted: 02.05.2005

Two-time Super Bowl linebacker Lionel Aldridge hallucinates himself into homelessness. The famous Russian dancer Vaslov Nijinsky swaps the stage for an institution. Nobel Prize winning mathematician John Nash hears strange voices that bring his work to a near halt. Miles and professions apart, these men have or had one thing in common: all were all ensnared in worlds where the fear and disordered thought that accompanies schizophrenia permanently altered their lives. Much is still unknown about the disease but for the first time scientists have identified a fault in schizophrenics' brain waves at a frequency called the gamma range—it cycles at between 30 to 100 brain waves per second—where healthy brains piece together perceptions. "We think this means that [schizophrenics] have a decreased deficiency of communication in between brain areas," says Robert McCarley, chair of the Harvard psychiatry department and chief of staff for mental health services at the VA Boston Healthcare System. "We see gamma as evidence that the brain is putting together all of these individual sensations to make a single perception. None of the other brain frequencies are involved in this process." McCarley, along with neuroscientist Kevin Spencer, also of the VA Boston Healthcare System and Harvard University, believe that this disturbance could explain what's behind particular symptoms in schizophrenics, including disordered thought and hallucinations. To look more closely at how gamma works in the brain, McCarley and Spencer used electroenchephalography (EEG) recordings that measure the electrical communication between nerve cells. Existing research had already shown that identifying a square shape elicited signals picked up in the gamma range, so the two recorded brain waves in twenty male schizophrenics and twenty healthy males, matched for age, education and parents' social status, as the groups were shown images and asked to press a button when they thought they saw a square. © ScienCentral, 2000- 2005.

Keyword: Schizophrenia
Link ID: 6819 - Posted: 06.24.2010

Biologists at Lehigh University and the University of Maryland have identified a cricket living in Hawaii's forests as the world's fastest-evolving invertebrate. Finicky mating behavior appears to be the driving force behind the speedy speciation of the Laupala cricket, the scientists wrote in the Jan. 27 issue of Nature magazine. Females in the Laupala genus detect tiny differences in the pulse rates of male courtship songs, which differ from one Laupala species to the next. They refuse to mate with males of other species, thus promoting the formation of new species. The scientists say their findings shed light on the role of individual choices in the evolution of species and the growth of biodiversity. "Animals with nervous systems and brains have preferences and can make choices," says Tamra Mendelson, an evolutionary biologist at Lehigh. "Changes in these preferences and choices appear to drive speciation. "That raises the question: Can something seemingly so individual as a choice have macro-evolutionary consequences in terms of increasing biodiversity? If so, this affects how life on the planet looks. The more species you have, the more complex the ecology is going to be."

Keyword: Sexual Behavior; Evolution
Link ID: 6818 - Posted: 02.05.2005

David Shiga Doctors could soon have a definitive diagnostic test for Alzheimer's disease, thanks to some tiny but sophisticated sensors. These nanoscale particles isolate extremely small quantities of protein clumps associated with the neurodegenerative disease. The researchers tested cerebrospinal fluid, which bathes the spinal cord and parts of the brain. They took samples from 15 people confirmed after death to have had the brain plaques characteristic of Alzheimer's disease and from 15 people who were free of the disease. The samples were collected from living people as well as from individuals who had died. With two exceptions, patients who might have been misdiagnosed, the nanoparticle test distinguished the two groups by detecting the prevalence of protein clumps called amyloid beta–diffusible ligands (ADDLs) in the Alzheimer's patients, the researchers say. ADDLs are "invisible to conventional neuropathology, but their presence or absence may be the real determinants of memory loss," says team member William L. Klein of Northwestern University in Evanston, Ill. For the test, Dimitra G. Georganopoulou, also of Northwestern, and her colleagues used iron particles coated with antibodies that stick to ADDLs. They mixed the iron particles into each sample and later used a magnetic field to extract them. The particles dragged along any ADDLs in the sample. Copyright ©2005 Science Service.

