By Michael Price Rod cells in our eyes help us see in dim light. They also ensure that the cones, the other light-sensitive cells we depend on for vision, get enough food, a new study reveals. The findings may shed light on a common cause of blindness. Approximately 100,000 people in the United States have retinitis pigmentosa, an incurable inherited retinal disease that leads to blindness. More than 40 genes can contribute to the disease, often by damaging important proteins in retinal cells. The disease's initial symptom, night-vision loss, appears when rods start dying off. This attrition usually begins in childhood, and though it's inconvenient, most people get by with their cones--the photoreceptive cells that work in bright light. But by the time affected people reach adulthood, the cones begin dying, too, ultimately resulting in total blindness. This has confounded scientists, because the faulty genes aren't active in the cones, only in the rods. To crack this mystery, biologist Constance Cepko of Harvard University and her colleague Claudio Punzo, a postdoctoral researcher, first evaluated previous theories. Some researchers thought that when the rods died, they produced a toxin that killed the cones. Others hypothesized that because rods use lots of oxygen in the retina, their death might leave behind a large amount of oxygen that overloads and damages the remaining cones. But neither of these seemed to fit the pattern, Cepko says, so he and Punzo decided to look for a new explanation. © 2008 American Association for the Advancement of Science.

Keyword: Vision
Link ID: 12316 - Posted: 06.24.2010

by Nora Schultz A dog might be a man's best friend, but only if it is being treated fairly. When a dog thinks it's getting a raw deal in comparison to other dogs, it doesn't shy away from expressing its envy. Until now, such overt dislike of unfairness had only been demonstrated in primates, but some scientists have suspected that other species that live cooperatively could also be sensitive to fair play - or a lack of one. To test this theory, Friederike Range and her colleagues at the University of Vienna, Austria, asked 43 trained dogs to extend their paw to a human in various situations. The animals performed the trick almost at every request, regardless of whether they were given a reward or not; as well as when working alone or alongside another dog. The dogs' enthusiasm quickly waned, though, when they saw the other dog being rewarded but received nothing themselves. The dogs that were ignored extended their paws significantly less often than in all other circumstances, doing so in only 13 out of 30 trials. They also showed significantly more symptoms of stress, such as licking or scratching themselves. © Copyright Reed Business Information Ltd

Keyword: Emotions; Evolution
Link ID: 12315 - Posted: 06.24.2010

By BENEDICT CAREY A long-awaited government report is calling on the military to test all new recruits for cognitive skills and then do large-scale studies of returning combat veterans to better evaluate and respond to traumatic brain injury, the signature wound of the Iraq war. For years, veterans’ advocates and researchers have called for more careful investigation of head injuries — not just severe wounds but also “closed head” injuries, which do not produce visible damage and do not show up on CT scans. Some doctors and veterans say the high blast impact of I.E.D.’s, the roadside explosives that have accounted for most head injuries to troops in Iraq, may be creating symptoms that differ from the sort of concussions suffered in sports or car accidents. Many veterans have complained of persistent, sometimes disabling symptoms like sleeplessness, dizziness and confusion that can resemble disorders like post-traumatic stress and can complicate disability assessments. The report, released Thursday by the Institute of Medicine, a government advisory group that studies health and medical issues, recommends that the Departments of Defense and Veterans Affairs conduct careful studies “to confirm reports of long-term or latent effects of exposure to blasts.” Some 5,500 military personnel have suffered brain injuries from mild to severe. The wounds account for an estimated 22 percent of all casualties in Afghanistan and Iraq — about twice the rate in Vietnam. Experts attribute this increase in part to better on-site medical care and body armor that allows ground troops to survive blasts that would otherwise be deadly. Copyright 2008 The New York Times Company

