Tina Hesman Saey Peter Pan won't be pleased to hear the latest theory about how Prozac works. A new study shows that the antidepressant stimulates growth of neurons in the hippocampus and speeds the young brain cells toward maturity. The maturation process could be the mechanism by which the drug relieves depression. Fluoxetine, the drug commonly known as Prozac, has been used to treat depression since the 1980s. Prozac and other SSRIs (selective serotonin reuptake inhibitors) block the ability of the neurons to take up serotonin, thereby raising levels of the active neurotransmitter in the brain. When people with depression begin taking such drugs, serotonin levels in the brain increase rapidly, but it often takes 2 to 4 weeks before they begin to feel better. The new study, published Feb. 6 in the Journal of Neuroscience, suggests that the lag is due to the time it takes for serotonin to stimulate new neurons to grow, mature, and integrate into brain circuits. René Hen, a neuroscientist at Columbia University, and his colleagues tested the long-term effects of Prozac treatment on a specially bred strain of nervous mice. Inside the brains of mice treated with Prozac, the researchers found many more newborn neurons in the dentate gyrus of the hippocampus, a part of the brain involved in learning and memory. ©2008 Society for Science & the Public.

Keyword: Depression; Neurogenesis
Link ID: 11297 - Posted: 06.24.2010

By Robynne Boyd The human brain is complex. It enables concertos to be composed, manifestos made, and equations solved elegantly. It's also the wellspring of feelings, behaviors, experiences and the repository of memory. So it's no surprise that the brain remains a mystery. Adding to that mystery is the contention that humans "only" employ 10 percent of their brain. If only regular folk could tap that other 90 percent they too could become savants who remember pi to the 20,000th decimal place or perhaps even a psychic. Though an alluring idea, the "ten percent myth" is so wrong it is almost laughable, says neurologist Barry Gordon at Johns Hopkins University in Baltimore. While there’s no definitive culprit to the beginning of this legend, the notion has been linked to the American psychologist and author William James, who argued in The Energies of Men that “We are making use of only a small part of our possible mental and physical resources.” It's also been linked to Albert Einstein, who supposedly used it to explain his cosmic intellect. The myth's durability, Gordon says, stems from people's conceptions about their own brains: their own shortcomings demonstrate the existence of untapped gray matter. This is false. What is correct however, is that at certain moments in anyone's life, such as when we are simply sitting and thinking, we may be using only 10 percent of our brain. © 1996-2007 Scientific American Inc.

Keyword: Miscellaneous
Link ID: 11296 - Posted: 06.24.2010

James Owen Those who struggle to get out of bed in the morning may be able to hold their genes responsible, new research suggests. Scientists have discovered that a person's waking habits are mirrored by body cells that are equipped with their own daily alarm clocks. The work represents the first internal look at the biological clocks of those suffering from sleeping disorders, said study leader Steven A. Brown of the Institute for Pharmacology and Toxicology at the University of Zurich, Switzerland. "One of the big surprises was that so much of our daily behavior was genetically encoded," Brown said. "The idea that skin cells are telling us anything about our behavior was, for me, quite fascinating," he added. The study investigated the circadian rhythm—the brain-controlled phenomenon that governs various body functions over a 24-hour period—of extreme late and early risers. Suitable volunteers were recruited by the study team using TV advertisements shown between 3 a.m. and 4 a.m. "We got both our early types and our late types that way," Brown said. "Some had not yet gone to bed, while others were already up." Skin cells taken from the volunteers were cultured in the lab and injected with a bioluminescence gene found in fireflies. © 1996-2008 National Geographic Society

Keyword: Biological Rhythms; Genes & Behavior
Link ID: 11295 - Posted: 06.24.2010

