Chapter 2. Functional Neuroanatomy: The Nervous System and Behavior

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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

By Alison F. Takemura In the mid-1980s, György Buzsáki was trying to get inside rats’ heads. Working at the University of California, San Diego, he would anesthetize each animal with ether and hypothermia, cut through its scalp, and drill holes in its skull. Carefully, he’d screw 16 gold-plated stainless steel electrodes into the rat’s brain. When he was done with the surgery, these tiny pieces of metal—just 0.5 mm in diameter—allowed him to measure voltage changes from individual neurons deep in the brain’s folds, all while the rodent was awake and moving around. He could listen to the cells fire action potentials as the animal explored its environment, learning and remembering what it encountered (J Neurosci, 8:4007-26, 1988). In those days, recording from two cells simultaneously was the norm. The 16-site recording in Buzsáki’s 1988 study “was the largest ever in a rat,” he says. Nowadays, scientists can measure voltage changes from 1,000 neurons at the same time with silicon multielectrode arrays. But the basic techniques of using a probe to measure electrical activity within the brain (electrophysiology) or from outside it (electroencephalography, or EEG) are still workhorses of neural imaging labs. “The new tools don’t replace the old ones,” says Jessica Cardin, a neuroscientist at the Yale School of Medicine. “They add new layers of information.” Another decades-old neuroscientific technique that remains popular today is patch clamping. Developed in the late 1970s and early 1980s, it can detect changes in the electric potential of individual cells, or even single ion channels. With a tiny glass pipette suctioned against the cell’s membrane, researchers can make a small tear, sealed by the pipette tip, and detect voltage changes inside the cell. With some improvements, the patch clamp, like electrophysiology and EEG, has remained a regular part of the neuroscientist’s tool kit. Recently, researchers had a robot carry out the process (Nat Methods, 9:585-87, 2012). © 1986-2016 The Scientist

Keyword: Brain imaging
Link ID: 22783 - Posted: 10.25.2016

Robin McKie New visions of the brain and body’s detailed operations will be unveiled by a suite of medical scanners being opened this week. The newly refurbished Wolfson Brain Imaging Centre in the University of Cambridge has been equipped with some of the world’s most powerful magnetic resonance imaging (MRI) and positron emission tomography (PET) scanners and will give its researchers unprecedented power to make images of cancers, study the precise makeup of the cortex and analyse how chemicals in the brain – known as neurotransmitters – underpin the development of schizophrenia and depression. “It is a remarkable set of machines,” says Professor Ed Bullmore, head of neuroscience at Cambridge University. “We will be able to address clinical issues such as the detailed progression of Parkinson’s disease. At the same time, we will be able to address basic issues about the mind. How does the brain develop? How does the adult brain perform its functions?” At the heart of the refurbished centre – funded by the Medical Research Council, Wellcome Trust and Cancer Research UK – are three groundbreaking devices. Only a handful of these exist at institutions outside Cambridge and no institution – other than Cambridge – has all three. “The devices we have assembled are primarily for studying humans and will have a strong research focus,” Bullmore says. A key example is provided by the 7T MRI scanner. Current devices have magnetic fields that have strengths of around 3T (tesla) and can see structures 2-3 mm in size. By contrast, the new Cambridge scanner with its 7T field will have a resolution of around 0.5mm. © 2016 Guardian News and Media Limited

Keyword: Brain imaging
Link ID: 22782 - Posted: 10.24.2016

Sara Reardon Two heads are better than one: an idea that a new global brain initiative hopes to take advantage of. In recent years, brain-mapping initiatives have been popping up around the world. They have different goals and areas of expertise, but now researchers will attempt to apply their collective knowledge in a global push to more fully understand the brain. Thomas Shannon, US Under Secretary of State, announced the launch of the International Brain Initiative on 19 September at a meeting that accompanied the United Nations’ General Assembly in New York City. Details — including which US agency will spearhead the programme and who will pay for it — are still up in the air. However, researchers held a separate, but concurrent, meeting hosted by the US National Science Foundation at Rockefeller University to discuss which aspects of the programmes already in existence could be aligned under the global initiative. The reaction was a mixture of concerns over the fact that attemping to align projects could siphon money and attention from existing initiatives in other countries, and anticipation over the possibilities for advancing our knowledge about the brain. “I thought the most exciting moment in my scientific career was when the president announced the BRAIN Initiative in 2013,” says Cori Bargmann, a neuroscientist at the Rockefeller University in New York City and one of the main architects of the US Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative. “But this was better.” © 2016 Macmillan Publishers Limited,

