Chapter 2. Functional Neuroanatomy: The Nervous System and Behavior
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by Adam Gopnik Good myths turn on simple pairs— God and Lucifer, Sun and Moon, Jerry and George—and so an author who makes a vital duo is rewarded with a long-lived audience. No one in 1900 would have thought it possible that a century later more people would read Conan Doyle’s Holmes and Watson stories than anything of George Meredith’s, but we do. And so Gene Roddenberry’s “Star Trek,” despite the silly plots and the cardboard-seeming sets, persists in its many versions because it captures a deep and abiding divide. Mr. Spock speaks for the rational, analytic self who assumes that the mind is a mechanism and that everything it does is logical, Captain Kirk for the belief that what governs our life is not only irrational but inexplicable, and the better for being so. The division has had new energy in our time: we care most about a person who is like a thinking machine at a moment when we have begun to have machines that think. Captain Kirk, meanwhile, is not only a Romantic, like so many other heroes, but a Romantic on a starship in a vacuum in deep space. When your entire body is every day dissolved, reënergized, and sent down to a new planet, and you still believe in the ineffable human spirit, you have really earned the right to be a soul man. Writers on the brain and the mind tend to divide into Spocks and Kirks, either embracing the idea that consciousness can be located in a web of brain tissue or debunking it. For the past decade, at least, the Spocks have been running the Enterprise: there are books on your brain and music, books on your brain and storytelling, books that tell you why your brain makes you want to join the Army, and books that explain why you wish that Bar Refaeli were in the barracks with you. The neurological turn has become what the “cultural” turn was a few decades ago: the all-purpose non-explanation explanation of everything. Thirty years ago, you could feel loftily significant by attaching the word “culture” to anything you wanted to inspect: we didn’t live in a violent country, we lived in a “culture of violence”; we didn’t have sharp political differences, we lived in a “culture of complaint”; and so on. In those days, Time, taking up the American pursuit of pleasure, praised Christopher Lasch’s “The Culture of Narcissism”; now Time has a cover story on happiness and asks whether we are “hardwired” to pursue it. © 2013 Condé Nast.
By Maia Szalavitz That little zing you get when someone “likes” your picture or sings your praises on Facebook? That’s the reward center in your brain getting a boost. And that response can predict how much time and energy you put into the social media site, according to new research. In one of the first studies to explore the effects of social media on the brain, scientists led by Dar Meshi, a postdoctoral researcher at the Freie Universität in Berlin, imaged the brains of 31 Facebook users while they viewed pictures of either themselves or others that were accompanied by positive captions. The research was published in Frontiers in Human Neuroscience. “We found that we could predict the intensity of people’s Facebook use outside the scanner by looking at their brain’s response to positive social feedback inside the scanner,” says Meshi. Specifically, a region called the nucleus accumbens, which processes rewarding feelings about food, sex, money and social acceptance became more active in response to praise for oneself compared to praise of others. And that activation was associated with more time on the social media site. Social affirmation tends to be one of life’s great joys, whether it occurs online or off, so it’s not surprising that it would light up this area. Few people are immune to the lures of flattery, after all. But do these results suggest that the “likes” on Facebook can become addictive? While all addictive experiences activate the region, such activation alone isn’t sufficient to establish an addiction. © 2013 Time Inc
American researchers say they’ve performed what they believe is the first ever human-to-human brain interface, where one person was able to send a brain signal to trigger the hand motions of another person. “It was both exciting and eerie to watch an imagined section from my brain get translated into actual action by another brain,” said Rajesh Rao, a professor of computer science and engineering at the University of Washington, in a statement. Previous studies have done brain-to-brain transmissions between rats and one was done between a human and a rat. Rao was able to send a brain signal through the internet – utilizing electrical brain recordings and a form of magnetic stimulation – to the other side of the university campus to his colleague Andrea Stocco, an assistant professor of psychology, triggering Stocco’s finger to move on a keyboard. “The internet was a way to connect computers, and now it can be a way to connect brains,” said Stocco. “We want to take the knowledge of a brain and transmit it directly from brain to brain.” On Aug. 12, Rao sat in his lab with a cap on his head. The cap had electrodes hooked up to an electroencephalography machine, which reads the brain’s electrical activity. Meanwhile, Stocco was at his lab across campus, wearing a similar cap which had a transcranial magnetic stimulation coil place over his left motor cortex – the part of the brain that controls hand movement. Rao looked at a computer and in his mind, he played a video game. When he was supposed to fire a cannon at a target, he imagined moving his right hand, which stayed motionless. Stocco, almost instantaneously, moved his right index finger to push the space bar on the keyboard in front of him. Only simple brain signals, not thoughts “This was basically a one-way flow of information from my brain to his,” said Rao. © CBC 2013
