Chapter 2. Cells and Structures: The Anatomy of the Nervous System
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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
Jon Hamilton When the brain needs to remember a phone number or learn a new dance step, it creates a circuit by connecting different types of neurons. But scientists still don't know how many types of neurons there are or exactly what each type does. "How are we supposed to understand the brain and help doctors figure out what schizophrenia is or what paranoia is when we don't even know the different components," says Christof Koch, president and chief scientific officer of the Allen Institute for Brain Science, a nonprofit research center in Seattle. So the institute is creating a freely available online database that will eventually include thousands of nerve cells. For now, the Allen Cell Types Database has detailed information on 240 mouse cells, including their distinctive shapes. More than 100 years ago, Golgi staining on nerve cells opened the gates to modern neuroscience. Scientists recently developed the Technicolor version of Golgi staining, Brainbow, allowing more detailed reconstructions of brain circuits. "They look like different trees," Koch says. "Some fan out at the top. Some are like a Christmas tree; they fan out at the bottom. Others are like three-dimensional fuzz balls." The database also describes each cell by the electrical pattern it generates. And eventually it will include information about which genes are expressed. Once researchers have a complete inventory of details about the brain's building blocks, they'll need to know which combinations of blocks can be connected, Koch says. After all, he says, it is these connections that make us who we are. © 2015 NPR
Keyword: Brain imaging
Link ID: 20927 - Posted: 05.14.2015
Alison Abbott It is only when you read the words that Andreas Vesalius wrote as an angry young man in the 1540s that you get a feeling for what drove him to document every scrap of human anatomy his eye could see. His anger was directed at Galen, the second-century physician whose anatomical teachings had been held as gospel for more than a millennium. Roman Empire law had barred Galen from dissecting humans, so he had extrapolated as best he could from animal dissections — often wrongly. Human dissections were also banned in most of sixteenth-century Europe, so Vesalius travelled to wherever they were allowed. He saw Galen's errors and dared to report them, most explicitly in his seven-volume De Humani Corporis Fabrica (On the Fabric of the Human Body), which he began aged 24, working with some of the best art professionals of the time. His mission to learn through direct and systematic observation marked the start of a new way of doing science. In Brain Renaissance, neuroscientists Marco Catani and Stefano Sandrone present a translation from the Latin of the Fabrica's last volume, which focuses on the brain. Through it we can appreciate Vesalius's extraordinary attention to detail, and his willingness to believe his eyes, even when what he saw contradicted established knowledge. We learn his anatomical vocabulary. For example, he called the rounded surface protuberances near the brain stem “buttocks” and “testes”; these are now known as the inferior and superior colliculi, or 'little hills', which process sound and vision. © 2015 Macmillan Publishers Limited.
Keyword: Brain imaging
Link ID: 20924 - Posted: 05.14.2015
Andrew Griffin Companies are taking out a huge amount of patents related to reading brainwaves, according to analysis, with a range of different applications. Fewer than 400 neuro-technology related patents were filed between 2000-2009. But in 2010 alone that reached 800, and last year 1,600 were filed, according to research company SharpBrains. The patents are for a range of uses, not just for the healthcare technology that might be expected. The company with the most patents is market research firm Nielsen, which has 100. Microsoft also has 89 related patents. Other uses of the technology that have been patented include devices that can change the thoughts of feelings of those that they are used on. But there are still medical uses — some of those patents awarded include technology to measure brain lesions and improve vision. The volume and diversity of the patents shows that we are at the beginning of “the pervasive neurotechnology age”, the company’s CEO Alvaro Fernandez said. "Neurotech has gone well beyond medicine, with non-medical corporations, often under the radar, developing neurotechnologies to enhance work and life," said Fernandez.