Keyword: Brain Injury/Concussion
Link ID: 12314 - Posted: 06.24.2010

Catching a cold sore puts you at risk of Alzheimer's disease, mounting evidence suggests. The herpes virus behind cold sores is a major cause of the protein plaques that accumulate in the brains of people with Alzheimer's, scientists have shown. On the plus side, the latest discovery by the University of Manchester team may mean antiviral drugs used to treat cold sores could also prevent dementia. The findings are published in the Journal of Pathology. Professor Ruth Itzhaki and colleagues found DNA evidence of the herpes simplex virus (HSV) type 1 in 90% of plaques in Alzheimer's disease patients' brains. They had previously shown that HSV1 infection of nerve-type cells in mice leads to deposition of the main component of the plaques - beta amyloid. And that the virus is present in the brains of many elderly people and that in those people with a specific genetic factor, there is a high risk of developing Alzheimer's disease. Taken together, the researchers say the findings strongly implicate the cold sore-causing virus as a root cause of Alzheimer's dementia. Professor Itzhaki said: "We suggest that HSV1 enters the brain in the elderly as their immune systems decline and then establishes a dormant infection from which it is repeatedly activated by events such as stress, immunosuppression, and various infections." In turn, this causes damages the brain cells, which die and then disintegrate, releasing the proteins which develop into amyloid plaques, she said. The researchers now plan to test whether antiviral drugs used to treat cold sores, which block the action of HSV1, might stop the cell damage that leads to Alzheimer's. (C)BBC

Keyword: Alzheimers
Link ID: 12313 - Posted: 12.08.2008

By LISA SANDERS, M.D. The middle-aged man writhed on the gurney in the E.R. His eyes were squeezed shut. Low moans emerged from his parched lips. His sister and brother — the only members of his large Polynesian family who lived here in Portland, Ore. — tried to comfort him, but worry was etched deeply into their faces. Dr. David Peel, the emergency-room doctor at Providence Portland Medical Center, was also worried. This 53-year-old man had a fever and excruciating pain in his back. One leg was weak and he was confused. But the scariest part of all was that the man had been discharged from this hospital just three days earlier after being treated for the exact same thing. Peel quickly reviewed the records of that first weeklong stay in the hospital. The patient, a smoker, had a history of diabetes and high blood pressure. He came in confused and with a fever. During that admission, the medical team thought he had an infection in his brain, an encephalitis. His white-blood-cell count was high, which was consistent with an infection, and his spinal fluid was abnormal, suggesting inflammation. In addition, the amount of sodium in his blood — an essential mineral and one that is tightly regulated by the brain and the kidneys — was dangerously low, a condition known as hyponatremia. Infections can cause low sodium. So can severe vomiting and diarrhea. And both the encephalitis and the hyponatremia can cause confusion. The team put the patient on powerful antibiotics and was replacing the missing sodium. Treat both, the doctors thought, and the confusion should improve. But it didn’t. His fever went down; his sodium went up. But his confusion remained unchanged. He still didn’t know where he was or why he was there. Copyright 2008 The New York Times Company

Keyword: Miscellaneous
Link ID: 12312 - Posted: 06.24.2010

By MOLLY BIRNBAUM I MOVED to New York on a cold February morning in 2006. When I stepped off the train at Penn Station, lugging two suitcases and a good deal of anxiety, I didn’t smell the garbage overflowing in a bin next to the tracks. I didn’t smell the piping hot coffee in the terminal kiosks as I walked toward the stairs that led to the subway. I didn’t smell the homeless man who shared my car on the F train. When I arrived in New York, I could barely smell anything. There was a whiff of garlic here, a breath of laundry detergent there. But most of my sense of smell had vanished six months earlier, when, on a drizzly August morning while jogging near my family’s home in Boston, I had been hit by a Honda Civic and shattered its windshield with the back of my skull. The trauma of the impact had severed my olfactory neurons, which snake delicately behind the forehead en route to the brain. Before the accident, I had been doing prep work in the kitchen of a small bistro in Boston, training to become a chef. My nights were filled with pristine boxes of wild mushrooms, stacks of chocolate bars from Venezuela and carefully constructed plates of quail. I arrived home in the early morning hours smelling of chicken stock and butter. I loved it. Copyright 2008 The New York Times Company

Keyword: Chemical Senses (Smell & Taste); Regeneration
Link ID: 12311 - Posted: 06.24.2010

