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|By Karen Hopkin Sometimes it’s hard to see the light. Especially if it lies outside the visible spectrum, like x-rays or ultraviolet radiation. But if you long to see the unseeable, you might be interested to hear that under certain conditions people can catch a glimpse of usually invisible infrared light. That’s according to a study in the Proceedings of the National Academy of Sciences. [Grazyna Palczewska et al, Human infrared vision is triggered by two-photon chromophore isomerization] Our eyes are sensitive to elementary particles called photons that have sufficient energy to excite light-sensitive receptor proteins in our retinas. But the photons in infrared radiation don’t have enough oomph. We can detect these lower energy photons using what are sometimes called night-vision goggles or cameras. But the naked eye is usually blind to infrared radiation. But recently researchers in a laser lab noticed that they sometimes saw flashes of light while working with devices that emitted brief infrared pulses. So they filled a test tube with retinal cells and zapped it with their lasers. When the light pulses rapidly enough, the receptors can get hit with two photons at the same time—which supplies enough energy to excite the receptor. This double dose makes the infrared visible. One application of the finding is that it could give doctors a new tool to diagnose diseases of the retina. So they could eyeball trouble before it might otherwise be seen.

Keyword: Vision
Link ID: 20458 - Posted: 01.08.2015

By Virginia Morell Animals that live in larger societies tend to have larger brains. But why? Is it because a larger group size requires members to divide up the labor on tasks, thus causing some individuals to develop specialized brains and neural anatomy? (Compared with most humans, for instance, taxicab drivers have brains that have larger areas that are involved with spatial memory.) Or is it because the challenges of group living—needing to know all the foibles of your neighbors—cause the brains of all members to grow larger? Scientists tested the two hypotheses with wild colonies of acacia ants (Pseudomyrmex spinicola), which make their nests in the hollow spines of acacia trees in Panama. Ant workers at the base of the tree wait to attack intruders, while workers foraging on the leaves (as in the photo above), aren’t as aggressive but are faster at managing the colony’s brood. This division of labor is most marked in larger colonies (those found on larger trees), while workers in smaller colonies do both jobs. The scientists studied 17 colonies of ants and measured the brain volumes of 29 of the leaf ants and 34 of the trunk ants. As the colony size increased, the leaf ants showed a marked increase in the regions of the brain concerned with learning and memory, the scientists report today in the Proceedings of the Royal Society B. But the same neural areas decreased in the trunk ants. Thus, larger societies’ need for specialized workers, some strictly for defense, others for foraging and brood tending—rather than for social masters—seems to be the key to the expanding brain, at least in ants.

Keyword: Evolution
Link ID: 20457 - Posted: 01.08.2015

John Markoff MENLO PARK, CALIF. — Ann Lam delicately places a laboratory slide holding a slice of brain from a living human onto a small platform in a room the size of a walk-in refrigerator. She closes a heavy door and turns to a row of computers to monitor her experiments. She is using one of the world’s most sophisticated and powerful microscopes, the Stanford Synchrotron Radiation Lightsource, to learn about the distribution of metals in the brains of epilepsy patients. But she has another reason for being here as well. Traditional techniques for staining brain tissue produce byproducts and waste that are hazardous to the environment. And often, this sort of research is performed on animals, something Dr. Lam insists on avoiding. The radiation that illuminates the Stanford microscope was once a waste product produced by the particle accelerators. Now that it has been harnessed — recycled, in a sense — she is able to use it to examine tissue removed from living human patients, not animals. For Dr. Lam, those are important considerations. Indeed, scientists like her worry that neuroscience has become a dirty business. Too often, they say, labs are stocked with toxic chemicals, dangerous instruments and hapless animal subjects. Funding often comes from the military, and some neuroscientists fear their findings may soon be applied in ways that they never intended, raising moral questions that are seldom addressed. In 2012, Dr. Lam and Dr. Elan Ohayon, her husband, founded the Green Neuroscience Laboratory in a former industrial building in the Convoy District, an up-and-coming San Diego neighborhood. Solar panels rest on the roof, and a garden is lovingly tended on the second floor. © 2015 The New York Times Company

