The conventional wisdom that animals live longer if they eat less has been shown to be not entirely correct - at least in fruit flies. For these insects, it is the type of food and not just the quantity that controls their longevity. It has been known for decades that “calorie restriction” significantly lengthens the lifespan of many non-primate species - everything from worms to fleas to mice. Linda Partridge at University College London, UK, and colleagues wanted to see if the effect was merely due to a reduction of total calories or of particular nutrients in the diet. So the researchers divided up their Drosophila melanogaster fruit flies into four groups and put them on different diets. The control group got the standard fruit fly lab meal of yeast, which contains protein and fat, and sugar - a meal boasting about 1200 kilocalories per litre. The second group was fed on a calorie-restricted diet, with equal amounts of yeast and sugar - about 521 kilocalories per litre. The third group was given more yeast than sugar, while the fourth group got more sugar than yeast. The latter two diets had about 860 kilocalories per litre each. The flies on the calorie restricted diet lived the longest - 82% longer compared to the controls. But the flies on the higher calorie diet with reduced yeast intake did very well too. © Copyright Reed Business Information Ltd.

Keyword: Obesity
Link ID: 7413 - Posted: 06.24.2010

“Gender-bending” chemicals mimicking the female hormone oestrogen can disrupt the development of baby boys, suggests the first evidence linking certain chemicals in everyday plastics to effects in humans. The chemicals implicated are phthalates, which make plastics more pliable in many cosmetics, toys, baby-feeding bottles and paints and can leak into water and food. All previous studies suggesting these chemicals blunt the influence of the male hormone testosterone on healthy development of males have been in animals. “This research highlights the need for tougher controls of gender-bending chemicals,” says Gwynne Lyons, toxics adviser to the WWF, UK. Otherwise, “wildlife and baby boys will be the losers”. The incriminating findings came from a study of 85 baby boys born to women exposed to everyday levels of phthalates during pregnancy. It was carried out by Shanna Swan at the University of Rochester School of Medicine and Dentistry, New York, US, and colleagues. As an index of feminisation, she measured the “anogenital distance” (AGD) between the anus and to the base of the penis. She also measured the volume of each boy’s penis. Earlier studies have shown that the AGD is twice in boys what it is in girls, mainly because in boys the hormone testosterone extends the length of the perineum separating the anus from the testicles. In animals, AGD is reduced by phthalates - which mimic oestrogen - which keep testosterone from doing its normal job. At higher doses, animals develop more serious abnormalities such as undescended testicles and misplaced openings to the urethra on the penis - a group of symptoms called “phthalate syndrome” in animals. © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior
Link ID: 7412 - Posted: 06.24.2010

St. Paul, Minn. – A new therapy that uses magnetic pulses to stimulate the brain may improve recovery after a stroke, according to a study published in the May 24 issue of Neurology, the scientific journal of the American Academy of Neurology. The treatment, called repetitive transcranial magnetic stimulation, improved motor function in a small group of people. For the stimulation, an insulated wire coil is placed on the scalp, and a brief electrical current is passed through the coil, creating a magnetic pulse that stimulates the outer part of the brain, called the cortex. The study involved eight people, ages 35 to 63, who had a stroke within the last year and were relearning to use their affected hands. They were compared to six people who had never had a stroke. The stroke patients received three sessions of magnetic stimulation to the side of the brain that had not been affected by the stroke using different parameters, including sham (mock) stimulation. A sham is the application of the procedure excluding the actual treatment being studied and is intended to address the question of a placebo effect. The six healthy participants were tested with the same battery of tests to evaluate the learning effect associated with repeated testing. All of the participants performed tests before and after the stimulations. The tests evaluated the motor function of the hand that was affected by the stroke. For example, reaction time was tested, along with how many finger taps could be performed over a period of time.

