Linda Carroll TODAY contributor We all get lost or disoriented once in a while, but for Sharon Roseman, being lost is a way of life. A little quirk in her brain makes it impossible to recognize landmarks and find her way around neighborhoods that should have become familiar long ago. “I can literally see my house out the car window, but I have no clue that it’s my house,” Roseman told NBC’s Kristen Dahlgren. Roseman, 64, suffers from developmental topographical disorientation, or DTD, a disorder that had flown under brain researchers’ radar until very recently. DTD was first described as a single case study in a paper published online in 2008 in the journal Neuropsychologia. At the time, it was thought to be extremely rare, says the study’s lead author, Giuseppe Iaria, professor of cognitive neuroscience at the University of Calgary. But since then, Iaria has discovered nearly 1,000 other people with DTD and he thinks there may be a lot more. He currently estimates that about 2 percent of the population may be constantly coping with orientation and navigation problems caused by the disorder. DTD is a profound and disabling deficit. Nothing, not even the layout of a house you’ve lived in for decades, ever becomes familiar. And for Roseman that has made life very trying. When her kids would cry in the night, she would struggle to find her way to them.

Keyword: Attention
Link ID: 18155 - Posted: 05.14.2013

Pregnant mothers’ exposure to the flu was associated with a nearly fourfold increased risk that their child would develop bipolar disorder in adulthood, in a study funded by the National Institutes of Health. The findings add to mounting evidence of possible shared underlying causes and illness processes with schizophrenia, which some studies have also linked to prenatal exposure to influenza. “Prospective mothers should take common sense preventive measures, such as getting flu shots prior to and in the early stages of pregnancy and avoiding contact with people who are symptomatic,” said Alan Brown, M.D., M.P.H, of Columbia University and New York State Psychiatric Institute, a grantee of the NIH’s National Institute of Mental Health (NIMH). “In spite of public health recommendations, only a relatively small fraction of such women get immunized. The weight of evidence now suggests that benefits of the vaccine likely outweigh any possible risk to the mother or newborn.” Brown and colleagues reported their findings online May 8, 2013 in JAMA Psychiatry. Although there have been hints of a maternal influenza/bipolar disorder connection, the new study is the first to prospectively follow families in the same HMO, using physician-based diagnoses and structured standardized psychiatric measures. Access to unique Kaiser-Permanente, county and Child Health and Development Study External Web Site Policy databases made it possible to include more cases with detailed maternal flu exposure information than in previous studies.

Keyword: Schizophrenia; Development of the Brain
Link ID: 18154 - Posted: 05.14.2013

By ABIGAIL ZUGER, M.D. I hadn’t seen Larry in a dozen years when he reappeared in my office a few months ago, grinning. We were both grinning. I always liked Larry, even though he was a bit of a hustler, a little erratic in his appointments, a persistent dabbler in a variety of illegal substances. But he was always careful to avoid the hard stuff; he said he had a bad problem as a teenager and was going to stay out of trouble. It was to stay out of trouble that he left town all those years ago, and now he was back, grayer and thinner but still smiling. Then he pulled out a list of the medications he needed, and we both stopped smiling. According to Larry’s list, he was now taking giant quantities of one of the most addictive painkillers around, an immensely popular black-market drug most doctors automatically avoid prescribing except under the most exceptional circumstances. “I got a bad back now, Doc,” Larry said. Doctors hate pain. Let me count the ways. We hate it because we are (mostly) kindhearted and hate to see people suffer. We hate it because it is invisible, cannot be measured or monitored, and varies wildly and unpredictably from person to person. We hate it because it can drag us closer to the perilous zones of illegal practice than any other complaint. And we hate it most of all because unless we specifically seek out training in how to manage pain, we get virtually none at all, and wind up flying over all kinds of scary territory absolutely solo, without a map or a net. Copyright 2013 The New York Times Company