Keyword: Epilepsy; Animal Rights
Link ID: 20456 - Posted: 01.06.2015

Haroon Siddique Research that aims to map the activity of serotonin in the brain could revolutionise the use of antidepressants and behavioural therapy for people with mental illnesses. The neurotransmitter serotonin has long been associated with mood, with drugs that boost the chemical in the brain helping to alleviate the symptoms of common illnesses such as depression and anxiety, but scientists lack a deep understanding of how it mediates different mood disorders. By understanding the biology of serotonin, the hope is that drugs can be created that only target cells relevant to a particular disorder and behavioural therapies can be made more effective, reducing the need for antidepressants. Dr Jeremiah Cohen, an assistant professor at the Johns Hopkins Brain Science Institute in Baltimore, said: “The ultimate aim is to understand the biology of mood and how groups of cells in the brain connect to produce our emotional behaviour. Most antidepressants operate broadly in the entire serotonin system. What we hope to do with this map is use drugs that are available or design new drugs that will target only the components of that system relevant to a particular disorder.” The use of antidepressants in England has soared since the late 1990s, raising concerns in some quarters about over-prescription. Researchers from the Nuffield Trust and the Health Foundation found that 40m prescriptions for antidepressants were made in 2012, compared to 15m in 1998. Doctors write prescriptions for more than one in 10 adults in developed countries, with Iceland, Australia, Canada and European Nordic countries leading the way, according to 2013 data from the Organisation for Economic Co-operation and Development. More than 10% of American adults have used antidepressants.

Keyword: Depression
Link ID: 20455 - Posted: 01.06.2015

ARE you spending enough time in the sun? As well as keeping our bones strong, vitamin D – the hormone our skin makes when exposed to ultraviolet rays – may also help regulate our body clocks. We all have a small group of "clock genes" which switch on and off during the day. As a result, the levels of the proteins they code for rise and fall over a 24-hour period. Enforced routines such as night shift work can play havoc with our health – increasing our risk of a stroke, for example. To find out whether a lack of vitamin D might be responsible, Sean-Patrick Scott and his colleagues at the Monterrey Institute of Technology and Higher Education in Mexico looked at the behaviour of two clock genes in human fat cells. When the cells were immersed in blood serum, they acted as they would in the body: the clock genes' activity oscillated over a 24-hour period. Dosing the cells with vitamin D instead produced the same effect. No such effect was seen in cells placed inside a nutrient broth. "Vitamin D synchronises the cells," says Scott. "Our results explain some of the benefits of sunlight," he says. "Vitamin D is one of the ways we might be able to maintain circadian rhythms in the body." Julia Pakpoor of the University of Oxford says clinical trials are needed to confirm the effect in people, but she adds, "We should all make sure we are vitamin D replete regardless." The work was presented at the World Stem Cell Summit in San Antonio, Texas, last month. © Copyright Reed Business Information Ltd.

Keyword: Biological Rhythms
Link ID: 20454 - Posted: 01.06.2015

By Susan Milius Whole scientific careers have gone into understanding why a harmless handful of fluff like a California ground squirrel taunts rattlesnakes. Now Rulon Clark and his team at San Diego State University are exploring the puzzle of why the squirrels also seem to taunt rocks, sticks and the occasional shrub. On spotting a snake, a California ground squirrel (Otospermophilus beecheyi) stares and sniffs, or if the snake is uncoiled, may even kick sand at it. And in bursts, the squirrel flags its tail left and right “like a windshield wiper,” Clark says. A rattler can strike a target 30 centimeters away in less than 70 milliseconds. But ground squirrels twist and dodge fast enough to have a decent chance of escape. Also, adult squirrels from snake country have evolved some resistance to venom. So taunting is worth the risks as a signal to neighboring squirrels and to the snake that its ambush attempt has been discovered. After getting publicly and lengthily squirreled, snakes often just slip away. Yet the squirrels also nyah-nyah tail flag at places where snakes might be but aren’t. To see if flagging indicates wariness, Clark and his colleagues built a squirrel startler that shoots out a cork using the classic spring that launches gag snakes out of cans (see video below). At spots with no sign of real snakes, squirrels mostly nibbled seeds in apparent tranquility with only a rare tail flag. The pop of a cork typically sent these squirrels scampering off on four speed-blurred paws. © Society for Science & the Public 2000 - 2014.

