Chapter 2. Cells and Structures: The Anatomy of the Nervous System
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By Pallab Ghosh Science correspondent, BBC News, Boston Scientists are set to release the first batch of data from a project designed to create the first map of the human brain. The project could help shed light on why some people are naturally scientific, musical or artistic. Some of the first images were shown at the American Association for the Advancement of Science meeting in Boston. I found out how researchers are developing new brain imaging techniques for the project by having my own brain scanned. Scientists at Massachusetts General Hospital are pushing brain imaging to its limit using a purpose built scanner. It is one of the most powerful scanners in the world. The scanner's magnets need 22MW of electricity - enough to power a nuclear submarine. The researchers invited me to have my brain scanned. I was asked if I wanted "the 10-minute job or the 45-minute 'full monty'" which would give one of the most detailed scans of the brain ever carried out. Only 50 such scans have ever been done. I went for the full monty. It was a pleasant experience enclosed in the scanner's vast twin magnets. Powerful and rapidly changing magnetic fields were looking to see tiny particles of water travelling along the larger nerve fibres. By following the droplets, the scientists in the adjoining cubicle are able to trace the major connections within my brain. Arcs of understanding The result was a 3D computer image that revealed the important pathways of my brain in vivid colour. One of the lead researchers, Professor Van Wedeen, gave me a guided tour of the inside of my head. BBC © 2013
Keyword: Brain imaging
Link ID: 17814 - Posted: 02.18.2013
By JOHN MARKOFF The Obama administration is planning a decade-long scientific effort to examine the workings of the human brain and build a comprehensive map of its activity, seeking to do for the brain what the Human Genome Project did for genetics. The project, which the administration has been looking to unveil as early as March, will include federal agencies, private foundations and teams of neuroscientists and nanoscientists in a concerted effort to advance the knowledge of the brain’s billions of neurons and gain greater insights into perception, actions and, ultimately, consciousness. Scientists with the highest hopes for the project also see it as a way to develop the technology essential to understanding diseases like Alzheimer’s and Parkinson’s, as well as to find new therapies for a variety of mental illnesses. Moreover, the project holds the potential of paving the way for advances in artificial intelligence. The project, which could ultimately cost billions of dollars, is expected to be part of the president’s budget proposal next month. And, four scientists and representatives of research institutions said they had participated in planning for what is being called the Brain Activity Map project. The details are not final, and it is not clear how much federal money would be proposed or approved for the project in a time of fiscal constraint or how far the research would be able to get without significant federal financing. © 2013 The New York Times Company
Keyword: Brain imaging
Link ID: 17813 - Posted: 02.18.2013
The use of an advanced imaging shortly after the onset of acute stroke failed to identify a subgroup of patients who could benefit from a clot-removal procedure, a study has found. The randomized controlled trial known as Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy (MR RESCUE) was funded by the National Institute of Neurological Disorder and Stroke (NINDS), part of the National Institutes of Health, and was published online Feb. 8 in the New England Journal of Medicine. In patients with ischemic stroke (caused by a blockage in an artery), brain cells deprived of blood die within minutes to hours. Rapidly opening the artery can halt brain cell death. Intravenous tissue plasminogen activator (t-PA), a drug that dissolves clots has been shown to improve outcomes in such stroke patients. However intravenous t-PA is not effective in many patients with large clots blocking the major brain arteries that cause the most devastating strokes. MR RESCUE investigators tested an invasive clot removal strategy designed to remove clots from these large arteries. Patients in the study were enrolled at 22 centers in the United States within approximately 5.5 hours of their stroke onset. Their ability to function independently was assessed at 90 days. All MR-RESCUE patients underwent emergency computed tomography (CT) or magnetic resonance (MRI) perfusion imaging to identify regions of the brain with decreased blood flow, as well as regions that could not be salvaged.
By Breanna Draxler Brain differences between the 23 participants were quantified at each surface vertex. Values below the global mean are shown in cool colors while values above this average are shown in warm colors. Image courtesy of Sophia Mueller et al. Every person thinks and acts a little differently than the other 7 billion on the planet. Scientists now say that variations in brain connections account for much of this individuality, and they’ve narrowed it down to a few specific regions of the brain. This might help us better understand the evolution of the human brain as well as its development in individuals. Each human brain has a unique connectome—the network of neural pathways that tie all of its parts together. Like a fingerprint, every person’s connectome is unique. To find out where these individual connectomes differed the most, researchers used an MRI scanning technique to take cross-sectional pictures of 23 people’s brains at rest. Researchers found very little variation in the areas of the participants’ brains responsible for basic senses and motor skills. It’s a pretty straight shot from the finger to the part of the brain that registers touch, for example, or from the eye to the vision center. Thus we apparently all sense the world in more or less the same way. The real variety arose in the parts of the brain associated with personality, like the frontoparietal lobe. This multipurpose area in the brain curates sensory data into complex thoughts, feelings or actions and allows us to interpret the things we sense (i.e., we recognize a red, round object as an apple). Because there are many ways to get from sensation to reaction, and many different ways to react to what we sense, each individual’s brain blazes its own paths.
