Chapter 2. Cells and Structures: The Anatomy of the Nervous System

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Jon Hamilton What Einstein did for physics, a Spaniard named Santiago Ramón y Cajal did for neuroscience more than a century ago. Back in the 1890s, Cajal produced a series of drawings of brain cells that would radically change scientists' understanding of the brain. And Cajal's drawings aren't just important to science. They are considered so striking that the Weisman Art Museum in Minneapolis has organized a traveling exhibition of Cajal's work called The Beautiful Brain. "Cahal was the founder of modern neuroscience," says Larry Swanson, a brain scientist at the University of Southern California who wrote an essay for the book that accompanies the exhibit. "Before Cajal it was just completely different," Swanson says. "Most of the neuroscientists in the mid-19th century thought the nervous system was organized almost like a fishing net." They saw the brain and nervous system as a single, continuous web, not a collection of separate cells. But Cajal reached a different conclusion. "Cajal looked under the microscope at different parts of the brain and said, 'It's not like a fishing net,'" Swanson says. "There are individual units called nerve cells or neurons that are put together in chains to form circuits." Cajal didn't just take notes on what he saw. He made thousands of highly detailed drawings, many of which are considered works of art. © 2017 npr

Keyword: Brain imaging
Link ID: 23152 - Posted: 01.27.2017

Esther Landhuis As big brain-mapping initiatives go, Taiwan's might seem small. Scientists there are studying the humble fruit fly, reverse-engineering its brain from images of single neurons. Their efforts have produced 3D maps of brain circuitry in stunning detail. Researchers need only a computer mouse and web browser to home in on individual cells and zoom back out to intertwined networks of nerve bundles. The wiring diagrams look like colourful threads on a tapestry, and they're clear enough to show which cell clusters control specific behaviours. By stimulating a specific neural circuit, researchers can cue a fly to flap its left wing or swing its head from side to side — feats that roused a late-afternoon crowd in November at the annual meeting of the Society for Neuroscience in San Diego, California. But even for such a small creature, it has taken the team a full decade to image 60,000 neurons, at a rate of 1 gigabyte per cell, says project leader Ann-Shyn Chiang, a neuroscientist at the National Tsing Hua University in Hsinchu City, Taiwan — and that's not even half of the nerve cells in the Drosophila brain. Using the same protocol to image the 86 billion neurons in the human brain would take an estimated 17 million years, Chiang reported at the meeting. Other technologies are more tractable. In July 2016, an international team published a map of the human brain's wrinkled outer layer, the cerebral cortex1. Many scientists consider the result to be the most detailed human brain-connectivity map so far. Yet, even at its highest spatial resolution (1 cubic millimetre), each voxel — the smallest distinguishable element of a 3D object — contains tens of thousands of neurons. That's a far cry from the neural connections that have been mapped at single-cell resolution in the fruit fly. © 2017 Macmillan Publishers Limited

Keyword: Brain imaging
Link ID: 23151 - Posted: 01.26.2017

What are you like? A look at your brain may tell you. A study has found a link between some elements of brain structure and certain personality traits. The study involved scanning the brains of 500 volunteers, and assessing their personalities in terms of five traits – neuroticism, openness, extraversion, agreeableness, and conscientiousness. The researchers focused on the structure of the cortex, the outer layer of the brain. They found that in people who are more neurotic and prone to mood changes, the cortex tends to be thicker and less wrinkly. People who appear more open – for example, curious and creative – show the opposite pattern. More mature The link between structure and personality may help explain how we mature as we get older. Folds and wrinkles are thought to increase the surface area of the brain, but make the cortex thinner. The cortex continues to stretch and fold throughout childhood and adolescence, and into adulthood. As we grow up, people generally become less neurotic, and more conscientious and agreeable. “Our work supports the notion that personality is, to some degree, associated with brain maturation,” says Roberta Riccelli, at Magna Graecia University in Catanzaro, Italy. Journal reference: Social Cognitive and Affective Neuroscience © Copyright Reed Business Information Ltd.

