Chapter 16. None
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By Janice Neumann (Reuters Health) - Moderate-intensity exercise, or even just walking, can improve quality of life for depressed middle-aged women, a large Australian study suggests. Women who averaged 150 minutes of moderate exercise (golf, tennis, aerobics classes, swimming, or line-dancing) or 200 minutes of walking every week had more energy, socialized more, felt better emotionally, and weren't as limited by their depression when researchers followed up after three years. They also had less pain and did better physically, although the psychological benefit was greater. With depression so prevalent, "there is an urgent need" to identify treatments, including non-medical options that people can do themselves, said Kristiann Heesch, who led the study. Heesch, senior lecturer at Queensland University of Technology, and her colleagues point out in a January 13 online article in the American Journal of Preventive Medicine that depression is expected to be the second-leading cause of global disease by 2030 and the leading cause in high-income countries. One in 10 U.S. adults suffers from depression, according to the Centers for Disease Control and Prevention. Women are 70% more likely to be depressed at some point in their lives than men, according to the National Institute of Mental Health. In previous research, Heesch found that exercise and walking could boost physical and emotional health in women who are not depressed. © 2015 Scientific American
Link ID: 20536 - Posted: 01.31.2015
Ewen Callaway Since August 2014, more than 100 children and young adults in the United States have developed a mysterious paralysis. Many of them had fevers before losing strength in one or more limbs, and the cases coincided with a wider epidemic of a little-known respiratory pathogen. That virus, enterovirus D68 (EV-D68), is the leading candidate for the cause of the paralysis, which few children have recovered from. Yet researchers have not definitively linked the two, or determined how the virus could cause the children’s symptoms. A study published on 28 January in The Lancet1 that describes a cluster of cases from Denver, Colorado, strengthens the link, but falls short of providing a 'smoking gun'. Here is what we know about the virus — and what scientists are trying to find out. It belongs to the enterovirus family, which includes poliovirus and the pathogens that cause common colds; it is most similar to the rhinoviruses that cause respiratory infections. Although EV-D68 was first isolated in the 1960s, it is relatively uncommon among enteroviruses circulating worldwide. However, since August 2014, the virus has been linked to more than 1,000 respiratory infections in the United States, some of them severe, and France has seen cases, too. John Watson, a medical epidemiologist at the US Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, says that last year, EV-D68 was the predominant type of enterovirus circulating in the country. “That’s a first,” he says. Genome sequencing2 of viruses recovered from respiratory cases in St Louis, Missouri, shows that the EV-D68 strain circulating in the United States is most closely related to viruses that caused a pneumonia-like illness in three children in Thailand in 20113. What is the evidence that links EV-D68 to the cases of paralysis? © 2015 Nature Publishing Group
Keyword: Movement Disorders
Link ID: 20533 - Posted: 01.29.2015
By Michael Balter Our ancestors likely had sex with Neandertals, but when and where did these encounters take place? The discovery of a 55,000-year-old partial skull of a modern human in an Israeli cave, the first sighting of Homo sapiens in this time and place, offers skeletal evidence to support the idea that Neandertals and moderns mated in the Middle East between 50,000 and 60,000 years ago. What’s more, the skull could belong to an ancestor of the modern humans who later swept across Europe and Asia and replaced the Neandertals. The find supports a raft of recent genetic studies. A 2010 analysis, for example, found that up to 2% of the genomes of today’s Europeans and Asians consist of Neandertal DNA, a clear sign of at least limited interbreeding in the past. Two years later, scientists compared ancient DNA extracted from Neandertal fossils to that of contemporary modern human populations around the world, concluding that this interbreeding took place in the Middle East, most likely between 47,000 and 65,000 years ago. And last year, a 45,000-year-old modern human found in Siberia, the oldest modern to have its genome sequenced, was revealed to have harbored a little more than 2% Neandertal DNA, allowing researchers to refine the interbreeding event to roughly 50,000 to 60,000 years ago. From the Neandertal side, this time and place make sense. That’s because numerous skeletons dated to that time period have been found in caves in Israel and other parts of the Middle East over the years, and Neandertals were still living in the region as late as 49,000 years ago. Yet the other side of this mating partnership has been conspicuously absent from the fossil record of the Middle East. © 2015 American Association for the Advancement of Science