Keyword: Alzheimers
Link ID: 6817 - Posted: 06.24.2010

COLUMBUS, Ohio – A new study suggests that people with autism may perform unusually well on some tests of visual processing. The researchers found that autistic people were less likely than others to have false memories about images they had seen earlier. The researchers had previously demonstrated this kind of effect with verbal material, but not with visual material. In this case, the results suggest that the autistic people had trouble seeing the images in context – a hallmark of the disorder. The study's findings point out that the effects of autism may be more general than researchers once thought. "We thought that the effects of autism might go beyond language problems – that it affects different areas of the brain," said David Beversdorf, a study co-author and an assistant professor of neurology at Ohio State University. In 2000, he led a similar study that looked at the effect of autism on language. "We wanted to see if we'd get similar results with a visual model, and we did." Beversdorf and his colleagues presented their findings on February 4 in St. Louis at the annual meeting of the International Neuropsychological Society. The researchers tested a total of 28 adults, 14 of whom were high-functioning autistics – these participants could verbalize their thoughts (people with severe forms of autism often can't or don't speak.)

Keyword: Autism
Link ID: 6816 - Posted: 06.24.2010

RESTON, Va.--Scientists have demonstrated a new way to assess the potentially damaging effects of prenatal drug exposure--a technique that could also be used to monitor a fetus's response to therapeutic drugs--using sophisticated, noninvasive medical imaging tools. Scientists at the U.S. Department of Energy's Brookhaven National Laboratory, whose findings are reported in the February issue of the Society of Nuclear Medicine's Journal of Nuclear Medicine, used positron emission tomography (PET) combined with magnetic resonance imaging (MRI) to track the uptake and distribution of trace amounts of cocaine in pregnant monkeys and found significant differences in where and how fast the drug accumulates in maternal and fetal organs. "Understanding how drugs are transferred between a mother and her fetus during pregnancy may help us unravel the mechanisms of the drug's damaging effects on unborn children," said SNM member Helene Benveniste, M.D., Ph.D., chair of Brookhaven's medical department in Upton, N.Y., and lead author of the paper, "Maternal and Fetal 11C-Cocaine Uptake and Kinetics Measured In Vivo by Combined PET and MRI in Pregnant Nonhuman Primates." "While studies that follow human drug abusers and their children over decades provide valuable information, animal studies can more quickly provide clues to the underlying mechanisms of damage and suggest ways to test new treatment or prevention strategies," said Benveniste.

Keyword: Drug Abuse; Development of the Brain
Link ID: 6815 - Posted: 02.05.2005

Michael Hopkin The evolutionary biologist Ernst Mayr died on 3 February at the age of 100, after a short illness. A hugely prolific writer and researcher, he was instrumental in developing modern ideas in evolutionary theory. As an ornithologist, Mayr classified many birds, most notably risking the hostile terrain of New Guinea to catalogue the region's birds of paradise. But he will arguably be best remembered for formulating the concept of species that students still use today. It was Mayr who defined a species as a group of individuals that are capable of breeding with one another, but not with others outside the group. This led to the idea that new species can arise when an existing species becomes separated into two populations that gradually become too distinct to interbreed; it was an answer to a biological conundrum that had eluded Charles Darwin. Born in Bavaria, Germany, on 5 July 1904, the young Mayr was fascinated with wildlife but, at 20, was set to enter the medical profession. When offered the chance to visit the tropics to study birds, he completed a PhD in just 16 months before taking up a position at the Berlin Museum in 1926, from which sprang his work in New Guinea. ©2005 Nature Publishing Group

Keyword: Evolution
Link ID: 6814 - Posted: 06.24.2010

Roxanne Khamsi As people grow older, their vision can actually get better in some ways, according to a Canadian study. The findings suggest that neurological changes could help the elderly to spot small motions in otherwise uniform scenes. Part of visual processing in the human brain involves cells that suppress each other's activity. This allows the mind to focus on a scene's important features while ignoring trivial regions. But as people age, these inhibitory interactions seem to weaken. To explore the effects of this change, researchers tested people between 18 and 31 years old, and others aged 60 and above. Subjects viewed a computer screen showing moving, vertical black-and-white stripes. They then had to decide in which direction the bands were travelling. Previous studies have shown that, as the number of stripes in view increases, young people become much worse at identifying their movement. Scientists think that the stripes' large, stark borders activate the brains inhibitory mechanisms. The mind starts disregarding these monotonous forms. ©2005 Nature Publishing Group

