Chapter 2. Cells and Structures: The Anatomy of the Nervous System
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By Ferris Jabr In the 1970s biologist Sydney Brenner and his colleagues began preserving tiny hermaphroditic roundworms known as Caenorhabditis elegans in agar and osmium fixative, slicing up their bodies like pepperoni and photographing their cells through a powerful electron microscope. The goal was to create a wiring diagram—a map of all 302 neurons in the C. elegans nervous system as well as all the 7,000 connections, or synapses, between those neurons. In 1986 the scientists published a near complete draft of the diagram. More than 20 years later, Dmitri Chklovskii of Janelia Farm Research Campus and his collaborators published an even more comprehensive version. Today, scientists call such diagrams "connectomes." So far, C. elegans is the only organism that boasts a complete connectome. Researchers are also working on connectomes for the fruit fly nervous system and the mouse brain. In recent years some neuroscientists have proposed creating a connectome for the entire human brain—or at least big chunks of it. Perhaps the most famous proponent of connectomics is Sebastian Seung of the Massachusetts Institute of Technology, whose impressive credentials, TED talk, popular book, charisma and distinctive fashion sense (he is known to wear gold sneakers) have made him a veritable neuroscience rock star. Other neuroscientists think that connectomics at such a large scale—the human brain contains around 86 billion neurons and 100 trillion synapses—is not the best use of limited resources. It would take far too long to produce such a massive map, they argue, and, even if we had one, we would not really know how to interpret it. To bolster their argument, some critics point out that the C. elegans connectome has not provided many insights into the worm's behavior. In a debate* with Seung at Columbia University earlier this year, Anthony Movshon of New York University said, "I think it's fair to say…that our understanding of the worm has not been materially enhanced by having that connectome available to us. We don't have a comprehensive model of how the worm's nervous system actually produces the behaviors. What we have is a sort of a bed on which we can build experiments—and many people have built many elegant experiments on that bed. But that connectome by itself has not explained anything." © 2012 Scientific American
Keyword: Development of the Brain
Link ID: 17325 - Posted: 10.03.2012
The brain that revolutionized physics now can be downloaded as an app for $9.99. But it won't help you win at Angry Birds. While Albert Einstein's genius isn't included, an exclusive iPad application launched Tuesday promises to make detailed images of his brain more accessible to scientists than ever before. Teachers, students and anyone who's curious also can get a look. A medical museum under development in Chicago obtained funding to scan and digitize nearly 350 fragile and priceless slides made from slices of Einstein's brain after his death in 1955. The application will allow researchers and novices to peer into the eccentric Nobel winner's brain as if they were looking through a microscope. "I can't wait to find out what they'll discover," said Steve Landers, a consultant for the National Museum of Health and Medicine Chicago who designed the app. "I'd like to think Einstein would have been excited." After Einstein died, a pathologist named Thomas Harvey performed an autopsy, removing the great man's brain in hopes that future researchers could discover the secrets behind his genius. Harvey gave samples to researchers and collaborated on a 1999 study published in the Lancet. That study showed a region of Einstein's brain - the parietal lobe - was 15 percent wider than normal. The parietal lobe is important to the understanding of math, language and spatial relationships. © 2012 Hearst Communications Inc
Link ID: 17302 - Posted: 09.26.2012
The human brain is big and complicated. There has been a map for gene expression in mice brains available for a number of years but human brains are a thousand times bigger and a little harder to come by for post-mortem research. But published today is a high-resolution 3D atlas of the human brain created by an international team led by Michael Hawrylycz of the Allen Institute for Brain Science in Seattle. The project was launched in March 2008 with a budget of $55 million. Working with just two whole male brains and a single hemisphere from a third, the team used around 900 precise subdivisions and 60,000 gene expression probes to create the atlas. This image is a 3D rendering of just one of the genes in internal brain structures overlaid onto an MRI scan. The level of gene expression at the different points on the map is indicated on a colour scale, with blue dots reflecting relatively low expression and red dots reflecting high expression. The aim of the project is to provide a platform for further study into gene expression in the brain and how it is involved in normal and abnormal brain function. The Allen Brain Atlas is freely accessible online. Journal reference: Nature, DOI: 10.1038/nature11405 © Copyright Reed Business Information Ltd.