Patients with a certain gene variant drank less and experienced better overall clinical outcomes than patients without the variant while taking the medication naltrexone, according to an analysis of participants in the National Institutes of Health's 2001-2004 COMBINE (Combined Pharmacotherapies and Behavioral Interventions for Alcohol Dependence) Study. About 87 percent of patients with the variant who received naltrexone experienced good outcomes, compared with about 49 percent of those who received a placebo. About 55 percent of patients without the variant experienced a good outcome regardless of whether they received naltrexone or placebo. Good outcome was defined as abstinence or moderate drinking without related problems, according to an article in the Feb. 4 issue of the Archives of General Psychiatry (http://archpsyc.ama-assn.org/cgi/content/abstract/65/2/135). Drinking alcohol increases the release of endogenous opioids, compounds that originate in the body and promote a sense of pleasure or well-being. An opioid antagonist, naltrexone blocks brain receptors for endogenous opioids, making it easier for patients to remain abstinent or stop quickly in the event of a slip. In clinical studies, naltrexone has been shown to reduce relapse and craving for alcohol in some but not all treated patients. Earlier studies had suggested that a specific DNA variant of the opioid receptor gene (OPRM1) might have role in patients' response to naltrexone. "Analysis of the large COMBINE patient population increases confidence that the OPRM1 variant is in part responsible for positive responses to naltrexone." said National Institute on Alcohol Abuse and Alcoholism (NIAAA) director Ting-Kai Li, M.D.

Keyword: Drug Abuse; Genes & Behavior
Link ID: 11294 - Posted: 02.08.2008

By Elizabeth Quill Johann Sebastian Bach, Edgar Allan Poe, and Albert Einstein all married cousins. Maybe these creative geniuses were on to something. A new study suggests that mating with relatives has reproductive advantages. Many societies regard inbreeding as taboo. Research seems to back this up, showing that children of related couples are more likely to inherit two copies of disease-causing recessive genes. Other work, however, has shown a positive outcome--namely, that married cousins have more children. But those studies--carried out in India and Pakistan--have not been conclusive because the data are hard to disentangle from social and economic factors. For example, poorer women tend not only to marry relatives but also to marry at a younger age, leaving more time to have children. Geneticist Kári Stefánsson and colleagues at deCODE Genetics, a biopharmaceutical company based in Reykjavik, Iceland, decided to look at couples in their own country. Social and economic factors are more uniform in Iceland because the income gap is not wide and there is little variation in family size, use of contraceptives, or marriage practices. In addition, because deCODE already had a genealogical database for all of Iceland going back 1000 years, Stefánsson says, the team just needed to do some calculations. After determining the relationships between all known Icelandic couples born between 1800 and 1965, they compared the number of children and grandchildren descended from these couples. © 2008 American Association for the Advancement of Science.

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 11293 - Posted: 06.24.2010

Becoming overweight as a child is more likely to be the result of your genes than your lifestyle, claims a study. University College London researchers examined more than 5,000 pairs of identical and non-identical twins. Their American Journal of Clinical Nutrition study found that differences in body mass index and waist size were 77% governed by genes. An anti-obesity group said regardless of genes, a balanced diet and exercise were vital to good health. Children who are overweight are likely to be overweight or obese in adulthood, raising the risk of certain cancers, heart disease, stroke and diabetes later in life. However, despite the emergence of some possible genes that contribute to obesity, there is still debate as to the extent to which we are pre-programmed to be overweight by our genetic makeup. The study, from the Cancer Research UK Health Behaviour Research Centre at UCL, goes some way to answering that question. Twin studies are a good way to test how far our genes or our environment influence our development. Identical twins have exactly the same genes, while non-identical twins are genetically different, like brother and sister. However, because they were born at the same time, and raised in the same household, they can be assumed to have roughly similar upbringing in terms of food. (C)BBC