Keyword: Emotions; Brain imaging
Link ID: 23142 - Posted: 01.25.2017

written by Claire Lehmann I learned about Debra through reading her LA Times op-ed on the futility of gender neutral parenting. I got in touch with Debra because I wanted to learn more about her field of sex neuroscience, her own research and her thoughts on studying sex differences in the brain. Because the study of sex and sex differences is often fraught with political roadblocks, I also wanted to get a picture of how a neuroscientist-sex researcher approaches some of these contentious issues. Hi Debra, thanks for chatting to Quillette. Can you briefly tell us who you are — where you studied, who was your supervisor and what made you interested in neuroscience, in particular sex neuroscience? I am a sex researcher at York University in Toronto and I write about the science of sex for several media outlets, including Playboy. For my PhD, which I just defended, I worked with Dr. Keith Schneider, who has pioneered new methods in high-resolution fMRI and is the Director of the University of Delaware’s Center for Biomedical and Brain Imaging, and Dr. James Cantor at the University of Toronto, who is a world expert in the brain imaging of pedophilia. I remember opening up a textbook during my first neuroscience course as an undergraduate student, seeing images from an fMRI study, and thinking it was incredible. I decided to pursue neuroscience in grad school and had the opportunity to do a placement in sexology as part of my Master’s degree. That’s how I got hooked! And I haven’t looked back. © 2017 Quillette

Keyword: Sexual Behavior; Brain imaging
Link ID: 23137 - Posted: 01.24.2017

By NICHOLAS ST. FLEUR The tale of the Tasmanian tiger was tragic. Once numerous across Tasmania, the doglike marsupial was branded a sheep killer by colonists in the 1830s and hunted to extinction. The last of its kind, Benjamin, died in a zoo in 1936, and with it many secrets into the animals’ lives were lost. The striped creature, which is also known as the thylacine, was hardly studied when it was alive, depriving scientists of understanding the behavior of an important predator from Australia’s recent biological past. Now, for the first time, researchers have performed neural scans on the extinct carnivore’s brain, revealing insights that had been lost since the species went extinct. “Part of the myth about them is what exactly did they eat, how did they hunt and were they social?” said Dr. Gregory Berns, a neuroscientist at Emory University and lead author on the study, which was published Wednesday in the journal PLOS One. “These are questions nobody really knows the answers to.” Dr. Berns’s main research pertains to dogs and the inner workings of the canine brain, but after learning more about Tasmanian tigers, he became fascinated by the beasts. With their slender bodies, long snouts and sharp teeth, Tasmanian tigers looked as if they could be related to dogs, wolves or coyotes. But actually they are separated by more than 150 million years of evolution. It is a classic example of convergent evolution, in which two organisms that are not closely related develop similar features because of the environment they adapted to and the ecological role they played. To better understand thylacines, Dr. Berns spent two years tracking down two preserved Tasmanian tiger brains, one at the Smithsonian Institution and the other at the Australian Museum. Their brains, like those of all marsupials, are very different from the brains of placental mammals. The biggest difference is that they lack a corpus callosum, which is the part of the brain that connects the left and right hemispheres. © 2017 The New York Times Company

Keyword: Evolution; Brain imaging
Link ID: 23131 - Posted: 01.21.2017

NEUROSCIENCE, like many other sciences, has a bottomless appetite for data. Flashy enterprises such as the BRAIN Initiative, announced by Barack Obama in 2013, or the Human Brain Project, approved by the European Union in the same year, aim to analyse the way that thousands or even millions of nerve cells interact in a real brain. The hope is that the torrents of data these schemes generate will contain some crucial nuggets that let neuroscientists get closer to understanding how exactly the brain does what it does. But a paper just published in PLOS Computational Biology questions whether more information is the same thing as more understanding. It does so by way of neuroscience’s favourite analogy: comparing the brain to a computer. Like brains, computers process information by shuffling electricity around complicated circuits. Unlike the workings of brains, though, those of computers are understood on every level. Eric Jonas of the University of California, Berkeley, and Konrad Kording of Northwestern University, in Chicago, who both have backgrounds in neuroscience and electronic engineering, reasoned that a computer was therefore a good way to test the analytical toolkit used by modern neuroscience. Their idea was to see whether applying those techniques to a microprocessor produced information that matched what they already knew to be true about how the chip works. © The Economist Newspaper Limited 2017.