A telltale boost of activity at the back of the brain while processing emotional information predicted whether depressed patients would respond to an experimental rapid-acting antidepressant, a National Institutes of Health study has found. “We have discovered a potential neuroimaging biomarker that may eventually help to personalize treatment selection by revealing brain-based differences between patients,” explained Maura Furey, Ph.D., of NIH’s National Institute of Mental Health (NIMH). Furey, NIMH’s Carlos Zarate, M.D., and colleagues, reported on their functional magnetic resonance imaging (fMRI) study of a pre-treatment biomarker for the antidepressant response to scopolamine, Jan. 30, 2013, online in JAMA Psychiatry. Scopolamine, better known as a treatment for motion sickness, has been under study since Furey and colleagues discovered its fast-acting antidepressant properties in 2006. Unlike ketamine, scopolamine works through the brain’s acetylcholine chemical messenger system. The NIMH team’s research has demonstrated that by blocking receptors for acetylcholine on neurons, scopolamine can lift depression in many patients within a few days; conventional antidepressants typically take weeks to work. But not all patients respond, spurring interest in a predictive biomarker. The acetylcholine system plays a pivotal role in working memory, holding information in mind temporarily, but appears to act by influencing the processing of information rather than through memory. Imaging studies suggest that visual working memory performance can be enhanced by modulating acetylcholine-induced activity in the brain’s visual processing area, called the visual cortex, when processing information that is important to the task.
By JUDY BATTISTA NEW ORLEANS — The N.F.L., faced with increasing concern about the toll of concussions and confronted with litigation involving thousands of former players, is planning to form a partnership with General Electric to jump-start development of imaging technology that would detect concussions and encourage the creation of materials to better protect the brain. The four-year initiative, which is expected to begin in March with at least $50 million from the league and G.E., is the result of a late October conversation between Commissioner Roger Goodell and G.E.’s chief executive, Jeffrey Immelt, a former offensive tackle at Dartmouth. When Goodell explained his idea of getting leading companies in innovation to join the N.F.L. to accelerate research, Immelt said he wanted to help. After years of insisting there was no link between head injuries sustained on the field and long-term cognitive impairment, the N.F.L. has altered rules, fined and suspended players who hit opponents in the head and contributed millions of dollars for the study of head injuries. “Is this their way of defending themselves with this cloud over the sport? I’d be lying if I told you it had nothing to do with it,” Kevin Guskiewicz, the founding director of the Matthew Gfeller Sport-Related Traumatic Brain Injury Research Center at the University of North Carolina, said of the initiative. Guskiewicz is a member of the league’s Head, Neck and Spine Committee and the chairman of a subcommittee focused on safety equipment and playing rules. He will work with the N.F.L. and G.E. to identify areas of focus. © 2013 The New York Times Company
By R. Douglas Fields Imagine if your biggest health problem could be solved with the flip of a switch. Deep-brain stimulation (DBS) offers such a dramatic recovery for a range of neurological illnesses, including Parkinson's disease, epilepsy and major depression. Yet the metal electrodes implanted in the brain are too bulky to tap into intricate neural circuitry with precision and corrode in contact with tissue, so their performance degrades over time. Now neurophysiologists have developed a method of DBS that avoids these problems by using microscopic magnets to stimulate neurons. In experiments published in June 2012 in Nature Communications, neurophysiologist John T. Gale of the Cleveland Clinic and his colleague Giorgio Bonmassar, a physicist at Harvard Medical School and an expert on brain imaging, tested whether micromagnets (which are half a millimeter in diameter) could induce neurons from rabbit retinas to fire. They found that when they electrically energized a micromagnet positioned next to a neuron, it fired. In contrast to the electric currents induced by DBS, which excite neurons in all directions, magnetic fields follow organized pathways from pole to pole, like the magnetic field that surrounds the earth. The researchers found that they could direct the stimulus precisely to individual neurons, and even to particular areas of a neuron, by orienting the magnetic coil appropriately. “That may help us avoid the side effects we see in DBS,” Gale says, referring to, for instance, the intense negative emotions that are sometimes accidentally triggered when DBS is used to relieve motor problems in Parkinson's. © 2013 Scientific American