Erika Check Hayden US behavioural researchers have been handed a dubious distinction — they are more likely than their colleagues in other parts of the world to exaggerate findings, according to a study published today. The research highlights the importance of unconscious biases that might affect research integrity, says Brian Martinson, a social scientist at the HealthPartners Institute for Education and Research in Minneapolis, Minnesota, who was not involved with the study. “The take-home here is that the ‘bad guy/good guy’ narrative — the idea that we only need to worry about the monsters out there who are making up data — is naive,” Martinson says. The study, published in Proceedings of the National Academy of Sciences1, was conducted by John Ioannidis, a physician at Stanford University in California, and Daniele Fanelli, an evolutionary biologist at the University of Edinburgh, UK. The pair examined 82 meta-analyses in genetics and psychiatry that collectively combined results from 1,174 individual studies. The researchers compared meta-analyses of studies based on non-behavioural parameters, such as physiological measurements, to those based on behavioural parameters, such as progression of dementia or depression. The researchers then determined how well the strength of an observed result or effect reported in a given study agreed with that of the meta-analysis in which the study was included. They found that, worldwide, behavioural studies were more likely than non-behavioural studies to report ‘extreme effects’ — findings that deviated from the overall effects reported by the meta-analyses. And US-based behavioural researchers were more likely than behavioural researchers elsewhere to report extreme effects that deviated in favour of their starting hypotheses. © 2013 Nature Publishing Group
By Laura Sanders Despite the adage, there actually is such a thing as bad publicity, a fact that brain scientists have lately discovered. A couple of high-profile opinion pieces in the New York Times have questioned the usefulness of neuroscience, claiming, as columnist David Brooks did in June, that studying brain activity will never reveal the mind. Or that neuroscience is a pesky distraction from solving real social problems, as scholar Benjamin Fong wrote on August 11. Let’s start with Brooks. Some of his complaints about brain scans, with their colorful blobs lighting up active parts of the brain, are quite legitimate. Functional MRI studies are notoriously difficult to make sense of. In fact, this powerful technology has been used to find brain activity in a dead salmon. Dubious fMRI studies do trickle into the hands of sensationalistic journalists, medical hucksters and marketers, who twist the results into self-serving sound bites. All true. But Brooks’ essay conflates the entire field of neuroscience with some bad seeds. Some studies should never have been done, others mislead people, waste resources and sensationalize their results. But for every one of those studies, countless others tell us something important about how the human brain works. Serious scientists use a huge variety of techniques — yes, even fMRI — responsibly, and interpret their results cautiously. Judging the whole enterprise of neuroscience by its weakest studies is disingenuous. There is bad science, just like there’s bad food, bad music and bad TV. Trashing all brain research because a tiny bit of it stinks is like throwing your new flat screen off a balcony because you accidentally turned on Jersey Shore. © Society for Science & the Public 2000 - 2013
By: George Will, Washington Post PRINCETON, N.J. — Fifty years from now, when Malia and Sasha are grandmothers, their father’s presidency might seem most consequential because of a small sum — $100 million —for studying something small. “As humans,” Barack Obama said when announcing the initiative to study the brain, “we can identify galaxies light-years away ... but we still haven’t unlocked the mystery of the three pounds of matter that sits between our ears.” Actually, understanding the brain will be a resounding success without unlocking the essential mystery, which is: How does matter become conscious of itself? Or should we say, how does it become — or acquire — consciousness? Just trying to describe this subject takes scientists onto intellectual terrain long occupied by philosophers. Those whose field is the philosophy of mind will learn from scientists such as Princeton’s David Tank, aleader of the BRAIN Initiative, which aims at understanding how brain regions and cells work together, moment to moment, throughout our lives. If, as is said, a physicist is an atom’s way of knowing about atoms, thena neuroscientist like Tank is a brain cell’s way of knowing about brain cells. Each of us has about 100 billion of those, each of which communicates with an average of 10,000 other nerve cells. The goal of neuroscientists is to discover how these neural conversations give rise to a thought, a memory ora decision. And to understand how the brain functions, from which we may understand disorders such as autism, schizophrenia and epilepsy. © 2013 Forum Communications Co.