Keyword: Stroke
Link ID: 7411 - Posted: 06.24.2010

How a mother reads her baby's emotions may be more important for the child's development than the family's social status, researchers say. The findings will be used to inform the work of initiatives such as the Sure Start, which provide support to new parents. A team from the Economic and Social Research Council studied more than 200 mothers and their babies. Half of the women left school at 16 and were unemployed or in low-skilled jobs. The interplay between mothers and their babies was assessed when the babies were at eight, 14 and 24 months old. The researchers made videos of mother-and-child play sessions, and noted what was said by the women at the time. The mother's comments were deemed appropriate if she appeared to be "reading" her child's emotions correctly, such as remarking that the baby was content when quietly playing with a toy. Other mothers seemed to misread their babies, perhaps by saying he or she was upset or tired when the child showed no signs of this. When the babies were assessed at 24 months, those born to mothers from poorer backgrounds did score less well in language and play tests. The researchers also found that those in the lowest 10% were more likely to have mothers in the lowest of the social and work brackets. But the researchers, led by Dr Elizabeth Meins of the University of Durham said, even though these links were significant, they were not strong. Factors such as post-natal depression and how much support the mother had were found to have little effect on the child's talking and playing abilities. But the researchers said they did find a definite link between mothers who could read their baby's emotions - labelled as "mind-minded" mothers - and the development of children by the age of two. Infants whose mothers fell into this category had higher test scores and were less likely to be in the bottom 10%. (C)BBC

Keyword: Development of the Brain; Emotions
Link ID: 7410 - Posted: 05.27.2005

By GINA KOLATA The new federal study suggesting that people tend to live longer if they are slightly overweight was challenged yesterday by scientists from the Harvard School of Public Health and the American Cancer Society as well as a heart disease researcher. But authors of the federal research said in interviews that they stood by their conclusions and that the criticisms were based on misrepresentations of what they had done. The study under attack was published last month by researchers at the Centers for Disease Control and Prevention and the National Cancer Institute. It concluded that people who are overweight but not obese have a lower death risk than people of normal weight. The scientists also reported that being very thin increased the risk of death, even if the thinness was longstanding and not due to illness. In a seminar and news conference yesterday at the public health school, in Boston, the critics said other studies, including their own, had found that the death risk from excess pounds increased continuously from normal weight to overweight to obesity. Dr. Scott M. Grundy, a heart researcher at the University of Texas Southwestern Medical Center, said excess weight clearly led to heart disease and death. Dr. Michael Thune of the American Cancer Society said the same applied to cancer. Copyright 2005 The New York Times Company

Keyword: Obesity
Link ID: 7409 - Posted: 05.27.2005

ORAL contraceptives may free a woman to have sex without fear of getting pregnant, but they could also extinguish her desire. The pill has been associated with many side effects, including blood clots, migraines and weight gain. Perhaps least talked about is its tendency to dull libido by decreasing testosterone levels. Contraceptive drugs curb the hormone's production in the ovaries and also raise levels of sex hormone binding globulin (SHBG), a substance that takes it out of play. But it is unclear how common problems are in pill users. Until now, any sexual dysfunction, including loss of libido, muted or non-existent orgasms or painful intercourse, was thought to be reversible when women stopped taking the drug. Irwin Goldstein, Claudia Panzer and their colleagues at Boston University studied 125 young women who attended a sexual dysfunction clinic. Sixty-two of them were taking oral contraceptives, 40 had previously taken them and 23 had never taken them. The team measured levels of SHBG in the women every three months for a year, and found that in pill users they were seven times as high as in women who had never taken them. Levels had declined a bit in women who had stopped taking the pill, but remained three to four times as high as in those who had never taken it, the researchers told a meeting of the American Association of Clinical Endocrinologists in Washington DC last week. "There's the possibility it is imprinting a woman for the rest of her life," says Goldstein. From issue 2501 of New Scientist magazine, 27 May 2005, page 17 © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 7408 - Posted: 06.24.2010

By Rita Zeidner Jennie Anthony negotiates for a living. But until recently, closing a deal with a handshake was out of the question. The Philadelphia mortgage banker preferred to keep her hands buried in her pockets, gripped around a wad of tissues. Otherwise, she said, "my hands dripped like faucets." Because sweat also poured from her armpits, Anthony, 31, wore only clothes that were black or white -- the two colors that best concealed ever-present sweat rings under her arms. Sandals were out as footwear because her feet always were sopping. Such heavy sweating, called hyperhidrosis, is the result of a supercharged sympathetic nervous system -- a network of nerves in the chest. While for most people, stimulation of those nerves by heat or nervous tension is needed to cause perspiration, millions with hyperhidrosis sweat for no reason at all. "I would sweat at the drop of a hat -- winter or summer, hot or cold," said Anthony. "It didn't matter what I was wearing. I would even sweat if I was freezing cold." No one knows what causes hyperhidrosis. But last June, Anthony got relief for the symptoms through a minimally invasive surgery that blocks the nerve impulses that cause sweating in the hands and underarms. During the hour-long operation, known as endoscopic thoracic sympathectomy (ETS), thoracic surgeon Blair Marshall made two tiny needle holes under each arm and inserted a tiny camera and instruments to locate, and then sever, the sympathetic nerve chain. Once designated ganglions, or nerve cell masses, are cut, the overcharged "sweat" signals don't get sent to places like the arms, hands and feet. © Copyright 1996-2005 The Washington Post Company

