Chapter 2. Cells and Structures: The Anatomy of the Nervous System
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Claudia Dreifus Cornelia Bargmann, a neurobiologist at Rockefeller University in New York, studies how genes interact with neurons to create behavior. Two years ago, President Obama named Dr. Bargmann, who is known as Cori, a co-chairwoman of the advisory commission for the Brain Initiative, which he has described as “giving scientists the tools they need to get a dynamic picture of the brain in action.” I spoke with Dr. Bargmann, 53, for two hours at the Manhattan apartment she shares with her husband, Dr. Richard Axel, a neuroscientist at Columbia University. Our interview has been edited and condensed. Q. As an M.I.T. graduate student, you made a discovery that ultimately led to the breast cancer drug Herceptin. How did it happen? A. What I did was discover a mutated gene that triggered an obscure cancer in rats. Afterwards, it was discovered — by others — that this same gene is also altered in human breast cancers. Since our work in the rat cancer showed that the immune system could attack the product of this gene, Genentech developed a way to deploy the immune system. That’s Herceptin. It is an antibody against the gene that sits on the surface of a cancer cell. It can attack the cancer cell growing because of that gene. Currently, you spend your time trying to understand the nervous system of a tiny worm, C. elegans. Why do you study this worm? Well, the reason is this: Understanding the human brain is a great and complex problem. To solve the brain’s mysteries, you often have to break a problem down to a simpler form. Your brain has 86 billion nerve cells, and in any mental process, millions of them are engaged. Information is sweeping across these millions of neurons. With present technology, it’s impossible to study that process at the level of detail and speed you would want. © 2015 The New York Times Company
Helen Shen Neuroscientists have used ultrasound to stimulate individual brain cells in a worm, and hope that the technique — which they call ‘sonogenetics’ — might be adapted to switch on neurons in mice and larger animals. The technique relies on touch-sensitive ‘channel’ proteins, which can be added to particular brain cells through genetic engineering. The channels open when hit by an ultrasonic pulse, which allows ions to flood into a neuron and so causes it to turn on. Ultrasound could be a less-invasive way for researchers to stimulate specific cell types or individual neurons, rather than using implanted electrodes or fibre-optic cables, says neurobiologist Sreekanth Chalasani, at the Salk Institute for Biological Studies in La Jolla, California, who led the study reported today in Nature Communications1. “Our hope is to create a toolbox of different channels that would each respond to different intensities of ultrasound,” he says. "It's a cool new idea, and they show that this could really be feasible," says Jon Pierce-Shimomura, a neuroscientist who studies the nematode Caenorhabditis elegans at the University of Texas at Austin. “This could open a whole new way for manipulating the nervous system non-invasively through genetically encodable tools.” © 2015 Nature Publishing Group,
Keyword: Brain imaging
Link ID: 21417 - Posted: 09.16.2015
by Julia Belluz When neuroscientists stuck a dead salmon in an fMRI machine and watched its brain light up, they knew they had a problem. It wasn't that there was a dead fish in their expensive imaging machine; they'd put it there on purpose, after all. It was that the medical device seemed to be giving these researchers impossible results. Dead fish should not have active brains. The lit of brain of a dead salmon — a cautionary neuroscience tale. (University of California Santa Barbara research poster) The researchers shared their findings in 2009 as a cautionary tale: If you don't run the proper statistical tests on your neuroscience data, you can come up with any number of implausible conclusions — even emotional reactions from a dead fish. In the 1990s, neuroscientists started using the massive, round fMRI (or functional magnetic resonance imaging) machines to peer into their subjects' brains. But since then, the field has suffered from a rash of false positive results and studies that lack enough statistical power — the likelihood of finding a real result when it exists — to deliver insights about the brain. When other scientists try to reproduce the results of original studies, they too often fail. Without better methods, it'll be difficult to develop new treatments for brain disorders and diseases like Alzheimer's and depression — let alone learn anything useful about our most mysterious organ. © 2015 Vox Media, Inc
Keyword: Brain imaging
Link ID: 21292 - Posted: 08.13.2015