Keyword: Vision
Link ID: 6813 - Posted: 06.24.2010

Katherine Seligman, Chronicle Staff Writer California's mysterious explosion of autism cases worsened in 2004, disappointing researchers who had hoped the number of new diagnoses would level off as they searched for an explanation for the neurological disorder. The number of people treated for autism at regional centers operated by the state Department of Developmental Services increased 13 percent last year from 2003, according to agency figures. Autism now accounts for a little more than half of the new cases handled at the centers, which treat a variety of developmental problems. An average of nine new autism cases a day come to the state's attention, the vast majority in children 13 and younger. Scientists have various theories, but there is little agreement about what is driving the growth of autism cases in California. The number of autistic people getting services at the centers has increased from 5,000 in 1993 to more than 26,000 now. "I'm really worried," said Jim Burton, head of the state-funded Regional Center for the East Bay, which provides treatment referrals and services for people with autism. "The burden is huge, and it's going to strain all our resources." ©2005 San Francisco Chronicle

Keyword: Autism
Link ID: 6812 - Posted: 06.24.2010

By BARNABY J. FEDER The Food and Drug Administration said yesterday that it might permit an implantable electrical device for the treatment of epilepsy made by Cyberonics to also be marketed as a therapy for chronic depression that is resistant to other treatments. The agency set a number of conditions on the tentative approval, and Cyberonics said it hoped to meet them before the end of May. Cyberonics, based in Houston, said 4.4 million Americans suffer the severe and recurring forms of depression that might be treated with the $15,000 device, more than 10 times the number who might use it to reduce or eliminate epileptic seizures. "If it is adopted for depression at the same rate as it has been for epilepsy, we will pass $1 billion in sales by 2010," said Robert P. Cummins, the chairman, chief executive and president of the company. Shares of Cyberonics rose $11.53, or nearly 42 percent, to $39.01 in heavy trading. Cyberonics lost $4.93 million on sales of $50.57 million in the first half of the current fiscal year, which ends in April. Copyright 2005 The New York Times Company

Keyword: Depression
Link ID: 6811 - Posted: 02.04.2005

By BENEDICT CAREY In the wake of a yearlong debate over the risks of antidepressants to minors, an analysis of World Health Organization medical records has found that infants whose mothers took the drugs while pregnant may suffer withdrawal symptoms. The study challenges the assurances that many doctors have long given pregnant women with depression that taking the drugs would not affect their babies. But experts said that the study, appearing today in the journal Lancet, was not definitive and must be weighed against the benefits of drug treatment. Untreated maternal depression can also harm a developing fetus, the experts said, and may lead to lasting childhood problems; all of the infants in the study recovered completely from withdrawal symptoms within 24 hours. "This study is important in that it gives us a red flag that babies exposed to antidepressants during pregnancy should be closely observed, and may go through unusual behaviors at first," said Dr. Timothy Oberlander, a developmental pediatrician at the University of British Columbia. Dr. Oberlander was not involved in the research and does not conduct research or act as a consultant for pharmaceutical companies. Some 10 percent to 15 percent of women suffer bouts of depression during the hormonal chaos of pregnancy, and about a quarter of those women get antidepressant treatment, doctors estimate, usually with drugs like Prozac, Paxil and Zoloft. If not treated, these women may also be at increased risk of postpartum depression, a devastating disorder that not only clouds the relationship between mother and child but can also interfere with the child's social development, according to Dr. Janet DiPietro, a professor at the Johns Hopkins School of Public Health. Copyright 2005 The New York Times Company

Keyword: Depression; Development of the Brain
Link ID: 6810 - Posted: 02.04.2005

Recent evidence suggesting that antidepressants may act by triggering the birth of new neurons in the adult hippocampus, the brain's memory hub, has heightened interest in such adult neurogenesis and raised the question: Could new neurons also be sprouting up in the parts of the adult brain involved in the thinking and mood disturbances of depression and anxiety? Now, scientists at the National Institute of Health's (NIH) National Institute of Mental Health (NIMH) have found newly born neurons that communicate via the chemical messenger GABA (gamma-aminobutyric acid) in adult rat cortex, seat of higher order "executive" functions, and in the striatum, site of habits, reward and motor skill learning. In the cortex, the new neurons appear to arise from previously unknown precursor cells native to the area, rather than from cells migrating in from another area. NIMH's Drs. Heather Cameron, Alexandre Dayer, and colleagues, report on their findings in the January 31, 2005 Journal of Cell Biology. Their discovery adds to the scientific debate over adult neurogenesis, which has potential implications for understanding a variety of brain disorders, possibly including Alzheimer's and schizophrenia. While most researchers agree that new neurons are generated in the adult hippocampus and olfactory bulb, the existence of adult neurogenesis in other brain regions remains controversial.