Keyword: Aggression; Animal Communication
Link ID: 20453 - Posted: 01.06.2015

By SINDYA N. BHANOO That bats use echolocation to navigate and to find food is well known. But some blind people use the technique, too, clicking their tongues and snapping fingers to help identify objects. Now, a study reports that human echolocators can experience illusions, just as sighted individuals do. Gavin Buckingham, a psychology lecturer at Heriot-Watt University in Scotland, and his colleagues at the University of Western Ontario asked 10 study subjects to pick up strings attached to three boxes of identical weight but different sizes. Overwhelmingly, the sighted individuals succumbed to what is known as the “size-weight illusion.” The bigger boxes felt lighter to them. Blind study subjects who picked up each of the three strings did not experience the illusion. They correctly surmised that the boxes were of equal weight. But blind participants who relied on echolocation to get a sense of the box sizes before picking up the strings fell into the same trap as the sighted subjects and misjudged the weights. The research, published in the journal Psychological Science, supports other research suggesting that echolocation techniques may stimulate the brain in ways that resemble visual input. “It does mean this is more than a functional tool,” Dr. Buckingham said. Echolocation “doesn’t help them appreciate art or tell the difference between the color red or color blue, but it’s a step in that direction.” © 2015 The New York Times Company

Keyword: Vision; Hearing
Link ID: 20452 - Posted: 01.06.2015

Carl Zimmer Among scientists who study how our DNA affects our weight, a gene called FTO stands out. “It’s the poster child for the genetics of obesity,” said Struan F. Grant, an associate professor of pediatrics at the University of Pennsylvania School of Medicine. In 2007, researchers discovered that people with a common variant of FTO tend to be heavier than those without it. Since then, studies have repeatedly confirmed the link. On average, one copy of the risky variant adds up to 3.5 extra pounds of weight. Two copies of the gene bring 7 extra pounds — and increase a person’s risk of becoming obese by 50 percent. But the gene doesn’t seem to have always been a problem. If scientists had studied FTO just a few decades ago, they would have found no link to weight whatsoever. A new study shows that FTO became a risk only in people born after World War II. The research, published this week in the Proceedings of the National Academy of Sciences, raises questions that extend far beyond obesity. Genes clearly influence our health in many ways, but so does our environment; often, it is the interplay between them that makes the difference in whether we develop obesity or cancer or another ailment. But the relative importance of certain genes may shift over the years, the new study suggests, as our environment changes. James Niels Rosenquist of Massachusetts General Hospital and his colleagues were inspired to conduct the study by recent research documenting how people’s experiences alter the effects of their genes. A variant of a gene called AKT1, for example, can raise the risk of psychosis — but only if the carrier smokes a lot of marijuana. If he avoids smoking, the AKT1 variant doesn’t cause a problem. © 2015 The New York Times Company

Keyword: Obesity; Genes & Behavior
Link ID: 20451 - Posted: 01.01.2015

By Stephanie M. Lee Decorating the house has always been challenging for Sheila Carter. Like other color-blind people, she limits her wardrobe to a few bold hues that can be easily mixed and matched, like blue and black. But a new pair of glasses she recently started wearing, she said, has changed her worldview. Carter owns high-tech eyewear made by EnChroma, a Berkeley startup that wants to help people with color deficiency see the full spectrum of the rainbow. Carter is among an estimated 32 million Americans who are color-blind, either from birth or as a result of some condition, like head trauma. The condition is most prevalent among people of Northern European descent, affecting 8 percent of men and 0.5 percent of women. EnChroma makes color-enhancing sunglasses for the vast majority of such people, who have trouble seeing red or green due to a genetic defect. The company has sold more than 1,000 pairs in two years. Last month, it introduced glasses with polycarbonate lenses for children, athletes and prescription- and nonprescription-wearers at prices ranging from $325 to $450. The proprietary lens contains a filter that blocks a portion of the spectrum where the overlap between the two cones occurs and restores the separation between them. “It’s essentially taking out that stuff that’s confusing the signal,” said Andy Schmeder, vice president of technology.