Link ID: 20532 - Posted: 01.29.2015
By Nicholas Weiler If you find people watching oddly compelling, you’re not alone. A new study suggests that gregarious European starlings (Sturnus vulgaris) get a kick out of looking at their fellow birds, even if it’s just on a computer screen. Researchers took 10 captive starlings from their flock and isolated them for 4 days in a cage with plenty of food and water and a large flat-screen monitor. Most of the birds quickly discovered that poking their beaks into one sensor in the cage flashed a life-size photograph of an unknown starling onto the screen, while a second sensor produced a picture of a suburban landscape. The lonely birds seemed to enjoy looking at other starlings, the researchers found. On average, they triggered a new starling photo every 6 minutes, 7 hours a day, for 4 days. They only threw in a landscape every 20 minutes or so. It wasn’t just that the landscapes were boring. Given the choice between photos of starlings and photos of monkeys, a second group of five birds also pecked to view their own kind three times more often. The results suggest starlings have a natural yearning for social stimulation, the authors report online this month in Animal Cognition. In the future, starlings’ drive to view photos of one another could be used to study the social rewards that knit communities together. © 2015 American Association for the Advancement of Science
|By Daniel Yudkin Imagine you are with some friends at a concert, and the bouncer approaches the group and says that, because you are all looking so ravishing tonight, he’s been instructed to offer one of you—just one!—a backstage pass to meet the artist. Do you raise your hand? For most people, this would be a no-brainer: who wouldn’t leap at the chance to meet a famous singer or secure a long-sought autograph? The results of a recent study, published in Psychological Science by Gus Cooney, Daniel Gilbert, and Timothy Wilson, however, suggest taking a second’s pause before snapping up that backstage pass. Cooney, Gilbert, and Wilson suspected that extraordinary experiences—like meeting a musical idol—carry hidden costs. They hypothesized that, while such occurrences undoubtedly make us happier in the moment, they also risk separating us from our peers, leading to a sense of isolation so unpleasant as to outweigh whatever enjoyment they initially confer. To test this idea, the researchers recruited subjects in groups of four and had them watch a video clip. Of the group, three were told that they would watch a clip that previous viewers had given a 2-star rating; the remaining subject, by contrast, was granted the opportunity to view a special 4-star clip. After watching the videos, all four subjects were given some time to talk amongst themselves, and then each reported on their general happiness. © 2015 Scientific American
Link ID: 20527 - Posted: 01.28.2015
Ian Sample, science editor People who carry a mutated gene linked to longer lifespan have extra tissue in part of the brain that seems to protect them against mental decline in old age. The finding has shed light on a biological pathway that researchers now hope to turn into a therapy that slows the progression of Alzheimer’s disease and other forms of dementia. Brain scans of more than 400 healthy men and women aged 53 and over found that those who carried a single copy of a particular gene variant had a larger brain region that deals with planning and decision making. Further tests on the group found that those with an enlarged right dorsolateral prefrontal cortex (rDLPFC), as the brain region is known, fared better on a series of mental tasks. About one in five people inherits a single copy of the gene variant, or allele, known as KL-VS, which improves heart and kidney function, and on average adds about three years to human lifespan, according to Dena Dubal, a neurologist at University of California, San Francisco. Her latest work suggests that the same genetic mutation has broader effects on the brain. While having a larger rDLPFC accounted for only 12% of the improvement in people’s mental test scores, Dubal suspects the gene alters the brain in other ways, perhaps by improving the connections that form between neurons.