Alison Abbott This is the crackle of neural activity that allows a fruit-fly (Drosophila melanogaster) larva to crawl backwards: a flash in the brain and a surge that undulates through the nervous system from the top of the larva’s tiny body to the bottom. When the larva moves forwards, the surge flows the other way. The video — captured almost at the resolution of single neurons — demonstrates the latest development in a technique to film neural activity throughout an entire organism. The original method was invented by Philipp Keller and Misha Ahrens at the Howard Hughes Medical Institute's Janelia Research Campus in Ashburn, Virginia. The researchers genetically modify neurons so that each cell fluoresces when it fires; they then use innovative microscopy that involves firing sheets of light into the brain to record that activity. In 2013, the researchers produced a video of neural activity across the brain of a (transparent) zebrafish larva1. The fruit-fly larva that is mapped in the latest film, published in Nature Communications on 11 August2, is more complicated. The video shows neural activity not just in the brain, but throughout the entire central nervous system (CNS), including the fruit-fly equivalent of a mammalian spinal cord. And unlike the zebrafish, the fruit fly's nervous system is not completely transparent, which makes it harder to image. The researchers stripped the CNS from the larva’s body to examine it. For up to an hour after removal, the CNS continues to spontaneously fire the coordinated patterns of activity that typically drive crawling (and other behaviours). © 2015 Nature Publishing Group
Keyword: Brain imaging
Link ID: 21291 - Posted: 08.12.2015
By SAM ROBERTS Dr. Louis Sokoloff, who pioneered the PET scan technique for measuring human brain function and diagnosing disorders, died on July 30 in Washington. He was 93. His death was confirmed by his daughter, Ann, his only immediate survivor. Dr. Sokoloff, who headed the brain metabolism laboratory at the National Institute of Mental Health in Bethesda, Md., received the Albert Lasker Clinical Medical Research Award in 1981 for his role in developing the vivid color images that map brain function. The technique measures the metabolism of its primary fuel, glucose, through a radioactive substitute that, unlike glucose, lingers long enough to undergo chemical analysis. “The Sokoloff method,” the Lasker Foundation said, “has facilitated the diagnosis, understanding and possible future treatment of such disorders of the brain as schizophrenia, epilepsy, brain changes due to drug addiction and senile dementia.” As early as the mid-1940s, when he was practicing psychotherapy in the Army as chief of neuropsychiatry at Camp Lee, Va. (now Fort Lee), he believed there was a physiological and biochemical component to mental illness. “Of course, the psychoanalysts said it had nothing to do with the brain; it had to do with the mind — it could have been anywhere, it could have been in the big toe,” he said in an interview in 2005, shortly after he officially retired from the institute. “For me, mind and brain were inextricably linked,” he wrote in an autobiographical essay published in 1996, “a linkage that was irrelevant to psychiatry at that time.” © 2015 The New York Times Company
Keyword: Brain imaging
Link ID: 21273 - Posted: 08.08.2015
A dipstick inserted into the brain can check its energy levels, just like checking oil levels in a car. The dipstick is already available and can save lives, according to some neuroscientists. “The goal is to save brain tissue,” says Elham Rostami of the Karolinska Institute in Stockholm, Sweden. Last month, Rostami and 47 others published guidelines about how and when to use the technique, known as brain microdialysis, in the hope of encouraging more hospitals to adopt it. The approach involves inserting a slim, 1-centimetre-long probe directly into the brain. It measures levels of chemicals in the fluid that bathes brain cells, including glucose, the brain’s main energy source. When used to monitor the brains of people in intensive care after a stroke or head injury, it warns doctors if glucose starts to dip – which can cause brain damage. The probe can theoretically monitor almost any molecule, but Rostami says the most useful parameters are glucose, which shows if there is a good blood supply, and lactate and pyruvate, two metabolites that indicate if brain cells are using the glucose to release energy. Although widely available, the device has so far mainly been used as a research tool rather than to guide treatment. Rostami believes her use of the probe helped save a woman’s life last year. The woman was in intensive care after a stroke involving bleeding on the surface of her brain. The probe revealed that although the bleeding had stopped, the woman’s brain glucose levels had fallen, probably caused by other blood vessels constricting. © Copyright Reed Business Information Ltd.