Keyword: Vision
Link ID: 20450 - Posted: 01.01.2015

Christopher Dean Hopkins If you've ever listened to karaoke at a bar, you know that drinking can affect how well someone can sing. Christopher Olson and his colleagues at Oregon Health and Science University recently set out to find if the same was true for birds, specifically zebra finches. "We just showed up in the morning and mixed a little bit of juice with 6 percent alcohol, and put it in their water bottles and put it in the cages," Olson told All Things Considered's Arun Rath. "At first we were thinking that they wouldn't drink on their own because, you know, a lot of animals just won't touch the stuff. But they seem to tolerate it pretty well and be somewhat willing to consume it." The finches long have been used as a model to study human vocal learning, or how people learn to communicate using language, Olson said. Obviously, alcohol affects human speech, so Olson and his team checked for similar problems with the birds. The blood alcohol levels achieved — .05 to .08 percent — would be laughed off by many college students, but because birds metabolize alcohol differently it was plenty to produce the effects the scientists were looking for. Listen to the audio, and you'll hear that the finches' song gets a bit quieter and just a little slurred, or as Olson puts it, "a bit less organized in their sound production" — like a roommate calling from a bar to get a ride home. © 2014 NPR

Keyword: Drug Abuse; Language
Link ID: 20449 - Posted: 01.01.2015

by Lisa Seachrist Chiu Just before winter break, my fifth grader came home from school, opened her mouth and produced what sounded to me like a stuttering mess of gibberish. After complaining that when she spends the entire day immersed in Chinese, she sometimes can’t figure out what language to use, she carried on speaking flawless English to me and Chinese to a friend while they did their homework. Quite honestly, I had been eagerly anticipating this very day for a long time. Having worked several years to establish the Chinese language immersion elementary school my daughter attends, I could barely contain my excitement at this demonstration that she truly grasps a second language. Early language programs are hot, in no small part because, when it comes to language, kids under the age of 7 are geniuses. Like many parents, I wanted my child to be fluent in as many languages as possible so she can communicate with more people and because it gives her a prime tool to explore different cultures. Turns out, it may also benefit her brain. With the help of advanced imaging tools that reveal neural processes in specific brain structures, researchers are coalescing around the idea that fluency in more than one language heightens executive function — the ability to regulate and control cognitive processes. It’s a radical shift from just a few decades ago when psychologists routinely warned against raising children who speak two languages, lest they become confused and suffer delays in learning. © Society for Science & the Public 2000 - 2014

Keyword: Language
Link ID: 20448 - Posted: 01.01.2015

Three-year outcomes from an ongoing clinical trial suggest that high-dose immunosuppressive therapy followed by transplantation of a person's own blood-forming stem cells may induce sustained remission in some people with relapsing-remitting multiple sclerosis (RRMS). RRMS is the most common form of MS, a progressive autoimmune disease in which the immune system attacks the brain and spinal cord. The trial is funded by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, and conducted by the NIAID-funded Immune Tolerance Network (ITN) External Web Site Policy. Three years after the treatment, called high-dose immunosuppressive therapy and autologous hematopoietic cell transplant or HDIT/HCT, nearly 80 percent of trial participants had survived without experiencing an increase in disability, a relapse of MS symptoms or new brain lesions. Investigators observed few serious early complications or unexpected side effects, although many participants experienced expected side effects of high-dose immunosuppression, including infections and gastrointestinal problems. The three-year findings are published in the Dec. 29, 2014, online issue of JAMA Neurology. “These promising results support the need for future studies to further evaluate the benefits and risks of HDIT/HCT and directly compare this treatment strategy to current MS therapies,” said NIAID Director Anthony S. Fauci, M.D. “If the findings from this study are confirmed, HDIT/HCT may become a potential therapeutic option for people with this often-debilitating disease, particularly those who have not been helped by standard treatments.”