2012 by Graham Lawton My usual pick-me-up on a Monday morning is a cup of coffee. Today it's going to be something very different. I've been up since 6 am. I've had a breath test for alcohol, a urine test for drugs and a psychological test for mental health. Then I'm handed a red pill and a glass of water. I swallow it… and I'm told to relax. Which is easier said than done when you don't know if you've just taken vitamin C or 83 milligrams of pure MDMA. Half an hour later I'm inside an fMRI brain scanner, my head clamped in place and a visor over my face. It's noisy and claustrophobic but I'm reassured by the panic button in my hand and a voice from the control room. And then I start to feel it. A tingle of energy, like pins and needles, starts in the pit of my stomach and rises slowly, not unpleasant but not exactly pleasurable either. It builds in intensity, then breaks into a wave of bliss. The placebo effect can be powerful but when it happens again, I'm in no doubt. I'm coming up. I'm taking part in a groundbreaking study on MDMA, the drug commonly known as ecstasy. The research is run by David Nutt of Imperial College London, a former government adviser and one of the few UK researchers licensed to study class-A drugsMovie Camera. His main aim is to discover what MDMA does to the human brain, something that, remarkably, has never been done before. A second goal is to study MDMA as a therapy for post-traumatic stress disorder. © Copyright Reed Business Information Ltd
by Douglas Heaven Nanoparticles often meet a sticky end in the brain. In theory, the tiny structures could deliver therapeutic drugs to a brain tumour, but navigating the narrow, syrupy spaces between brain cells is difficult. A spot of lubrication could help. Justin Hanes at Johns Hopkins University in Baltimore, Maryland, was surprised to discover just how impermeable brain tissue is to nanoparticles. "It's very sticky stuff," he says, similar in adhesiveness to mucus, which protects parts of the body – such as the respiratory system – by trapping foreign particles. It was thought that the adhesiveness of brain tissue limited the size of particles that can smoothly spread through the brain. Signalling molecules, nutrients and waste products below 64 nanometres in diameter can pass through the tissue with relative ease, but larger nanoparticles – suitable for delivering a payload of drugs to a specific location in the brain – quickly get stuck. Now Hanes and his colleagues have doubled that size limit. They coated their nanoparticles with a densely-packed polymer shield, which lubricates their surface by preventing electrostatic and hydrophobic interactions with the surrounding tissue. "A nice hydrated shell around the particle prevents it from adhering to cells," says Hanes. Using this approach, they were able to observe the diffusion of nanoparticles 114 nanometres in diameter through live mouse brains and dissected human and rat brain tissue. Hanes believes the true upper size limit now lies somewhere between 114 nm and 200 nm. "Things were starting to slow down at 114," he says. © Copyright Reed Business Information Ltd.
Link ID: 17219 - Posted: 08.30.2012
By Stephani Sutherland Ice cream headache is a familiar summertime sensation, but the pain's source has been mysterious until now. A team led by Jorge Serrador of Harvard Medical School produced brain scans of “second-by-second changes” in blood flow while subjects sipped iced water through a straw pressed against the roof of the mouth, which caused the brain's major artery to widen. “Blood flow changes actually preceded the pain” that subjects reported, Serrador says. As the vessel narrowed again, the discomfort ebbed. He suspects that the influx of blood is meant to protect the brain from extreme cold and that increased pressure inside the skull could cause the pain. Serrador presented the results at Experimental Biology 2012 in April in San Diego. © 2012 Scientific American
Keyword: Pain & Touch
Link ID: 17205 - Posted: 08.27.2012
By Carrie Arnold Like an overwhelmed traffic cop, the depressed brain may transmit signals among regions in a dysfunctional way. Recent brain-imaging studies suggest that areas of the brain involved in mood, concentration and conscious thought are hyperconnected, which scientists believe could lead to the problems with focus, anxiety and memory frequently seen in depression. Using functional MRI and electroencephalography (EEG), psychiatrist Andrew Leuchter of the University of California, Los Angeles, and his colleagues measured the activity of depressed patients' brains at rest. They found that the limbic and cortical areas, which together produce and process our emotions, sent a barrage of neural messages back and forth to one another—much more than in the brains of healthy patients. These signals, Leuchter says, can amplify depressed people's negative thoughts and act like white noise, drowning out the other neural messages telling them to move on. A separate study by psychiatrist Shuqiao Yao of Central South University in Hunan, China, produced a more nuanced view of these two areas' hyperconnectivity. In work published in Biological Psychiatry in April, Yao and his colleagues reported that stronger links among certain corticolimbic circuits are seen in patients more prone to rumination, the act of continuously replaying negative thoughts. Less connectivity in other corticolimbic circuits corresponded to autobiographical memory impairments, which is another common feature that appears in depression. © 2012 Scientific American
Link ID: 17197 - Posted: 08.25.2012
by Sara Reardon The carnival trick of guessing a person's age has just gained a lot more rigour. A new brain imaging technique can predict a child's age to within a year. The technique could be useful for determining whether a child is developing normally, or confirm that a young person is the age they say they are. There is no doubt that children of the same age often have vast differences in their maturity and mental ability, says Timothy Brown of the University of California in San Diego. But what hasn't been clear is how much of that difference is psychological and how much is biological. To simplify the question, Brown and his colleagues looked at brain structure rather than brain activity. Working with 10 hospitals in different parts of the US, they recruited 885 children and young adults between the ages of 3 and 20. They ensured that the participants represented many different races, socioeconomic statuses and education levels. The group performed structural magnetic resonance imaging (MRI) on the young peoples' brains. The images showed features such as the size of each brain region, the level of connectivity between neurons, and how much white matter was insulating the neurons. By putting all these features together in an algorithm, the researchers formed a picture of what the average brain looks like at each year of childhood. Different areas and features of the brain varied between individuals, but the algorithm correctly predicted a child's age to within a year in 92 per cent of cases. © Copyright Reed Business Information Ltd.