Keyword: Brain imaging
Link ID: 18560 - Posted: 08.26.2013
By CARL ZIMMER Evolutionary biologists have come to recognize humans as a tremendous evolutionary force. In hospitals, we drive the evolution of resistant bacteria by giving patients antibiotics. In the oceans, we drive the evolution of small-bodied fish by catching the big ones. In a new study, a University of Minnesota biologist, Emilie C. Snell-Rood, offers evidence suggesting we may be driving evolution in a more surprising way. As we alter the places where animals live, we may be fueling the evolution of bigger brains. Dr. Snell-Rood bases her conclusion on a collection of mammal skulls kept at the Bell Museum of Natural History at the University of Minnesota. Dr. Snell-Rood picked out 10 species to study, including mice, shrews, bats and gophers. She selected dozens of individual skulls that were collected as far back as a century ago. An undergraduate student named Naomi Wick measured the dimensions of the skulls, making it possible to estimate the size of their brains. Two important results emerged from their research. In two species — the white-footed mouse and the meadow vole — the brains of animals from cities or suburbs were about 6 percent bigger than the brains of animals collected from farms or other rural areas. Dr. Snell-Rood concludes that when these species moved to cities and towns, their brains became significantly bigger. Dr. Snell-Rood and Ms. Wick also found that in rural parts of Minnesota, two species of shrews and two species of bats experienced an increase in brain size as well. Dr. Snell-Rood proposes that the brains of all six species have gotten bigger because humans have radically changed Minnesota. Where there were once pristine forests and prairies, there are now cities and farms. In this disrupted environment, animals that were better at learning new things were more likely to survive and have offspring. © 2013 The New York Times Company
By Michelle Roberts Health editor, BBC News online Brain scans may allow detection of dyslexia in pre-school children even before they start to read, say researchers. A US team found tell-tale signs on scans that have already been seen in adults with the condition. And these brain differences could be a cause rather than a consequence of dyslexia - something unknown until now - the Journal of Neuroscience reports. Scans could allow early diagnosis and intervention, experts hope. The part of the brain affected is called the arcuate fasciculus. Among the 40 school-entry children they studied they found some had shrinkage of this brain region, which processes word sounds and language. They asked the same children to do several different types of pre-reading tests, such as trying out different sounds in words. Those children with a smaller arcuate fasciculus had lower scores. It is too early to say if the structural brain differences found in the study are a marker of dyslexia. The researchers plan to follow up groups of children as they progress through school to determine this. Lead researcher Prof John Gabrieli said: "We don't know yet how it plays out over time, and that's the big question. BBC © 2013
By Scicurious There are lots of challenges when it comes to studying the brain, but one of the biggest is that it’s very hard to see. Aside from being, you know, inside your skull, the many electrical and chemical signals which the brain uses are impossible to see with the naked eye. We have ways to look at neurons and how they convey information. For example, to record the electrical signals from a single neuron, you can piece it with a tiny electrode, to get access inside the membrane (electrophysiology). You can then stimulate the neuron to fire, or record as it fires spontaneously. For techniques like optogenetics, you can insert a gene into the neuron that makes it fire (or not) in response to light. When you shine the light, you can make the neuron fire. So you can make a neuron fire, or see a neuron fire. With things like voltammetry, we can see neurotransmitters, chemicals as they are released from a neuron and sent as signals on to other neurons. Techniques like these have made huge strides in what we understand about neurons and how they work. But…you can only do this for a few neurons at a time. This becomes a problem, because the brain does not work as one neuron at a time. Instead, neurons organize into networks, A neuron fires, which impinges upon many more neurons, all of which will react in different ways, depending on what input they receive and when. Often many neurons have to fire to get a result, often it’s a single specific pattern of neurons. An ideal technique would be one where we could see neurons fire spontaneously, in real time, and then see where those signals GO, to actually see a network in action. And where we could see it…without taking the brain out first. It looks like that technique might be here. © 2013 Scientific American