Keyword: Obesity; Genes & Behavior
Link ID: 11292 - Posted: 02.07.2008

Doctors hope to use the body's own nerves to bridge the gap in the spinal cord left by paralysing injuries. Marie Filbin, from the City University of New York, took a nerve leaving the spine just above an injury, and reattached it below. New Scientist magazine reports that rats used in the experiment showed some signs of renewed movement. A UK expert said the injury location could govern whether a suitable nerve was available for surgery. An injury that breaks or severely damages the spinal cord can cause permanent disability, with the extent set by exactly how far down the spine the damage has happened. Scientists are hunting for ways to repair that damage, including using growth-promoting chemicals to encourage healing across the 'gap', and grafts of nerve fibres from elsewhere in the body. The New York approach is slightly different - it takes one of the nerves that naturally leaves the spinal column, disconnects it from its destination, then plugs it back into the spinal cord using a protein "glue". In the case of the rats, this was a nerve heading for the abdominal muscles, which was taken just above a break in the spinal cord, and reattached below. After just two weeks, it became clear that the new arrangement was working, with the nerve growing and starting to form connections with its new neighbour. Sending electrical impulses down the spinal cord caused twitching in the lower limbs, again indicating that connections had been made. There were no ill-effects in the abdominal muscle, as other nerves connected to it compensated for the loss of one connection. (C)BBC

Keyword: Regeneration
Link ID: 11291 - Posted: 02.07.2008

By Roni Caryn Rabin When Benjamin Kidd was in pre-K last year, his teachers marveled at how bright, attentive and well-behaved he was — in the morning. Later in the day, Ben was a different child. He was fidgety and he couldn’t focus. He couldn’t sit still for a story. And he burst into tears and temper tantrums at the slightest provocation. After taking him to one specialist after another, his mother, Michelle Kidd, who lives in Hillsborough N.J., finally figured out what the problem was: 5-year-old Ben was exhausted. Doctors who ran an overnight sleep study on him last fall said he was suffering from obstructive sleep apnea, a sleep disorder associated with middle age but not uncommon in preschoolers, where it can lead to behavior easily mistaken for hyperactivity — even though it’s actually caused by fatigue. “You know how it is when you let your kid stay up too late, and they’re bouncing off the walls and don’t listen?” says Kidd, who had consulted physicians at the Somerset Medical Center’s Sleep for Life Center in Hillsborough. “It was a lot of that.” © 2008 Microsoft

Keyword: ADHD; Sleep
Link ID: 11290 - Posted: 06.24.2010

Jim Giles AN INAPPROPRIATE analysis of clinical trial data by researchers at GlaxoSmithKline obscured suicide risks associated with paroxetine, a profitable antidepressant, for 15 years, suggest court documents (897kb, requires Acrobat Reader) released last month. Not until 2006 did GSK alert people to raised suicide risks associated with the drug, marketed as Paxil and Seroxat. “Not until 2006 did GlaxoSmithKline alert people to raised suicide risks associated with Paxil/Seroxat”An analysis of internal GSK memos and reports, which were released to US lawyers seeking damages, suggests that the company had trial data demonstrating an eightfold increase in suicide risk as early as 1989. Harvard University psychiatrist Joseph Glenmullen, who studied the papers for the lawyers, says it's "virtually impossible" that GSK simply misunderstood the data - a claim the company describes as "absolutely false". Glenmullen's report rests on documents obtained by lawyers in Los Angeles, who are bringing around 30 cases against GSK linking suicides and suicide attempts to the use of Paxil. The report was under seal at a district court in Sacramento, California, until 18 January, when the judge agreed to make parts of it public. © Copyright Reed Business Information Ltd.

Keyword: Depression
Link ID: 11289 - Posted: 06.24.2010

Heidi Ledford The brain protein plaques characteristic of Alzheimer’s disease can form extraordinarily fast, and seem to be the starting point of further degeneration in the brain — at least in mice. The results, published today in Nature1, help to settle a long-standing debate about whether such plaques are a primary cause or a symptom of Alzheimer's, and may have implications for how the disease is treated. "It’s a very exciting story," says Dennis Selkoe of Brigham and Women’s Hospital in Boston, Massachusetts, who has worked in the past with the research team involved. The chicken-and-egg question about which comes first — protein plaques or damaged brain cells — has been "argued about for decades", he says. The argument has centred on clumps of a protein called amyloid-â that accumulate in the brains of patients with Alzheimer’s disease. These protein plaques are surrounded by abnormal neurons and immune cells called microglia. Previous work in mice has suggested that amyloid plaques were critical to development of Alzheimer's disease, but researchers debated whether the plaques were a primary cause of the disease. It wasn’t clear whether the plaques recruited microglia, or if the microglia caused the plaques, says Selkoe. © 2008 Nature Publishing Group