By Eliot Marshall In perhaps the most famous study of childhood neglect, researchers have closely tracked the progress, or lack of it, in children who lived as infants in Romania’s bleak orphanages and are now teenagers. A new analysis now shows that these children, who display a variety of behavioral and cognitive problems, have less white matter in their brains than do a group of comparable children in local families. The affected brain regions include nerve bundles that support attention, general cognition, and emotion processing. The work suggests that sensory deprivation early in life can have dramatic anatomical impacts on the brain and may help explain the previously documented long-term negative affects on behavior. But there’s some potential good news: A small group of children who were taken out of orphanages and moved into foster homes at age 2 appeared to bounce back, at least in brain structure. “This is an exciting and important study,” says Harvard Medical School psychiatric researcher Martin Teicher, who directs the developmental biopsychiatry research program at McLean Hospital in Belmont, Massachusetts. The “crucial question” of whether children can recover from the setbacks of early adversity had not been answered before, he adds. The work is based on MRI scans and other measures taken in Romania by researchers at the Bucharest Early Intervention Project (BEIP). The group, headed by neurologist Charles Nelson of Harvard Medical School, was spurred to action by the collapse of Romania’s Nicolae Ceauceșcu regime in 1989, which had shunted tens of thousands of unwanted children into state-run orphanages. Nelson says that caretakers in the orphanages worked in factorylike shifts; children might see as many as 17 different caretakers in a week. Infants rarely enjoyed the one-on-one interactions that are considered essential to normal development. © 2015 American Association for the Advancement of Science
|By Christof Koch Faces are the glue that holds us together and that gives us our identity. All of us but the visually impaired and blind are experts at recognizing people's identity, gender, age and ethnicity from looking at their faces. First impressions of attractiveness or competence take but a brief glimpse of somebody's face. Newly born infants already tend to fixate on faces. This bias also turns up in art. Paintings and movies are filled with faces staring at the viewer. Who can forget the endless close-ups of the feuding husband and wife in Ingmar Bergman's Cimmerian masterpiece Scenes from a Marriage? Because recognizing a face is so vital to our social lives, it comes as no surprise that a lot of real estate in the cerebral cortex—the highly convoluted region that makes up the bulk of our brain—is devoted to a task crucial to processing faces and their identity. We note whether someone looks our way or not. We discern emotional expressions, whether they register joy, fear or anger. Indeed, functional brain imaging has identified a set of adjacent regions, referred to as the fusiform face area (FFA), that are situated on the left and the right sides of the brain, at the bottom of the temporal lobe of the cerebral cortex. The FFA turns up its activity when subjects look at portraits or close-ups of faces or even when they just think about these images. Two just published studies of the brain's visual networks, including the FFA, enlarge what we know about the physical basis of face perception. Both explore the unique access to the brain afforded by patients whose epileptic seizures have proved resistant to drugs. A surgical treatment finds the locations in the brain where the hypersynchronized activity that characterizes a seizure begins before spreading from its point of origin to engulf one or sometimes both hemispheres. If a single point—a focus where the seizure begins—can be found, it can be removed. After this procedure, a patient usually has significantly fewer seizures—and some remain seizure-free. To triangulate the location of the focus, neurosurgeons insert electrodes into the brain to monitor electrical activity that occurs during a seizure. © 2015 Scientific American
Link ID: 20523 - Posted: 01.27.2015
David Cox Bernd Heinrich was on a hike through the woods of New England when he observed something which would go on to change our perception of animal psychology. A group of ravens had gathered to feed on a dead moose. But rather than choosing to keep the bounty for themselves, they were making a strange call, one which seemed to be deliberately attracting more ravens to the feast. A biologist at the University of Vermont, Heinrich was initially confused. By helping their competitors, the ravens appeared to be defying all natural biological instinct. But as it transpired, their motivation was actually deeply selfish. The birds were juveniles who had discovered the moose in an adult raven’s territory. By inviting other ravens to join them, their intrusion was more likely to go unchallenged. Last month, an astonishing video emerged of a rhesus macaque successfully resuscitating another of its species which had been electrocuted at a train station in India. It is tempting to describe the sustained display of persistence and apparent concern as almost human. But there is a danger in viewing animal behaviour through the misty lens of human emotion. What both Heinrich’s “sharing ravens’ and the macaques of Kampur do provide is a window into the gradual evolution of one of the most human of traits – altruism. Altruism in its purest form should be an entirely selfless action. “If there’s any kind of selfish interest at stake, like secretly hoping for a return favour or even doing it deliberately because you know it will make you feel good, then that doesn’t really count at all,” says psychologist Michael Platt of the Center for Cognitive Neuroscience at Duke University, North Carolina.
