Chapter 2. Cells and Structures: The Anatomy of the Nervous System
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Mo Costandi The father of modern neuroscience had a sharp eye and an even sharper mind, but he evidently overlooked something rather significant about the basic structure of brain cells. Santiago Ramón y Cajal spent his entire career examining and comparing nervous tissue from different species. He observed the intricate branches we now call dendrites, and the thicker axonal fibres. He also recognised them as distinct components of the neuron, and convinced others that neurons are fundamental components of the nervous system. For Cajal, these cells were “the mysterious butterflies of the soul… whose beating of wings may one day reveal to us the secrets of the mind.” He hunted for them in “the gardens of the grey matter” and, being an accomplished artist, meticulously catalogued the many “delicate and elaborate forms” that they take. As his beautiful drawings show, all neurons have a single axon emanating from one area of the cell body, and one or more dendrites arising from another. This basic structure has been enshrined in textbooks ever since. But there appear to be unusual varieties of soul butterflies that Cajal failed to spot – neuroscientists in Germany have identified neurons that have axons growing from their dendrites, a discovery that challenges our century-old assumption about the form and function of these cells. Cajal stated that information flows through neurons in only one direction – from the dendrites, which receive electrical impulses from other neurons, to the cell body, which processes the information and conveys it to the initial segment of the axon, which then produces its own impulses that travel down it to the nerve terminal. (He indicated this with small arrows in some of his diagrams, such as the one above.) © 2014 Guardian News and Media Limited
Keyword: Brain imaging
Link ID: 20301 - Posted: 11.11.2014
Sara Reardon Delivering medications to the brain could become easier, thanks to molecules that can escort drugs through the notoriously impervious sheath that separates blood vessels from neurons. In a proof-of-concept study in monkeys, biologists used the system to reduce levels of the protein amyloid-β, which accumulates in the brain plaques associated with Alzheimer's disease1. The blood–brain barrier is a layer of cells lining the inner surface of the capillaries that feed the central nervous system. It is nature's way of protecting the delicate brain from infectious agents and toxic compounds, while letting nutrients and oxygen in and waste products out. Because the barrier strictly regulates the passage of larger molecules and often prevents drug molecules from entering the brain, it has long posed one of the most difficult challenges in developing treatments for brain disorders. Several approaches to bypassing the barrier are being tested, including nanoparticles that are small enough to pass through the barrier's cellular membranes and deliver their payload; catheters that carry a drug directly into the brain; and ultrasound pulses that push microbubbles through the barrier. But no approach has yet found broad therapeutic application. Neurobiologist Ryan Watts and his colleagues at the biotechnology company Genentech in South San Francisco have sought to break through the barrier by exploiting transferrin, a protein that sits on the surface of blood vessels and carries iron into the brain. The team created an antibody with two ends. One end binds loosely to transferrin and uses the protein to transport itself into the brain. And once the antibody is inside, its other end targets an enzyme called β-secretase 1 (BACE1), which produces amyloid-β. Crucially, the antibody binds more tightly to BACE1 than to transferrin, and this pulls it off the blood vessel and into the brain. It locks BACE1 shut and prevents it from making amyloid-β. © 2014 Nature Publishing Group,
Link ID: 20286 - Posted: 11.06.2014
James Gorman Here is something to keep arachnophobes up at night. The inside of a spider is under pressure, like the air in a balloon, because spiders move by pushing fluid through valves. They are hydraulic. This works well for the spiders, but less so for those who want to study what goes on in the brain of a jumping spider, an aristocrat of arachnids that, according to Ronald R. Hoy, a professor of neurobiology and behavior at Cornell University, is one of the smartest of all invertebrates. If you insert an electrode into the spider’s brain, what’s inside might squirt out, and while that is not the kind of thing that most people want to think about, it is something that the researchers at Cornell had to consider. Dr. Hoy and his colleagues wanted to study jumping spiders because they are very different from most of their kind. They do not wait in a sticky web for lunch to fall into a trap. They search out prey, stalk it and pounce. “They’ve essentially become cats,” Dr. Hoy said. And they do all this with a brain the size of a poppy seed and a visual system that is completely different from that of a mammal: two big eyes dedicated to high-resolution vision and six smaller eyes that pick up motion. Dr. Hoy gathered four graduate students in various disciplines to solve the problem of recording activity in a jumping spider’s brain when it spots something interesting — a feat nobody had accomplished before. In the end, they not only managed to record from the brain, but discovered that one neuron seemed to be integrating the information from the spider’s two independent sets of eyes, a computation that might be expected to involve a network of brain cells. © 2014 The New York Times Company
by Helen Thomson As you read this, your neurons are firing – that brain activity can now be decoded to reveal the silent words in your head TALKING to yourself used to be a strictly private pastime. That's no longer the case – researchers have eavesdropped on our internal monologue for the first time. The achievement is a step towards helping people who cannot physically speak communicate with the outside world. "If you're reading text in a newspaper or a book, you hear a voice in your own head," says Brian Pasley at the University of California, Berkeley. "We're trying to decode the brain activity related to that voice to create a medical prosthesis that can allow someone who is paralysed or locked in to speak." When you hear someone speak, sound waves activate sensory neurons in your inner ear. These neurons pass information to areas of the brain where different aspects of the sound are extracted and interpreted as words. In a previous study, Pasley and his colleagues recorded brain activity in people who already had electrodes implanted in their brain to treat epilepsy, while they listened to speech. The team found that certain neurons in the brain's temporal lobe were only active in response to certain aspects of sound, such as a specific frequency. One set of neurons might only react to sound waves that had a frequency of 1000 hertz, for example, while another set only cares about those at 2000 hertz. Armed with this knowledge, the team built an algorithm that could decode the words heard based on neural activity aloneMovie Camera (PLoS Biology, doi.org/fzv269). © Copyright Reed Business Information Ltd.