Keyword: Pain & Touch; Drug Abuse
Link ID: 18153 - Posted: 05.14.2013

By Scicurious Aging happens. As you get older, your body slows down, eventually your brain slows down, too. Some things go gradually, and some go suddenly. To many people, this might seem like a pretty random process. We used to think of aging this way, as just…well cells get old, which means we get old, too. DNA replication after a while starts making errors in repair, the errors build up, and on the whole body scale the whole thing just kind of goes downhill. It seems random. But in fact, it’s not. There are specific proteins which can help control this process. And one of these, NF-kB, in one particular brain region, may have a very important role indeed. NF-kB (which stands for nuclear factor kappa-light-chain-enhancer of activated B cells, which is why we use NF-kB) is a protein complex that has a lot of roles to play. It’s an important starting player in the immune system, where it helps to stimulate antibodies. It’s important in memory and stress responses. NF-kB is something called a transcription factor, which helps to control what DNA is transcribed to RNA, and therefore what proteins will eventually be produced. Transcription factors, as you can see, can have a very large number of functions. But in the hypothalamus, NF-kB may have the added function of helping to control aging. The hypothalamus is an area of many small nuclei (further sub areas of neurons) located at the base of the brain. It’s been coming more and more into vogue lately among neuroscientists. In the past, we were interested in the hypothalamus mostly for its role in controlling hormone release from the dangling pituitary gland before it, but now we are learning that the hypothalamus can play roles in fear, mood, food intake, reproduction, and now…aging. © 2013 Scientific American

Keyword: Development of the Brain; Hormones & Behavior
Link ID: 18152 - Posted: 05.14.2013

Zoe Cormier A study of two ancient hominins from South Africa suggests that changes in the shape and size of the middle ear occurred early in our evolution. Such alterations could have profoundly changed what our ancestors could hear — and perhaps how they could communicate. Palaeoanthropologist Rolf Quam of Binghamton University in New York state and his colleagues recovered and analysed a complete set of the three tiny middle-ear bones, or ossicles, from a 1.8-million-year-old specimen of Paranthropus robustus and an incomplete set of ossicles from Australopithecus africanus, which lived from about 3.3 million to around 2.1 million years ago. The ossicles are the smallest bones in the human body, and are rarely preserved intact in hominin fossils, Quam says. In both specimens, the team found that the malleus (the first in the chain of the three middle-ear bones) was human-like — smaller in proportion compared to the ones in our ape relatives. Its size would also imply a smaller eardrum. The similarity between the two species points to a “deep and ancient origin” of this feature, Quam says. “This could be like bipedalism: a defining characteristic of hominins.” It is hard to draw conclusions about hearing just from the shape of the middle-ear bones because the process involves so many different ear structures, as well as the brain itself. However, some studies have shown that the relative sizes of the middle-ear bones do affect what primates can hear2. Genomic comparisons with gorillas have indicated that changes in the genes that code for these structures might also demarcate humans from apes3. © 2013 Nature Publishing Group

Keyword: Hearing; Evolution
Link ID: 18151 - Posted: 05.14.2013

by Michael Balter Researchers debate when language first evolved, but one thing is sure: Language requires us not only to talk but also to listen. A team of scientists now reports recovering the earliest known complete set of the three tiny middle ear bones—the malleus ("hammer"), incus ("anvil"), and stapes ("stirrup")—in a 2.0-million-year-old skull of Paranthropus robustus, a distant human relative found in South Africa (see photo). Reporting online today in the Proceedings of the National Academy of Sciences, the researchers found that the malleus of P. robustus, as well one found earlier in the early human relative Australopithecus africanus, is similar to that of modern humans, whereas the two other ear bones most closely resemble existing African and Asian great apes. The team is not entirely sure what this precocious appearance of a human-like malleus means. But since the malleus is attached directly to the eardrum, the researchers suggest that it might be an early sign of the high human sensitivity to middle-range acoustic frequencies between 2 and 4 kilohertz—frequencies critical to spoken language, but which apes and other primates are much less sensitive to. © 2010 American Association for the Advancement of Science