Laura Sanders A type of brain cell formerly known for its supporting role has landed a glamorous new job. Astrocytes, a type of glial cell known to feed, clean and guide the growth of their flashier nerve cell neighbors, also help nerve cells send electrical transmissions, scientists report in the Aug. 5 Journal of Neuroscience. The results are the latest in scientists’ efforts to uncover the mysterious and important ways in which cells other than nerve cells keep the nervous system humming. Astrocytes deliver nutrients to nerve cells, flush waste out of the brain (SN: 9/22/12) and even help control appetite (SN: 6/28/14). The latest study suggests that these star-shaped cells also help electrical messages move along certain nerve cells’ message-sending axons, a job already attributed to other glial cells called oligodendrocytes and Schwann cells. Courtney Sobieski of Washington University School of Medicine in St. Louis and colleagues grew individual rat nerve cells in a single dish that contained patches of astrocytes. Some nerve cells grew on the patches; others did not. The nerve cells deprived of astrocyte contact showed signs of sluggishness. The researchers think that astrocytes guide nerve cell growth in a way that enables the nerve cells to later fire off quick and precise messages. It’s not clear how the astrocytes do that, but the results suggest that proximity is the key: Astrocytes needed to be close to the nerve cell to help messages move. © Society for Science & the Public 2000 - 2015
Alison Abbott Six years might seem like a long time to spend piecing together the structure of a scrap of tissue vastly smaller than a bead of sweat. But that is how long it has taken a team led by cell biologist Jeff Lichtman from Harvard University in Cambridge, Massachusetts, to digitally reconstruct a tiny cube of mouse brain tissue. The resulting three-dimensional map1 is the first complete reconstruction of a piece of tissue in the mammalian neocortex, the most recently evolved region of the brain. Covering just 1,500 cubic microns, it is still a far cry from reconstructing all 100 billion or so cells that make up the entire human brain. But Christof Koch, president of the Allen Institute for Brain Science in Seattle, Washington, notes that the various technologies involved will speed up “tremendously” over the next decade: “I would call this a very exciting promissory note,” he says. Lichtman’s team already has its eyes on a much bigger challenge: reconstructing a cubic millimetre of rodent neocortex — a piece of tissue around 600,000 times larger than the present achievement. The researchers will be doing this as part of a consortium that earlier this month received preliminary approval for major funding by the US government agency IARPA (Intelligence Advanced Research Projects Activity), which promotes high-risk, high pay-off research. The goal of the consortium, based at Harvard and at the Massachusetts Institute of Technology (MIT) in Cambridge, is to map the function as well as the anatomy of this tiny brain volume, while also working out how it computes information as an animal learns. © 2015 Nature Publishing Group,
Keyword: Brain imaging
Link ID: 21249 - Posted: 08.01.2015
Jon Hamilton Lihong Wang creates the sort of medical technology you'd expect to find on the starship Enterprise. Wang, a professor of biomedical engineering at Washington University in St. Louis, has already helped develop instruments that can detect individual cancer cells in the bloodstream and oxygen consumption deep within the body. He has also created a camera that shoots at 100 billion frames a second, fast enough to freeze an object traveling at the speed of light. "It's really about turning some of these ideas that we thought were science fiction into fact," says Richard Conroy, who directs the Division of Applied Science & Technology at the National Institute of Biomedical Imaging and Bioengineering. Wang's ultimate goal is to use a combination of light and sound to solve the mysteries of the human brain. The brain is a "magical black box we still don't understand," he says. Wang describes himself as a toolmaker. And when President Obama unveiled his BRAIN initiative a couple of years ago to accelerate efforts to understand how we think and learn and remember, Wang realized that brain researchers really needed a tool he'd been working on for years. "We want to conquer the brain," Wang says. "But even for a mouse brain, which is only a few millimeters thick, we really don't have a technique that allows us to see throughout the whole brain." Current brain-imaging techniques such as functional MRI or PET scans all have drawbacks. They're slow, or not sharp enough, or they can only see things near the surface. So Wang has been developing another approach, one he believes will be fast enough to monitor brain activity in real time and sharp enough to reveal an individual brain cell. © 2015 NPR