How Magic Mushrooms Rearrange Your Brain By Brandon Keim A new way of looking at brain activity may give insight into how psychedelic drugs produce their consciousness-altering effects. In recent years, a focus on brain structures and regions has given way to an emphasis on neurological networks: how cells and regions interact, with consciousness shaped not by any given set of brain regions, but by their interplay. Understanding the networks, however, is no easy task, and researchers are developing ever more sophisticated ways of characterizing them. One such approach, described in a new Proceedings of the Royal Society Interface study, involves not simply networks but networks of networks. Perhaps some aspects of consciousness arise from these meta-networks—and to investigate the proposition, the researchers analyzed fMRI scans of 15 people after being injected with psilocybin, the active ingredient in magic mushrooms, and compared them to scans of their brain activity after receiving a placebo. Investigating psychedelia wasn’t the direct purpose of the experiment, said study co-author Giovanni Petri, a mathematician at Italy’s Institute for Scientific Interchange. Rather, psilocybin makes for an ideal test system: It’s a sure-fire way of altering consciousness. “In a normal brain, many things are happening. You don’t know what is going on, or what is responsible for that,” said Petri. “So you try to perturb the state of consciousness a bit, and see what happens.” A representation of that is seen in the image above. Each circle depicts relationships between networks—the dots and colors correspond not to brain regions, but to especially connection-rich networks—with normal-state brains at left, and psilocybin-influenced brains at right. © 2014 Condé Nast.
By Neuroskeptic A new paper threatens to turn the world of autism neuroscience upside down. Its title is Anatomical Abnormalities in Autism?, and it claims that, well, there aren’t very many. Published in Cerebral Cortex by Israeli researchers Shlomi Haar and colleagues, the new research reports that there are virtually no differences in brain anatomy between people with autism and those without. What makes Haar et al.’s essentially negative claims so powerful is that their study had a huge sample size: they included structural MRI scans from 539 people diagnosed with high-functioning autism spectrum disorder (ASD) and 573 controls. This makes the paper an order of magnitude bigger than a typical structural MRI anatomy study in this field. The age range was 6 to 35. The scans came from the public Autism Brain Imaging Data Exchange (ABIDE) database, a data sharing initiative which pools scans from 18 different neuroimaging centers. Haar et al. examined the neuroanatomy of the cases and controls using the popular FreeSurfer software package. What did they find? Well… not much. First off, the ASD group had no differences in overall brain size (intracranial volume). Nor were there any group differences in the volumes of most brain areas; the only significant finding here was an increased ventricle volume in the ASD group, but even this had a small effect size (d = 0.34). Enlarged ventricles is not specific to ASD by any means – the same thing has been reported in schizophrenia, dementia, and many other brain disorders.
by Clare Wilson Call them the neuron whisperers. Researchers are eavesdropping on conversations going on between brain cells in a dish. Rather than hearing the chatter, they watch neurons that have been genetically modified so that the electrical impulses moving along their branched tendrils cause sparkles of red light (see video). Filming these cells at up to 100,000 frames a second is allowing researchers to analyse their firing in unprecedented detail. Until recently, a neuron's electrical activity could only be measured with tiny electrodes. As well as being technically difficult, such "patch clamping" only reveals the voltage at those specific points. The new approach makes the neuron's entire surface fluoresce as the impulse passes by. "Now we see the whole thing sweep through," says Adam Cohen of Harvard University. "We get much more information - like how fast and where does it start and what happens at a branch." The idea is a reverse form of optogenetics – where neurons are given a gene from bacteria that make a light-sensitive protein, so the cells fire when illuminated. The new approach uses genes that make the neurons do the opposite - glow when they fire. "It's pretty cool," says Dimitri Kullmann of University College London. "It's amazing that you can dispense with electrodes." Cohen's team is using the technique to compare cells from typical brains with those from people with disorders such as motor neuron disease or amyotrophic lateral sclerosis. Rather than taking a brain sample, they remove some of the person's skin cells and grow them alongside chemicals that rewind the cells into an embryonic-like state. Another set of chemicals is used to turn these stem cells into neurons. "You can recreate something reminiscent of the person's brain in the dish," says Cohen. © Copyright Reed Business Information Ltd.