Keyword: Hearing; Evolution
Link ID: 18150 - Posted: 05.14.2013

By DAVID DOBBS In the autistic person, it seems, hums a vital and distinctive essence — but one whose nature is obscured by thick layers of behavior and perception. Or, as Temple Grandin puts it, “two panes of glass.” For a quarter century, Dr. Grandin — the brainy, straight-speaking, cowboy-shirt-wearing animal scientist and slaughterhouse designer who at 62 is perhaps the world’s most famous autistic person — has been helping people break through the barriers separating autistic from nonautistic experience. Like Dr. Sacks, who made her famous as the title figure in his 1995 collection “An Anthropologist on Mars,” Dr. Grandin has helped us understand autism not just as a phenomenon, but as a different but coherent mode of existence that otherwise confounds us. In her own books and public appearances, she excels at finding concrete examples that reveal the perceptual and social limitations of autistic and “neurotypical” people alike. In “The Autistic Brain,” her latest book, written with the science author Richard Panek, she shows this talent most vividly in a middle chapter that looks at the sensory world of autism. It is a world filled with anomalies, in which everyday sensations can be overwhelming: A school bell can feel like a dentist’s drill, a scratchy shirt like a swarm of fire ants. In other cases the autistic person may feel so little sensation that she’ll try to fill the vacuum and create some sort of order — hence the rocking, twirling, hand-flapping, noisemaking behaviors that can discomfit and alienate onlookers. © 2013 The New York Times Company

Keyword: Autism
Link ID: 18149 - Posted: 05.14.2013

By Melanie Tannenbaum Imagine that you’re an infant monkey, and you’ve just been thrown into a cage after several hours in isolation. You’ve been deprived of food, so you’re starving. Facing you are two adult-looking (fake) monkeys, designed to look like each one could potentially be your mother. On the left is a “wire mother,” equipped with a bottle and feeding tube so you can cling to her and fill your belly with milk. On the right is a “cloth mother,” with no bottle, but with a fuzzy terrycloth exterior that will allow for hours of soft, warm snuggles. You can only run to one of the monkeys. Which one will you choose? Six or seven decades ago, many psychologists would have claimed that any affection that we experience towards our parental figures is a purely behaviorist response. After many instances of conditioning a sense of “positive affect” after receiving life-sustaining food from mothers, children associate that positive emotion with these caregivers, an association that serves as the sole explanation for why people “love” their mothers. But that’s not what Harry Harlow thought. Harlow, a psychologist working at the University of Wisconsin – Madison during the 1960s, believed that there was something more important underlying our affection for Mom and Dad than our primal need to eat and survive. He believed that there was an additional factor: Comfort. What Harlow did to test this hypothesis was arguably ingenious, though inarguably cruel.1 Harlow deprived monkeys of food, making them desperately hungry, and then stuck them into a cage where they had a choice of two “mother figures” to run towards. On the left was a wire mother – cold and uncomfortable, yet equipped with a bottle that would feed the baby with life-sustaining nutrients. On the right was a cloth mother – warm, soft, and comfortable, yet unable to provide the infant with any food. If the only reason why we “love” our mothers (and fathers) is based on a conditioned response to our need for food, then the infant monkeys should run to the wire mothers who can feed them every time. © 2013 Scientific American

Keyword: Sexual Behavior; Development of the Brain
Link ID: 18148 - Posted: 05.14.2013

By ANDREW C. REVKIN Twenty-two months ago, I interrupted my nonstop reporting about paths toward a sustainable future for our species to focus on sustaining myself. The hiatus was not by choice, but was mandated by a stroke — the out-of-the-blue variant, the rare kind of “brain attack” (the term preferred by some neurologists) that is most often seen in otherwise healthy, youngish middle-aged people. It’s Fourth of July weekend, 2011 — a beautiful, if hot, morning for a run in the Hudson Valley woods with my son Daniel, back from brief service in the Israeli army. I’m eager to be pushed hard. I’m not even a lapsed middle-aged athlete; I’m truly negligent when it comes to exercise. We’re jogging up a steep path, and my breathing gets deeper and faster. At a particularly tough turn, I pause, hands on knees. “Come on, keep it up, Dad.” I’m panting but don’t want to disappoint. We press on. But I stop again, this time insisting that Daniel run ahead. I rest in the mottled shade and sunlight of the woods until he returns. Then I realize that through my left eye, the world appears paisley — as if I were looking through a patterned curtain. Something is really wrong. We make it back to the car. Daniel takes the wheel. Back home, I take a shower, thinking that cooling off will help. For the first time, a thought flickers. Could this be a stroke? Almost unconsciously, I take half a dozen baby aspirin. I know enough about aspirin’s blood-thinning properties to think this can’t hurt. Copyright 2013 The New York Times Company