Keyword: Brain imaging
Link ID: 23126 - Posted: 01.21.2017

Russell Poldrack Sex, Lies, and Brain Scans: How fMRI Reveals What Really Goes on in our Minds Barbara J. Sahakian & Julia Gottwald Oxford University Press: 2017. Since its 1992 debut, functional magnetic resonance imaging (fMRI) has revolutionized our ability to view the human brain in action and understand the processes that underlie mental functions such as decision-making. As brain-imaging technologies have grown more powerful, their influence has seeped from the laboratory into the real world. In Sex, Lies, and Brain Scans, clinical neuropsychologist Barbara Sahakian and neuroscientist Julia Gottwald give a whistle-stop tour of some ways in which neuroimaging has begun to affect our views on human behaviour and society. Their discussion balances a rightful enthusiasm for fMRI with a sober appreciation of its limitations and risks. After the obligatory introduction to fMRI, which measures blood oxygenation to image neural activity, Sahakian and Gottwald address a question at the heart of neuroimaging: can it read minds? The answer largely depends on one's definition of mind-reading. As the authors outline, in recent years fMRI data have been used to decode the contents of thoughts (such as words viewed by a study participant) and mental states (such as a person's intention to carry out an action), even in sleep. These methods don't yet enable researchers to decode the 'language of thought', which is what mind-reading connotes for many. But given the growing use of advanced machine-learning methods such as deep neural networks to analyse neuroimaging data, that may just be a matter of time. © 2017 Macmillan Publishers Limited

Keyword: Brain imaging
Link ID: 23091 - Posted: 01.13.2017

By SAM BORDEN, MIKA GRÖNDAHL and JOE WARD When player No. 81 took this blow to his head several years ago, it was just one of many concussions that have occurred throughout college football and the N.F.L. But what made this one different was that this player was wearing a mouth guard with motion sensors. The information from those sensors has given researchers a more detailed and precise window into what was happening within the player’s brain in the milliseconds after the hit. Here is what happened to his brain. One common belief has been that just after a person’s head (or helmet) makes contact with something – an airbag, a wall, another person – the brain within bounces around in the skull like an egg yolk in a shell, leaving bruises on the brain’s outer surface, or gray matter. Now, though, many scientists and medical experts believe that this understanding is incomplete. Yes, there is some movement in the skull, but the real damage from concussions, they say, actually occurs deeper in the brain – in the so-called white matter – as a result of fibers pulling and twisting after impact. To stick with the food analogy, think Jell-O, not an egg. You know what happens when you take a plate of Jell-O and give it a hard shake? The stretches and contortions approximate what is happening to all the wiring throughout the brain. To better track the brain’s reaction to these hits, scientists in several labs have been working on a variety of mechanisms, some of which, like the one used during the impact shown above, are moving away from ones connected directly to a football helmet because the helmet can move independently of the skull. “The forces you’re measuring with those are not really exactly what the brain is seeing,” said Robert Cantu, clinical professor of neurosurgery at the Boston University School of Medicine. The mouth guard that was used was developed by the bioengineer David Camarillo and his team at the Cam Lab at Stanford. Camarillo and others have speculated that the most damaging blows are those that cause the head to snap quickly from ear to ear, like the one shown above, or those that cause a violent rotation or twisting of the head through a glancing blow. “The brain’s wiring, essentially, is all running from left to right, not front to back,” Camarillo said, referring to the primary wiring that connects the brain’s hemispheres. “So the direction you are struck can have a very different effect within the brain. In football, the presence of the face mask can make that sort of twisting even more extreme.” © 2017 The New York Times Company

Keyword: Brain Injury/Concussion; Brain imaging
Link ID: 23085 - Posted: 01.11.2017