By Jason G. Goldman The largest fish in the ocean is the whale shark (Rhincodon typus). This massive, migratory fish can grow up to twelve meters in length, but its enormous mouth is designed to eat the smallest of critters: plankton. While the biggest, the whale shark isn’t the only gigantic filter-feeding shark out there: the basking shark and the megamouth shark also sieve enormous amounts of the tiny organisms from the sea in order to survive. While scientists like Al Dove and Craig McClain (of Deep Sea News) are learning more and more about the basic biology and behavior of these magnificent creatures, other scientists are busy investigating their neuroanatomy. A few years ago, Kara E. Yopak and Lawrence R. Frank from the University of California in San Diego got their hands on two whale shark brains from an aquarium, and put them into an MRI scanner. But they weren’t just interested in imaging the brains of the whale sharks. What they wanted to know was how the organization of whale shark brains compared to the brains of other shark species for which scientists had previously obtained neuroanatomical data. Would the brains of two species be more similar if they shared a recent evolutionary ancestor, and were therefore more genetically related? Or would shark brains be more similar among species that shared a similar lifestyle, such as those that patrol the middle and surface of the water column (pelagic sharks, such as the great white, oceanic whitetip, blue, mako, and whale sharks) versus those that live along the sea floor (benthic sharks, such as the nurse and cat sharks). Or perhaps the brains of sharks would be grouped according to their habitat, such as those that live in coastal waters, around reefs, or in the open ocean. Maybe sharks brains ought to be grouped according to behavioral specialization, such as hunting methods. Answers to these questions could shed some important light on brain evolution, both in sharks as well as more generally. © 2012 Scientific American
by Molly Docherty The brain drain is real. There is a network of previously unrecognised vessels that rid the brain of unwanted extracellular fluids and other substances, including amyloid-beta – a peptide that accumulates in the brain of people with Alzheimer's. The new discovery looks set to add to our understanding of the disease. Jeffrey Iliff at the University of Rochester Medical Center, New York, and his colleagues, were intrigued by the fact that there are no obvious lymphatic vessels in the brain. Among other things, the lymphatic system removes waste interstitial fluids from body tissue. "It seemed strange that such an important and active organ wouldn't have a specialised waste-removal system," says Iliff. When the researchers added fluorescent and radioactive tracers to the cerebrospinal fluid of live mice, the tracers quickly spread throughout the rodents' brains. Using two-photon microscopy to visualise the movement in real-time, the team saw cerebrospinal fluid permeating the entire brain through 'pipes' surrounding blood vessels, similar to the lymphatic system that services all other organs. The pipes work on hydraulic principles, though, and so the system breaks upon opening, making it hard to identify it outside living organisms. © Copyright Reed Business Information Ltd.