Keyword: Brain imaging
Link ID: 22680 - Posted: 09.22.2016

By Meredith Wadman While the United Nations General Assembly prepared for its sometimes divisive annual general debate on Monday, a less official United Nations of Brain Projects met nearby in a display of international amity and unbounded enthusiasm for the idea that transnational cooperation can, must, and will, at last, explain the brain. The tribe of some 400 neuroscientists, computational biologists, physicists, physicians, ethicists, government science counselors, and private funders convened at The Rockefeller University on Manhattan’s Upper East Side in New York City. The Coordinating Global Brain Projects gathering was mandated by the U.S. Congress in a 2015 law funding the U.S. Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative. The meeting aimed to synchronize the explosion of big, ambitious neuroscience efforts being launched from Europe to China. Nearly 50 speakers from more than a dozen countries explained how their nations are plumbing brain science; all seemed eager to be part of the as-yet unmapped coordination that they hope will lead to a mellifluous symphony rather than a cacophony of competing chords. “We are really seeing international cooperation at a level that we have not seen before,” said Rockefeller’s Cori Bargmann, a neurobiologist who with Rafael Yuste of Columbia University convened the meeting with the backing of the universities, the National Science Foundation (NSF), and the Kavli Foundation, a private funder of neuroscience and nanoscience. Bargmann and Yuste have been integral to planning the BRAIN Initiative launched by President Barack Obama in the spring of 2013, which, along with the European Human Brain Project, started the new push for large-scale neuroscience initiatives. “This could be historic,” Yuste said. “I could imagine out of this meeting that groups of people could get together and start international collaborations the way the astronomers and the physicists have been doing for decades.” © 2016 American Association for the Advancement of Science

Keyword: Brain imaging
Link ID: 22678 - Posted: 09.21.2016

By Rajeev Raizada These brain maps show how accurately it was possible to predict neural activation patterns for new, previously unseen sentences, in different regions of the brain. The brighter the area, the higher the accuracy. The most accurate area, which can be seen as the bright yellow strip, is a region in the left side of the brain known as the Superior Temporal Sulcus. This region achieved statistically significant sentence predictions in 11 out of the 14 people whose brains were scanned. Although that was the most accurate region, several other regions, broadly distributed across the brain, also produced significantly accurate sentence predictions Credit: University of Rochester graphic / Andrew Anderson and Xixi Wang. Used with permission Words, like people, can achieve a lot more when they work together than when they stand on their own. Words working together make sentences, and sentences can express meanings that are unboundedly rich. How the human brain represents the meanings of sentences has been an unsolved problem in neuroscience, but my colleagues and I recently published work in the journal Cerebral Cortex that casts some light on the question. Here, my aim is to give a bigger-picture overview of what that work was about, and what it told us that we did not know before. To measure people's brain activation, we used fMRI (functional Magnetic Resonance Imaging). When fMRI studies were first carried out, in the early 1990s, they mostly just asked which parts of the brain "light up,” i.e. which brain areas are active when people perform a given task. © 2016 Scientific American

Keyword: Language; Brain imaging
Link ID: 22676 - Posted: 09.21.2016

By Catherine Caruso Most of us think little of hopping on Google Maps to look at everything from a bird’s-eye view of an entire continent to an on-the-ground view of a specific street, all carefully labeled. Thanks to a digital atlas published this week, the same is now possible with the human brain. Ed Lein and colleagues at the Allen Institute for Brain Science in Seattle have created a comprehensive, open-access digital atlas of the human brain, which was published this week in The Journal of Comparative Neurology. “Essentially what we were trying to do is to create a new reference standard for a very fine anatomical structural map of the complete human brain,” says Lein, the principal investigator on the project. “It may seem a little bit odd, but actually we are a bit lacking in types of basic reference materials for mapping the human brain that we have in other organisms like mouse or like monkey, and that is in large part because of the enormous size and complexity of the human brain.” The project, which spanned five years, focused on a single healthy postmortem brain from a 34-year-old woman. The researchers started with the big picture: They did a complete scan of the brain using two imaging techniques (magnetic resonance imaging and diffusion weighted imaging), which allowed them to capture both overall brain structure and the connectivity of brain fibers. Next the researchers took the brain and sliced it into 2,716 very thin sections for fine-scale, cellular analysis. They stained a portion of the sections with a traditional Nissl stain to gather information about general cell architecture. They then used two other stains to selectively label certain aspects of the brain, including structural elements of cells, fibers in the white matter, and specific types of neurons. © 2016 Scientific American

Keyword: Brain imaging; Development of the Brain
Link ID: 22663 - Posted: 09.17.2016

Laurel Hamers The brains of human ancestors didn’t just grow bigger over evolutionary time. They also amped up their metabolism, demanding more energy for a given volume, a new study suggests. Those increased energy demands might reflect changes in brain structure and organization as cognitive abilities increased, says physiologist Roger Seymour of the University of Adelaide in Australia, a coauthor of the report, published online August 31 in Royal Society Open Science. Blood vessels passing through bones leave behind holes in skulls; bigger holes correspond to bigger blood vessels. And since larger vessels carry more blood, scientists can use hole size to estimate blood flow in extinct hominids’ brains. Blood flow in turn indicates how much energy the brain consumed. (In modern humans, the brain eats up 20 to 25 percent of the energy the body generates when at rest.) Seymour and colleagues focused on the carotid arteries, the vessels that deliver the bulk of the brain’s blood. The team looked at nearly three dozen skulls from 12 hominid species from the last 3 million years, including Australopithecus africanus, Homo neanderthalensis and Homo erectus. In each, the researchers compared the brain’s overall volume with the diameter of the carotid artery’s tiny entrance hole at the base of the skull. “We expected to find that the rate of blood flow was proportional to the brain size,” Seymour says. “But we found that wasn’t the case.” Instead, bigger brains required more blood flow per unit volume than smaller brains. |© Society for Science & the Public 2000 - 2016.

Keyword: Evolution
Link ID: 22616 - Posted: 08.31.2016