Keyword: Brain imaging
Link ID: 18496 - Posted: 08.13.2013
By Neuroskeptic Thanks to newly-developed “super-resolution” microscopy techniques, a group of French neuroscientists have discovered a remarkable world of complexity on a tiny scale. Writing in the Journal of Neuroscience, Deepak Nair colleagues report that: Super-Resolution Imaging Reveals That AMPA Receptors Inside Synapses Are Dynamically Organized in Nanodomains Regulated by PSD95 Neurons communicate with each other via chemical synapses. Here, two cells almost touch each other, and one of them can release a messenger molecule (neurotransmitter) which activates proteins (receptors) on the receiving (postsynaptic) neuron, thus conveying information. Here’s part of a single cell: the synapses are where the little ‘spines’ or ‘bulbs’ meet those present on another cell (not pictured).Until now, it’s been believed that within a synapse, receptors are just randomly distributed over the postsynaptic cell membrane. However, Nair et al’s work reveals an unsuspected level of organization. It turns out that receptors – or at least AMPA receptors, the only kind they looked at – are in fact clustered together into structures the authors dub nanodomains. Each nanodomain contains about 20 receptors, and is about 70 nanometers across. This is small. It’s roughly the size of a virus, and about 1/1000th the width of a human hair. When I saw this picture, it didn’t call to mind anything else I’d ever seen in neuroscience. Rather, it reminded me of the Hubble Deep Field images of distant galaxies… and funnily enough, one of the proteins that plays a secondary role in this paper is called stargazin.
Keyword: Brain imaging
Link ID: 18492 - Posted: 08.12.2013
By Bahar Gholipour, Children with Asperger's syndrome show patterns of brain connectivity distinct from those of children with autism, according to a new study. The findings suggest the two conditions, which are now in one category in the new psychiatry diagnostic manual, may be biologically different. The researchers used electroencephalography (EEG) recordings to measure the amount of signaling occurring between brain areas in children. They had previously used this measure of brain connectivity to develop a test that could distinguish between children with autism and normally developing children. "We looked at a group of 26 children with Asperger's, to see whether measures of brain connectivity would indicate they're part of autism group, or they stood separately," said study researcher Dr. Frank Duffy, a neurologist at Boston's Children Hospital. The study also included more than 400 children with autism, and about 550 normally developing children, who served as controls. At first, the test showed that children with Asperger's and those with autism were similar: both showed weaker connections, compared with normal children, in a region of the brain's left hemisphere called the arcuate fasciculus, which is involved in language. However, when looking at connectivity between other parts of the brain, the researchers saw differences. Connections between several regions in the left hemisphere were stronger in children with Asperger's than in both children with autism and normally developing children. © 2013 Yahoo! Inc
By Andrea Anderson In spring a band of brainy rodents made headlines for zipping through mazes and mastering memory tricks. Scientists credited the impressive intellectual feats to human cells transplanted into their brains shortly after birth. But the increased mental muster did not come from neurons, the lanky nerve cells that swap electrical signals and stimulate muscles. The mice benefited from human stem cells called glial progenitors, immature cells poised to become astrocytes and other glia cells, the supposed support cells of the brain. Astrocytes are known for mopping up excess neuro-transmitters and maintaining balance in brain systems. During the past couple of decades, however, researchers started suspecting astrocytes of making more complex cognitive contributions. In the 1990s the cells got caught using calcium to accomplish a form of nonelectrical signaling. Studies since then have revealed how extensively astrocytes interact with neurons, even coordinating their activity in some cases. Perhaps even more intriguing, our astrocytes are enormous compared with the astrocytes of other animals—20 times larger than rodent astrocytes—and