Keyword: Brain imaging
Link ID: 21226 - Posted: 07.27.2015
A study showed that scientists can wirelessly determine the path a mouse walks with a press of a button. Researchers at the Washington University School of Medicine, St. Louis, and University of Illinois, Urbana-Champaign, created a remote controlled, next-generation tissue implant that allows neuroscientists to inject drugs and shine lights on neurons deep inside the brains of mice. The revolutionary device is described online in the journal Cell. Its development was partially funded by the National Institutes of Health. “It unplugs a world of possibilities for scientists to learn how brain circuits work in a more natural setting.” said Michael R. Bruchas, Ph.D., associate professor of anesthesiology and neurobiology at Washington University School of Medicine and a senior author of the study. The Bruchas lab studies circuits that control a variety of disorders including stress, depression, addiction, and pain. Typically, scientists who study these circuits have to choose between injecting drugs through bulky metal tubes and delivering lights through fiber optic cables. Both options require surgery that can damage parts of the brain and introduce experimental conditions that hinder animals’ natural movements. To address these issues, Jae-Woong Jeong, Ph.D., a bioengineer formerly at the University of Illinois at Urbana-Champaign, worked with Jordan G. McCall, Ph.D., a graduate student in the Bruchas lab, to construct a remote controlled, optofluidic implant. The device is made out of soft materials that are a tenth the diameter of a human hair and can simultaneously deliver drugs and lights.
Keyword: Brain imaging
Link ID: 21184 - Posted: 07.18.2015
By Ariel Sabar In televised remarks from the East Room of the White House on April 2, 2013, President Obama unveiled a scientific mission as grand as the Apollo program. The goal wasn’t outer space, but a frontier every bit as bewitching: the human brain. Obama challenged the nation’s “most imaginative and effective researchers” to map in real time the flickerings of all 100 billion nerve cells in the brain of a living person, a voyage deep into the neural cosmos never attempted at so fine a scale. A panoramic view of electric pulses pinballing across the brain could lead to major new understandings of how we think, remember and learn, and how ills from autism to Alzheimer’s rewire our mental circuitry. “We have a chance to improve the lives of not just millions,” the president said, “but billions of people on this planet.” The next month, six miles from the White House, a Harvard professor named Florian Engert grabbed a mic and, in front of the nation’s top neuroscientists, declared Obama’s effort essentially futile. “We have those data now,” said Engert, who, in a room full of professorial blazers and cardigans, was wearing a muscle shirt that afforded ample views of his bulging biceps. “We discovered they’re actually not all that useful.” (“I think whole-brain imaging is just a bunch of bull----,” is how he put it to me later.) To the other researchers, he must have sounded like a traitor. Engert, who is 48, was basically the first person on the planet to observe a brain in the wall-to-wall way Obama envisioned. He and his colleagues had done it with a sci-fi-worthy experiment that recorded every blip of brain activity in a transparent baby zebrafish, a landmark feat published just a year earlier in the marquee scientific journal Nature. For Engert to suggest that the president’s brain quest was bunk was a bit like John Glenn returning from orbit and telling JFK not to bother with a lunar landing.