by Carrie Arnold Studying the links between brain and behavior may have just gotten easier. For the first time, neuroscientists have found a way to watch neurons fire in an independently moving animal. Though the study was done in fish, it may hold clues to how the human brain works. "This technique will really help us understand how we make sense of the world and why we behave the way we do," says Martin Meyer, a neuroscientist at King's College London who was not involved in the work. The study was carried out in zebrafish, a popular animal model because they're small and easy to breed. More important, zebrafish larvae are transparent, which gives scientists an advantage in identifying the neural circuits that make them tick. Yet, under a typical optical microscope, neurons that are active and firing look much the same as their quieter counterparts. To see what neurons are active and when, neuroscientists have therefore developed a variety of indicators and dyes. For example, when a neuron fires, it is flooded with calcium ions, which can cause some of the dyes to light up. Still, the approach has limitations. Traditionally, Meyer explains, researchers would immobilize the head or entire body of a zebrafish larvae so that they could get a clearer picture of what was happening inside the brain. Even so, it was difficult to interpret neural activity for just a few neurons and over a short period of time. Researchers needed a better way to study the zebrafish brain in real time. © 2010 American Association for the Advancement of Science
Keyword: Brain imaging
Link ID: 17742 - Posted: 02.02.2013
Alison Abbott & Quirin Schiermeier Two of the biggest awards ever made for research have gone to boosting studies of the wonder material graphene and an elaborate simulation of the brain. The winners of the European Commission’s two-year Future and Emerging Technologies ‘flagship’ competition, announced on 28 January, will receive €500 million (US$670 million) each for their planned work, which the commission hopes will help to improve the lives, health and prosperity of millions of Europeans. The Human Brain Project, a supercomputer simulation of the human brain conceived and led by neuroscientist Henry Markram at the Swiss Federal Insitute of Technology in Lausanne, scooped one of the prizes. The other winning team, led by Jari Kinaret at Chalmers University of Technology in Gothenburg, Sweden, hopes to develop the potential of graphene — an ultrathin, flexible, electrically conducting form of carbon — in applications such as personal-communication technologies, energy storage and sensors. The size of the awards — matching funds raised by the participants are expected to bring each project’s budget up to €1 billion over ten years — have some researchers worrying that the flagship programme may draw resources from other research. And both winners have already faced criticism. Many neuroscientists have argued, for example, that the Human Brain Project’s approach to modelling the brain is too cumbersome to succeed (see Nature 482, 456–458; 2012). Markram is unfazed. He explains that the project will have three main thrusts. One will be to study the structure of the mouse brain, from the molecular to the cellular scale and up. Another will generate similar human data. A third will try to identify the brain wiring associated with particular behaviours. The long-term goals, Markram says, include improved diagnosis and treatment of brain diseases, and brain-inspired technology. © 2013 Nature Publishing Group
By Sandra G. Boodman Still clutching his discharge instructions from a suburban Maryland emergency room, Brian Harms struggled to make sense of what the neurosurgeon was saying. The ER staff had told Harms, admitted hours earlier, that his diagnoses were headache and vertigo and that he should go home and rest. A CT scan had found a benign cyst in his brain, but the staff didn’t convey any urgency about treating it. As the 29-year-old College Park resident was gathering his things, a neurosurgeon rushed in, telling Harms he would not be going home. “I need to get this information to you quickly,” Harms remembers the specialist telling him on the morning of Sept. 28, 2011. “You are in a lot of trouble, and you need surgery as soon as possible.” The neurosurgeon had been trying to arrange a transfer to Johns Hopkins Hospital in Baltimore, but doctors were worried that he might die en route. “I highly suggest you trust me and let me do this procedure here,” Harms remembers the surgeon telling him, but the decision was his. For Harms, who had seen several doctors for headaches and other symptoms during the previous 18 months, the news was beyond shocking. “It felt like the floor dropped out beneath me,” he recalled. “I was scared witless.” Only later would Harms, a University of Maryland doctoral candidate in geochemistry, learn how lucky he was to have survived both a series of misdiagnoses and a test, performed hours before his emergency surgery, that could have killed him. © 1996-2013 The Washington Post
Keyword: Pain & Touch
Link ID: 17727 - Posted: 01.29.2013
By Lisa Raffensperger Among the many unpleasant side effects of chemotherapy treatment, researchers have just confirmed another: chemo brain. The term refers to the mental fog that chemotherapy patients report feeling during and after treatment. According to Jame Abraham, a professor at West Virginia University, about a quarter of patients undergoing chemotherapy have trouble focusing, processing numbers, and using short-term memory. A recent study points to the cause. The study relied on PET (positron emission tomography) brain scanning to examine brain blood flow, a marker for brain activity. Abraham and colleagues scanned the brains of 128 breast cancer patients before chemotherapy began and then 6 months later. The results showed a significant decrease in activity in regions responsible for memory, attention, planning and prioritizing. The findings aren’t immediately useful for treating or preventing the condition of chemo brain, but the hard and fast evidence may comfort those experiencing chemo-related forgetfulness. And luckily chemo brain is almost always temporary: patients’ mental processing generally returns to normal within a year or two after chemotherapy treatment ends.