they make contact with millions of neurons apiece. Neurons, on the other hand, are nearly identical in all mammals, from rodents to great apes like us. Such clues suggest astrocytes could be evolutionary contributors to our outsized intellect. The new study, published in March in Cell Stem Cell, tested this hypothesis. A subset of the implanted human stem cells matured into rotund, humanlike astrocytes in the animals' brains, taking over operations from the native mouse astrocytes. When tested under a microscope, these human astrocytes accomplished calcium signaling at least three times faster than the mouse astrocytes did. The enhanced mice masterfully memorized new objects, swiftly learned to link certain sounds or situations to an unpleasant foot shock, and displayed unusually savvy maze navigation—signs of mental acuity that surpassed skills exhibited by either typical mice or mice transplanted with glial progenitor cells from their own species. © 2013 Scientific American
By Daniel Engber Brain-bashing, once an idle pastime of the science commentariat, went mainstream in June. At the beginning of the month, Slate contributor Sally Satel and Scott O. Lilienfeld published Brainwashed: The Seductive Appeal of Mindless Neuroscience, a well-informed attack on the extravagances of “neurocentrist” thought. We’re living in dangerous era, they warn in the book’s introduction. “Naïve media, slick neuroentrepreneurs, and even an occasional overzealous neuroscientist exaggerate the capacity of scans to reveal the contents of our minds, exalt brain physiology as inherently the most valuable level of explanation for understanding behavior, and rush to apply underdeveloped, if dazzling, science for commercial and forensic use.” In the United Kingdom, the neuro-gadfly Raymond Tallis—whose own attack on popular brain science, Aping Mankind, came out in 2011—added to the early-summer beat-down, complaining in the Observer that “studies that locate irreducibly social phenomena … in the function or dysfunction of bits of our brains are conceptually misconceived.” By mid-June, these sharp rebukes made their way into the mind of David Brooks, a long-time dabbler in neural data who proposed not long ago that “brain science helps fill the hole left by the atrophy of theology and philosophy.” Brooks read Brainwashed and became a convert to its cause: “From personal experience, I can tell you that you get captivated by [neuroscience] and sometimes go off to extremes,” he wrote in a recent column with the headline “Beyond the Brain.” Then he gave the following advice: “The next time somebody tells you what a brain scan says, be a little skeptical. The brain is not the mind.” © 2013 The Slate Group, LLC
Keyword: Brain imaging
Link ID: 18424 - Posted: 07.30.2013
By Simon Makin One common complaint about psychiatry is its subjective nature: it lacks definitive tests for many diseases. So the idea of diagnosing disorders using only brain scans holds great appeal. A paper published recently in PLOS ONE describes such a system, although it was presented only as an initial proof of concept. News reports, however, trumpeted the advent of “objective” psychiatric diagnoses. The paper used data from several earlier studies, in which researchers outlined key brain regions in MRI scans of people with bipolar disorder, ADHD, schizophrenia or Tourette's syndrome; people with low or high risk of developing major depressive disorder; and a healthy group. The scans were also labeled with the disorder or depression risk level of the original study participant. In the new study, scientists divided the scans randomly into two sets, one to build the diagnostic system and the other to test it. Their software then grouped the scans in the first set by the shape of various regions. Each group was labeled with the most common diagnosis found within it. During testing, the system analyzed the shapes of brain regions in each test scan and assigned it to the group it most resembled. The scientists checked its work by comparing the new labels on the test scans with the original clinical diagnoses. They repeated the procedure several times with different randomly generated sets. When the system chose between two disorders or one ailment and a clean bill of health, its accuracy was nearly perfect. When deciding among three alternatives, it did much worse. © 2013 Scientific American