Keyword: Stroke
Link ID: 18147 - Posted: 05.14.2013

By ANAHAD O'CONNOR The nation’s largest cardiovascular health organization has a new message for Americans: Owning a dog may protect you from heart disease. The unusual message was contained in a scientific statement published on Thursday by the American Heart Association, which convened a panel of experts to review years of data on the cardiovascular benefits of owning a pet. The group concluded that owning a dog, in particular, was “probably associated” with a reduced risk of heart disease. People who own dogs certainly have more reason to get outside and take walks, and studies show that most owners form such close bonds with their pets that being in their presence blunts the owners’ reactions to stress and lowers their heart rate, said Dr. Glenn N. Levine, the head of the committee that wrote the statement. But most of the evidence is observational, which makes it impossible to rule out the prospect that people who are healthier and more active in the first place are simply more likely to bring a dog or cat into their home. “We didn’t want to make this too strong of a statement,” said Dr. Levine, a professor at the Baylor College of Medicine. “But there are plausible psychological, sociological and physiological reasons to believe that pet ownership might actually have a causal role in decreasing cardiovascular risk.” Nationwide, Americans keep roughly 70 million dogs and 74 million cats as pets. Copyright 2013 The New York Times Company

Keyword: Emotions; Neuroimmunology
Link ID: 18146 - Posted: 05.11.2013

By Puneet Kollipara Identical twin mice sharing the same mazelike environment develop distinct personalities based on how much they explore their surroundings, researchers report in the May 10 Science. After death, those differences were reflected in the animals’ brains. The study “highlights something for which we had some intuition before, but actually quantifies it,” says Fred Gage, a neuroscientist at the Salk Institute for Biological Studies in La Jolla, Calif. Some character and biological differences between identical twins may originate as early as pregnancy. But twins become more and more different as life goes on, even when they grow up together. Scientists have recognized that having distinct experiences within the same environment might boost such personality differences, but that’s difficult to test in humans. Studying it in animals has multiple benefits. “You can keep the genes constant and also keep the environment constant,” says Gerd Kempermann of the Center for Regenerative Therapies Dresden in Germany. “It’s much more controlled than in a human situation.” Researchers led by Kempermann put 40 genetically identical female mice in an elaborate cage and observed their behavior. The cage had multiple levels linked together by tubes and contained toys and other features that the animals could explore. The researchers equipped each mouse with a microchip that tracked its location, using the animals’ movements as a measure of exploratory behavior. Initially, the mice differed only slightly in their tendency to roam. As they grew older, all tended to explore more often, but the differences among the mice grew more pronounced. © Society for Science & the Public 2000 - 2013

