By Nathan Seppa The constant stress of "fight-or-flight" mode out of deep sleep may exacerbate other health problems over time. A common breathing disorder that disrupts sleep also, over time, increases the risk of death, a study in the August Sleep suggests. But people who use a nighttime breathing apparatus face less risk, the research shows. Obstructive sleep apnea is a disorder marked by gaps in breathing during sleep that rob the blood of oxygen until a person gasps for air. People with apnea stop breathing many times in an hour, which can jar them out of restful sleep and wreak havoc with blood pressure, heart rate and internal stress responses. In the United States, about one in six people may have sleep apnea, with one-fourth of those cases severe, Terry Young, an epidemiologist at the University of Wisconsin–Madison, estimates. Sleep apnea has received widespread attention as a health problem in the past 15 years, but data generated by Young’s team suggest 85 percent of sleep apnea cases still go undetected. While studies have suggested it carries risks, no study had, until now, tracked a population of healthy, middle-aged individuals for more than a decade to measure apnea’s effects. © Society for Science & the Public 2000 - 2008

Keyword: Sleep
Link ID: 11892 - Posted: 06.24.2010

By Tina Hesman Saey Dumb flies (and perhaps people) may need a little more shuteye, or a shot of dopamine, to boost their brain power. Fruit flies need sleep in order to learn, a study in the August 5 Current Biology shows. Keeping Drosophila up for hours after their normal bedtime impaired the flies’ ability to learn a complex task. But activating a particular receptor for the neurotransmitter dopamine in a brain structure called the mushroom bodies erased the learning deficits, researchers from Washington University in St. Louis found. The new study raises the possibility that learning is impaired not because sleep sneaks up on us when we’re supposed to be paying attention, but because staying awake too long erodes some biological process in the brain critical for learning and forming memories, says David Dinges, an experimental psychologist at the University of Pennsylvania School of Medicine in Philadelphia. Such hard evidence for a direct link between sleep and learning has eluded researchers who study sleep in people and other animals, says Marcos Frank, a sleep researcher at the University of Pennsylvania School of Medicine. That’s not for lack of trying. Scientists have amassed reams of data demonstrating behavioral evidence for the connection, but humans and other mammals are complex, making molecular studies difficult. © Society for Science & the Public 2000 - 2008

Keyword: Sleep; Learning & Memory
Link ID: 11891 - Posted: 06.24.2010

Chronic exposure to estrogen can impair memory, U.S. researchers report. The brain area affected is the prefrontal cortex, which controls working memory and allows a person to remember information pertaining to a certain task. Also affected are the ability to plan, respond to changing conditions and moderate or control one's behaviour. The pre-frontal cortex has estrogen receptors, meaning it binds to estrogen. Researchers conducted tests on rats, administering them to animals that had been given estrogen and to those who hadn't. Those who were exposed to estrogen performed poorly compared to those who hadn't been exposed, in both memory and waiting tests that involved pressing levers and responding to a stimulus. "That's the test where we really saw the most striking effects with estradiol," said Susan Schantz, lead author of the study. The estradiol-treated rats "were not as good at waiting," she said. The rats that had received estrogen were a lot more active that the rats that didn't receive estrogen, the researchers found. © CBC 2008

Keyword: Hormones & Behavior; Learning & Memory
Link ID: 11890 - Posted: 06.24.2010

By Emily Anthes Birds of a feather don’t just flock together—they also work together to obtain food. Recent research makes rooks the first nonprimates observed to successfully cooperate to retrieve a food-laden platform, according to a June 22 study in the journal Proceedings of the Royal Society B: Biological Sciences. Scientists at the University of Cambridge tested the rooks, which are Eurasian members of the crow family, by placing dishes of food on a platform out of reach of a bird enclosure. A single string looped from the enclosure to the platform and back again. Moving the platform closer required pulling on both ends of the string simultaneously, a feat that is only possible if two birds work together, each tugging on one end. The researchers found that rook pairs spontaneously learned how to solve the problem. “We were amazed that the rooks performed so well,” says lead author Amanda Seed, now at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. “It’s really hard to coordinate your actions. If you wait an extra second, you miss your chance.” Chimpanzees, and possibly a few other primates, are the only other species that have proved themselves capable of the same task. Rooks are extremely social birds, living in colonies of hundreds of members, and are likely to have faced evolutionary pressure to learn to cooperate, Seed says. © 1996-2008 Scientific American Inc.