By Greg Miller Babies born prematurely are prone to problems later in life—they’re more likely to develop autism or attention deficit hyperactivity disorder, and more likely to struggle in school. A new study that’s among the first to investigate brain activity in human fetuses suggests that the underlying neurological issues may begin in the womb. The findings provide the first direct evidence of altered brain function in fetuses that go on to be born prematurely, and they might ultimately point to ways to remediate or even prevent such early injuries. In the new study, published 9 January in Scientific Reports, developmental neuroscientist Moriah Thomason of Wayne State University School of Medicine in Detroit, Michigan, and colleagues report a difference in how certain brain regions communicate with each other in fetuses that were later born prematurely compared with fetuses that were carried to term. Although the findings are preliminary because the study was small, Thomason and other researchers say the work illustrates the potential (and the challenges) of the emerging field of fetal neuroimaging. “Harnessing the power of these advanced tools is offering us for the very first time the opportunity to explore the onset of neurologic insults that are happening in utero,” says Catherine Limperopoulos, a pediatric neuroscientist at Children’s National Medical Center in Washington, D.C. Thomason and colleagues used functional magnetic resonance imaging (fMRI) to investigate brain activity in 32 fetuses. The pregnant mothers were participants in a larger, long-term study of brain development led by Thomason. “The majority have just normal pregnancies, but they’re drawn from a low-resource population that’s at greater risk of early delivery and developmental problems,” she says. In the end, 14 of the fetuses were born prematurely. © 2017 American Association for the Advancement of Science.

Keyword: Brain imaging; Development of the Brain
Link ID: 23072 - Posted: 01.09.2017

Alexander Fornito, The human brain is an extraordinarily complex network, comprising an estimated 86 billion neurons connected by 100 trillion synapses. A connectome is a comprehensive map of these links—a wiring diagram of the brain. With current technology, it is not possible to map a network of this size at the level of every neuron and synapse. Instead researchers use techniques such as magnetic resonance imaging to map connections between areas of the human brain that span several millimeters and contain many thousands of neurons. At this macroscopic scale, each area comprises a specialized population of neurons that work together to perform particular functions that contribute to cognition. For example, different parts of your visual cortex contain cells that process specific types of information, such as the orientation of a line and the direction in which it moves. Separate brain regions process information from your other senses, such as sound, smell and touch, and other areas control your movements, regulate your emotional responses, and so on. These specialized functions are not processed in isolation but are integrated to provide a unitary and coherent experience of the world. This integration is hypothesized to occur when different populations of cells synchronize their activity. The fiber bundles that connect different parts of the brain—the wires of the connectome—provide the substrate for this communication. These connections ensure that brain activity unfolds through time as a rhythmic symphony rather than a disordered cacophony. © 2017 Scientific American

Keyword: Brain imaging
Link ID: 23049 - Posted: 01.03.2017

Joy Ho The hipbone's connected to the leg bone, connected to the knee bone. That's not actually what those body parts are called, but we'll forgive you if you don't sing about the innominate bone connecting to the femur connecting to the patella. It just doesn't have the same ring to it. When the ancient Greeks were naming body parts, they were probably trying to give them names that were easy to remember, says Mary Fissell, a professor in the Department of the History of Medicine at Johns Hopkins. "Sure, there were texts, but the ancient world was very oral, and the people learning this stuff have to remember it." So the Greek scholars, and later Roman and medieval scholars, named bones and organs and muscles after what they looked like. The thick bone at the front of your lower leg, the tibia, is named after a similar-looking flute. And although you or I might get confused when a paleoanthropologist writes about the foramen magnum (which translates to "really big hole") a native Latin speaker would know exactly what to look for — the really big hole where your brain attaches to your spine. Sometimes the names get a little bit more abstract. Take the tragus, a tiny flap of skin on the outer ear. It's named after goats not because it looks like them, but because some people have tufts of hair on the tragus like goats do on their chins. "I'm fascinated by the struggle of translating sensory experiences to words, and that's what these early anatomists were doing. Sometimes in the names or descriptions you can almost feel the struggle of someone seeing this object and trying to reduce it to words,"says Fissell. © 2016 npr