Keyword: Epigenetics; Genes & Behavior
Link ID: 18145 - Posted: 05.11.2013

Heidi Ledford Nassir Ghaemi, director of the Mood Disorders Program at Tufts Medical Center in Boston, Massachusetts, has felt shackled by the Diagnostic and Statistical Manual of Mental Disorders (DSM), often called the bible of psychiatry. Some of his depressed patients occasionally show manic behaviour but do not fulfil the DSM’s criteria for a diagnosis of bipolar disorder. Ghaemi is interested in whether such patients might respond better to drugs for bipolar disorder than for depression. But his colleagues warned him against straying from the DSM when he applied for funding at the US National Institute of Mental Health (NIMH), because peer reviewers tended to insist on research that hewed to DSM categories. Ghaemi held off from applying. If NIMH director Thomas Insel has his way, Ghaemi and other mental-health researchers will no longer feel the weight of the DSM. “NIMH will be re-orienting its research away from DSM categories,” Insel wrote in a blog entry on 29 April. The latest edition, the DSM-5, will be unveiled on 22 May at the annual meeting of the American Psychiatric Association in San Francisco, California. Like many psychiatrists, Insel questions whether the DSM’s categories accurately reflect the way the brain works. He is pushing a project that aims to create a new framework that classifies mental-health disorders according to their biological roots. “Going forward, we will be supporting research projects that look across current categories — or sub-divide current categories — to begin to develop a better system,” Insel wrote. The blog post made waves in the media and rattled some psychiatric clinicians and researchers. But Insel says that he has been talking about the issue since 2008. “The word was just still not out there,” he says. Insel says that he has increasingly received complaints from grant applicants who have tried to follow his guidance, only to be shot down by peer reviewers for eschewing DSM scripture. © 2013 Nature Publishing Group

Keyword: Schizophrenia; Depression
Link ID: 18144 - Posted: 05.11.2013

by Claudia M Gold It seems that the National Institute of Mental Health (NIMH) may have dealt a death blow to the recently published Diagnostic and Statistical Manual of Mental Disorders (DSM 5) when the organization declared they would no longer fund research based on the DSM system of diagnosis. The views of NIMH director Thomas Insel were referenced in the recent New York Times article on the subject. His goal was to reshape the direction of psychiatric research to focus on biology, genetics and neuroscience so that scientists can define disorders by their causes, rather than their symptoms. I am no fan of the DSM system, which reduces complex experience to lists of symptoms; focusing on the "what" rather than the "why." However, the NIMH model has limits as well. There seems to be a wish to study mental illness in the same way we study cancer or diabetes. While I certainly have great respect for the complexity of the pancreas, or the process of malignant transformation of cells, trying to understand the brain/mind in an analogous way seems to be an unnecessary and even undesirable reduction of human experience. What is missing from both paradigms is recognition of the relational and historical context of being human. Fortunately there seems to be awareness that neither paradigm is complete. The Times article goes on to say: Dr. Insel is one of a growing number of scientists who think that the field needs an entirely new paradigm for understanding mental disorders, though neither he nor anyone else knows exactly what it will look like. © 2013 NY Times Co.

Keyword: Schizophrenia; Depression
Link ID: 18143 - Posted: 05.11.2013

by Helen Thomson "I was sitting on the toilet. I suddenly felt an explosion in the left side of my head and ended up on the floor. I think the only thing that kept me conscious was that I didn't want to be found with my pants down. Then the other side of my head went bang! I woke up in hospital and looked out of the window to see the tree was sprouting numbers. 3, 6, 9. Then I started talking in rhyme…" Ten days after having a subarachnoid haemorrhage – a stroke caused by bleeding in and around the brain – Tommy McHugh, an ex-con who'd been in his fair share of scraps, became a new man, with a personality that nobody recognised. When he was a young man, Tommy did time in prison. But after his stroke at age 51, everything changed. "I could taste the femininity inside of myself," he said. "My head was full of rhymes and images and pictures." Not only did he feel a sudden urge to write poetry, but he also began to paint and draw obsessively for up to 19 hours a day. He was never artistic before – in fact, he joked that he'd never even been in an art gallery "except to maybe steal something". Desperate to find out what was going on, Tommy wrote to several neuroscientists and end up working closely with Alice Flaherty at Harvard Medical School and Mark Lythgoe at University College London. © Copyright Reed Business Information Ltd.