Keyword: Intelligence; Evolution
Link ID: 11889 - Posted: 06.24.2010

It may not be just your diet, but how you spice it that keeps diabetes under control. A natural yellow pigment in the curry spice turmeric, already known to have other health benefits, can also improve symptoms of diabetes in mice. "Maybe obese people can become normal in their sugars without necessarily losing the weight," says physician and research scientist Drew Tortoriello. "Obviously, losing weight is the optimum way to go, but maybe along the way while they're working towards that goal we can help with a little bit of these natural remedies." Tortoriello and his colleagues fed lean mice a high fat diet and, similarly to people, they became obese and diabetic. The researchers then added a high dose of turmeric's pigment, called curcumin, to the same high fat diet of half the mice. "We noticed a very significant drop in their blood sugars. So basically after two weeks of consuming curcumin orally, their diabetes was essentially gone," says Tortoriello. He adds that the treated mice no longer had fatty livers and inflammation of the fat or adipose tissue was reduced. The mice that got the curcumin actually ate more of the food, apparently enjoying the taste. Yet, they lost a small amount of weight. And although they remained obese, these symptoms of obesity were reduced. © ScienCentral, 2000-2008.

Keyword: Obesity
Link ID: 11888 - Posted: 06.24.2010

Linda Geddes A gene variant has been identified that appears to be associated with female-to-male transsexuality – the feeling some women have that they belong to the opposite sex. While such complex behaviour is likely the result of multiple genes, environmental and cultural factors, the researchers say the discovery suggests that transsexuality does have a genetic component. The variation is in the gene for an enzyme called cytochrome P17, which is involved in the metabolism of sex hormones. Its presence leads to higher than average tissue concentrations of male and female sex hormones, which may in turn influence early brain development. Clemens Tempfer and his colleagues at the Medical University of Vienna in Austria discovered the variant after analysing DNA samples from 49 female-to-male (FtM) and 102 male-to-female (MtF) transsexuals, as well as 1669 non-transsexual controls. The variant was more common in men than women, although it doesn’t seem to be implicated in MtF transsexuality as the proportion of MtF transsexuals with it was similar to that in non-transsexual men. In women, however, there were some differences: 44% of FtM transsexuals carried it, compared with 31% of non-transsexual women. While there are many women with the variant who are not transsexual and many FtM transsexuals who lack it, the finding raises the possibility that the variant makes women more likely to feel that their bodies are of the wrong sex, and that this is a result of their brains having been exposed to higher than average levels of sex hormones during development. © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 11887 - Posted: 06.24.2010

Drug addiction dramatically shifts a person’s attention, priorities, and behaviors towards a focus almost entirely on seeking out and taking drugs. Now, an animal study funded by the National Institute on Drug Abuse, part of the National Institutes of Health, has identified some of the specific long-term adaptations in the brain’s reward system that may contribute to this shift. These long-lasting brain changes may underlie the maladaptive learning that contributes to addiction and to the propensity for relapse, even after years of abstinence from the drug. The study was published in Neuron on July 30, 2008. Investigators from the University of California, San Francisco (UCSF) using an animal model of addiction, were able to distinguish brain changes in rats trained to self-administer cocaine, versus those animals that were trained to self-administer natural rewards such as food, or sucrose for several weeks. The investigators also were able to look at how much the "expectation" of receiving the drug influenced those brain changes by comparing rats trained to self-administer the drug versus animals who received the same amount of cocaine, but received it passively, i.e. they could not control their own drug taking by self-administration. It has been hypothesized that persistent drug seeking alters the brain’s natural reward and motivational system. The current study focuses on how drug seeking alters the communication between brain cells in this critical circuitry. In the normal processes of learning and memory formation there is a well documented strengthening of communication between brain cells, this process is known as "long-term potentiation" (LTP). The new study reports that LTP was similar in the rats that had learned to self administer cocaine, food or sucrose, but with a critical distinction. The increase in LTP due to cocaine persisted for up to three months of abstinence, but the increase in response to natural rewards dissipated after only three weeks. Importantly, the nature of the cocaine experience had a strong effect on the outcome, since rats exposed to cocaine when they did not expect it (passive infusions) displayed no LTP, neither transient nor long lasting.