By Will Boggs MD (Reuters Health) – There are so many different genetic forms of autism that using the singular term, autism, is misleading, researchers say. “We believe a better term to use is ‘the autisms,’ or ‘the autism spectrum disorders’ (that is, plural),” Dr. Stephen W. Scherer told Reuters Health by email. “There are many different forms of autism. In other words, autism is more of a collection of different disorders that have a common clinical manifestation.” The DNA of affected individuals varies remarkably, his team found. Two-thirds of brothers and sisters with what’s still called autism spectrum disorder, or ASD, showed different genetic changes. Scherer, from The Hospital for Sick Children in Toronto, Ontario, Canada, is part of a team that aims to identify all the genetic changes in individuals with ASD. In the U.S., the Centers for Disease Control and Prevention (CDC) estimates that 1 in 68 children (1 in 42 boys and 1 in 189 girls) have an autism spectrum disorder. Recent estimates in Europe, the CDC says, are that one to two percent of children there are affected. When Scherer's team looked for genetic changes in the entire DNA from 85 pairs of brothers and sisters with ASD and their parents, they found an average of roughly 73 genetic changes per set of DNA -- but only 36 of the 85 families (42.4 percent) had mutations that researchers could relate to genes already linked in some way to ASD. © 2015 Scientific American
Link ID: 20520 - Posted: 01.27.2015
|By Tori Rodriguez Scientists have studied brain structure for decades, so most disease-related structural anomalies have been long known. New findings of this nature are rare—yet last summer one neuroscientist studying depression published just that. Over nine years of sorting through countless brain images, Jerome J. Maller of Monash University and Alfred Hospital in Melbourne noticed a particular type of brain abnormality that seemed to show up more often in depressed patients. Their occipital lobes were often wrapped around each other. Maller and his colleagues investigated further and found that depressed patients are indeed three times as likely to have wraparound lobes. Occipital bending occurred in 35.3 percent of the depressed patients and 12.5 percent of the control subjects, according to their paper, published in Brain. The effect was even more pronounced in women: 45.8 percent of female patients with major depressive disorder exhibited occipital bending versus only 5.9 percent of women without depression, possibly because women's brains fit more snugly in their skulls than men's do. Previous studies have also found that occipital bending is more common in patients with schizophrenia. Maller suggests the lobes may wrap around each other when space for brain growth becomes constricted, perhaps because the brain is not doing enough neural pruning—the process by which the brain gets rid of neurons that are no longer needed. Indeed, many other studies have found that depressed brains are hyperconnected. Maller does not know if the finding will have clinical implications beyond helping to diagnose depression, but experts hope that this avenue of research will eventually lead to a deeper understanding of the disorder. “It really suggests some significant biological basis for at least some forms of depression,” says William Hopkins, a professor of neuroscience at Georgia State University, who was not involved in the study. © 2015 Scientific American
By Ling Xin For many, the hardest part of learning to speak Chinese is mastering its complex tonal variations. Now, new research suggests a surprising explanation for how those tones arose: a humid climate. By examining the correlation between humidity and the role of tone in more than 3700 languages, scientists found that tonal languages are remarkably rare in arid regions like Central Europe, whereas languages with complex tone pitches are prevalent in relatively humid regions such as the tropics, subtropical Asia, and Central Africa. Humidity keeps the voice box moist and elastic, allowing it to produce correct and complex tones, the scientists explain online this month in the Proceedings of the National Academy of Sciences. “If the United Kingdom had been a humid jungle, English may also have developed into a tonal language,” they claim. So, next time you go to your Chinese class, don’t forget to wet your whistle! © 2015 American Association for the Advancement of Science.
Link ID: 20517 - Posted: 01.26.2015
By Tina Hesman Saey Gustometer guhs-TOH-meh-ter n. A device used to squirt measured amounts of liquids into the mouth of a person in a taste study. Researchers often pair the instrument with brain scanning technology. Recently, a study of wine tasting pitted 10 of the top sommeliers from France and Switzerland against 10 novices. Researchers led by Lionel Pazart of Besançon University Hospital in France custom-built a gustometer to conduct the blind taste test. The scientists compared how brain activity changed when people tasted chardonnay, pinot noir or water. When sipping wine, the experts had greater activity in several parts of their brains, including regions involved in memory, than novices did, the researchers report in October in Frontiers in Behavioral Neuroscience. Sommeliers’ expertise may allow them to process sensory input about a wine — its taste and bouquet — while simultaneously recalling other information, such as the reputation of the winery that produced the beverage. Citations L. Pazart et al. An fMRI study on the influence of sommeliers’ expertise on the integration of flavor. Frontiers in Behavioral Neuroscience Vol. 8, October 16, 2014. doi: 10.3389/fnbeh.2014.00358. © Society for Science & the Public 2000 - 2015.