By MALCOLM RITTER NEW YORK -- Healthy people should have the right to boost their brains with pills, like those prescribed for hyperactive kids or memory-impaired older folks, several scientists contend in a provocative commentary. College students are already illegally taking prescription stimulants like Ritalin to help them study, and demand for such drugs is likely to grow elsewhere, they say. "We should welcome new methods of improving our brain function," and doing it with pills is no more morally objectionable than eating right or getting a good night's sleep, these experts wrote in an opinion piece published online Sunday by the journal Nature. The commentary calls for more research and a variety of steps for managing the risks. As more effective brain-boosting pills are developed, demand for them is likely to grow among middle-aged people who want youthful memory powers and multitasking workers who need to keep track of multiple demands, said one commentary author, brain scientist Martha Farah of the University of Pennsylvania. "Almost everybody is going to want to use it," Farah said. © 2008 The Associated Press

Keyword: Sleep; Drug Abuse
Link ID: 12310 - Posted: 06.24.2010

Heidi Ledford Fresh evidence suggests that melatonin, a hormone that regulates the body's biological clock, is associated with type 2 diabetes. Epidemiological studies have shown that shift workers have an increased risk of developing type 2 diabetes. And patients with type 1 diabetes have sometimes reported higher blood-sugar levels after taking synthetic melatonin, which can be used to ease jet lag or as a sleep aid. Now, two separate studies by researchers based in Europe and the United States have found that variants of a gene called MTNR1B, which produces a receptor protein that binds and responds to melatonin, is linked to an increased chance of developing type 2 diabetes1,2. In 2007, endocrinologist Leif Groop of Lund University in Sweden and his colleagues published a genetic analysis of nearly 3,000 people, half of whom had type 2 diabetes3. Further work indicated that a sequence variation in the MTNR1B gene was associated with increased levels of glucose in the blood under fasting conditions. Although an abnormally high fasting-glucose level is a symptom of diabetes, the study did not find a link between the variant and the disease. But Groop suspected that the study may have been too small to pick up the association. © 2008 Nature Publishing Group

Keyword: Biological Rhythms
Link ID: 12309 - Posted: 06.24.2010

By Brendan Borrell The baby-faced gunman of Mumbai, Azam Amir Kasab, now in the custody of Indian police, is the sole surviving attacker in the three-day rampage that began on the night of November 26 and left more than 170 people dead and scores of others injured. After the attacks, Indian officials immediately began pointing fingers at longtime rival, Pakistan, as the source of the 10 militants—a charge that Pakistan President Asif Ali Zardari disputed last night on CNN. During police interrogations, Kasab himself claimed to hail from the Punjab region of Pakistan and to have trained with the Pakistan-based extremist group, Lashkar-e-Taiba. Of course, Kasab could be making this all up. The only way that interrogators can tap a man's memory is to ask him. But what if the person is unwilling to spill the beans or, at least, the real ones? If only there were only a way to plug a USB cable to the back of Kasab's head and just download the experiences. While such technology may be the stuff of science fiction, Indian government officials have announced they will employ another technique that seems to leap from the pages of a 1940s pulp novel: truth serum. Also known as narcoanalysis, administering psychoactive drugs for interrogation purposes has been around for just under a century, but it has been viewed with skepticism from the start. Indeed, the practice is banned in most democracies, and evidence obtained from such an interrogation would have a hard time making it into an American court. © 1996-2008 Scientific American Inc.