Keyword: Drug Abuse; Learning & Memory
Link ID: 11886 - Posted: 06.24.2010

Malcolm Ritter -- Here's a couch potato's dream: What if a drug could help you gain some of the benefits of exercise without working up a sweat? Scientists reported Thursday that there is such a drug -- if you happen to be a mouse. Sedentary mice that took the drug for four weeks burned more calories and had less fat than untreated mice. And when tested on a treadmill, they could run about 44 percent farther and 23 percent longer than untreated mice. Just how well those results might translate to people is an open question. But someday, researchers say, such a drug might help treat obesity, diabetes and people with medical conditions that keep them from exercising. "We have exercise in a pill," said Ron Evans, an author of the study. "With no exercise, you can take a drug and chemically mimic it." Evans, of the Salk Institute for Biological Studies in La Jolla, Calif., and the Howard Hughes Medical Institute reports the work with colleagues in a paper published online Thursday by the journal Cell. They also report that in mice that did exercise training, a second drug made their workout much more effective at boosting endurance. After a month of taking that drug and exercising, mice could run 68 percent longer and 70 percent farther than other mice that exercised but didn't get the drug. © 2008 Discovery Communications, LLC.

Keyword: Obesity
Link ID: 11885 - Posted: 06.24.2010

Peter Aldhous You can think of it as recreating a deadly disease in the Petri dish. Scientists have grown motor neurons by "reprogramming" skin cells taken from a patient with the neurodegenerative disease amyotrophic lateral sclerosis (ALS). Now they aim to study the cells to gain a better understanding of what goes wrong in the condition, and to screen for drugs that might help prevent the damage. ALS affects cells in the spinal cord that send nerves into the muscles, controlling movement. Patients with the disease become progressively paralysed, and may eventually be unable to breathe. Famous sufferers include the US baseball player Lou Gehrig, who died of the condition in 1941, and the British theoretical physicist Stephen Hawking. Reprogrammed cells It is not possible to culture the affected cells directly from a patient's spinal cord. So researchers led by Kevin Eggan of the Harvard Stem Cell Institute, and Christopher Henderson of Columbia University, New York, took skin cells from an 82-year-old woman with ALS, and her sister, aged 89, who also has the disease. The researchers first used the genetic reprogramming technique pioneered by Shinya Yamanaka of Kyoto University in Japan to make cells known as induced pluripotent stem cells (iPS cells) from both women's skin cells. © Copyright Reed Business Information Ltd.

Keyword: Stem Cells; ALS-Lou Gehrig's Disease
Link ID: 11884 - Posted: 06.24.2010

American scientists say they are closer to understanding why some mothers suffer post-natal depression. They found mice lacking a chemical receptor in their brains developed similar symptoms. The study suggests the receptor helps stop brain cells firing too often in response to changes in hormone levels during pregnancy and birth. A British specialist said the research, published in Neuron, could lead to better treatments for the disorder. Between 5% and 25% of all new mothers are thought to suffer some form of post-natal depression, and can find it hard to cope with the demands of the baby, or even to form a bond with it. The precise reasons why some women develop it and some do not are uncertain, but the team at the University of California in Los Angeles say they may have some more answers. They focused their work on a chemical messaging system in the brain already known to play a key part in the regulation of mood and anxiety. A chemical called GABA can decrease the activity of certain nerve cells after coming into contact with receptors on that cell's surface. The Californian team noticed that a particular type of this receptor appeared to be highly active during pregnancy and the period after birth in mice. Their theory is that this variety of receptor might help, in normal circumstances, to keep control over the brain's response to huge hormonal changes during and immediately after pregnancy. Failure to do this effectively may be the root of some post-natal mood problems, they said. (C)BBC