Keyword: Neurogenesis
Link ID: 6809 - Posted: 02.04.2005

A study led by Princeton biologists has revealed a remarkably simple mechanism that allows flocking birds, schooling fish or running herds to travel in unison without any recognized leaders or signaling system. The finding, published in the Feb. 3 issue of Nature, helps settle age-old questions about how animals coordinate their actions. Previously, scientists had looked for subtle signals or other explicit systems that animals may use in disseminating information through groups. The new study showed that such complexity is not necessary: Large groups easily make accurate decisions about where to go even when no individuals are regarded as leaders and very few individuals have any pertinent information. In addition to shedding light on the graceful coordination of animal groups, the results may be useful in understanding how humans behave in crowds and in designing robots that explore remote locations such as the ocean or other planets. "When you see apparently complex behaviors, the mechanisms that coordinate these behaviors may be surprisingly simple and generic," said Iain Couzin, a postdoctoral researcher in Princeton's Department of Ecology and Evolutionary Biology and lead author of the study.

Keyword: Animal Migration
Link ID: 6808 - Posted: 02.04.2005

Dyslexia can impair a driver's reactions as much as a moderate drinking session. That is the conclusion of a small study which compared how quickly dyslexic and non-dyslexic drivers react to traffic signs. Those with dyslexia, which is characterised by difficulties with reading and writing, took on average 30% longer to react. The controversial finding will raise questions about whether people with dyslexia should have extra tests before being allowed behind the wheel. Drivers just over the UK's alcohol limit, which can be exceeded by drinking two pints of beer, are typically 10% slower than normal to react. In the study, Hermundur Sigmundsson at the Norwegian University of Science and Technology in Trondheim gave 17 volunteers, six of whom were dyslexic, two different tests. The first involved a 4-minute drive along a simulated country road at 50 to 80 kilometres per hour. In the second task, the volunteers drove through a city at lower speeds for 10 minutes. The simulator flashed up traffic signs in the drivers' field of view and measured how quickly they responded by pushing a button or saying "now". In the rural drive, the signs appeared directly ahead, while in the city they appeared in a variety of places. © Copyright Reed Business Information Ltd.

Keyword: Dyslexia
Link ID: 6807 - Posted: 06.24.2010

While its causes are many, stuttering used to carry with it the stigma of being a "psychological problem." Now, researchers are finding that stutterers' brains process language differently, even when they aren't speaking. "Stuttering is known to be a very complex disorder, and there has been evidence that language plays an important role in stuttering," explains Christine Weber-Fox, a cognitive neuroscientist at Purdue University. "For example, when children begin stuttering it's not when they're saying their first word, it's when they start combining words, and when language becomes more complex and they're having to formulate more. So we were very interested in knowing the role of language processing in stutterers, even when people who stutter aren't required to speak at all." Weber-Fox and her team compared the brain activity of 22 adults, half stutterers and half non-stutterers, measuring the activity of brain cells in milliseconds using what looks like a wired-up swimming cap with electrodes that sit on the scalp. The adults were shown two words on a computer screen, and their job was to identify—silently, by pressing a button—which pairs of words rhymed. Some word pairs, like "own" and "gown," were spelled similarly but did not rhyme; some, like "own" and "cone," rhymed but were not spelled similarly, and some, like "own" and "cake," neither rhymed nor were spelled similarly. © ScienCentral, 2000- 2005.