Keyword: Brain imaging
Link ID: 17174 - Posted: 08.16.2012
By Katherine Harmon Jill, a 60-year-old woman in Milwaukee, has overcome extreme poverty. So, now that she has enough money to put food in the fridge, she fills it. She also fills her freezer, her cupboard and every other corner of her home. “I use duct tape to close the freezer door sometimes when I’ve got too many things in there,” she told A&E’s Hoarders. Film footage of her kitchen shows a cat scrambling over a rotten grapefruit; her counters—and most surfaces in her home—seemed to be covered with several inches of clutter and spoiled food. “I was horrified,” her younger sister said after visiting Jill. And the landlord threatened eviction because the living conditions became unsafe. Jill joins many others who have been outed on reality TV as a “hoarder.” We might have once called people with these tendencies “collectors” or “eccentrics.” But in recent years, psychiatrists had suggested they have a specific type of obsessive-compulsive disorder (OCD). A movement is underfoot, however, for the new edition of the psychiatric field’s diagnostic bible (the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, or DSM-5), to move hoarding disorder to its own class of illness. And findings from a new brain scan study, published online August 6 in Archives of General Psychiatry, support this new categorization. Hoarding disorder is categorized as “the excessive acquisition of and inability to discard objects, resulting in debilitating clutter,” wrote the researchers behind the new study, led by Yale University School of Medicine’s David Tolin. © 2012 Scientific American,
Scientists have discovered a biological marker that may help to identify which depressed patients will respond to an experimental, rapid-acting antidepressant. The brain signal, detectable by noninvasive imaging, also holds clues to the agent’s underlying mechanism, which are vital for drug development, say National Institutes of Health researchers. The signal is among the latest of several such markers, including factors detectable in blood, genetic markers, and a sleep-specific brain wave, recently uncovered by the NIH team and grantee collaborators. They illuminate the workings of the agent, called ketamine, and may hold promise for more personalized treatment. "These clues help focus the search for the molecular targets of a future generation of medications that will lift depression within hours instead of weeks," explained Carlos Zarate, M.D., of the NIH’s National Institute of Mental Health (NIMH). "The more precisely we understand how this mechanism works, the more narrowly treatment can be targeted to achieve rapid antidepressant effects and avoid undesirable side effects." Previous research had shown that ketamine can lift symptoms of depression within hours in many patients. But side effects hamper its use as a first-line medication. So researchers are studying its mechanism of action in hopes of developing a safer agent that works similarly. Ketamine works through a different brain chemical system than conventional antidepressants. It initially blocks a protein on brain neurons, called the NMDA receptor, to which the chemical messenger glutamate binds.
By Melissa Healy Los Angeles Times Measuring human intelligence may be controversial and oh-so-very-tricky to do. But like obscenity, we think we know it when we see it. A new study, however, demonstrates a more rigorous way to see and measure differences in intelligence between individuals. It finds that connectedness among the brain's disparate regions is a key factor that separates the plodding from the penetrating. As many researchers have long suspected, intelligence does have a "seat" in the human brain: an area just behind each of the temples called the lateral prefrontal cortex. But researchers writing in the journal Neuroscience found that human behavior that is exceptionally flexible, responsive and capable of navigating complexity requires something beyond a strong and active prefrontal cortex: strong and agile runners must link that seat to brain regions involved in perception, memory, language and mobility. The researchers estimate that the strength of those connections, as measured when subjects rested between mental tasks, explains about 10% of differences in intelligence among individuals. That makes this measure an even better predictor of intelligence than brain size -- a measure that scientists believe may explain about 7% of the variation in intelligence among individuals. To detect this relationship, the Neuroscience study compared functional magnetic resonance imaging (fMRI) brain scans of 78 men and women between 18 and 40 years old with those subjects' performance on tests of cognitive performance that required "fluid intelligence" and "cognitive control." Subjects, for instance, were asked to count backwards by, say, nine, or to watch a series of visual images and then indicate whether a single image shown had been among them. Copyright 2012
Monya Baker Last week, the Sacramento Bee reported that two neurosurgeons at the University of California, Davis, had been banned from research on humans after deliberately infecting three terminally ill cancer patients with pathogenic bacteria in an attempt to treat them. All three died, two showing complications from the infection. Nature explores what happened and the science behind it. Who authorized the researchers to infect the patients? All three patients consented to infection. However, anyone testing experimental drugs in the United States requires approval from their university’s Institutional Review Board (IRB) and oversight by the country's Food and Drug Administration (FDA), both of which review evidence for safety and efficacy. Neurosurgeons Paul Muizelaar and Rudolph Schrot at the University of California (UC), Davis, did not obtain this approval; they say they did not think it was required. Harris Lewin, the vice-chancellor of research at UC Davis, wrote a letter to the FDA describing what had occurred as “serious and continuing noncompliance”. In 2008, working under instructions from Muizelaar, Schrot asked the FDA about the possibility of deliberately infecting a postoperative wound in a particular patient with glioblastoma with the bacterium Enterobacter aerogenes. He was told that animal studies were needed first. Muizelaar did not infect that patient, but arranged for a graduate student to begin tests in rats. Although bacteria were purchased as research materials not to be used in humans, they were eventually used in three other patients with glioblastoma. © 2012 Nature Publishing Group