Keyword: Multiple Sclerosis; Stem Cells
Link ID: 20447 - Posted: 01.01.2015

By Abby Phillip Your smartphone addiction is doing more than giving your thumbs a workout, it is also changing your brain. A new study suggests that using a smartphone -- touching the fingertips against the smooth surface of a screen -- can make the brain more sensitive to the thumb, index and middle finger tips being touched. The study, which was published in the journal Current Biology this week, found that the differences between people when it comes to how the brain responds to thumb stimulation is partly explained by how often they use their smartphones. "I was really surprised by the scale of the changes introduced by the use of smartphones," said Arko Ghosh, of the Institute of Neuroinformatics of the University of Zurich and one of the study's authors, in a news release. Other research has shown that musicians and expert video gamers show the same type of brain adaptations. Smartphone use isn't something most people would consider an "expertise," but frequent use of the devices might similarly lead to brain adaptations. Researchers used an electroencephalography (EEG) device to record the activity that occurred in the brain when people touched their thumbs, index and middle fingers to a mechanical object. They compared the brain recordings of smartphone users and regular cellphone users.

Keyword: Pain & Touch
Link ID: 20446 - Posted: 01.01.2015

By KEVIN RANDALL MILWAUKEE — When two financiers purchased the Milwaukee Bucks for $550 million last April, they promised to pour not only money and new management into the moribund franchise, but also the same kind of creative and critical thinking that had helped make them hedge fund billionaires. It was not enough to increase the franchise’s sales force or beef up the team’s analytics department — the Bucks were looking for a more elusive edge. So in May, the team hired Dan Hill, a facial coding expert who reads the faces of college prospects and N.B.A. players to determine if they have the right emotional attributes to help the Bucks. The approach may sound like palm reading to some, but the Bucks were so impressed with Hill’s work before the 2014 draft that they retained him to analyze their players and team chemistry throughout this season. With the tenets of “Moneyball” now employed in the front offices of every major sport, perhaps it was inevitable that professional teams would turn to emotion metrics and neuroscience tools to try to gain an edge in evaluating players. Many sports teams have adopted advanced data analytics to help determine a player’s athletic abilities and value. And now, some are taking it a step further — trying to analyze the psychological aspects of the players as well. “We spend quite a bit of time evaluating the players as basketball players and analytically,” said David Morway, Milwaukee’s assistant general manager, who works for the owners Wesley Edens and Marc Lasry. “But the difficult piece of the puzzle is the psychological side of it, and not only psychological, character and personality issues, but also team chemistry issues.” © 2014 The New York Times Company

Keyword: Emotions
Link ID: 20445 - Posted: 12.27.2014

By Maria Konnikova Last year, Dimitris Xygalatas, the head of the experimental anthropology lab at the University of Connecticut, decided to conduct a curious experiment in Mauritius, during the annual Thaipusam festival, a celebration of the Hindu god Murugan. For the ten days prior to the festival, devotees abstain from meat and sex. As the festival begins, they can choose to show their devotion in the form of several communal rituals. One is fairly mild. It involves communal prayer and singing beside the temple devoted to Murugan, on the top of a mountain. The other, however—the Kavadi—is one of the more painful modern religious rituals still in practice. Participants must pierce multiple parts of their bodies with needles and skewers and attach hooks to their backs, with which they then drag a cart for more than four hours. After that, they climb the mountain where Murugan’s temple is located. Immediately after each ritual was complete, the worshippers were asked if they would be willing to spend a few minutes answering some questions in a room near the temple. Xygalatas had them rate their experience, their attitude toward others, and their religiosity. Then he asked them a simple question: They would be paid two hundred rupees for their participation (about two days’ wages for an unskilled worker); did they want to anonymously donate any of those earnings to the temple? His goal was to figure out if the pain of the Kavadi led to increased affinity for the temple. For centuries, societies have used pain as a way of creating deep bonds. There are religious rites, such as self-flagellation, solitary pilgrimages, and physical mutilation.