Keyword: Drug Abuse; Stress
Link ID: 12308 - Posted: 06.24.2010

By Melinda Wenner This year 2.25 million Americans will get married—and a million will get divorced. Could birth control be to blame for some of these breakups? Recent research suggests that the contraceptive pill—which prevents women from ovulating by fooling their body into believing it is pregnant—could affect which types of men women desire. Going on or off the pill during a relationship, therefore, may tempt a woman away from her man. It’s all about scent. Hidden in a man’s smell are clues about his major histocompatibility complex (MHC) genes, which play an important role in immune system surveillance. Studies suggest that females prefer the scent of males whose MHC genes differ from their own, a preference that has probably evolved because it helps offspring survive: couples with different MHC genes are less likely to be related to each other than couples with similar genes are, and their children are born with more varied MHC profiles and thus more robust immune systems. A study published in August in the Proceedings of the Royal Society B, however, suggests that women on the pill undergo a shift in preference toward men who share similar MHC genes. The female subjects were more likely to rate these genetically similar men’s scents (via a T-shirt the men had worn for two nights) as pleasant and desirable after they went on the pill as compared with before. Although no one knows why the pill affects attraction, some scientists believe that pregnancy—or in this case, the hormonal changes that mimic pregnancy—draws women toward nurturing relatives. © 1996-2008 Scientific American Inc.

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 12307 - Posted: 06.24.2010

By Bruce Bower There may be no single, simple explanation for reports of recovered memories of childhood sexual abuse. Witness the first evidence that people who report such recall display either of two cognitive profiles, one signaling a susceptibility to retrieving false memories and the other a tendency to have forgotten earlier recollections of actual abuse. Members of the first group typically salvage child sex-abuse memories gradually via psychotherapy that includes hypnosis and other suggestive techniques, say psychologist Elke Geraerts of the University of St. Andrews, Scotland, and her colleagues. Those in the second group suddenly recover memories of abuse, due to unexpected reminders of what happened, the researchers assert in the January Psychological Science. The new research is based on the results of memory tests taken by 120 middle-aged volunteers, mostly women. The work reveals that different ways of remembering and forgetting correspond to how people recover memories of child abuse. Spontaneous recall of actual childhood sexual abuse often produces an illusion of not having remembered those events earlier, Geraerts contends. Her team refers to this phenomenon, which hinges on having recalled the same event in different contexts, as the forgot-it-all-along effect. © Society for Science & the Public 2000 - 2008

Keyword: Learning & Memory
Link ID: 12306 - Posted: 06.24.2010

By Jennifer Couzin With a tanking economy and global violence on the rise, there's at least one thing to smile about: A pair of scientists is reporting that happiness can spread through social networks, meaning that friends of the cheery contract the happiness bug themselves. The data behind the new findings come from, of all things, a massive study of cardiovascular disease. In 1948, researchers began collecting health and other information on U.S. adults as part of the Framingham Heart Study. Today, the project has data on more than 14,000 people, and it has helped researchers identify many of the major risk factors behind heart disease and stroke. Because the Framingham leaders, trying to track volunteers over many years, worried about losing contact with them, they asked all subjects to provide the name of a friend who would know how to find them if necessary. Often, those friends were also part of the study. Nicholas Christakis, formerly a hospice physician at Harvard, and James Fowler, a political scientist at the University of California, San Diego, used these data to create a social network of nearly 5000 people. The duo then matched the information with various health data. Last year, they reported that weight loss and weight gain could "spread" through the network, meaning that a guy whose friends were overweight was more likely to pack on the pounds himself (ScienceNOW, 25 July 2007). Christakis and Fowler published a similar finding on smoking earlier this year. © 2008 American Association for the Advancement of Science.

Keyword: Emotions
Link ID: 12305 - Posted: 06.24.2010

By Guest Columnists Placebos are supposed to be nothing. They’re sugar pills, shots of saline, fake creams; they’re given to the comparison group in drug trials so doctors can see whether a new treatment is better than no treatment. But placebos aren’t nothing. Their ingredients may be bogus, but the elicited reactions are real. “The placebo effect is in some way the bane of the pharma industry’s existence because people have this nasty habit of getting better even without a specific drug,” says David Spiegel, a psychiatrist at Stanford University School of Medicine. It all boils down to expectation. If you expect pain to diminish, the brain releases natural painkillers. If you expect pain to get worse, the brain shuts off the processes that provide pain relief. Somehow, anticipation trips the same neural wires as actual treatment does. Scientists are using imaging techniques to probe brains on placebos and watch the placebo effect in real time. Such studies show, for example, that the pleasure chemical dopamine and the brain’s natural painkillers, opioids, work oppositely depending on whether people expect pain to get better or worse. Other research shows that placebos can reduce anxiety. © Society for Science & the Public 2000 - 2008