Keyword: Language
Link ID: 6806 - Posted: 06.24.2010

Could a chemical cousin of antifreeze someday help people with spinal cord injuries walk again? Researchers at Purdue University are studying this in dogs with paralyzed hind legs. They injected 19 injured dogs with a drug called polyethylene glycol (PEG)—a nontoxic liquid polymer related to antifreeze—on top of providing them with the standard drugs, surgery and rehab, and showed that PEG targets damaged nerve cells, protecting some of the injured cells from progressive damage and death. "The dogs that come in that receive conventional management, that is, just surgery and rehabilitation, about 15 to 20 percent of those dogs will have some quality of life just through spontaneous repair," says Richard Borgens, director of Purdue University Center for Paralysis Research, who reported his findings in the Journal of Neurotrauma. "But most of them, about 80 percent, will remain paraplegic for the rest of their lives. What this [PEG] compound does when we inject it is it reverses those odds, it really goes from about 20-80 to 80-20; about 80 percent are leading very normal lives, good quality of life, and only about 20 percent have any kind of real problem at the end of the study time, which was, we followed them out to about a year." In the study, 13 of the 19 dogs (about 68 percent) injected with PEG regained use of their hind legs and were able to walk within eight weeks. The dogs were injected twice—when they were brought into the lab (within three days of their injuries), and then after standard surgery and steroids to reduce inflammation. In a group of 24 dogs that only received the standard treatment, only about 25 percent regained a similar level of mobility and 62 percent remained paraplegic. © ScienCentral, 2000- 2005.

Keyword: Regeneration
Link ID: 6805 - Posted: 06.24.2010

Among the principal obstacles to regenerating spinal cord and brain cells after injury is the "braking" machinery in neurons that prevents regeneration. While peripheral nerves have no such machinery and can readily regenerate, central nervous system (CNS) neurons have their brakes firmly in place and locked. Now, two groups of scientists have independently found a new component of that braking machinery, adding to understanding of the regulation of neuronal regeneration and of possible treatments to switch off the brakes on regrowth of spinal cord or brain tissue. The two groups--one group led by Jong Bae Park, Glenn Yiu, and colleagues from Children's Hospital Boston and the other led by Sha Mi and colleagues of Biogen Idec, Inc.--discovered that a protein variously called TAJ or TROY acts as an important part of the receptor on neurons that responds to growth-inhibitory molecules in myelin. Specifically, these molecules prevent the growth of the cablelike axons of injured neurons. Myelin is the fatty sheath that encases neurons and acts as an insulator and aid to the transmission of nerve impulses. Researchers knew that CNS neurons had receptors on their surface that accepted the inhibitory molecules--like a key fitting a lock--and switched-on inhibitory signaling within the neuron. They had also shown that a protein called p75 could function as a component of the complex of proteins that make up this receptor. The puzzle, however, was that p75 is not widely made in the adult neurons in which this inhibitory receptor complex is known to function.

Keyword: Regeneration
Link ID: 6804 - Posted: 02.03.2005

Researchers have discovered an important chemical in the brain's neuronal machinery that triggers some of the withdrawal symptoms of opioid drugs like morphine and heroin. They believe that drugs to inhibit the chemical--called a transporter--could relieve some of the early physical symptoms of withdrawal, such as teeth-chattering, uncontrolled shaking, and jumpiness. Such drugs could become part of the arsenal of medicines and behavioral techniques aimed at helping addicts kick their habits. To zero in on the machinery underlying withdrawal symptoms, researchers led by Elena Bagley and Macdonald Christie of the Pain Management Research Institute at Royal North Shore Hospital (a division of the University of Sydney) performed biochemical studies on brain slices from mice that had been treated with morphine. Their objective was to understand what happens to a particular region of the midbrain--called the periaqueductal gray (PAG)--known to be involved in such withdrawal symptoms. Opiate addiction inhibits neuron activity in this region, which alters the neuronal machinery to compensate for this inhibition. Upon opiate withdrawal, the neurons rebound, becoming hyperactive. The scientists' analysis revealed that a transporter molecule for the neurotransmitter GABA was responsible for the electrical abnormalities that produce a hyperexcitability in the neurons. Neurotransmitters are the molecular ammunition that one neuron fires at its neighbor to trigger a nerve impulse in the neighbor. Propagation of such nerve impulses through the networks of neurons in the brain is the basis of all neural activity. Transporter molecules are the proteins that retrieve neurotransmitter molecules from the spaces between neurons after they trigger nerve impulse, to reload the neuron for its next signaling burst.

Keyword: Drug Abuse; Pain & Touch
Link ID: 6803 - Posted: 02.03.2005