Keyword: Brain imaging
Link ID: 22995 - Posted: 12.17.2016

By James Gallagher Health and science reporter, BBC News website Detailed MRI scans should be offered to some women in pregnancy to help spot brain defects in the developing baby, say researchers. Ultrasounds are already used to look inside the womb and check that the baby is growing properly. However, the study on 570 women published in the Lancet showed doctors were able to make a much better diagnosis using MRI scans. Experts called for the scans to become routine practice. Pregnant women are offered an ultrasound scan at about 20 weeks that can spot abnormalities in the brain. They are detected in three in every 1,000 pregnancies. If the brain fails to develop properly it can result in miscarriage or still birth. Couples are generally offered counselling and some choose to have an abortion More certainty The study, carried out across 16 centres in the UK, analysed the impact of using MRI scans - which use magnetic fields and radio waves to image the body - to confirm any diagnoses. Overall, it showed ultrasound gave the correct diagnosis 68% of the time. But combining that with MRI increased the accuracy to 93%. Image copyright SPL Image caption The detailed picture of the developing baby's brain revealed by MRI The extra tests were most useful in borderline cases where doctors were uncertain of the outcome. The number of pregnant women who were given an "unknown" diagnosis was more than halved by the extra scans, increasing the confidence that the developing baby's brain was healthy or not. © 2016 BBC.

Keyword: Brain imaging; Development of the Brain
Link ID: 22989 - Posted: 12.15.2016

A little over a decade ago, neuroscientists began using a new technique to inspect what was going on in the brains of their subjects. Rather than giving their subjects a task to complete and watching their brains to see which parts lit up, they’d tell them to lie back, let their minds wander, and try not to fall asleep for about six minutes. That technique is called resting state functional magnetic resonance imaging, and it shares a problem with other types of fMRI: It only tracks changes in the blood in the brain, not the neurons sending the signals in the first place. Researchers have recently called fMRI into question for its reliance on possibly-faulty statistics. And things get even less certain when the brain isn’t engaged in any particular task. “These signals are, by definition, random,” says Elizabeth Hillman, a biomedical engineer at Columbia’s Zuckerman Institute. “And when you’re trying to measure something that’s random amidst a whole bunch of noise, it becomes very hard to tell what’s actually random and what isn’t.” Six years ago, Hillman, along with many others in the field, was deeply skeptical of resting state fMRI’s ability to measure what it promised to. But this week, in a paper in Proceedings of the National Academy of Sciences, she presents compelling evidence to the contrary: a comprehensive visualization of neural activity throughout the entire brain at rest, and evidence that the blood rushing around in your brain is actually a good indicator of what your neurons are doing. Ever since 1992, when researcher Bharat Biswal first started scanning people who were just sitting around, resting state fMRI has become increasingly popular. Partly, that’s because it’s just way simpler than regular, task-based fMRI.

Keyword: Brain imaging; Attention
Link ID: 22986 - Posted: 12.14.2016

By Chloé Hecketsweiler Can brain science predict when someone will commit a crime, or tell whether a defendant knew right from wrong? In recent decades, scientists and criminal justice experts have been trying to answer tantalizing questions like these — with mixed success. The science of predicting crime using algorithms is still shaky, and while sophisticated tools such as neuroimaging are increasingly being used in courtrooms, they raise a host of tricky questions: What kind of brain defect or brain injury should count when assessing a defendant’s responsibility for a crime? Can brain imaging distinguish truth from falsehood? Can neuroscience predict human behavior? Judith Edersheim, an assistant professor of psychiatry at Harvard Medical School and also a lawyer who specializes in forensic evaluations, focuses her research on these gray areas. In 2009, she co-founded the Center for Law, Brain, and Behavior at Massachusetts General Hospital, with the goal of “translating neuroscience into the legal arena.” And on December 15, at an event at Brigham and Women’s Hospital in Boston, Edersheim will talk about the vulnerability of the aging brain, highlighting the case of a man affected by an undetected brain disease. For this installment of the Undark Five, we asked her what brain imaging can reveal about the “criminal brain,” how relationships between brain functioning and behavior can inform the courtroom, and what controversies this iconoclastic science may raise. Questions and answers have been edited for length and clarity, and Undark has supplied some additional links. UNDARK — Using brain imaging, scientists have identified correlations between certain brain abnormalities and criminal behaviors. Is there a signature for the “criminal brain”? JUDITH EDERSHEIM — There may be no criminal minds; there may be criminal moments. Copyright 2016 Undark