Keyword: Pain & Touch
Link ID: 12304 - Posted: 06.24.2010

Mark A. W. Andrews, professor of physiology and director of the Independent Study Pathway at the Lake Erie College of Osteo­pathic Medicine, replies: Generally speaking, heaviness of the muscles around the eyes, including the levator muscles that open the upper eyelids, is similar to fatigue of any muscle of the body. Ocular and brow muscles are especially prone to fatigue because they are active for most of our waking hours. Over the course of the day, they gradually grow leaden with extended use, as our arms and legs do. Such a feeling may be compounded by general fatigue, including a lack of sleep, or by specific muscle overuse related to long hours of focusing on, say, a computer monitor. Excess skin of the eyelid, or prolapsed fat pads underneath the eyes, makes an individual more prone to this sensation. Chronic allergies and sinus infections may also exacerbate the heaviness, and sun exposure may cause eyelid swelling and thereby increase the probability that the drooping will interfere with vision. Although heavy eyelids do not typically indicate underlying medical issues, some conditions do cause drooping eyelids, or ptosis. A stroke or a muscular disorder such as myasthenia gravis or myotonic dystrophy can damage facial muscles or their nerves and cause ptosis, as can elective facial surgery or interventions such as Botox injections to the brow. © 1996-2008 Scientific American Inc.

Keyword: Sleep
Link ID: 12303 - Posted: 06.24.2010

A vast increase in brain research in recent years is giving us a much improved picture of what's going on in our white and grey matter. In case you hadn't noticed, NewScientist.com is now making the last 12 months' of articles free for everyone to read. Here we round up the top 10 in-depth articles on the brain from 2008 Is it worth going to the mind gym? Brains apart: The real difference between the sexes A unified theory of the brain? How primate porn reveals what we really want The secret life of the brain The subconscious mind: Your unsung hero Forgetfulness is key to a healthy mind Does the brain feature built-in noise? Do supercharged brains give rise to autism? The outer limits of the human brain © Copyright Reed Business Information Ltd.

Keyword: Miscellaneous
Link ID: 12302 - Posted: 06.24.2010

by Ewen Callaway Eyewitness accounts of crimes could be more untrustworthy than we thought. Describing an event straight after it occurs makes witnesses more susceptible to providing false information in subsequent retellings, a new study finds. "In a real-life situation, if you're an eyewitness, the first thing you're going to do after you witness an event is call 911," says Jason Chan, a psychologist at Iowa State University in Ames, who led the new study. This initial recollection could prime a witness' brain to accept a mistaken account, he says, be it from television, lawyers, the police, or another witness. Rather than crimes, Chan's team tested the memories of 36 university students and 60 retirees who watched an episode of the television drama 24. Immediately after seeing the episode - in which terrorists hijack a jet - half of the subjects took a quiz on what they had just seen. About 30 minutes later, everyone listened to a short description of the episode, which included details that were either lies or truths. For instance: "The terrorist knocks the flight attendant unconscious with a hypodermic needle" (true); or "The terrorist knocks the flight attendant unconscious with a chloroform rag" (false). © Copyright Reed Business Information Ltd.

Keyword: Learning & Memory
Link ID: 12301 - Posted: 06.24.2010

By Peggy Curran For more than 50 years, Henry G. Molaison has been one of the most studied, famous and anonymous patients in the history of modern medicine. The 82-year-old man scientists have known only as HM died of heart failure Tuesday after decades in a Connecticut chronic care home, unaware of what he gave to science. “He never recognized me, even if I’d been with him all day” Brenda Milner, the pioneering neuropsychologist at the Montreal Neurological Institute who treated HM, said a few years ago. “He was always an extremely polite man. But I could pass him in the waiting room and he wouldn’t bat an eyelid. If you ever said anything, he would just say, ‘I’m sorry, I have a bit of trouble with my memory.’ ” Milner, 90, still works at the MNI, a respected doyenne whose ground-breaking research in human memory systems began in 1956 when Dr. Wilder Penfield and her mentor Dr. Donald Hebb sent her to Hartford to meet the man now known to generations of medical students as “H.M.” A 30-year-old assembly line worker, Molaison had suffered memory loss after parts of his temporal lobe were removed during experimental surgery to relieve severe epilepsy, which was causing him to have seizures and blackouts several times a week. © 2008 Canwest Publishing Inc.