Scientists say they have found a way to distinguish between different types of dementia without the need for invasive tests, like a lumbar puncture. US experts could accurately identify Alzheimer's disease and another type of dementia from structural brain patterns on medical scans, Neurology reports. Currently, doctors can struggle to diagnose dementia, meaning the most appropriate treatment may be delayed. More invasive tests can help, but are unpleasant for the patient. Despite being two distinct diseases, Alzheimer's and frontotemporal dementia, share similar clinical features and symptoms and can be hard to tell apart without medical tests. Both cause the person to be confused and forgetful and can affect their personality, emotions and behaviour. Alzheimer's tends to attack the cerebral cortex - the layer of grey matter covering the brain - where as frontotemporal dementia, as the name suggests, tends to affect the temporal and frontal lobes of the brain, which can show up on brain scans, but these are not always diagnostic. A lumbar puncture - a needle in the spine - may also be used to check protein levels in the brain, which tend to be higher in Alzheimer's than with frontotemporal dementia. BBC © 2012
Posted by Heidi Ledford Just in time for the holidays, a team of MIT and Max Planck researchers has released EyeWire: an online game that allows users to trace neural connections through the retina. In the proud tradition of Foldit and other ‘citizen science’ endeavours, EyeWire aims to harness the power of the people to map the projections of retinal cells called JAM-B cells. JAM-B cells respond specifically to upward motion (which appears downward to the retina, because it receives inverted images), and were the first retinal ganglion cells distinguished on the basis of a molecular marker — a protein called ‘Junctional Adhesion Molecule B’ (JAM-B). Does the downward trajectory of the JAM-B cell projections relate to their function? The scientists behind EyeWire hope to find out. EyeWire, launched 10 December, is spearheaded by MIT’s Sebastian Seung, best known for taking the concept of mapping neural connections and turning it into the surprisingly digestible and well-read popular science book Connectomics: How the Brain’s Wiring Makes Us Who We Are. Seung and his colleagues chart the retinal connectome by taking serial electron micrographs of thin slices of tissue. They then trace individual neural projections through each slice and stitch it all together again into a three dimensional image. Seung’s team could use all the help it can get: in a review of Seung’s book, Caltech neuroscientist Christoph Koch estimated that to map a cubic millimetre of brain would require a billion images and a million working-years of analysis time for a trained technician. © 2012 Nature Publishing Group
Keyword: Brain imaging
Link ID: 17597 - Posted: 12.11.2012
By Scicurious This past weekend, I read an interesting piece in the New Yorker. It’s another one of the current rash of pieces that are warning us (rightly!) to beware of neuro-hype. It references another recent piece in the New York Times, which referenced those fighting back against things like “How Creativity Works” (correct answer: it’s very complicated and we don’t know), and the ever-present fMRI studies hyped in the news (I’ve been guilty of a few of those, though I try very hard to be skeptical). Both pieces referenced the excellent Neuroskeptic and Neurocritic (though sadly, the NYT didn’t give them the links they definitely deserve). And both pieces warned that neuroscience is more, and better than, the gee-whiz of “This is your brain on poker“. I particularly liked the New Yorker piece, for making clear the incredible complexity of the human brain. The brain, though, rarely works that way. Most of the interesting things that the brain does involve many different pieces of tissue working together. Saying that emotion is in the amygdala, or that decision-making is the prefrontal cortex, is at best a shorthand, and a misleading one at that. Different emotions, for example, rely on different combinations of neural substrates. The act of comprehending a sentence likely involves Broca’s area (the language-related spot on the left side of the brain that they may have told you about in college), but it also draws on the parts of the brain in the temporal lobe that analyze acoustic signals, and part of sensorimotor cortex and the basal ganglia become active as well. (In congenitally blind people, some of the visual cortex also plays a role.) It’s not one spot, it’s many, some of which may be less active but still vital, and what really matters is how vast networks of neural tissue work together. © 2012 Scientific American
Keyword: Brain imaging
Link ID: 17568 - Posted: 12.04.2012