Keyword: Aggression; Brain imaging
Link ID: 22978 - Posted: 12.12.2016

By Jessica Wright, A laboratory mouse has a modest home: a small, smelly cage lined with soft bedding, which it shares with up to four other animals. But it is home nonetheless—a place of comfort. That is, until the massive hand of a researcher reaches in to pluck it out for an experiment. The experiment might gauge whether a mouse feels anxious or social, or tap the activity in its brain. But does the intrusion of the researcher’s hand influence the very behavior under study? Yes, says Timothy Murphy, professor of cellular and physiological sciences at the University of British Columbia in Vancouver, Canada. Murphy’s team has developed a high-tech cage that allows a mouse to go about its business uninterrupted^1. The cage records the mouse’s every move. Whenever the animal is thirsty, it enters a corridor, attaches its head to an apparatus, and takes a drink while a microscope takes a picture of its brain activity. Murphy and his colleagues have used the cages to measure synchrony between mouse brain regions. In one experiment, the researchers captured more than 7,000 snapshots of brain activity in less than two months—all of them after the mice voluntarily ‘posed’ for the camera. We asked Murphy how he trains mice to participate, and how this approach could help autism research. © 2016 Scientific American

Keyword: Brain imaging
Link ID: 22889 - Posted: 11.19.2016

By Jef Akst WIKIMEDIA COMMONS, GERRYSHAWThe deeper scientists probe into the complexity of the human brain, the more questions seem to arise. One of the most fundamental questions is how many different types of brain cells there are, and how to categorize individual cell types. That dilemma was discussed during a session yesterday (November 11) at the ongoing Society for Neuroscience (SfN) conference in San Diego, California. As Evan Macosko of the Broad Institute said, the human brain comprises billions of brain cells—about 170 billion, according to one recent estimate—and there is a “tremendous amount of diversity in their function.” Now, new tools are supporting the study of single-cell transcriptomes, and the number of brain cell subtypes is skyrocketing. “We saw even greater degrees of heterogeneity in these cell populations than had been appreciated before,” Macosko said of his own single-cell interrogations of the mouse brain. He and others continue to characterize more brain regions, clustering cell types based on differences in gene expression, and then creating subclusters to look for diversity within each cell population. Following Macosko’s talk, Bosiljka Tasic of the Allen Institute for Brain Science emphasized that categorizing cell types into subgroups based on gene expression is not enough. Researchers will need to combine such data with traditional metrics, such as morphology and electrophysiology to “ultimately come up with an integrative taxonomy of cell types,” Tasic said. “Multimodal data acquisition—it’s a big deal and I think it’s going to be a big focus of our future endeavors.” © 1986-2016 The Scientist

Keyword: Brain imaging
Link ID: 22886 - Posted: 11.19.2016

Amber Dance In a study published in Science in September, Cossart, a neurobiologist at the Institute of Neurobiology of the Mediterranean in Marseilles, France, opened up mouse brains to visualize their neural activity as the animals raced on treadmills and rested. As the mice ran, some 50 neurons in their hippocampi fired in sequence, possibly to help the animals measure the distance travelled. Later, when the mice were resting, certain subsets of those neurons turned on again1. This reactivation, Cossart suspects, has to do with encoding and retrieving memory — as if the mouse is recalling its earlier exercise. “The power of imaging is really to be able to see the cells, to see not only the active ones but also the silent ones and to map them on the anatomical structure of the brain,” she says. It has not yet provided proof for Cossart's hypothesis, but the microscope and neural-activity markers behind the techniques represent the very latest in methods to study brain connectivity. In the past, researchers studied just a few neurons at a time using electrodes implanted into the brain. But that gives a fairly crude picture of what is going on, like looking at a monitor with just a couple of functioning pixels, says Rafael Yuste, director of the NeuroTechnology Center at Columbia University in New York City. But new techniques are fleshing out the picture. Scientists can now watch neurons live and in colour, helping them to work out which cells work together. Methods such as Cossart's zoom in at the microscopic scale to catch individual neurons in the act; others provide a whole-brain, or mesoscopic, view. And although it is possible to perform these experiments with an off-the-shelf microscope, scientists have been customizing them to suit their specific purposes; these devices are in various stages of commercialization. © 2016 Macmillan Publishers Limited,