By Jonathan Webb Science reporter, BBC News Scientists have stumbled upon one of the secrets behind the big gulps of the world's biggest whales: the nerves in their jaws are stretchy. Rorquals, a family that includes blue and humpback whales, feed by engulfing huge volumes of water and food, sometimes bigger than themselves. Researchers made the discovery by inadvertently stretching a thick cable they found in the jaw of a fin whale. Most nerves are fragile and inelastic, so this find is first for vertebrates. The work is reported in the journal Current Biology. A Canadian research team had travelled to Iceland to investigate some of these whales' other anatomical adaptations to "lunge feeding" - things like their muscles, or the remarkable sensory organ in their jaws, discovered in 2012. They were working with specimens in collaboration with commercial whalers. "It's probably one of the only places in the world where you can do this sort of work, because these animals are so huge that even getting in through the skin is something you can't do without having heavy machinery around," said Prof Wayne Vogl, an anatomist at the University of British Columbia and the study's first author. When you are working with a 20m fin whale, it's important to have the right equipment, he said. "If a heart falls on you, it could kill you." © 2015 BBC.
By Ashley Yeager The image is made using Brainbow, a technique developed in 2007 that inserts genes for fluorescent proteins into animals. When activated, the proteins illuminate some cells in a range of colors. While most researchers use Brainbow to visualize connections between nerve cells in the brain, Alain Chédotal of the Institut de la Vision in Paris and colleagues customized the technique to trace networks of cells called oligodendrocytes. These cells wrap a material called myelin, the biological equivalent of electrical insulation, around long strands of nerve cells that transmit electrical signals in the brain and throughout the body. How oligodendrocytes work together to wrap nerve fibers in myelin becomes evident in Brainbow photos of the roughly 3-millimeter-long optic nerve, the team reports in the April Glia. The myelin shields the precious link between brain and eyes. Studying interactions among oligodendrocytes as well as the cells’ reactions to various drugs may lead to improved therapies for multiple sclerosis, a disease caused by the destruction of myelin. Citations L. Dumas et al. Multicolor analysis of oligodendrocyte morphology, interactions, and development with Brainbow. Glia. Vol. 63, April 2015, p. 699. doi: 10.1002/glia.22779 © Society for Science & the Public 2000 - 2015.
by Simon Oxenham As regular readers will be well aware, much of what I've covered on this blog has been about the use and abuse of the prefix "neuro" to mislead. You don't have to look far to see that most people seem to be pretty disconnected from the science of the brain. This becomes a problem once you realize how this allows us to be misled. Take, for example, the adverts for "brain training" games that stalk you on the internet with claims that don't even remotely hold water; or the fact that a laughable technique called "Brain Gym" that involves making children perform pointless exercises and is based on no evidence whatsoever continues to be widespread in schools across the world at a cost of hundreds of thousands of dollars, and has been used by as many as 39 percent of teachers in the UK. Drop a few brain-related words and it seems even teachers can lose the capacity for critical thought en masse. In 2008, a paper titled "The Seductive Allure of Neuroscience Explanations," struck a chord with me when it made the case that we can be suckered into judging bad psychological explanations as better than they really are if they are served with a side order of irrelevant neuroscience. Another paper published the same year suggested that just showing an image of the brain alongside articles describing fictitious neuroscience research (for example claiming that watching TV improves mathematical ability) resulted in people rating the standard of reasoning in the articles as higher. In 2013 however, a paper was published that remains a strong contender for the award of best-named paper of all time: "The Seductive Allure of Seductive Allure." The paper pointed out flaws in both of the 2008 papers: The neuroscience explanations were longer and arguably added to the psychological explanations. It could be the case that more complicated-sounding, or seemingly better-explained explanations are simply more persuasive. © Copyright 2015, The Big Think, Inc.