Posted by Gary Marcus In the early nineteen-nineties, David Poeppel, then a graduate student at M.I.T. (and a classmate of mine)—discovered an astonishing thing. He was studying the neurophysiological basis of speech perception, and a new technique had just come into vogue, called positron emission tomography (PET). About half a dozen PET studies of speech perception had been published, all in top journals, and David tried to synthesize them, essentially by comparing which parts of the brain were said to be active during the processing of speech in each of the studies. What he found, shockingly, was that there was virtually no agreement. Every new study had published with great fanfare, but collectively they were so inconsistent they seemed to add up to nothing. It was like six different witnesses describing a crime in six different ways. This was terrible news for neuroscience—if six studies led to six different answers, why should anybody believe anything that neuroscientists had to say? Much hand-wringing followed. Was it because PET, which involves injecting a radioactive tracer into the brain, was unreliable? Were the studies themselves somehow sloppy? Nobody seemed to know. And then, surprisingly, the field prospered. Brain imaging became more, not less, popular. The technique of PET was replaced with the more flexible technique of functional magnetic resonance imaging (fMRI), which allowed scientists to study people’s brains without the use of the risky radioactive tracers, and to conduct longer studies that collected more data and yielded more reliable results. Experimental methods gradually become more careful. As fMRI machines become more widely available, and methods became more standardized and refined, researchers finally started to find a degree of consensus between labs. © 2012 Condé Nast.
Keyword: Brain imaging
Link ID: 17567 - Posted: 12.04.2012
By Laura Sanders A new computer simulation of the brain can count, remember and gamble. And the system, called Spaun, performs these tasks in a way that’s eerily similar to how people do. Short for Semantic Pointer Architecture Unified Network, Spaun is a crude approximation of the human brain. But scientists hope that the program and efforts like it could be a proving ground to test ideas about the brain. Several groups of scientists have been racing to construct a realistic model of the human brain, or at least parts of it. What distinguishes Spaun from other attempts is that the model actually does something, says computational neuroscientist Christian Machens of the Champalimaud Centre for the Unknown in Lisbon, Portugal. At the end of an intense computational session, Spaun spits out instructions for a behavior, such as how to reproduce a number it’s been shown. “And of course, that’s why the brain is interesting,” Machens says. “That’s what makes it different from a plant.” Like a digital Frankenstein’s monster, Spaun was cobbled together from bits and pieces of knowledge gleaned from years of basic brain research. The behavior of 2.5 million nerve cells in parts of the brain important for vision, memory, reasoning and other tasks forms the basis of the new system, says Chris Eliasmith of the University of Waterloo in Canada, coauthor of the study, which appears in the Nov. 30 Science. © Society for Science & the Public 2000 - 2012
Link ID: 17557 - Posted: 12.01.2012
High-resolution real-time images show in mice how nerves may be damaged during the earliest stages of multiple sclerosis. The results suggest that the critical step happens when fibrinogen, a blood-clotting protein, leaks into the central nervous system and activates immune cells called microglia. "We have shown that fibrinogen is the trigger," said Katerina Akassoglou, Ph.D., an associate investigator at the Gladstone Institute for Neurological Disease and professor of neurology at the University of California, San Francisco, and senior author of the paper published online in Nature Communications. Multiple sclerosis, or MS, is thought to be an autoimmune disease in which cells that normally protect the body against infections attack nerve cells in the brain and spinal cord, often leading to problems with vision, muscle strength, balance and coordination, thinking and memory. Typically during MS, the immune cells destroy myelin, a protective sheath surrounding nerves, and eventually leading to nerve damage. The immune attack also causes leaks in the blood-brain barrier, which normally separates the brain from potentially harmful substances in the blood. "Dr. Akassoglou has focused on the role of the blood-brain barrier leak in MS and has discovered that leakage of the blood clotting protein fibrinogen can trigger brain inflammation," said Ursula Utz, Ph.D., M.B.A., a program director at NIH's National Institute of Neurological Disorders and Stroke (NINDS). Microglia are cells traditionally thought to control immunity in the nervous system. Previous studies suggested that leakage of fibrinogen activates microglia.