Keyword: Alzheimers
Link ID: 11288 - Posted: 06.24.2010

Mobile phone use does not raise the risk of brain tumours, a Japanese study suggests. The research is the first to look at the effects of hand set radiation levels on different parts of the brain. Tokyo Women's Medical University found no increased risk of the three main types of brain cancer among regular mobile phone users. The study, comparing 322 brain cancer patients and 683 healthy people, appears in British Journal of Cancer. The cancer patients had one of the three most common types of brain tumour - glioma, meningioma or pituitary adenoma. The researchers rated each subject according to how many years they had been using a mobile phone, and how long they spent talking on it each day. They studied the radiation emitted from various types of mobile phone, and placed them into one of four categories relating to radiation strength. And they also analysied how each phone was likely to affect different areas of the brain. Lead researcher Professor Naohito Yamaguchi said: "Using our newly developed and more accurate techniques, we found no association between mobile phone use and cancer, providing more evidence to suggest they don't cause brain cancer." (C)BBC

Keyword: Miscellaneous
Link ID: 11287 - Posted: 02.06.2008

By JEFF BELL FOR some of us the trouble starts before we even step into a restaurant. Some might find themselves separating the salt and pepper shakers or worrying whether the cutlery is clean enough. If Carole Johnson, a retired school administrator who lives near Sacramento, Calif., happens to have a distressing thought while passing through a doorway, she needs to “clear” the thought by passing through the door twice more, doing it precisely three times. My own challenge is fighting the urge to return to my parked car and check yet again that the parking brake is secure. If I don’t, how can I be sure my car won’t roll into something — or worse, someone? Ms. Johnson and I are but two of the estimated five to seven million Americans battling obsessive-compulsive disorder, an anxiety disorder characterized by intrusive distressing thoughts and repetitive rituals aimed at dislodging those thoughts. We are an eclectic bunch spanning every imaginable cross-section of society, and we battle an equally eclectic mix of obsessions and compulsions. Some of us obsess about contamination, others about hurting people, and still others about symmetry. Almost all of us can find something to obsess about at a restaurant. Copyright 2008 The New York Times Company

Keyword: OCD - Obsessive Compulsive Disorder
Link ID: 11286 - Posted: 06.24.2010

CHICAGO - Brain scans of people in chronic pain show a state of constant activity in areas that should be at rest, U.S. researchers said on Tuesday, a finding that could help explain why pain patients have higher rates of depression, anxiety and other disorders. They said chronic pain seems to alter the way people process information that is unrelated to pain. “It seems that enduring pain for a long time affects brain function in response to even minimally demanding attention tasks completely unrelated to pain,” the researchers wrote in the Journal of Neuroscience. Dante Chialvo, a researcher at Northwestern University in Chicago who worked on the study, said: “People with chronic pain — meaning pain that lasts more than six months after their injury — have many other issues that affect their quality of life as much as pain. It is not known where they come from.” Recent studies have shown that in healthy people, certain regions of the brain take over during a resting state, something known as a default mode network. “It takes care of your brain when your brain is at rest,” Chialvo said in a telephone interview. Copyright 2008 Reuters.