Alison Abbott When neurobiologist Bill Newsome got a phone call from Francis Collins in March, his first reaction was one of dismay. The director of the US National Institutes of Health had contacted him out of the blue to ask if he would co-chair a rapid planning effort for a ten-year assault on how the brain works. To Newsome, that sounded like the sort of thankless, amorphous and onerous task that would ruin a good summer. But after turning it over in his mind for 24 hours, his dismay gave way to enthusiasm. “The timing is right,” says Newsome, who is based at Stanford University School of Medicine in California. He accepted the task. “The brain is the intellectual excitement for the twenty-first century.” It helped that the request for the brain onslaught was actually coming from Collins's ultimate boss — US President Barack Obama. Just two weeks after that call, on 2 April, Obama announced a US$100-million initial investment to launch the BRAIN Initiative, a research effort expected to eventually cost perhaps ten times that amount. The European Commission has equal ambitions. On 28 January, it announced that it would launch the flagship Human Brain Project with a 2013 budget of €54 million (US$69 million), and contribute to its projected billion-euro funding over the next ten years (see Nature 482, 456–458; 2012). Although the aims of the two projects differ, both are, in effect, bold bids for the neuroscientist's ultimate challenge: to work out exactly how the billions of neurons and trillions of connections, or synapses, in the human brain organize themselves into working neural circuits that allow us to fall in love, go to war, solve mathematical theorems or write poetry. What's more, researchers want to understand the ways in which brain circuitry changes — through the constant growth and retreat of synapses — as life rolls by. © 2013 Nature Publishing Group
Keyword: Brain imaging
Link ID: 18382 - Posted: 07.18.2013
Ransom Stephens - The video linked here shows how a team of UC Berkeley researchers (two neuroscientists, a bioengineer, two statisticians, and a psychologist) decoded images from brain scans of test subjects watching videos. Yes, by analyzing the scans, they reproduced the videos that the subjects watched. While the reproduced videos are hazy, the ability to reproduce images from the very thoughts of individuals is striking. Here’s how it works: fMRI (functional magnetic resonance imaging) scans light up pixels in three dimensions, 2 mm cubes called voxels. You’ve seen the images, color maps of the brain. The colors represent the volume of blood flow in each voxel. Since an fMRI scan takes about a second to record, the voxel colors represent the time-average blood flow during a given second. Three different subjects (each of whom were also authors of the paper) watched YouTube videos from within an fMRI scanner. Brain scans were taken as rapidly as possible as they watched a large number of 12 minute videos. Each video was watched one time. The resulting scans were used to “train” models. The models consisted of fits to the 3D scans and unique models were developed for each person. By fitting a subject’s model to the time-ordered series of scans and then optimizing the model over a large sample of known videos, the model translates between measured blood flow and features in the video like shapes, edges, and motion. © 2013 UBM Tech,
by Douglas Heaven Toss a stone into a pool and it leaves ripples long after it sinks. Ideas and experiences have a similar affect on our brains: short bouts of intense neural activity leave ripples in the brain's background activity that can still be detected 24 hours later. The finding effectively opens a window into a person's recent past. Previous studies have shown that it is possible to use brain activity to detect simple thoughts or words, and even what image someone is looking at. But this is the first time activity from the past has been observed. Even when you are doing nothing, the brain is busy. Cut off from external stimuli and left to "idle", the brain enters a resting state. "You would expect it to quieten down," says Rafael Malach at the Weizmann Institute of Science in Rehovot, Israel. But instead, the brain just switches gear, producing patterns of activity that are slower but no less noisy. "The activity is very organised, very rich and very consistent," says Malach. But what it means is largely a mystery. Malach and his colleagues wondered whether the activity might in fact be a kind of echo. Could it tell us something about what the brain had been up to previously? "It might be a window into the previous day's activity," says Malach. To test the idea, the team compared fMRI scans of 20 people taken before, during and after a period of intense cognitive activity. They focused on a region of the brain called the dorsal anterior cingulate cortex, which is linked to decision-making and volition. © Copyright Reed Business Information Ltd.