Keyword: Laterality; Stroke
Link ID: 18142 - Posted: 05.11.2013

By Ian Chant Most people make good decisions most of the time. But when drug addiction, disease or brain injury enters the picture, rational thinking can go awry. What if the damaged brain just needed a little reminder of how it feels to choose wisely? Enter the MIMO neural prosthesis, an array of electrodes implanted in the brain that make contact with eight neuron circuits in the prefrontal cor-tex, the brain's command center for decision making. The device can both record the brain activity associated with good choices and stimulate the relevant neurons to get the brain back on track. Although the implant can listen in only on a tiny subset of the neurons in this region, the scientists who developed it, based at Wake Forest Baptist Medical Center, were surprised to discover that they could still pick up signature patterns associated with correct choices, at least in the context of a simple task. The researchers tested the neural prosthesis on monkeys that were trained to move a cursor over a picture on a computer screen to get a food reward. The implant first recorded the brain activity associated with choosing the correct picture. Then the monkeys were given cocaine, and their performance plummeted. But when the implant was switched on to send electric current to the neurons that had earlier been associated with the correct answers, the monkeys immediately started selecting the right pictures again. Some of them did an even better job than they had before receiving cocaine. © 2013 Scientific American,

Keyword: Drug Abuse; Learning & Memory
Link ID: 18141 - Posted: 05.11.2013

By Bruce Bower Provocative evidence that certain memory exercises make people smarter has sparked the rise of online brain-training programs such as Lumosity. But at least one type of brain training may not work as advertised, a new study finds. As expected, practicing improved volunteers’ performance on tests of memory and the ability to locate items quickly in busy scenes, say psychologist Thomas Redick of Indiana University Purdue University Columbus and his colleagues. That improvement did not, however, translate into higher scores on tests of intelligence and multitasking, the researchers report in the May Journal of Experimental Psychology: General. Redick’s investigation is part of a growing scientific debate about brain training, which is promoted by some companies as having a variety of mental benefits. Some researchers say that extensive instruction and training on memory tasks can indeed fortify reasoning and problem solving. Others are skeptical that vigorous memory sessions produce such wide-ranging effects. The dispute feeds into a longstanding scientific controversy about whether enriched environments can increase intelligence, as measured on IQ tests. What’s not up for debate is that many people feel smarter after brain training. In the new study, 10 of 23 individuals who completed memory sessions said that the program helped them to think, multitask and focus better in daily life. But the scientists say that even if some participants performed daily tasks better after memory training, they may simply have tried harder or felt better about their efforts due to a belief that training had strengthened their minds. © Society for Science & the Public 2000 - 2013

Keyword: Learning & Memory
Link ID: 18140 - Posted: 05.11.2013

By John McCarthy Into brains of newborn mice, researchers implanted human “progenitor cells.” These mature into a type of brain cell called astrocytes (see below). They grew into human astrocytes, crowding out mouse astrocytes. The mouse brains became chimeras of human and mouse, with the workhorse mouse brain cells – neurons – nurtured by billions of human astrocytes. Neuroscience is only beginning to discover what astrocytes do in brains. One job that is known is that they help neurons build connections (synapses) with other neurons. (Firing neurotransmitter molecules across synapses is how neurons communicate.) Human astrocytes are larger and more complex than those of other mammals. Humans’ unique brain capabilities may depend on this complexity. Human astrocytes certainly inspired the mice. Their neurons did indeed build stronger synapses. (Perhaps this was because human astrocytes signal three times faster than mouse astrocytes do.) Mouse learning sharpened, too. On the first try, for instance, altered mice perceived the connection between a noise and an electric shock (a standard learning test in mouse research). Normal mice need a few repetitions to get the idea. Memories of the doctored mice were better too: they remembered mazes, object locations, and the shock lessons longer. The reciprocal pulsing of billions of human and mouse brain cells inside a mouse skull is a little creepy. Imagine one of these hybrid mice exploring your living room. Would you feel like a Stone Age tribesman observing a toy robot? Does the thing think? © 2013 Scientific American