By Sandra Upson All elite athletes train hard, possess great skills and stay mentally sharp during competition. But what separates a gold medalist from an equally dedicated athlete who comes in 10th place? A small structure deep in the brain may give winners an extra edge. Recent studies indicate that the brain's insular cortex may help a sprinter drive his body forward just a little more efficiently than his competitors. This region may prepare a boxer to better fend off a punch his opponent is beginning to throw as well as assist a diver as she calculates her spinning body's position so she hits the water with barely a splash. The insula, as it is commonly called, may help a marksman retain a sharp focus on the bull's-eye as his finger pulls back on the trigger and help a basketball player at the free-throw line block out the distracting screams and arm-waving of fans seated behind the backboard. The insula does all this by anticipating an athlete's future feelings, according to a new theory. Researchers at the OptiBrain Center, a consortium based at the University of California, San Diego, and the Naval Health Research Center, suggest that an athlete possesses a hyper-attuned insula that can generate strikingly accurate predictions of how the body will feel in the next moment. That model of the body's future condition instructs other brain areas to initiate actions that are more tailored to coming demands than those of also-rans and couch potatoes. This heightened awareness could allow Olympians to activate their muscles more resourcefully to swim faster, run farther and leap higher than mere mortals. In experiments published in 2012, brain scans of elite athletes appeared to differ most dramatically from ordinary subjects in the functioning of their insulas. © 2012 Scientific American
Keyword: Brain imaging
Link ID: 17088 - Posted: 07.25.2012
Rebecca Goldin, Ph.D., Cindy S. Merrick With the news media telling us that neuroscience – and brain scans – can explain everything from a global pandemic of Justin Bieber fever to whether you are likely to stay with your spouse, we investigate what neuroscience can and can’t tell us about who we are and why we do the things we do. In the first part of an ongoing series, we look at functional magnetic resonance imaging, and whether it’s really the window on the mind that some in the media – and science – would have us believe. Gone are the days when the only people who believed in technologies that could read minds were distinguishable from the rest of us by their tin foil hats. With the advent of functional magnetic resonance imaging (fMRI), we are able to see, in near-video quality, the ebb and flow of a live mind at work. Or so it seems. Something, for certain, is at work, and there are lots of people willing to tell you they know exactly how to interpret what we can see. Certainly this new technology has already produced fascinating results: surgeons use it real-time to avoid critical regions while operating on brain tumors; physicians use it to look for changes in the brain activity of stroke victims as they experience physical rehabilitation; and fMRI data showing activity in the brains of patients thought to be in a vegetative state may be blurring the line that defines consciousness. Along with these advances, though, have appeared many somewhat less credible stories. The media reports claims ranging from fMRI’s ability to detect lies to its predicting future addictive behavior or determining whether or not you really love your spouse, or, maybe, your iPhone. Already, attempts have been made to use fMRI as admissible evidence of lie detection in court (so far, they have failed); and in another court case, fMRI results and a neuroscientist’s testimony were admitted in the sentencing hearing. The data were used as evidence that the defendant, a violent offender, was psychopathic.
Keyword: Brain imaging
Link ID: 17047 - Posted: 07.17.2012
Will Ferguson, reporter You can't visit this tropical jungle. It's a forest of neurons snaking through a pig's brain. The brain cells, enlarged and coloured here, are being investigated to give scientists a clearer view of the mechanics of brain matter when it is hit hard. Michel Destrade, an applied mathematician at the National University of Ireland, Galway, and colleagues obtained samples of pig brains from a local slaughterhouse to study the mechanics of brain matter undergoing rapid impacts. With the aim of improving the treatment of traumatic head injuries, they used the samples to create computer models of electrical signals inside the brain. But during the course of the experiment, Destrade's student Badar Rashid decided to find out what white and grey matter inside a brain look like. He started with an image of neuron bundles taken using scanning electron microscopy, and blew it up to 4,000 times its actual size. He then added colour to the black and white result according to his own aesthetic. The image appears in Physics Today (DOI:10.1063/PT.3.1651). © Copyright Reed Business Information Ltd.