Keyword: Depression; Hormones & Behavior
Link ID: 11883 - Posted: 07.31.2008

By Emma Wilkinson UK scientists have developed a drug which may halt the progression of Alzheimer's disease. Trials of the drug, known as Rember, in 321 patients showed an 81% difference in rate of mental decline compared with those not taking the treatment. The Aberdeen University researchers said the drug targeted the build-up of a specific protein in the brain. Alzheimer's experts were optimistic about the results, but said larger trials were now needed. Presenting the results at the International Conference on Alzheimer's Disease, Professor Claude Wischik said the drug may be on the market by 2012. Patients with mild to moderate Alzheimer's disease were given either 30, 60 or 100mg of the drug or a placebo. The 60mg dose produced the most pronounced effect - over 50 weeks there was a seven-point difference on a scale used to measure severity of dementia. At 19 months there was no significant decline in mental function in patients taking the drug, the researchers said. Imaging data also suggests the drug may be having its biggest effect in the parts of the brain responsible for memory. The link between clumps or "tangles" of protein inside nerve cells in the brain and Alzheimer's disease was first made over 100 years ago. (C)BBC

Keyword: Alzheimers
Link ID: 11882 - Posted: 07.31.2008

By BINA VENKATARAMAN The song of the blue whale, one of the eeriest sounds in the ocean, has mysteriously grown deeper. The calls have been steadily dropping in frequency for seven populations of blue whales around the world over the past 40 years, say researchers at the Scripps Institution of Oceanography, the National Oceanic and Atmospheric Administration and WhaleAcoustics, a private research company. The scientists analyzed data collected with hydrophones and other tools and found that the songs, which they believe are by males advertising for mates, had lowered by as much as 30 percent in certain populations. Much of the song lies at frequencies too low to be detected by the human ear. The study, though not yet published, has been reviewed by several experts in the field who, in interviews, called the global decline “dramatic,” “significant,” “convincing” and “unequivocal.” Scientists cannot explain why blue whales from places as disparate as the northern Pacific and the Southern Ocean, which surrounds Antarctica, would drop the pitch of their songs. Each blue whale population has a distinct tempo and tone set to its vocals. John Hildebrand, professor of oceanography at Scripps and an author of the study, said the drop might signal a rebound in the population of blue whales since commercial whaling bans began to take effect in the 1970s. Copyright 2008 The New York Times Company

Keyword: Animal Communication; Hearing
Link ID: 11881 - Posted: 06.24.2010

By Melinda Wenner Once an alcoholic, always an alcoholic—the saying is decades old, but scientists have only recently uncovered why it is often true. Long-term alcohol abuse changes the brain, making a person more sensitive to stress and more likely to reach for the bottle to soothe his or her anxiety. According to a new study, drugs that inhibit these stress pathways could help recovering alcoholics stay in control. Scientists at the National Institutes of Health and University College Lon­don bred mice lacking the neuro­kinin 1 receptor (NK1R), a protein involved in the brain’s stress response. The mice were given unlimited access to alcohol-spiked water for 60 days, during which the alcohol content was incrementally raised from 3 to 15 percent. The NK1R-deficient mice consumed far less alcohol—especially later in the trial when alcohol concentration was higher—than the normal mice did. They were also more sensitive to alcohol’s effects than the normal mice were; studies have shown that the more sensitive a person is to alcohol, the less likely he or she is to abuse it. The team then treated 25 highly anxious recovering alcoholics with a drug that blocks the NK1 receptor. After four weeks of hospital treatment, the subjects taking the drug reported fewer spontaneous and stress-induced alcohol cravings than patients given a placebo did. When the scientists used functional MRI to look at the subjects’ brain activity, they found that the treated subjects showed less activity in the insula, a region associated with craving. The scientists believe the drug targets a stress pathway specific to alcoholics because it has been shown to have little effect on stress levels in other types of patients. © 1996-2008 Scientific American Inc.