Keyword: Brain imaging
Link ID: 22861 - Posted: 11.12.2016

By Alison F. Takemura In the 1980s, neuroscientists were facing an imaging problem. They had developed a new way to detect neuronal activity with calcium dyes, but visualizing the markers proved challenging. The dyes fluoresced in the presence of calcium ions when illuminated with ultraviolet (UV) light, but it was difficult to build UV lenses for confocal microscopes—instruments that allowed scientists to peer hundreds of micrometers deep into the brain. To make matters worse, because biological tissue scatters light so effectively, confocal scopes required excessive light intensities, which caused irreparable damage to samples. “You basically burned your tissue,” says Winfried Denk, director of the Max Planck Institute of Neurobiology in Martinsried, Germany. The time was ripe for a gentler option, and Denk developed two-photon excitation microscopy in 1990. Instead of using a single photon to excite a calcium dye, scientists could use two photons and half the illumination energy—red or infrared lasers, instead of ultraviolet. The scatter of such low-energy rays caused far less damage to surrounding tissue. The technology had another advantage. To excite a molecule, both photons had to reach it simultaneously. This meant the laser could only excite a tiny patch of tissue where its photons were most concentrated, giving scientists a new level of precision. © 1986-2016 The Scientist

Keyword: Brain imaging
Link ID: 22852 - Posted: 11.10.2016

Sara Reardon Major brain-mapping projects have multiplied in recent years, as neuroscientists develop new technologies to decipher how the brain works. These initiatives focus on understanding the brain, but the World Health Organization (WHO) wants to ensure that they work to translate their early discoveries and technological advances into tests and treatments for brain disorders. “We think there are side branches from projects that could be pursued with a very small investment to benefit public health,” says Shekhar Saxena, director of the WHO’s mental-health and substance-abuse department. Saxena will make that case on 12 November at the annual meeting of the Society for Neuroscience in San Diego, California — continuing a discussion that began in July at the WHO’s headquarters in Geneva, Switzerland. Among the roughly 70 people who attended that first meeting were leaders of the major brain initiatives, including the US BRAIN (Brain Research through Advancing Innovative Neurotechnologies) Initiative, launched in 2013; the European Human Brain Project, started in 2013; and the Japanese Brain/MINDS project, launched in 2014. All of these projects focus on basic research on the brain or the development of sophisticated tools to study it. Clinical applications are an ultimate, rather than an immediate, goal. But at the Geneva meeting, project leaders agreed, in principle, that they should do more to adapt brain-imaging technologies for use in clinical diagnoses. “The WHO is concerned that the emphasis on building these very expensive devices could worsen the health disparities that we have now between the developed and underdeveloped world,” says Walter Koroshetz, director of the US National Institute of Neurological Disorders and Stroke, which is part of the BRAIN Initiative. © 2016 Macmillan Publishers Limited

Keyword: Brain imaging
Link ID: 22846 - Posted: 11.09.2016

By LISA SANDERS, M.D. Yesterday we challenged Well readers to take on the case of a 63-year-old artist who, over the course of several months, developed excruciating headaches, along with changes in his personality, his thinking, even in the way he painted. We provided you with some of the doctor’s notes and medical imaging results that led the doctor who finally made the diagnosis in the right direction. After an extensive evaluation, that doctor asked a single question that led him to make the diagnosis. We asked Well readers to figure out the question the doctor asked and the diagnosis it suggested. It must have been a tough case — or else you were all too worried about the coming election to rise to the challenge — because we got just over 200 responses, fewer than usual. Of those, only six of you figured out the right diagnosis, and only three of you got the question right as well. Despite that, I was very impressed by the thinking of even those who didn’t come up with the right diagnosis. Many of you thought about environmental factors like his recent retirement and his exposure to possible toxins from his painting, and that kind of thinking was, in my opinion, the very essence of thinking like a doctor. Strong work, all of you. The question the doctor asked that led him to the correct diagnosis was: Can you hear your heartbeat in your ears? The patient could. And that suggested the diagnosis: A dural-arteriovenous fistula, or DAVF © 2016 The New York Times Company

Keyword: Pain & Touch
Link ID: 22839 - Posted: 11.07.2016