Keyword: Emotions
Link ID: 7407 - Posted: 06.24.2010

Scientists for the first time have watched agents of brain-wasting diseases, called transmissible spongiform encephalopathies (TSE), as they invade a nerve cell and then travel along wire-like circuits to points of contact with other cells. These findings will help scientists better understand TSE diseases and may lead to ways to prevent or minimize their effects. TSE, or prion, diseases include scrapie in sheep and goats; chronic wasting disease in deer and elk; mad cow disease in cattle; and Creutzfeldt-Jacob disease in humans. Under the direction of Byron Caughey, Ph.D., at the Rocky Mountain Laboratories (RML) and Marco Prado, Ph.D. at the University of Minas Gerais in Belo Horizonte, Brazil, the team performed the research in laboratory cultures using a rodent-adapted form of scrapie protein and cells taken from the central nervous system of mouse and hamster brains. The proteins were first “branded” with fluorescent dyes so they could be easily tracked. The work also revealed that a similar trafficking process might occur with the key plaque-forming protein in Alzheimer’s disease, which is not a TSE but a different type of degenerative brain disease, according to Gerald Baron, Ph.D., one of the lead RML researchers. RML, located in Hamilton, MT, is part of the National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health. The new report appears in the May 25 issue of The Journal of Neuroscience. “These findings offer intriguing leads toward developing therapies to stop the spread of TSE and possibly other degenerative brain diseases,” says NIAID Director Dr. Anthony Fauci.

Keyword: Prions
Link ID: 7406 - Posted: 06.24.2010

The same protein that "translates" sound into nerve signals to the brain and enables individuals to hear is also required for pain perception, researchers from Northwestern University Feinberg School of Medicine have found. Because the protein, TRPA1, is found in the majority – about 75 percent -- of the body's pain-perceiving neurons, but not in major organs, drugs that could block TRPA1 would be novel pain killers with few or no side effects, although targeting the inner ear may have to be avoided, said Jaime Garcia-Aņoveros, who led the research. Garcia-Aņoveros, assistant professor of anesthesiology, neurology and physiology at Feinberg and the Northwestern University Institute for Neuroscience and a fellow of the Hugh Knowles Center for Hearing Research, described the dual role of the protein, TRPA1, in the cover article of the April 20 issue of the Journal of Neuroscience. The other authors, all members of his research group at Northwestern University, were Keiichi Nagata, Anne Duggan and Gagan Kumar. Garcia-Aņoveros and his colleagues showed conclusive evidence that TRPA1, in addition to being expressed in nociceptors, or pain neurons, is present in the stereocilia of hair cells, the sensory part of the cells of the inner ear used for hearing as well as detecting gravity and maintaining balance.

Keyword: Pain & Touch; Hearing
Link ID: 7405 - Posted: 06.24.2010

What does it take to fathom a proverb – catch the figurative meaning of "an apple doesn't fall far from the tree"? According to research led by V. S. Ramachandran, director of the Center for Brain and Cognition at the University of California, San Diego, a region of the brain known as the angular gyrus is probably at least partly responsible for the human ability to understand metaphor. Ramachandran and colleagues tested four right-handed patients with damage to the left angular gyrus. Fluent in English and otherwise intelligent and mentally lucid, the patients showed gross deficits in comprehending such common proverbs as "the grass is always greener on the other side" and "an empty vessel makes more noise." Asked to explain the sayings, the patients tended give responses that were literal. The metaphorical meaning escaped them almost entirely. When pressed to provide deeper or more general accounts, Ramachandran said, "the patients often came up with elaborate, even ingenious interpretations – that were completely off the mark." Patient SJ, for example, a former physician who could maintain the flow of normal conversation and even retained the ability to correctly diagnose descriptions of symptoms, got all 20 of the 20 proverbs he was tested on wrong. Prodded on "all that glitters is not gold," he finally said that it meant you had to be very careful when buying jewelry because you might get robbed.