Keyword: Brain imaging
Link ID: 20870 - Posted: 05.02.2015
By Laura Sanders Studying the human brain requires grandiose thinking, but rarely do actual theatrical skills come into play. In her latest stint as a video star, MIT neuroscientist Nancy Kanwisher does not buzz saw her skull open to give viewers a glimpse of her brain. But she does perhaps the next best thing: She clips off her shoulder-length gray hair and shaves her head on camera. Kanwisher’s smooth, bald head then becomes a canvas for graduate student and artist Rosa Lafer-Sousa, who meticulously draws in the brain’s wrinkles — the sulci and the gyri that give rise to thoughts, memories and behaviors. All the while, Kanwisher provides a voice-over describing which areas of the brain recognize faces, process language and even think about what another person is thinking. The video is the latest in Kanwisher’s occasional online series, Nancy’s Brain Talks. Pithy, clever and cleanly produced, the more than two dozen videos she has made so far bring brain science to people who might otherwise miss out. In another neurostunt, brain-zapping technology called transcranial magnetic stimulation makes Kanwisher’s hand jump involuntarily. These demonstrations capture people’s attention more than a dry scientific paper would. “I think scientists owe it to the public to share the cool stuff we discover,” Kanwisher says. Her own lab’s discoveries focus on how the brain’s disparate parts work together to construct a mind. Some brain areas have very specific job descriptions while others are far more general. Compiling a tally of brain regions and figuring out what they do is one of the first steps toward understanding the brain. “It starts to give us a set of basic components of the mind,” Kanwisher says. “It’s like a parts list.” © Society for Science & the Public 2000 - 2015.
Keyword: Brain imaging
Link ID: 20853 - Posted: 04.28.2015
Jon Hamilton The simple act of thinking can accelerate the growth of many brain tumors. That's the conclusion of a paper in Cell published Thursday that showed how activity in the cerebral cortex affected high-grade gliomas, which represent about 80 percent of all malignant brain tumors in people. "This tumor is utilizing the core function of the brain, thinking, to promote its own growth," says Michelle Monje, a researcher and neurologist at Stanford who is the paper's senior author. In theory, doctors could slow the growth of these tumors by using sedatives or other drugs to reduce mental activity, Monje says. But that's not a viable option because it wouldn't eliminate the tumor and "we don't want to stop people with brain tumors from thinking or learning or being active." Even so, the discovery suggests other ways to slow down some of the most difficult brain tumors, says Tracy Batchelor, who directs the neuro-oncology program at Massachusetts General Hospital and was not involved in the research. "We really don't have any curative treatments for high-grade gliomas," Batchelor says. The discovery of a link between tumor growth and brain activity "has opened up a window into potential therapeutic interventions," he says. The discovery came from a team of scientists who studied human glioma tumors implanted in mouse brains. The scientists used a technique called optogenetics, which uses light to control brain cells, to increase the activity of cells near the tumors. © 2015 NPR
Link ID: 20846 - Posted: 04.25.2015
By Rachel Feltman This is either fascinating, incredibly creepy, or both. Probably both. But also science! The video wasn't created for an all-MRI production of "The Wizard of Oz." It's an example of a high-speed, high-resolution MRI technique. The technique, which is being developed by the Bioimaging Science and Technology Group at the Beckman Institute, acquires about 100 frames per second. A description of the technique was published Tuesday in the journal Magnetic Resonance in Medicine. Working about 10 times faster than a standard MRI, the machine was able to pick up the muscular nuances required for singing. You can see the vocal folds hard at work creating the tune. These two flaps inside the larynx sit over the windpipe, coming together whenever we're not breathing. Air passes through the closed folds, causing them to vibrate. We use our larynx to control the tension of our vocal folds, which changes the pitch of our vocalizations. The researchers weren't just goofing off in order to display the MRI's capabilities: The high-speed and high-resolution images help them keep tabs on the tongue and neck muscles during vocalization. They're hoping to learn more about what health vocalization looks like, and whether or not singing can be used as a therapy to help the elderly regain more control over their speech.
Keyword: Brain imaging
Link ID: 20838 - Posted: 04.23.2015
By Antonio Regalado Various powerful new tools for exploring and manipulating the brain have been developed over the last few years. Some use electronics, while others use light or chemicals. At one MIT lab, materials scientist Polina Anikeeva has hit on a way to manufacture what amounts to a brain-science Swiss Army knife. The neural probes she builds carry light while collecting and transmitting electricity, and they also have tiny channels through which to pump drugs. That’s an advance over metal wires or silicon electrodes conventionally used to study neurons. Anikeeva makes the probes by assembling polymers and metals into large-scale blocks, or preforms, and then stretching them into flexible, ultrathin fibers. Multifunctional fibers offer new ways to study animal behavior, since they can record from neurons as well as stimulating them. New types of medical technology could also result. Imagine, as Anikeeva does, bionic wiring that bridges a spinal-cord injury, collecting electrical signals from the brain and transmitting them to the muscles of a paralyzed hand. Anikeeva made her first multifunctional probe while studying at Stanford. It was crude: she simply wrapped metal wires around a glass filament. But this made it possible to combine standard electrode measurements with a new technology, optogenetics, in which light is fired at neurons to activate them or shut them down.