Keyword: Brain imaging
Link ID: 18326 - Posted: 06.29.2013
By Dwayne Godwin and Jorge Cham A new initiative aims to invent new technologies for understanding the brain
Keyword: Brain imaging
Link ID: 18322 - Posted: 06.29.2013
By Ben Thomas Your neurons are outnumbered. Many of the cells in your brain – in your whole nervous system, in fact – are not neurons, but glia. These busy little cells shape and insulate neural connections, provide vital nutrients for your neurons, regulate many of the automatic processes that keep you alive, and even enable your brain to learn and form memories. The latest research is revealing that glia are far more active and mysterious than we’d ever suspected. But their journey into the spotlight hasn’t been an easy one. Unlike neurons, which earned their starring roles in neuroscience as soon as researchers demonstrated what they did, neuroglia didn’t get much respect until more than a century after their discovery. The man who first noted the existence of glia – a French physician named Rene Dutrochet – didn’t even bother to give them a name when he noticed them in 1824; he just described them as “globules” that adhered between nerve fibers. In 1856, when the German anatomist Rudolf Virchow examined these “globules” in more detail, he figured they must be some sort of neural adhesive, which he named neuroglia – “nerve glue” in Greek. As publicity campaigns go, it wasn’t the most promising start. Even worse, as other biologists investigated neuroglia over the next few decades, they started jumping to a variety of conclusions – not all of them accurate. For example, since glia appeared not to have axons – the long connective fibers that carry signals from one neuron to the next – most researchers assumed these cells must act as structural support; essentially serving as a stage on which neurons, the real stars of the show, could play their roles. Some even wondered if glia might not be nerve cells at all, but specially adapted skin cells instead. Though a few scientists did argue that glia also seemed to be crucial for neuron nutrition and healing, it was rare for anyone even to speculate that these cells might actually be involved in neural communication. © 2013 Scientific American
By Tina Hesman Saey Cells that sheathe the brain’s electrical wires in a protective coating called myelin have a brief career, a new study of zebrafish finds. Specialized brain cells known as oligodendrocytes wrap myelin around axons, long fibers that carry electrical messages between nerve cells. After only five hours, the cells bow out of the myelin production business, researchers from the University of Edinburgh report in the June 24 Developmental Cell. Myelination is crucial for brain function, and when it breaks down, so does communication among brain cells. The new results could influence treatment strategies for diseases such as multiple sclerosis, which damages myelin. Instead of coaxing existing cells to replenish myelin, doctors may need to stimulate new oligodendrocyte growth in patients’ nervous systems. In the new study, researchers made time-lapse movies of neural development in zebrafish by tagging electricity-generating neurons and myelin-making oligodendrocytes in the fishes’ spinal cords with different colors. A protein called Fyn kinase stimulates oligodendrocytes to produce more myelin sheaths for the first five hours of the cells’ existence, but the protein can’t persuade the cells to postpone retirement, the researchers discovered. © Society for Science & the Public 2000 - 2013