Keyword: Drug Abuse; Emotions
Link ID: 11880 - Posted: 06.24.2010

By Jocelyn Kaiser Two large studies of schizophrenia patients have yielded the most convincing evidence yet that the disease can be caused by mistakes in genes. The researchers linked a much higher risk for schizophrenia to three chromosomal regions that are missing chunks of DNA. Although only a tiny fraction of patients carried these particular glitches, similar errors may help explain other cases of the disease. Schizophrenia is a severe mental disorder involving hallucinations and delusions that affects as many as 1 in 100 people; it often runs in families. So far, searches for common genes linked to schizophrenia have been unsuccessful. In March, however, researchers reported a new clue in Science: Schizophrenics are more likely than healthy people to have rare variations in gene copy number--that is, they have fewer or more copies of a gene than most other people. Many of these copy number changes occurred in only one individual or one family, however, and the study could not pin down the risks associated with a particular variant. Now the largest studies to date have bolstered the case for copy number variants. The U.S.–European International Schizophrenia Consortium, which compared copy numbers in about 3400 patients and 3200 controls, found that large chunks of extra or missing DNA were 15% more common in people with the disease compared with controls. Moreover, the researchers found a much greater risk for patients with DNA deletions in two specific locations on chromosome 1 and chromosome 15. A second study by deCODE Genetics in Reykjavik, Iceland, and a European consortium known as SGENE, which involved about 4700 schizophrenia cases and 41,200 controls, pinpointed these same two variants and an additional one on chromosome 15. Both papers are published online today in Nature. © 2008 American Association for the Advancement of Science.

Keyword: Schizophrenia; Genes & Behavior
Link ID: 11879 - Posted: 06.24.2010

By Steve Mitchell While we snooze, scientists think, our brains are busy forming new memories by replaying the events of the day. But aging may rob us of this process and set us up for having "senior moments." A new study has found that older rats seem to replay previous events less and, as a result, have more trouble remembering than younger animals. How our brains form memories is not entirely understood, but sleep may be vital. The hippocampus region of our brain seems to rerun experiences we had while awake, a process that scientists believe helps cement memories. A team led by neuroscientist Carol Barnes at the University of Arizona, Tucson, noticed that older rats--just like older people--sometimes have trouble remembering. Could those memory problems be due to a decline in the brain's replay during sleep? In the study, 11 young and 11 older rats learned the locations of food rewards in several mazes. Meanwhile, researchers recorded the electrical activity of their hippocampi with probes inserted into their brains. That night, while the rats slept, the researchers monitored the hippocampus activity again. The young rats showed roughly the same kind of hippocampus activity in their sleep as they did when they were navigating the mazes; apparently, they were replaying the events. But the older rats did not, indicating that the replay process was impaired, the researchers report in the 30 July issue of The Journal of Neuroscience. Further experiments showed that the whippersnappers had a sharper memory; they were faster and more accurate than the older animals in remembering where a hidden platform was located while swimming in a tank of water. © 2008 American Association for the Advancement of Science

Keyword: Sleep; Alzheimers
Link ID: 11878 - Posted: 06.24.2010

ESSAY By JAMES POTASH, M.D. New research lends more credence than ever to the concept of "comfort foods." (AP Photo)Some patients with depression will eat a pint of Ben and Jerry's ice cream at night before they go to bed. They feel comforted -- at least briefly -- by the high-calorie treat. Of course, it doesn't take too many nights of this before the pounds start piling up. New research published in the journal Nature Neuroscience this month may shed some light on the biological relationship between depression and appetite. While it does not show that Ben and Jerry's is an antidepressant, it does suggest that a brain chemical, that motivates the consumption of the ice cream, may be. The chemical is called ghrelin, and it is naturally produced in the brain and the stomach. It was only discovered in 1999 by researchers who named it based on the Proto-Indo-European word root "ghre" for "grow," referring to its ability to stimulate growth hormone. But it turns out to be the most potent appetite stimulant known. © 2008 ABCNews Internet Ventures

Keyword: Depression; Obesity
Link ID: 11877 - Posted: 06.24.2010

Scientists have found further evidence that taking commonly used cholesterol- lowering statins may protect against dementia and memory loss. The study, published in Neurology, found that statins - normally taken to reduce heart disease risk - may cut the risk of dementia by half. The five-year project examined 1,674 Mexican Americans aged 60 and over at heightened risk of dementia. The Alzheimer's Research Trust said the research is "encouraging". A quarter of the patients took a statin, and in total 130 went on to develop dementia. Once the researchers had taken account of other risk factors, including education, smoking, and diabetes, they calculated that those who took statins had an approximately 50% lower risk of developing dementia. The study comes hot on the heels of separate research which suggests that drugs to reduce blood pressure can also cut the risk of dementia. It is estimated that 4 million people in England and Wales alone currently take statins. Lead researcher Professor Mary Haan, of the University of Michigan, said: "The bottom line is that if a person takes statins over a course of about five to seven years, it reduces the risk of dementia by half, and that's a really big change." Statins help to reduce the risk of heart disease by lowering levels of cholesterol which clog up the blood vessels. It is thought that a poor supply of blood to the brain may be one factor which promotes the development of dementia. Therefore, if statins help keep the blood vessels healthy, and blood flowing freely to the brain, they may help protect against the disease. (C)BBC