Keyword: Brain imaging
Link ID: 20832 - Posted: 04.22.2015
By Neuroskeptic According to a large study just published in the Journal of Autism and Developmental Disorders, there’s no correlation between brain anatomy and self-reported autistic traits. Dutch researchers P. Cedric M. P. Koolschijn and colleagues looked at two samples of young Dutch adults: an ‘exploration’ sample of 204, and a separate ‘validation’ group of 304 individuals. Most of the participants did not have autism. The researchers looked for associations between various aspects of brain structure and autistic traits, using the AQ questionnaire, a popular self-report measure. Autistic traits are personality or behavior features similar to (but generally milder than) autism symptoms. For example, the first item on the AQ is “I prefer to do things with others rather than on my own.” If you disagree with that, you get a point. More points means more autistic traits. Koolschijn et al. used VBM, vertex-based cortical thickness analysis, and diffusion weighted imaging to explore different aspects of brain grey and white matter anatomy. However, although AQ scores were weakly correlated with the volume of a few brain areas in the exploration sample, none of these correlations were confirmed in the larger validation sample, suggesting that they were just false positives caused by the large number of multiple comparisons.
By KEN BELSON The developers of a new drug aimed at diagnosing chronic traumatic encephalopathy, a degenerative brain disease linked to repeated head trauma, are under scrutiny by the Food and Drug Administration. In February, the F.D.A.’s Office of Prescription Drug Promotion sent a letter to two researchers at U.C.L.A. warning them that they had improperly marketed their drug on the Internet and had made overstated claims about the drug’s potential efficacy. The researchers at U.C.L.A. have been developing a biomarker called FDDNP, which aims to identify tau protein deposits in the brain (a signature of C.T.E.) when patients are given a PET scan. To date, researchers have been able to detect C.T.E. only in brain tissue obtained posthumously. The demand for a technique that can diagnose the disease in living patients is potentially large, given growing concerns about the impact of head trauma in athletes, soldiers and others. In its letter, the F.D.A. warned that the researchers, who are partners with the company Taumark, were not allowed to market the drug and make claims about its safety or effectiveness. “Thus, these claims and presentations suggest in a promotional context that FDDNP, an investigational new drug, is safe or effective for such uses, when F.D.A. has not approved FDDNP for any use,” the letter said. The Los Angeles Times first reported the details of the F.D.A.’s letter to the researchers, Dr. Gary Small and Dr. Jorge Barrio. The researchers were told to adjust the language on Taumark’s website, which is now disabled. © 2015 The New York Times Company
by Anil Ananthaswamy HOLD that thought. When it comes to consciousness, the brain may be doing just that. It now seems that conscious perception requires brain activity to hold steady for hundreds of milliseconds. This signature in the pattern of brainwaves can be used to distinguish between levels of impaired consciousness in people with brain injury. The new study by Aaron Schurger at the Swiss Federal Institute of Technology in Lausanne doesn't explain the so-called "hard problem of consciousness" – how roughly a kilogram of nerve cells is responsible for the miasma of sensations, thoughts and emotions that make up our mental experience. However, it does chip away at it, and support the idea that it may one day be explained in terms of how the brain processes information. Neuroscientists think that consciousness requires neurons to fire in such a way that they produce a stable pattern of brain activity. The exact pattern will depend on what the sensory information is, but once information has been processed, the idea is that the brain should hold a pattern steady for a short period of time – almost as if it needs a moment to read out the information. In 2009, Schurger tested this theory by scanning 12 people's brains with fMRI machines. The volunteers were shown two images simultaneously, one for each eye. One eye saw a red-on-green line drawing and the other eye saw green-on-red. This confusion caused the volunteers to sometimes consciously perceive the drawing and sometimes not. © Copyright Reed Business Information Ltd.