Keyword: Language
Link ID: 7404 - Posted: 06.24.2010

SUSPICIONS that pesticides could cause Parkinson's disease have been strengthened. The more pesticide you are exposed to, the higher your risk of developing the disease, say investigators who have studied almost 3000 people in five European countries. The results reinforce the need for amateur gardeners and farmers alike to wear protective equipment when spraying pesticides, the team concludes. "It considerably strengthens the case for pesticides being relevant to occupational risk of Parkinson's disease," says Anthony Seaton of the University of Aberdeen, UK, principal investigator of the Geoparkinson study, which was funded by the European Commission and followed volunteers in Scotland, Italy, Sweden, Romania and Malta. Researchers questioned 767 people with Parkinson's disease and 1989 healthy controls with similar backgrounds about several risk factors associated with the disease, including exposure to pesticides. People with Parkinson's were more likely to have used pesticides regularly. Users with low exposure such as amateur gardeners were 9 per cent more likely than non-users to develop the disease, and high-exposure users such as farmers were 43 per cent more likely. David Coggon of the University of Southampton, UK, and chairman of the British government's Advisory Committee on Pesticides, said the study's weakness, acknowledged by the authors, is that it could not identify which pesticides were responsible. "It's possible that just one or two are causing it, but slipped through the regulatory net," says Coggon. It would be more helpful, he adds, for studies to monitor exposure to individual pesticides as and when they are used, rather than relying on people's memories of their usage. © Copyright Reed Business Information Ltd.

Keyword: Parkinsons; Neurotoxins
Link ID: 7403 - Posted: 06.24.2010

Doctors are hailing a new drug that can prevent premature ejaculation during sexual intercourse. A meeting of the American Urological Association heard how dapoxetine can lengthen the duration of intercourse by three to four times. Experts believe up to a third of the male population has problems with premature ejaculation. However, it will still be some time before the drug is available in pharmacies. The US drug approval agency the Food and Drug Administration is reviewing an application for dapoxetine, which was developed by Ortho-McNeil Pharmaceutical, an affiliate of Johnson and Johnson. But a spokesman for Otho-McNeil said the company had not decided whether to make similar applications to European regulators. Dapoxetine is chemically similar to a family of antidepressants called SSRIs (selective serotonin reuptake inhibitors). These types of antidepressants are known to have an impact on ejaculation. (C)BBC

Keyword: Sexual Behavior; Depression
Link ID: 7402 - Posted: 05.25.2005

Antisocial behaviour in some children could be the result of their genetic make-up, a study says. UK research on twins suggests children with early psychopathic tendencies, such as lack of remorse, are likely to have inherited it from their parents. These young children are also likely to display inherited antisocial behaviour, the Institute of Psychiatry team found. But environmental factors are also important and, if favourable, could act as a buffer, they stressed. And antisocial behaviour in children with no psychopathic tendencies is likely to be down to mainly environmental factors, they believe. Previously, the same researchers had found boys who had a particular version of a gene were much more likely to display antisocial behaviour if they suffer maltreatment when young. In the current study, published in the Journal of Child Psychology and Psychiatry, Professor Terrie Moffitt and colleagues from King's College, London, followed 3,687 pairs of seven-year-old twins. Twins are often used to investigate inherited traits because identical twins share the same genes, and therefore the same inherited influences, whereas non-identical twins do not. The researchers used teacher ratings of antisocial behaviour and psychopathic tendencies - lack of empathy and remorse - to rank the twins into groups. Those falling in the top 10% for antisocial behaviour were split into two groups - those with and without psychopathic tendencies. (C)BBC

Keyword: Aggression; Genes & Behavior
Link ID: 7401 - Posted: 05.25.2005

By BENEDICT CAREY Minor brain damage need not be all bad, two Swiss neurologists report. It can bring about an artistic transformation, which is what happened in two cases of painters who suffered mild strokes. "Any change in brain network can modify someone's approach to creativity, and a minor stroke must not always be seen as a handicap but also sometimes as a modification of functioning that can bring new strategies," Dr. Jean-Marie Annoni said in an e-mail message. More often, of course, the effect of a stroke is damaging. Dr. Annoni is a neurologist and the lead author of a report on the two painters in the current issue of The Journal of Neurology, Neurosurgery and Psychiatry. It is well known that people with certain dementias sometimes become compulsive about painting, drawing or photography. And an injury to the prefrontal area of the brain, which is involved in editing and organizing, can free emotional currents that find their way into drawing or painting, some neuroscientists say. Now, Dr. Annoni and colleagues at Lausanne University in Switzerland have documented a change in the work of two skilled Swiss painters who suffered mild strokes. This research, unlike many earlier studies documenting deficits in spatial and cognitive abilities, showed that the artists had little change in personality or talent, and did not notice changes in their work until perceptive friends pointed them out. Independent judges confirmed that the artists' use of color and line had altered significantly. Copyright 2005 The New York Times Company