By Tanya Lewis A coma patient’s chances of surviving and waking up could be predicted by changes in the brain’s ability to discriminate sounds, new research suggests. Recovery from coma has been linked to auditory function before, but it wasn’t clear whether function depended on the time of assessment. Whereas previous studies tested patients several days or weeks after comas set in, a new study looks at the critical phase during the first 48 hours. At early stages, comatose brains can still distinguish between different sound patterns,. How this ability progresses over time can predict whether a coma patient will survive and ultimately awaken, researchers report. “It’s a very promising tool for prognosis,” says neurologist Mélanie Boly of the Belgian National Fund for Scientific Research, who was not involved with the study. “For the family, it’s very important to know if someone will recover or not.” A team led by neuroscientist Marzia De Lucia of the University of Lausanne in Switzerland studied 30 coma patients who had experienced heart attacks that deprived their brains of oxygen. All the patients underwent therapeutic hypothermia, a standard treatment to minimize brain damage, in which their bodies were cooled to 33° Celsius for 24 hours. De Lucia and colleagues played sounds for the patients and recorded their brain activity using scalp electrodes — once in hypothermic conditions during the first 24 hours of coma, and again a day later at normal body temperature. The sounds were a series of pure tones interspersed with sounds of different pitch, duration or location. The brain signals revealed how well patients could discriminate the sounds, compared with five healthy subjects. © Society for Science & the Public 2000 - 2012
By ALISSA QUART THIS fall, science writers have made sport of yet another instance of bad neuroscience. The culprit this time is Naomi Wolf; her new book, “Vagina,” has been roundly drubbed for misrepresenting the brain and neurochemicals like dopamine and oxytocin. Earlier in the year, Chris Mooney raised similar ire with the book “The Republican Brain,” which claims that Republicans are genetically different from — and, many readers deduced, lesser to — Democrats. “If Mooney’s argument sounds familiar to you, it should,” scoffed two science writers. “It’s called ‘eugenics,’ and it was based on the belief that some humans are genetically inferior.” Sharp words from disapproving science writers are but the tip of the hippocampus: today’s pop neuroscience, coarsened for mass audiences, is under a much larger attack. Meet the “neuro doubters.” The neuro doubter may like neuroscience but does not like what he or she considers its bastardization by glib, sometimes ill-informed, popularizers. A gaggle of energetic and amusing, mostly anonymous, neuroscience bloggers — including Neurocritic, Neuroskeptic, Neurobonkers and Mind Hacks — now regularly point out the lapses and folly contained in mainstream neuroscientific discourse. This group, for example, slammed a recent Newsweek article in which a neurosurgeon claimed to have discovered that “heaven is real” after his cortex “shut down.” Such journalism, these critics contend, is “shoddy,” nothing more than “simplified pop.” Additionally, publications from The Guardian to the New Statesman have published pieces blasting popular neuroscience-dependent writers like Jonah Lehrer and Malcolm Gladwell. The Oxford neuropsychologist Dorothy Bishop’s scolding lecture on the science of bad neuroscience was an online sensation last summer. © 2012 The New York Times Company
Keyword: Brain imaging
Link ID: 17524 - Posted: 11.24.2012
by Douglas Heaven MEANINGS of words can be hard to locate when they are on the tip of your tongue, let alone in the brain. Now, for the first time, patterns of brain activity have been matched with the meanings of specific words. The discovery is a step forward in our attempts to read thoughts from brain activity alone, and could help doctors identify awareness in people with brain damage. Machines can already eavesdrop on our brains to distinguish which words we are listening toMovie Camera, but Joao Correia at Maastricht University in the Netherlands wanted to get beyond the brain's representation of the words themselves and identify the activity that underlies their meaning. Somewhere in the brain, he hypothesised, written and spoken representations of words are integrated and meaning is processed. "We wanted to find the hub," he says. To begin the hunt, Correia and his colleagues used an fMRI scanner to study the brain activity of eight bilingual volunteers as they listened to the names of four animals, bull, horse, shark and duck, spoken in English. The team monitored patterns of neural activity in the left anterior temporal cortex - known to be involved in a range of semantic tasks - and trained an algorithm to identify which word a participant had heard based on the pattern of activity. Since the team wanted to pinpoint activity related to meaning, they picked words that were as similar as possible - all four contain one syllable and belong to the concept of animals. They also chose words that would have been learned at roughly the same time of life and took a similar time for the brain to process. © Copyright Reed Business Information Ltd.