Keyword: Pain & Touch
Link ID: 11285 - Posted: 06.24.2010

Men are more rewarded by video games than women on a neural level, which explains why they're more likely to become addicted to them, researchers at Stanford University claim. In a brain-imaging study by Stanford's school of medicine, researchers discovered that, when playing video games, the part of the brain that generates feelings of reward is more stimulated in men than in women. That helps explain why they're more likely to get hooked, the study's authors say. Men have more activity in their mesocorticolimbic centre, the region of the brain researchers say is associated with reward and addiction, than women. (Associated Press/Jim Mone) The researchers, whose work was recently published online in the Journal of Psychiatric Research, created a video game where a vertical line, or a "wall," divided the middle of the screen. Ten balls would appear at the right of the screen and move toward the wall, and test participants would have to click on them before they hit. If the balls were clicked on before they hit the wall, the player would gain territory; if the player missed, space would be lost. The test subjects — 11 men and 11 women — were told to click on as many balls as possible but were not told that they would win or lose territory. © CBC 2008

Keyword: Drug Abuse
Link ID: 11284 - Posted: 06.24.2010

NEW YORK - Giving infants a small dose of a sugar solution just before they get injections seems to make the pain more tolerable, a study shows. Researchers gave babies ages 2 and 4 months the solution two minutes before getting routine immunizations and noted that it seemed to help them recover from the pain of the injection more quickly, the medical journal Pediatrics reported. Dr. Linda A. Hatfield, at the Pennsylvania State University School of Nursing in University Park, and her associates gave the sugar solution to 38 infants and plain water to 45 infants before they were to get a series of injections. The first, second and third injections were administered at 2 minutes, 5 minutes, and 7 minutes after the solutions were given. To assess the babies’ experience of pain, the investigators used a validated composite pain scale that measures crying, facial expression, behavior, body movement, and sleep. The scale goes from 0 to 5, with higher scores representing greater pain. Pain was assessed immediately after each injection, and at 9 minutes. Copyright 2008 Reuters.

Keyword: Pain & Touch; Development of the Brain
Link ID: 11283 - Posted: 06.24.2010

Women who endure severe stress early in pregnancy may be more likely to have children that go on to develop schizophrenia, research suggests. A University of Manchester team looked at data from 1.38 million Danish births occurring between 1973 and 1995. The risk of schizophrenia and related disorders was around 67% greater among the offspring of women who lost a relative during their first trimester. The study appears in the journal Archives of General Psychiatry. The findings appear to confirm the theory that a mother's psychological state can have a profound influence on her unborn baby. Previous research has linked stress in pregnancy to a raised risk of low birth weight and prematurity. And some studies have also suggested that the abnormalities in brain structure and function that are associated with schizophrenia may begin to form in the earliest stages of development. However, the researchers found no evidence that a loss of a relative at any other time during the pregnancy, or in the six months leading up to a pregnancy, had any effect on the unborn baby. In addition, the association between bereavement and schizophrenia risk only appeared significant for people without a family history of mental illness. The researchers suggest that chemicals released by the mother's brain in response to stress may have a direct impact on the foetus's developing brain. These effects may be strongest in early pregnancy, when protective barriers between the mother and foetus are not fully constructed. They add that the risk of schizophrenia is likely to be influenced by other factors, such as genes. (C)BBC

Keyword: Schizophrenia; Stress
Link ID: 11282 - Posted: 02.05.2008

Dementia is three times more common in people whose blood is low in folates, a form of vitamin B particularly found in green vegetables, a study suggests. The Journal of Neurology, Neurosurgery and Psychiatry study followed 518 South Korean pensioners for two years. There is growing evidence linking levels of folates - or folic acid - and Alzheimer's disease, though deficiency could be a symptom of dementia. The UK is currently considering adding the vitamin to bread and flour. This is primarily for the benefit of pregnant women and their unborn children, as folic acid has been proven to prevent spinal problems in the growing foetus, but research increasingly suggests it could also ward off dementia. However, the exact relationship between folate deficiency and dementia remains unclear, as it could well be a symptom as much as a cause. The team led by the Chonnam National University Medical School in Gwangju acknowledged this in their study, noting that "changes in micronutrients could be linked with the other typical signs that precede dementia, including weight loss and low blood pressure. While weight loss is unlikely to alter micronutrients in the blood, it may indicate dietary changes in the quality of food intake." They found that 3.5% of their study group were folate deficient to start with. These people were 3.5 times more likely to have developed dementia by the end of the study. The disease was more common in those who were older, relatively poorly educated and inactive, the researchers found. (C)BBC