Keyword: Alzheimers
Link ID: 11876 - Posted: 07.29.2008

JoNel Aleccia The number of Americans who died at home after ingesting toxic combinations of prescription medications, alcohol and street drugs such as marijuana exploded by more than 3,000 percent during the past two decades, new research shows. The spike is a serious sign that many U.S. patients are having trouble coping with the shorter hospital stays, less clinical oversight and more powerful medications that have become hallmarks of medical care in recent years, said David P. Phillips, a sociologist at the University of California at San Diego. “In the old days, you’d stay in the hospital three times as long,” said Phillips, whose team analyzed more than 50 million U.S. death certificates from 1983 to 2004. More procedures are now performed on an outpatient basis and busy doctors are apt to prescribe more drugs with less follow-up, the researchers theorized. During the study period, the number of per capita prescriptions issued jumped by nearly 74 percent, researchers noted. “In an effort to save money, more and more of the burden of quality control has been placed on the shoulders of the patient,” he said. © 2008 MSNBC Interactive

Keyword: Drug Abuse
Link ID: 11875 - Posted: 06.24.2010

Patients with early Alzheimer's disease who exercised regularly saw less deterioration in the areas of the brain that control memory, according to a study released Sunday at a conference in Chicago. Magnetic resonance imaging (MRI) studies showed that exercise positively affected the hippocampus region of patients' brains, an area important for both memory and balance. In Alzheimer's, the hippocampus is one of the first parts of the brain to suffer damage. Exercise and physical fitness have been shown to slow down age-related brain cell death in healthy older adults, and earlier this month a preliminary study was published showing that exercise may help slow brain shrinkage in people with early Alzheimer's disease. Now, researchers at the University of Kansas Medical Center in Kansas City have used MRI and other neuroimaging tools to analyze how exercise affects the brains of those with early Alzheimer's. The study, released at the 2008 International Conference on Alzheimer's Disease (ICAD) in Chicago, found that patients with early Alzheimer's had a "significant relationship" between the size of key brain areas associated with memory and fitness, unlike healthy older adults. © The Canadian Press, 2008

Keyword: Alzheimers
Link ID: 11874 - Posted: 06.24.2010

By Adina Roskies and Walter Sinnott-Armstrong Cognitive science and moral philosophy might seem like strange bedfellows, but in the past decade they have become partners. In a recent issue of Cognition, the Harvard University psychologist Joshua Greene and colleagues extend this trend. Their experiment utilizes conventional behavioral methods, but it was designed to test a hypothesis stemming from previous fMRI investigations into the neural bases of moral judgments (see here and here). In their study Greene et al. give subjects difficult moral dilemmas in which one alternative leads to better consequences (such as more lives saved) but also violates an intuitive moral restriction (it requires a person to directly or intentionally cause harm to someone else). For example, in the “crying baby” dilemma subjects must judge whether it is wrong to smother their own baby in order to save a large group of people that includes the baby. In this scenario, which was also used by the television show M.A.S.H., enemy soldiers will hear the baby cry unless it is smothered. Sixty percent of people choose to smother the baby in order to save more lives. A judgment that it is appropriate to save the most lives, even if it requires you to suffocate a child, is labeled “utilitarian” by Greene et al., whereas a judgment that it is not appropriate is called “deontological.” These names pay homage to traditional moral philosophies. Based on previous fMRI studies, Greene proposes a dual-process model of moral judgments. This model makes two central claims. First, when subjects form deontological judgments, emotional processes are said to override controlled cognitive processes. © 1996-2008 Scientific American Inc.

Keyword: Emotions
Link ID: 11873 - Posted: 06.24.2010