Keyword: Glia; Learning & Memory
Link ID: 18139 - Posted: 05.11.2013

Roberta Kwok Sitting motionless in her wheelchair, paralysed from the neck down by a stroke, Cathy Hutchinson seems to take no notice of the cable rising from the top of her head through her curly dark hair. Instead, she stares intently at a bottle sitting on the table in front of her, a straw protruding from the top. Her gaze never wavers as she mentally guides a robot arm beside her to reach across the table, close its grippers around the bottle, then slowly lift the vessel towards her mouth. Only when she finally manages to take a sip does her face relax into a luminous smile. This video of 58-year-old Hutchinson illustrates the strides being taken in brain-controlled prosthetics1. Over the past 15 years, researchers have shown that a rat can make a robotic arm push a lever2, a monkey can play a video game3 and a person with quadriplegia — Hutchinson — can sip from a bottle of coffee1, all by simply thinking about the action. Improvements in prosthetic limbs have been equally dramatic, with devices now able to move individual fingers and bend at more than two dozen joints. But Hutchinson's focused stare in that video also illustrates the one crucial feature still missing from prosthetics. Her eyes could tell her where the arm was, but she could not feel what it was doing. Nor could she sense when the grippers touched the bottle, or whether it was slipping out of their grasp. Without this type of sensory feedback, even the simplest actions can be slow and clumsy, as Igor Spetic of Madison, Ohio, knows well. Fitted with a prosthetic after his right hand was crushed in an industrial accident in 2010, Spetic describes breaking dishes, grabbing fruit too hard and bruising it and dropping a can when trying to pick it up at the local shop. Having a sense of touch would be “tremendous”, he says. “It'd be one step closer to having the hand back.” © 2013 Nature Publishing Group,

Keyword: Pain & Touch; Robotics
Link ID: 18138 - Posted: 05.09.2013

Ed Yong Many moths have evolved sensitive hearing that can pick up the ultrasonic probes of bats that want to eat them. But one species comes pre-adapted for anything that bats might bring to this evolutionary arms race. Even though its ears are extremely simple — a pair of eardrums on its flanks that each vibrate four receptor cells — it can sense frequencies up to 300 kilohertz, well beyond the range of any other animal and higher than any bat can squeak. “A lot of previous work has suggested that some bats have evolved calls that are out of the hearing range of the moths they are hunting. But this moth can hear the calls of any bat,” says James Windmill, an acoustical engineer at the University of Strathclyde, UK, who discovered the ability in the greater wax moth (Galleria mellonella). His study is published in Biology Letters1. Windmill's collaborator Hannah Moir, a bioacoustician now at the University of Leeds, UK, played sounds of varying frequencies to immobilized wax moths. As the insects “listened”, Moir used a laser to measure the vibrations of their eardrums, and electrodes to record the activity of their auditory nerves. The moths were most sensitive to frequencies of around 80 kilohertz, the average frequency of their courtship calls. But when exposed to 300 kilohertz, the highest level that the team tested, the insects' eardrums still vibrated and their neurons still fired. © 2013 Nature Publishing Group

Keyword: Hearing; Evolution
Link ID: 18137 - Posted: 05.09.2013

By NICHOLAS BAKALAR Two studies have found that depression and the use of certain antidepressants are both associated with increased risk for Clostridium difficile infection, an increasingly common cause of diarrhea that in the worst cases can be fatal. Researchers studied 16,781 men and women, average age 68, using hospital records and interviews to record cases of the infection, often called C. diff, and diagnoses of depression. The interviews were conducted biennially from 1991 to 2007 to gather self-reports of feelings of sadness and other emotional problems. There were 404 cases of C. difficile infection. After adjusting for other variables, the researchers found that the risk of C. diff infection among people with a history of depression or depressive symptoms was 36 to 47 percent greater than among people without depression. A second study, involving 4,047 hospitalized patients, average age 58, found a similar association of infection with depression. In addition, it found an association of some antidepressants — Remeron, Prozac and trazodone — with C. diff infection. There was no association with other antidepressants. “We have known for a long time that depression is associated with changes in the gastrointestinal system,” said the lead author, Mary A.M. Rogers, a research assistant professor at the University of Michigan, “and this interaction between the brain and the gut deserves more study.” Both reports appeared in the journal BMC Medicine. Copyright 2013 The New York Times Company

Keyword: Depression; Neuroimmunology
Link ID: 18136 - Posted: 05.09.2013