Keyword: Chemical Senses (Smell & Taste)
Link ID: 20516 - Posted: 01.26.2015
Simon Parkin A few months before she died, my grandmother made a decision. Bobby, as her friends called her (theirs is a generation of nicknames), was a farmer’s wife who not only survived World War II but also found in it justification for her natural hoarding talent. ‘Waste not, want not’ was a principle she lived by long after England recovered from a war that left it buckled and wasted. So she kept old envelopes and bits of cardboard cereal boxes for note taking and lists. She kept frayed blankets and musty blouses from the 1950s in case she needed material to mend. By extension, she was also a meticulous chronicler. She kept albums of photographs of her family members. She kept the airmail love letters my late grandfather sent her while he travelled the world with the merchant navy in a box. Her home was filled with the debris of her memories. Yet in the months leading up to her death, the emphasis shifted from hoarding to sharing. Every time I visited my car would fill with stuff: unopened cartons of orange juice, balls of fraying wool, damp, antique books, empty glass jars. All things she needed to rehome now she faced her mortality. The memories too began to move out. She sent faded photographs to her children, grandchildren and friends, as well as letters containing vivid paragraphs detailing some experience or other. On 9 April, the afternoon before the night she died, she posted a letter to one of her late husband’s old childhood friends. In the envelope she enclosed some photographs of my grandfather and his friend playing as young children. “You must have them,” she wrote to him. It was a demand but also a plea, perhaps, that these things not be lost or forgotten when, a few hours later, she slipped away in her favourite armchair. © 2015 BBC
by Catherine Brahic Move over Homo habilis, you're being dethroned. A growing body of evidence – the latest published this week – suggests that our "handy" ancestor was not the first to use stone tools. In fact, the ape-like Australopithecus may have figured out how to be clever with stones before modern humans even evolved. Humans have a way with flint. Sure, other animals use tools. Chimps smash nuts and dip sticks into ant nests to pull out prey. But humans are unique in their ability to apply both precision and strength to their tools. It all began hundreds of thousands of years ago when a distant ancestor began using sharp stone flakes to scrape meat off skin and bones. So who were those first toolmakers? In 2010, German researchers working in Ethiopia discovered markings on two animal bones that were about 3.4 million years old. The cut marks had clearly been made using a sharp stone, and they were at a site that was used by Lucy's species, Australopithecus afarensis. The study, led by Shannon McPherron of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, was controversial. The bones were 800,000 years older than the oldest uncontested stone tools, and at the time few seriously thought that australopithecines had been tool users. Plus, McPherron hadn't found the tool itself. The problem, says McPherron, is that if we just go on tools that have been found, we must conclude that one day somebody made a beautifully flaked Oldowan hand axe, completely out of the blue. That seems unlikely. © Copyright Reed Business Information Ltd.
Link ID: 20512 - Posted: 01.23.2015
by Linda Geddes OUR personality literally shapes our world. It helps determine how many friends we have, which jobs we excel in and how we cope with adversity. Now it seems it may even play a role in our health – and not just in terms of any hypochondriac tendencies we harbour, but also how prone our bodies are to getting sick in the first place. It is a provocative idea but one that has been steadily gaining traction. We think of conscientiousness, for example, as a positive trait because it suggests caution, careful planning and an aversion to potential danger. But could it also be a symptom of underlying weakness in the immune system? That's one interpretation of a study published last month that sought to pick apart the links between personality traits and the immune system. It found that highly conscientious people had lower levels of inflammation; an immune response that helps the body fight infection and recover from injury. Highly extrovert people had higher levels. This may mean that extroverts are more physically robust – at least while they're young. While this sounds like good news, there's also a downside since sustained inflammation over a lifetime may leave you vulnerable to diabetes, atherosclerosis and cancer. "The biggest take-home message is that what happens in our health is connected to what happens in our heads and what happens in our lives," says Steven Cole at the University of California in Los Angeles (UCLA), who supervised the research. © Copyright Reed Business Information Ltd.
Link ID: 20510 - Posted: 01.22.2015
By Rachel Feltman Fear is one of our most basic evolutionary instincts, a sudden physical jolt to help us react to danger more quickly. In the modern world, fear often seems excessive -- in the absence of wild animals to flee, we're left screaming over roller coasters and scary movies. But for at least one woman, fear is unobtainable. And while she lives a normal life, her fearlessness is actually a handicap. The researchers who study her keep her closely guarded, using the code-name "SM" when publishing papers about her brave brainpower. And until this year, she'd never been interviewed. "Tell me what fear is," Tranel began. "Well, that's what I'm trying to -- to be honest, I truly have no clue," SM said, her voice raspy. That's actually a symptom of the condition that stole fear from her. Urbach-Wieth disease, which is characterized by a hoarse voice, small bumps around the eyes, and calcium deposits in the brain is rare in its own right -- only 400 people on the planet are known to have it -- but in SM's case, some of those brain-deposits happened to take over her amygdalae. These almond-shaped structures deep inside the brain are crucial to human fear response. And in SM's case, they've been totally calcified since she was a young woman. Now in her 40s, her fear-center is as good as gone. "It's a little bit as if you would go to this region and literally scoop it out," Antonio Damasio, another neuroscientist who studies SM, told "Invisibilia" hosts Lulu Miller and Alix Spiegel.