Keyword: Stroke; Laterality
Link ID: 7400 - Posted: 05.25.2005

Circadian rhythms in mammalian behavior, physiology, and biochemistry are controlled by the central clock within a brain structure known as the suprachiasmatic nucleus (SCN). The clock is synchronized to environmental cycles of light and dark. It is well known, from everyday experience, that adjusting to new light schedules takes several days, though the details of how this adaptation takes place are not well understood. Researchers now report findings that suggest this adaptation process does not necessarily involve a gradual and synchronous adaptation by the neurons that comprise the central circadian clock--rather, that different components of the clock tend to adapt to a shifted light schedule at two different speeds. The work is reported in the May 24 issue of Current Biology by a research team led by Johanna H. Meijer of Leiden University Medical Center in The Netherlands. The researchers studied clock-resetting behavior in rats that were exposed to a six-hour delay of the light schedule, a shift that mimics a transition from the eastern U.S. to western Europe. By performing electrophysiological analysis of cells that constitute the central circadian clock, the researchers made a surprising discovery: one part of the clock mechanism, represented by a dorsal (upper) group of cells, exhibited oscillations in activity that corresponded to slow resetting of the clock in response to the shifted light schedule, while another part of the clock, represented by a ventral (lower) group of cells, exhibited a distinct pattern of activity that corresponded to fast resetting of the clock.

Keyword: Biological Rhythms
Link ID: 7399 - Posted: 05.25.2005

By LISA BELKIN To suffer from obsessive-compulsive disorder, many patients say, is to ''know you are crazy.'' Other forms of psychosis may envelop the sufferers until they inhabit the delusion. Part of the torture of O.C.D. is, as patients describe it, watching as if from the outside as they act out their obsessions -- knowing that they are being irrational, but not being able to stop. They describe thoughts crowding their minds, nattering at them incessantly -- anxious thoughts, sexual thoughts, violent thoughts, sometimes all at the same time. Is the front door locked? Are there germs on my hands? Am I a murderer if I step on an ant? And they describe increasingly elaborate rituals to assuage those thoughts -- checking and rechecking door locks, washing and rewashing hands, walking carefully, slowly and in bizarre patterns to avoid stepping on anything. They feel driven to do things they know make no sense. There are researchers who believe that some of this disturbing cacophony -- specifically a subset found only in children -- is caused by something familiar and common. They call it Pediatric Autoimmune Neuropsychiatric Disorders Associated With Streptococcal Infection, or, because every disease needs an acronym, Pandas. And they are certain it is brought on by strep throat -- or more specifically, by the antibodies created to fight strep throat. If they are right, it is a compelling breakthrough, a map of the link between bacteria and at least one subcategory of mental illness. And if bacteria can cause O.C.D., then an antibiotic might mitigate or prevent it -- a Promised Land of a concept to parents who have watched their children change overnight from exuberant, confident and familiar to doubt-ridden, fear-laden strangers. Copyright 2005 The New York Times Company

Keyword: OCD - Obsessive Compulsive Disorder
Link ID: 7398 - Posted: 05.25.2005

By PETER EDIDIN ITHACA, N.Y. - In the basement of Uris Hall, the squat concrete building that houses the psychology department at Cornell University, Prof. Barbara L. Finlay unlocked the door to a room identified by a handwritten card as "The Looney Bin." "Here they are," Professor Finlay said, turning on the light in the cramped space cluttered with lab equipment. To one side was a small rolling cart carrying eight human brains in glass jars filled with formaldehyde. They looked rubbery, like Halloween gag items. One, the brain of an infamous criminal executed in 1871, was green. "A nice peppermint color," suggested Dr. Finlay, who has been a professor of cognitive and brain science at Cornell for 30 years. The brains on the cart are usually displayed in a glass cabinet on the second floor of Uris Hall. They serve no scientific purpose, Professor Finlay said, but they do make a powerful pedagogical point. "The students who come in here and pass by the display cabinet," she said, "are forced to confront the brain. This is the thing. This is where you happen. "I want them to confront the question, 'Is there something else or not?' " Professor Finlay, who researches evolution and brain development, is also curator of the university's Wilder Brain Collection, which consists of about 70 brains, most stored on shelves in an even more cramped closet next door. Copyright 2005 The New York Times Company