Keyword: Learning & Memory
Link ID: 12300 - Posted: 06.24.2010

By BENEDICT CAREY He knew his name. That much he could remember. H.M.’s Brain and the History of Memory (npr.org) He knew that his father’s family came from Thibodaux, La., and his mother was from Ireland, and he knew about the 1929 stock market crash and World War II and life in the 1940s. But he could remember almost nothing after that. In 1953, he underwent an experimental brain operation in Hartford to correct a seizure disorder, only to emerge from it fundamentally and irreparably changed. He developed a syndrome neurologists call profound amnesia. He had lost the ability to form new memories. For the next 55 years, each time he met a friend, each time he ate a meal, each time he walked in the woods, it was as if for the first time. And for those five decades, he was recognized as the most important patient in the history of brain science. As a participant in hundreds of studies, he helped scientists understand the biology of learning, memory and physical dexterity, as well as the fragile nature of human identity. On Tuesday evening at 5:05, Henry Gustav Molaison — known worldwide only as H. M., to protect his privacy — died of respiratory failure at a nursing home in Windsor Locks, Conn. Copyright 2008 The New York Times Company

Keyword: Learning & Memory
Link ID: 12299 - Posted: 06.24.2010

by Caroline Williams EVER had a feeling come over you that you just can't explain? Like suddenly getting all warm and fuzzy when you meet someone for the first time, while somebody else who looks just as good leaves you cold? Or experiencing a sudden pang of fear on a plane even though you're totally at ease with flying? These seemingly unrelated and illogical human reactions may have a reasonable explanation after all, although one that not everyone will be happy to hear. They may be reactions to other people's pheromones. Pheromones are something of a sensitive subject in human biology. Though they are found across the animal world from insects to mammals, research into human pheromones has been dogged by flaky experimental designs and dubious commercial endorsements, with the result that the entire field has a whiff of the disreputable about it. "It's not so much that the jury is out, but that the jury has been dismissed before the trial has begun," says Mike Meredith, a neuroscientist at Florida State University in Tallahassee, who studies animal pheromones. In recent years, though, this has begun to change. Evidence that animal pheromones don't always work in they way we thought, backed up by a growing number of brain-imaging studies in humans, is convincing some researchers that we really do make and respond to pheromones. As a result some think it's time to stop asking if human pheromones exist and start investigating exactly how they affect our behaviour. © Copyright Reed Business Information Ltd.

Keyword: Chemical Senses (Smell & Taste); Sexual Behavior
Link ID: 12298 - Posted: 06.24.2010

By Jennifer Viegas Nearly two pounds of still-green plant material found in a 2,700-year-old grave in the Gobi Desert has just been identified as the world's oldest marijuana stash, according to a paper in the latest issue of the Journal of Experimental Botany. A barrage of tests proves the marijuana possessed potent psychoactive properties and casts doubt on the theory that the ancients only grew the plant for hemp in order to make clothing, rope and other objects. They apparently were getting high too. Lead author Ethan Russo told Discovery News that the marijuana "is quite similar" to what's grown today. "We know from both the chemical analysis and genetics that it could produce THC (tetrahydrocannabinolic acid synthase, the main psychoactive chemical in the plant)," he explained, adding that no one could feel its effects today, due to decomposition over the millennia. Russo served as a visiting professor at the Chinese Academy of Sciences Institute of Botany while conducting the study. He and his international team analyzed the cannabis, which was excavated at the Yanghai Tombs near Turpan, China. It was found lightly pounded in a wooden bowl in a leather basket near the head of a blue-eyed Caucasian man who died when he was about 45. © 2008 Discovery Channel

Keyword: Drug Abuse
Link ID: 12297 - Posted: 06.24.2010