Keyword: Brain imaging
Link ID: 17042 - Posted: 07.16.2012
By Mahir Ozdemir Hardly a week passes without some sensational news about brain scans unleashing yet another secret of our cognitive faculties. Very recently I stumbled upon the news that according to recent research neuroscientists can tell, depending on your brain responses, whether you and your significant one will still be together in a few years: “You might hide it from friends and family. But you can’t hide it from neuroscientists”. The technique at the bottom of the study, just like the majority of studies making a big splash, is functional magnetic resonance imaging, fMRI. Researchers have been struggling to unfold ‘what’s under the hood’ through the lens of Neuroscience and they have been finding all sorts of insights into human behavior. They have been looking at everything from how multitasking is harder for seniors to how people love talking about themselves. Neural basis of love and hatred, compassion and admiration have all been studied with fMRI, yielding colored blobs representing the corresponding love or hatred centers in our brains. First a brief background: The fMRI technique measures brain activity indirectly via changes in blood oxygen levels in different parts of the brain as subjects participate in various activities. While lying down with head immobilized in a small confined chamber of the notoriously noisy MR scanner, subjects are shown experimental stimuli. They wear earplugs to reduce at least some part of the noise while performing these cognitive tasks. © 2012 Scientific American
Keyword: Brain imaging
Link ID: 17005 - Posted: 07.07.2012
By Daisy Yuhas At right is a picture of someone’s brain as seen through functional magnetic resonance imaging or fMRI. This particular subject is taxing his neurons with a working memory task—those sunny orange specks represent brain activity related to the task. fMRI images show the brain according to changes in blood oxygen level, a proxy for degree of mental activity. It’s a pretty amazing tool; it has validated a lot of assumptions about brain regions and helped us make comparisons between groups of people, shedding light on addiction, development and disease. Some scientists believe it can help us read minds (more on that later) or even predict the future. But fMRI doesn’t actually provide detail at the level of a cell. The 3-dimensionsal image it provides is built up in units called voxels. Each one represents a tidy cube of brain tissue—a 3-D image building block analogous to the 2-D pixel of computers screens, televisions or digital cameras. Each voxel can represent a million or so brain cells. Those orange blobs in the image above are actually clusters of voxels—perhaps tens or hundreds of them. fMRI is also too slow to capture all of the changes in the brain. Each scan requires a second or two, enough time for a neuron to fire more than a hundred times. That means it can’t provide a clear sense of precisely when things happen. Trying to explain whether activity in one spot causes activity in another is not possible through fMRI alone. Furthermore, you have to be careful with your conclusions. Just because voxels corresponding to one region ‘light up’ when your subject sees a terrifying tiger doesn’t mean that every time this region appears active, your subject is frightened. Many of the brain’s regions are quite complex and involved in multiple processes. © 2012 Scientific American
Keyword: Brain imaging
Link ID: 16957 - Posted: 06.23.2012
Neuroscientist and friend of the blog Bradley Voytek has a terrific piece about the relationship between popular science writing and neuroscience that’s well worth your time. In brief, he says, the primary problem are neuroscientists themselves. Or at least, some of the assumptions that neuroscientists make. The problem, he notes, is a problem that long term readers here are familiar with – the confusion of cause and effect, as well as an over-reductionist view of the brain. Namely, that imaging studies showing a portion of the brain “lighting up” when something happens means that that area of the brain is directly involved in the activity. Something that he analogizes to “like how when your arms swing faster when you run that means that your arms are ‘where running happens’.” Voytek also provides what I think is one of the best analogies I’ve read about the problem inherent in trying to isolate “which part of the brain does X”: Imagine asking “where is video located in my computer?” That doesn’t make any sense. Your monitor is required to see the video. Your graphics card is required to render the video. The software is required to generate the code for the video. But the “video” isn’t located anywhere in the computer. This is something that I think is exactly right. The best neuroscientists out there are, I think, very aware of this problem, but I think part of what’s going on here is the inherent limitations of our ability to experiment. Take fMRI’s, for example, which have provided an interesting look into what kinds of activity is going on in the brain while the person being imaged is doing or thinking something. It’s one of the best pieces of equipment available, but it’s very nature can be deceiving. Because it’s one of the few ways available to figure out what’s going on in the brain, it can be tempting to see what is measured by an fMRI image as definitive. 2012 Forbes.com LLC™
Keyword: Brain imaging
Link ID: 16927 - Posted: 06.19.2012