Keyword: Miscellaneous
Link ID: 7397 - Posted: 05.25.2005

Researchers at University of California, San Diego (UCSD) have found that Lafora disease, an inherited form of epilepsy that results in death by the age of 30, can be caused by mutations in a gene that regulates the concentration of the protein laforin. These findings are reported in the current issue of Proceedings of the National Academy of Sciences (PNAS). Lafora disease is characterized by normal development for the first decade of life, followed by an initial seizure in the second decade, progressively worsening seizures, early dementia, and death within 10 years of onset. Medications can ease the severity of initial symptoms, but there is no long-term treatment or cure for the disease. A puzzling aspect of the disease is the accumulation of starch-/glycogen-like granules in most tissues of Lafora disease patients. Thus, researchers have long thought that a defect in glycogen metabolism is intimately linked to the disease. Recessive mutations in two genes have been shown to cause Lafora disease. The genes encode the proteins laforin and malin, but the molecular mechanism defining how loss of laforin or malin causes Lafora disease has remained unclear. Jack E. Dixon, Ph.D., UCSD dean of scientific affairs and professor of pharmacology, and colleagues at UCSD investigated the role of malin in Lafora disease and found that malin physically interacts with laforin and regulates laforin's concentration by marking it for degradation. Their results show that approximately 40 percent of patients with Lafora disease have mutations in malin that render it unable to mark laforin for degradation. This increase in laforin may lead to Lafora disease through aberrant glycogen metabolism.

Keyword: Epilepsy; Genes & Behavior
Link ID: 7396 - Posted: 05.25.2005

Neurobiologists have discovered a specialized night-vision brain area in night-migratory songbirds. They believe the area might enable the birds to navigate by the stars, and to visually detect the earth's magnetic field through photoreceptor molecules, whose light-sensitivity is modulated by the field. The researchers published their findings May 23, 2005, in the early online edition of the Proceedings of the National Academy of Sciences. The collaboration was led by Henrik Mouritsen of the University of Oldenberg in Germany and Erich Jarvis of the Duke University Medical Center. Other co-authors were Gesa Feenders and Miriam Liedvogel in Mouritsen's laboratory and Kazuhiro Wada in Jarvis's laboratory. The research was supported by the VolkswagenStiftung to Mouritsen and the National Science Foundation's Waterman Award to Jarvis. To migrate successfully over thousands of miles at night, night-migratory birds need to see where they fly, as well as navigate by stars and the earth's magnetic field. Surprisingly, Jarvis said, recent scientific evidence has suggested that birds have specialized molecules in their visual system that translate magnetic compass information into visual patterns. Thus, , the researchers hypothesized that night migratory birds would need a specialized night-vision brain area. "There was no evidence of such a specialized region in night migratory birds before we began this research," Jarvis said.

Keyword: Vision
Link ID: 7395 - Posted: 05.25.2005

Scientists have found a link between neurons generated during adulthood and those that fall victim to diseases such as Alzheimer's. According to a new report, both types of brain cells have strangely low levels of a protein known as UCHL1. The discovery that new neurons can arise in adult brains--a feat first observed in songbirds--overturned the long-held belief that a vertebrate's complete supply of neurons is created at birth or soon thereafter. In the new work, Fernando Nottebohm of Rockefeller University and his colleagues investigated how latecomer neurons differ from lifelong ones. The researchers injected two types of dye into the brains of 19 songbirds and collected samples from both types of neurons, which are used in two different pathways in the brain. After analyzing genetic information from more than 3,000 cells from each animal, the team determined that one gene (UCHL1) showed remarkably low activity in the newer, or "replaceable neurons": the longstanding ones exhibited 2.5 times the amount of the UCHL1 protein. "Low levels of UCHL1 appear to be a feature of replaceable neurons wherever they occur," says study co-author Anthony Lombardino of Rockefeller University. Work with mice confirmed the correlation between low levels of UCHL1 and replaceable neurons. Finally, the scientists investigated whether levels of UCHL1 change when the animals sing--an activity that had previously been shown to increase the odds of survival for newly generated neurons. After the male birds sang to a female, the levels of UCHL1 in their replaceable neurons had increased. "These findings suggest that rising levels of UCHL1 may be associated with a reduced risk of neuronal death," Nottebohm explains. The results, published online this week by the Proceedings of the National Academy of Sciences, complement other studies that had linked deficiencies in UCHL1 to degenerative diseases such as Alzheimer's and Parkinson's disease. --Sarah Graham © 1996-2005 Scientific American, Inc

Keyword: Neurogenesis
Link ID: 7394 - Posted: 06.24.2010