Keyword: Alzheimers
Link ID: 11281 - Posted: 02.05.2008

By LAURAN NEERGAARD WASHINGTON (AP) -- It's a tiny vacuum cleaner for the brain: A new treatment for stroke victims promises to suction out clogged arteries in hopes of stopping the brain attack before it does permanent harm. Called Penumbra, the newly approved device is the latest in a series of inside-the-artery attempts to boost recovery from stroke, the nation's No. 3 killer. Now the question is how to determine which patients are good candidates - because, illogical as it may sound, unclogging isn't always the best option. "Is the patient at a stage of stroke where you're going to hurt them by pulling a clot out, or show benefit?" asks Dr. Walter Koroshetz of the National Institutes of Health. "It's good we have devices. Now we have to learn how to use them." More than 700,000 Americans suffer a stroke each year, and more than 150,000 of them die. Survivors often face serious disability. Most strokes occur when blood vessels feeding the brain become blocked, starving delicate brain cells of oxygen until they die. For those, the clot-busting drug TPA can mean the difference between permanent brain injury or recovery - but only if patients receive intravenous TPA within three hours of the first symptoms. © 2008 The Associated Press.

Keyword: Stroke
Link ID: 11280 - Posted: 06.24.2010

By Ann Gibbons In the past 100,000 years, modern humans have colonized the far corners of the globe, adapting to new environments as they migrated. Researchers have long assumed that these dramatic transitions resulted in a sort of accelerated evolution in which genes for traits such as skin color and stature changed rapidly to allow humans to survive in their new habitats. Now, a team of French and Spanish researchers has found powerful new evidence to support this idea, identifying 582 genes that have evolved differently in different populations in the past 60,000 years, including a dozen that protect people from obesity, diabetes, hypertension, and other diseases. The team, led by population geneticist Lluis Quintana-Murci of the Pasteur Institute and Centre National de le Recherche Scientifique in Paris, analyzed DNA of 210 individuals from the database of Phase II of the International HapMap Project, an effort to identify variations in human genes that cause disease. The researchers analyzed 2.8 million single nucleotide polymorphisms (SNPs)--mutations in a single nucleotide in a genome that varies between individuals or populations--from Europeans, Africans, and Asians. Then they sorted the mutations by type, focusing on 15,259 nonsynonymous mutations, which alter amino acids and thus a gene's function. © 2008 American Association for the Advancement of Science

Keyword: Evolution
Link ID: 11279 - Posted: 06.24.2010

John Whitfield Hanging out with dad brings benefits for the kids.Susan C. AlbertsIt's not just humans who benefit from having a father figure around; the longer a yellow baboon’s dad sticks around, the better it does, new research shows. The discovery shows that there’s more to male baboon life than sex and fighting, says Jeanne Altmann of Princeton University in New Jersey. “We haven’t given males due credit for the subtlety and complexity of their behaviour,” she says. Altmann and her colleagues studied yellow baboons (Papio cynocephalus ) living in Amboseli National Park in Kenya, near the base of Mount Kilimanjaro. They report their results in Proceedings of the National Academy of Sciences 1. The animals live in groups averaging 40 individuals. Females are generally loyal to the group they were born in, but males disperse. Some move regularly from group to group, others stay in the same group for several years. The researchers looked at 118 baboons born between 1982 and 2002, of which 40 were male. Testing DNA from faeces revealed the identity of each youngster’s father. The team had previously shown that adult males intercede in fights on their offsprings' behalf2. But the consequences of this weren’t clear. It has been suggested that males help out their young to show off their own qualities as a mate, rather than to specifically protect the juveniles. The new results, however, suggest that there is something in it for the kids, too. © 2008 Nature Publishing Group

Keyword: Sexual Behavior
Link ID: 11278 - Posted: 06.24.2010