Keyword: Pain & Touch; Emotions
Link ID: 20444 - Posted: 12.27.2014

by Bethany Brookshire Rats stink. First there’s the poop smell and the urine. And then there’s just that smell of rat — a kind of dusty, hairy little smell. But it turns out that rats don’t smell quite the same all the time. When they are stressed, they produce a different odor, one that makes other rats anxious. Now, Hideaki Inagaki and colleagues at the University of Tokyo in Japan have isolated the particular stress-related odor and identified the two specific chemicals behind it. The results reveal the first evidence of an isolated anxiety pheromone in rats, and give reason for scientists to look at — or maybe sniff — their behavioral experiments cautiously. And the findings could also offer glimmerings of a new flavor of rat-be-gone. Pheromones are chemicals that give off distinct odors that allow an animal to communicate within its own ranks. In rats, as in many other animals, many pheromones activate the vomeronasal organ, a small patch of cells at the base of the nasal cavity. Other researchers have found evidence of pheromones in maternal behavior and in the response of rat pups to their mothers. In the new study, the pheromones in question are about alarm and anxiety. Study coauthor Yasushi Kiyokawa of The University of Tokyo says he first came across the alarm odor when he was a graduate student. “I noticed the rats released a specific odor when I handled them for the first time, as they were stressed by the novel handling procedure,” he recalls. He went sniffing to find the source. “I found that the intensity of the odor was strongest around the anal region,” he says. Many mammals have glands around the anus that produce oils and odors. Since that first whiff of a clue, Kiyokawa and colleagues at the University of Tokyo have been working with what they called the “alarm pheromone.” While rats may be smelly to some, Kiyokawa says this particular smell isn’t unpleasant. “Like a hay or dried grass,” he says. “At least for me.” © Society for Science & the Public 2000 - 2014

Keyword: Chemical Senses (Smell & Taste); Emotions
Link ID: 20443 - Posted: 12.27.2014

ByDavid Malakoff This bird might look like a holiday ornament, but it is actually a rare half-female, half-male northern cardinal (Cardinalis cardinalis, pictured with female plumage on the left and male plumage on the right) spotted a few years ago in Rock Island, Illinois. Researchers have long known such split-sex “gynandromorphs” exist in insects, crustaceans, and birds. But scientists rarely get to extensively study a gynandromorph in the wild; most published observations cover just a day or so. Observers got to follow this bird, however, for more than 40 days between December 2008 and March 2010. They documented how it interacted with other birds and even how it responded to recorded calls. The results suggest being half-and-half carries consequences: The cardinal didn’t appear to have a mate, and observers never heard it sing, the researchers report this month in The Wilson Journal of Ornithology. On the other hand, it wasn’t “subjected to any unusual agonistic behaviors from other cardinals,” according to the paper. Intriguingly, another gynandromorph cardinal sighted briefly in 1969 had the opposite plumage, they note: the male’s bright red plumes on the right, the drabber female feathers on the left. © 2014 American Association for the Advancement of Science