Keyword: Brain imaging
Link ID: 21119 - Posted: 07.02.2015
By GARY MARCUS SCIENCE has a poor track record when it comes to comparing our brains to the technology of the day. Descartes thought that the brain was a kind of hydraulic pump, propelling the spirits of the nervous system through the body. Freud compared the brain to a steam engine. The neuroscientist Karl Pribram likened it to a holographic storage device. Many neuroscientists today would add to this list of failed comparisons the idea that the brain is a computer — just another analogy without a lot of substance. Some of them actively deny that there is much useful in the idea; most simply ignore it. Often, when scientists resist the idea of the brain as a computer, they have a particular target in mind, which you might call the serial, stored-program machine. Here, a program (or “app”) is loaded into a computer’s memory, and an algorithm, or recipe, is executed step by step. (Calculate this, then calculate that, then compare what you found in the first step with what you found in the second, etc.) But humans don’t download apps to their brains, the critics note, and the brain’s nerve cells are too slow and variable to be a good match for the transistors and logic gates that we use in modern computers. If the brain is not a serial algorithm-crunching machine, though, what is it? A lot of neuroscientists are inclined to disregard the big picture, focusing instead on understanding narrow, measurable phenomena (like the mechanics of how calcium ions are trafficked through a single neuron), without addressing the larger conceptual question of what it is that the brain does. This approach is misguided. Too many scientists have given up on the computer analogy, and far too little has been offered in its place. In my view, the analogy is due for a rethink. To begin with, all the standard arguments about why the brain might not be a computer are pretty weak. Take the argument that “brains are parallel, but computers are serial.” Critics are right to note that virtually every time a human does anything, many different parts of the brain are engaged; that’s parallel, not serial. © 2015 The New York Times Company
Keyword: Brain imaging
Link ID: 21099 - Posted: 06.27.2015
By Nellie Bowles One recent Friday night, at a software-development firm’s warehouse in San Francisco, Mikey Siegel called to order the hundred and fifty or so meditators, video gamers, and technocrats who had gathered for one of the city’s biweekly Consciousness Hacking meet-ups. Siegel, the primary organizer of the event and the founder of a Santa Cruz–based biofeedback startup called Bio Fluent, asked the crowd, men and women of widely varied ages, to go around the room introducing themselves in three words. Everyone laughed, but took the task seriously. The introductions moved quickly through the room in a brisk beat: “Me Technological Cartoon” “Heather Curious About Brains” “Neuromore Singularity Atom Here” “Dan Thoughtful Helpful Software” “Harry Self-Modification Exploration” “David Psychiatrist Technological Retarded Curious” “Jordan Moving Meditation Butts” “Juliana Joel’s Aunt” “Ben Existence Existence Existence” “Zohara Chocolate Maker Meditation Awareness” “Lila Awake Empath Warrior” San Francisco’s Consciousness Hacking meet-ups are an opportunity for engineers, entrepreneurs, and enthusiasts to test the fleet of still experimental self-examination technologies emerging largely from Silicon Valley. The region’s tech community is a body culture, obsessed with monitoring and perfecting its food (Soylent), fitness (Fitbit), and physiology (23andMe). As brain-wave technologies get cheaper and more popular, some company founders hope that consumers, who seem to be acclimating to devices like the increasingly ubiquitous Fitbit, will consider other, more cumbersome devices and procedures. Consciousness Hackers are a kind of self-selected early market-research group. Tonight, that was especially clear.
By Amanda Montañez As someone who works at the intersection of art and science, I have always found it easy to make the case that all artists are scientists. From the moment we pick up a crayon and make our first mark, we are experimenting. The perceived successes and failures of our craft are indelibly tied to the many variables—physical, chemical and psychological—inherent in the experiences of creating and consuming works of art. Yet, it seems a longer stretch, somehow, to argue that all scientists are artists. At the very least, in my experience, scientists seem less willing to claim this alternate title. In fact, almost anyone who does not see her or himself as artistically inclined tends to be a little too quick to proclaim, “Oh, I’m not an artist. I can’t even draw a straight line!” With a sigh, I’ll avoid the temptation to digress into the utter irrelevance of straight lines and one’s ability to draw them. Instead, I’d like to posit the idea that, while we may not all identify as artists, scientists, of all people, really should be artists. Throughout history, much of scientific discovery and advancement has hinged not just on our ability to see certain things, but also on our capacity to reproduce what we see in faithful, critical and/or meaningful ways. The drawings of the famous Spanish neuroscientist Santiago Ramón y Cajal provide an ideal example of this phenomenon. In the late 1800s, using a novel histological staining technique developed by Italian physician Camillo Golgi, Ramón y Cajal spent countless hours examining brain tissues under the microscope and recording what he saw in pen and ink.