Link ID: 20504 - Posted: 01.21.2015
Oliver Burkeman One spring morning in Tucson, Arizona, in 1994, an unknown philosopher named David Chalmers got up to give a talk on consciousness, by which he meant the feeling of being inside your head, looking out – or, to use the kind of language that might give a neuroscientist an aneurysm, of having a soul. Though he didn’t realise it at the time, the young Australian academic was about to ignite a war between philosophers and scientists, by drawing attention to a central mystery of human life – perhaps the central mystery of human life – and revealing how embarrassingly far they were from solving it. The scholars gathered at the University of Arizona – for what would later go down as a landmark conference on the subject – knew they were doing something edgy: in many quarters, consciousness was still taboo, too weird and new agey to take seriously, and some of the scientists in the audience were risking their reputations by attending. Yet the first two talks that day, before Chalmers’s, hadn’t proved thrilling. “Quite honestly, they were totally unintelligible and boring – I had no idea what anyone was talking about,” recalled Stuart Hameroff, the Arizona professor responsible for the event. “As the organiser, I’m looking around, and people are falling asleep, or getting restless.” He grew worried. “But then the third talk, right before the coffee break – that was Dave.” With his long, straggly hair and fondness for all-body denim, the 27-year-old Chalmers looked like he’d got lost en route to a Metallica concert. “He comes on stage, hair down to his butt, he’s prancing around like Mick Jagger,” Hameroff said. “But then he speaks. And that’s when everyone wakes up.”
Link ID: 20503 - Posted: 01.21.2015
The presence of a romantic partner during painful medical procedures could make women feel worse rather than better, researchers say. A small study found this increase in pain was most pronounced in women who tended to avoid closeness in their relationships. The authors say bringing a loved one along for support may not be the best strategy for every patient. The work appears in the journal Social Cognitive and Affective Neuroscience. Researchers from University College London, King's College London and the University of Hertfordshire say there has been very little scientific research into the effects of a partner's presence on someone's perception of pain, despite this being common medical advice. They recruited 39 heterosexual couples and asked them a series of questions to measure how much they sought or avoided closeness and emotional intimacy in relationships. Each female volunteer was then subjected to a series of painful laser pulses while her partner was in and then out of the room. The women were asked to score their level of pain. They also had their brain activity measured using a medical test called an EEG. The researchers found that certain women were more likely to score high levels of pain while their partner was in the room. These were women who said they preferred to avoid closeness, trusted themselves more than their partners and felt uncomfortable in their relationships. © 2015 BBC
Keyword: Pain & Touch
Link ID: 20502 - Posted: 01.21.2015
By JOHN MARKOFF A new laboratory technique enables researchers to see minuscule biological features, such as individual neurons and synapses, at a nearly molecular scale through conventional optical microscopes. In a paper published last week in the journal Science, researchers at M.I.T. said they were able to increase the physical size of cultured cells and tissue by as much as five times while still preserving their structure. The scientists call the new technique expansion microscopy. The idea of making objects larger to make them more visible is a radical solution to a vexing challenge. By extending the resolving power of conventional microscopes, scientists are able to glimpse such biological mysteries as the protein structures that form ion channels and the outline of the membrane that holds the genome within a cell. The researchers have examined minute neural circuits, gaining new insights into local connections in the brain and a better understanding of larger networks. The maximum resolving power of conventional optical microscopes is about 200 nanometers, about half the wavelength of visible light. (By contrast, a human hair is about 500 times wider.) In recent decades, scientists have struggled to push past these limits. Last year, three scientists received a Nobel Prize for a technique in which fluorescent molecules are used to extend the resolving power of optical microscopes. But the technique requires specialized equipment and is costly. With expansion microscopy, Edward S. Boyden, a co-director of the M.I.T. Center for Neurobiological Engineering, and his colleagues were able to observe objects originally measuring just 70 nanometers in cultured cells and brain tissue through an optical microscope. © 2015 The New York Times Company
Keyword: Brain imaging
Link ID: 20499 - Posted: 01.20.2015