Mo Costandi In 2009, researchers at the University of California, Santa Barbara performed a curious experiment. In many ways, it was routine — they placed a subject in the brain scanner, displayed some images, and monitored how the subject's brain responded. The measured brain activity showed up on the scans as red hot spots, like many other neuroimaging studies. Except that this time, the subject was an Atlantic salmon, and it was dead. Dead fish do not normally exhibit any kind of brain activity, of course. The study was a tongue-in-cheek reminder of the problems with brain scanning studies. Those colorful images of the human brain found in virtually all news media may have captivated the imagination of the public, but they have also been subject of controversy among scientists over the past decade or so. In fact, neuro-imagers are now debating how reliable brain scanning studies actually are, and are still mostly in the dark about exactly what it means when they see some part of the brain "light up." Functional magnetic resonance imaging (fMRI) measures brain activity indirectly by detecting changes in the flow of oxygen-rich blood, or the blood oxygen-level dependent (BOLD) signal, with its powerful magnets. The assumption is that areas receiving an extra supply of blood during a task have become more active. Typically, researchers would home in on one or a few "regions of interest," using 'voxels,' tiny cube-shaped chunks of brain tissue containing several million neurons, as their units of measurement.
Keyword: Brain imaging
Link ID: 20775 - Posted: 04.10.2015
By KEN BELSON One of the limitations of studying chronic traumatic encephalopathy, or C.T.E., the degenerative brain disease linked to repeated head trauma, has been that researchers have been able to detect it only in tissue obtained posthumously. A study published Monday by Proceedings of the National Academy of Sciences, though, suggests that researchers trying to develop a test that will detect the disease in living patients have taken a small step forward. The study, conducted at U.C.L.A., included 14 retired N.F.L. players who suffered from mood swings, depression and cognitive problems associated with C.T.E. The players were given PET, or positron emission tomography, scans that revealed tau protein deposits in their brains, a signature of C.T.E. Although the results were not conclusive, the distribution of tau in their brains was consistent with those found in the autopsies of players who had C.T.E. The 14 players were compared with 24 patients with Alzheimer’s disease and 28 patients in a control group with no significant cognitive problems. The scans showed that the tau deposits in the 14 players were “distinctly different” from those in the patients with Alzheimer’s disease. “There seems to be an emerging new pattern we haven’t seen in any known forms of dementia, and it is definitely not normal,” said Dr. Julian Bailes, a coauthor of the study and the chairman of neurosurgery at NorthShore Neurological Institute in Evanston, Ill. © 2015 The New York Times Company
Helen Shen An ambitious plan is afoot to build the world’s largest public catalogue of neuronal structures. The BigNeuron project, announced on 31 March by the Allen Institute for Brain Science in Seattle, Washington, is designed to help researchers to simulate and understand the human brain. The project might also push neuroscientists to wrestle with fundamental — sometimes even emotional — questions about how to classify neurons. It is the era of the mega-scale brain initiative: Europe’s Human Brain Project aims to model the human brain in a supercomputer, and the US BRAIN Initiative hopes to unravel how networks of neurons work together to produce thoughts and actions. Standing in the way of these projects is a surprising limitation. “We still don’t know how many classes of neurons are in the brain,” says neuroscientist Rafael Yuste at Columbia University in New York City. BigNeuron aims to generate detailed descriptions of tens of thousands of individual neurons from various species, including fruit flies, zebrafish, mice and humans, and to suggest the best computer algorithms for extracting the finely branched shapes of these cells from microscopy data — a difficult and error-prone process. Getting the details of the shapes right is crucial to accurately modelling the behaviour of neurons: their geometry helps to determine how they process and transmit information through electrical and chemical signals. © 2015 Nature Publishing Group
Keyword: Brain imaging
Link ID: 20746 - Posted: 04.01.2015