Keyword: Brain imaging
Link ID: 21083 - Posted: 06.23.2015
By THE ASSOCIATED PRESS NEW HAVEN, Connecticut — To the untrained eye, it looked like a seismograph recording of a violent earthquake or the gyrations of a very volatile day on Wall Street — jagged peaks and valleys in red, blue and green, displayed on a wall. But the story it told was not about geology or economics. It was a glimpse into the brains of Shaul Yahil and Shaw Bronner, two researchers at a Yale lab, as they had a little chat. "This is a fork," Yahil observed, describing the image on his computer. "A fork is something you use to stab food while you're eating it. Common piece of cutlery in the West." "It doesn't look like a real fancy sterling silver fork, but very useful," Bronner responded. And then she described her own screen: "This looks like a baby chimpanzee ..." The jagged, multicolored images depicted what was going on in the two researchers' heads — two brains in conversation, carrying out an intricate dance of internal activity. This is no parlor trick. The brain-tracking technology at work is just a small part of the quest to answer abiding questions about the workings of a three-pound chunk of fatty tissue with the consistency of cold porridge. How does this collection of nearly 100 billion densely packed nerve cells, acting through circuits with maybe 100 trillion connections, let us think, feel, act and perceive our world? How does this complex machine go wrong and make people depressed, or delusional, or demented? What can be done about that? These are the kinds of questions that spurred President Barack Obama to launch the BRAIN initiative in 2013. Its aim: to spur development of new tools to investigate the brain. Europe and Japan are also pursuing major efforts in brain research. © 2015 The New York Times Company
Keyword: Brain imaging
Link ID: 21081 - Posted: 06.22.2015
by Kate Solomon Jean-Dominique Bauby famously wrote The Diving Bell and The Butterfly by blinking as an assistant read out the alphabet, but locked-in patients could soon have a much easier way to communicate. For the first time, scientists have successfully transcribed brainwaves as text, which could mean that those unable to speak could use the system to "talk" via a computer. Carried out by a group of informatics, neuroscience and medical researchers at Albany Medical Centre, the team managed to identify the brainwaves relating to speech by using electrocorticographic (ECoG) technology to monitor the frontal and temporal lobes of seven epileptic volunteers. This involves using needles to record signals directly from a person's neurons; it's an invasive procedure requiring an incision through the skull. The participants then read aloud from a sample text while machine learning algorithms pulled out the most likely word sequence from the signals recorded by the EcOG. Existing speech-to-text tools then transcribed the continuously spoken speech directly from the brain activity. Error rates were as low as 25 percent during the study, which means the potential for the system is pretty vast. The findings could offer locked-in and mute patients a valuable communication method but it also means humans could one day communicate directly with a computer without needing any intermediary equipment.