Keyword: Sexual Behavior
Link ID: 20442 - Posted: 12.27.2014

Mo Costandi A team of neuroscientists at University College London has developed a new way of simultaneously recording and manipulating the activity of multiple cells in the brains of live animals using pulses of light. The technique, described today in the journal Nature Methods, combines two existing state-of-the-art neurotechnologies. It may eventually allow researchers to do away with the cumbersome microelectrodes they traditionally used to probe neuronal activity, and to interrogate the brain’s workings at the cellular level in real time and with unprecedented detail. One of them is optogenetics. This involves creating genetically engineered mice expressing algal proteins called Channelrhodopsins in specified groups of neurons. This renders the cells sensitive to light, allowing researchers to switch the cells on or off, depending on which Channelrhodopsin protein they express, and which wavelength of light is used. This can be done on a millisecond-by-millisecond timescale, using pulses of laser light delivered into the animals’ brains via an optical fibre. The other is calcium imaging. Calcium signals are crucial for just about every aspect of neuronal function, and nerve cells exhibit a sudden increase in calcium ion concentration when they begin to fire off nervous impulses. Using dyes that give off green fluorescence in response to increases in calcium concentration, combined with two-photon microscopy, researchers can detect this signature to see which cells are activated. In this way, they can effectively ‘read’ the activity of entire cell populations in brain tissue slices or live brains. Calcium-sensitive dyes are injectable, so targeting them with precision is difficult, and more recently, researchers have developed genetically-encoded calcium sensors to overcome this limitation. Mice can be genetically engineered to express these calcium-sensitive proteins in specific groups of cells; like the dyes before them, they, too, fluoresce in response to increases in calcium ion concentrations in the cells expressing them.

Keyword: Brain imaging
Link ID: 20441 - Posted: 12.23.2014

|By Stephen L. Macknik and Susana Martinez-Conde To a neuroscientist, the trouble with cocktail parties is not that we do not love cocktails or parties (many neuroscientists do). Instead what we call “the cocktail party problem” is the mystery of how anyone can have a conversation at a cocktail party at all. Consider a typical scene: You have a dozen or more lubricated and temporarily uninhibited adults telling loud, improbable stories at increasing volumes. Interlocutors guffaw and slap backs. Given the decibel level, it is a minor neural miracle that any one of these revelers can hear and parse one word from any other. The alcohol does not help, but it is not the main source of difficulties. The cocktail party problem is that there is just too much going on at once: How can our brain filter out the noise to focus on the wanted information? This problem is a central one for perceptual neuroscience—and not just during cocktail parties. The entire world we live in is quite literally too much to take in. Yet the brain does gather all of this information somehow and sorts it in real time, usually seamlessly and correctly. Whereas the physical reality consists of comparable amounts of signal and noise for many of the sounds and sights around you, your perception is that the conversation or object that interests you remains in clear focus. So how does the brain accomplish this feat? One critical component is that our neural circuits simplify the problem by actively ignoring—suppressing—anything that is not task-relevant. Our brain picks its battles. It stomps out irrelevant information so that the good stuff has a better chance of rising to awareness. This process, colloquially called attention, is how the brain sorts the wheat from the chaff. © 2014 Scientific American

Keyword: Attention; Vision
Link ID: 20440 - Posted: 12.23.2014

George Johnson Training a dog to salivate at the sound of a bell would have seemed pretty stupid to Ivan Pavlov. He was after much bigger things. Using instruments like metronomes and harmoniums, he demonstrated that a dog could make astonishingly fine discriminations — distinguishing between a rhythm of 96 and 104 beats a minute or an ascending and a descending musical scale. But what he really wanted to know was what his animals were thinking. His dream was a grand theory of the mind. He couldn’t put his subjects on a couch like his colleague Freud and ask them to free-associate, so he gauged their reactions to a variety of stimuli, meticulously counting their “psychic secretions,” those droplets of drool. He knew he was pricking at the skin of something deeper. “It would be stupid,” he said, “to reject the subjective world.” This is not the Pavlov most people think they know. In an excellent new biography, “Ivan Pavlov: A Russian Life in Science,” Daniel P. Todes, a medical historian, describes a man whose laboratory in pre-Soviet Russia was like an early-20th-century version of the White House Brain Initiative, with its aim “to revolutionize our understanding of the human mind.” That was also Pavlov’s goal: to build a science that would “brightly illuminate our mysterious nature” and “our consciousness and its torments.” He spoke those words 111 years ago and spent his life pursuing his goal. Yet when we hear his name, we reflexively think of a drooling dog and a clanging bell. Our brains have been conditioned with the myth. © 2014 The New York Times Company

Keyword: Learning & Memory
Link ID: 20439 - Posted: 12.23.2014