Elizabeth Gibney A simple injection is now all it takes to wire up a brain. A diverse team of physicists, neuroscientists and chemists has implanted mouse brains with a rolled-up, silky mesh studded with tiny electronic devices, and shown that it unfurls to spy on and stimulate individual neurons. The implant has the potential to unravel the workings of the mammalian brain in unprecedented detail. “I think it’s great, a very creative new approach to the problem of recording from large number of neurons in the brain,” says Rafael Yuste, director of the Neurotechnology Center at Columbia University in New York, who was not involved in the work. If eventually shown to be safe, the soft mesh might even be used in humans to treat conditions such as Parkinson’s disease, says Charles Lieber, a chemist at Harvard University on Cambridge, Massachusetts, who led the team. The work was published in Nature Nanotechnology on 8 June1. Neuroscientists still do not understand how the activities of individual brain cells translate to higher cognitive powers such as perception and emotion. The problem has spurred a hunt for technologies that will allow scientists to study thousands, or ideally millions, of neurons at once, but the use of brain implants is currently limited by several disadvantages. So far, even the best technologies have been composed of relatively rigid electronics that act like sandpaper on delicate neurons. They also struggle to track the same neuron over a long period, because individual cells move when an animal breathes or its heart beats. © 2015 Nature Publishing Group
Keyword: Brain imaging
Link ID: 21034 - Posted: 06.09.2015
by Hal Hodson Electricity is the brain's language, and now we can speak to it without wires or implants. Nanoparticles can be used to stimulate regions of the brain electrically, opening up new ways to treat brain diseases. It may even one day allow the routine exchange of data between computers and the brain. A material discovered in 2004 makes this possible. When "magnetoelectric" nanoparticles (MENs) are stimulated by an external magnetic field, they produce an electric field. If such nanoparticles are placed next to neurons, this electric field should allow them to communicate. To find out, Sakhrat Khizroev of Florida International University in Miami and his team inserted 20 billion of these nanoparticles into the brains of mice. They then switched on a magnetic field, aiming it at the clump of nanoparticles to induce an electric field. An electroencephalogram showed that the region surrounded by nanoparticles lit up, stimulated by this electric field that had been generated. "When MENs are exposed to even an extremely low frequency magnetic field, they generate their own local electric field at the same frequency," says Khizroev. "In turn, the electric field can directly couple to the electric circuitry of the neural network." Khizroev's goal is to build a system that can both image brain activity and precisely target medical treatments at the same time. Since the nanoparticles respond differently to different frequencies of magnetic field, they can be tuned to release drugs. © Copyright Reed Business Information Ltd
Keyword: Brain imaging
Link ID: 21033 - Posted: 06.09.2015
By Neuroskeptic | Neuroscientists might need to rethink much of what’s known about the amygdala, a small brain region that’s been the focus of a lot of research. That’s according to a new paper just published in Scientific Reports: fMRI measurements of amygdala activation are confounded by stimulus correlated signal fluctuation in nearby veins draining distant brain regions. The amygdala is believed to be involved in emotion, especially negative emotions such as fear. Much of the evidence for this comes from fMRI studies showing that the amygdala activates in response to stimuli such as images of scared faces. However, according to the authors of the new paper, Austrian neuroscientists Roland N. Boubela and colleagues, there’s a flaw in these fMRI studies. The problem, they say, is that the amygdala happens to be located next to a large vein, called the basal vein of Rosenthal (BVR). fMRI works by detecting blood oxygenation, so changes in the oxygen level in the blood within the BVR could produce signal changes that could be mistaken for activation in the amygdala. Because the BVR drains blood from several brain regions, some of which are themselves involved in emotion processing, the BVR could act as a proxy for emotion-related neural activation elsewhere in the brain, which is then projected onto the amygdala. Neuroscientists have long been aware of potential large vein contributions to the fMRI signal, but it hasn’t generally been seen as a serious concern. According to Boubela et al., however, the problem is serious, when it comes to the amygdala.
by Bas den Hond Watch your language. Words mean different things to different people – so the brainwaves they provoke could be a way to identify you. Blair Armstrong of the Basque Center on Cognition, Brain, and Language in Spain and his team recorded the brain signals of 45 volunteers as they read a list of 75 acronyms – such as FBI or DVD – then used computer programs to spot differences between individuals. The participants' responses varied enough that the programs could identify the volunteers with about 94 per cent accuracy when the experiment was repeated. The results hint that such brainwaves could be a way for security systems to verify individuals' identity. While the 94 per cent accuracy seen in this experiment would not be secure enough to guard, for example, a room or computer full of secrets, Armstrong says it's a promising start. Techniques for identifying people based on the electrical signals in their brain have been developed before. A desirable advantage of such techniques is that they could be used to verify someone's identity continuously, whereas passwords or fingerprints only provide a tool for one-off identification. Continuous verification – by face or ear recognition, or perhaps by monitoring brain activity – could in theory allow someone to interact with many computer systems simultaneously, or even with a variety of intelligent objects, without having to repeatedly enter passwords for each device. © Copyright Reed Business Information Ltd