Keyword: Brain imaging
Link ID: 20241 - Posted: 10.25.2014
by Helen Thomson For the first time, doctors have opened and closed the brain's protector – the blood-brain barrier – on demand. The breakthrough will allow drugs to reach diseased areas of the brain that are otherwise out of bounds. Ultimately, it could make it easier to treat conditions such as Alzheimer's and brain cancer. The blood-brain barrier (BBB) is a sheath of cells that wraps around blood vessels (in black) throughout the brain. It protects precious brain tissue from toxins in the bloodstream, but it is a major obstacle for treating brain disorders because it also blocks the passage of drugs. Several teams have opened the barrier in animals to sneak drugs through. Now Michael Canney at Paris-based medical start-up CarThera, and his colleagues have managed it in people using an ultrasound brain implant and an injection of microbubbles. When ultrasound waves meet microbubbles in the blood, they make the bubbles vibrate. This pushes apart the cells of the BBB. With surgeon Alexandre Carpentier at Pitié-Salpêtrière Hospital in Paris, Canney tested the approach in people with a recurrence of glioblastoma, the most aggressive type of brain tumour. People with this cancer have surgery to remove the tumours and then chemotherapy drugs, such as Carboplatin, are used to try to kill any remaining tumour cells. Tumours make the BBB leaky, allowing in a tiny amount of chemo drugs: if more could get through, their impact would be greater, says Canney. © Copyright Reed Business Information Ltd.
Keyword: Brain imaging
Link ID: 20235 - Posted: 10.23.2014
By Erin Allday When the United States’ top public health and political leaders declared the 1990s the “decade of the brain,” Dr. Pratik Mukherjee couldn’t help but feel a little dubious. “I was kind of laughing, because I didn’t think we’d make much progress in just a decade,” said Mukherjee, a neuro-radiologist at UCSF. Twenty-four years later, Mukherjee said he and his peers around the country are primed to plunge into what he’d like to call the century of the brain — a deep dive into the basic biology and mechanics of the impossibly complex organ that controls our every thought, action, behavior and mood. The National Institutes of Health last week announced $47 million in grants as part of President Obama’s Brain Initiative, a project announced 18 months ago to, in the simplest language, reverse-engineer the human brain. The grants were among the first in a roughly 11-year plan that could cost more than $3 billion. Most of the projects are in developing new technologies to help map the brain and study its mechanics — how cells communicate, what makes them turn on and off, and how large regions of the brain interact, for example. Ultimately, scientists hope these tools will help the next generation of neuroscientists solve the brain-centric disorders — from autism and Alzheimer’s to depression and schizophrenia — that have confounded doctors for centuries.
Keyword: Brain imaging
Link ID: 20183 - Posted: 10.09.2014
David Cyranoski Unlike its Western counterparts, Japan’s effort will be based on a rare resource — a large population of marmosets that its scientists have developed over the past decade — and on new genetic techniques that might be used to modify these highly social animals. The goal of the ten-year Brain/MINDS (Brain Mapping by Integrated Neurotechnologies for Disease Studies) project is to map the primate brain to accelerate understanding of human disorders such as Alzheimer’s disease and schizophrenia. On 11 September, the Japanese science ministry announced the names of the group leaders — and how the project would be organized. Funded at ¥3 billion (US$27 million) for the first year, probably rising to about ¥4 billion for the second, Brain/MINDS is a fraction of the size of the European Union’s Human Brain Project and the United States’ BRAIN (Brain Research through Advancing Innovative Neurotechnologies) Initiative, both of which are projected to receive at least US$1 billion over the next decade. But researchers involved in those efforts say that Brain/MINDS fills a crucial gap between disease models in smaller animals that too often fail to mimic human brain disorders, and models of the human brain that need validating data. “It is essential that we have a genetic primate model to study cognition and cognitive brain disorders such as schizophrenia and depression, for which we do not have good mouse models,” says neuroscientist Terry Sejnowski at the Salk Institute in La Jolla, California, who is a member of the National Institutes of Health BRAIN Initiative Working Group. “Other groups in the United States and China have started transgenic-primate projects, but none is as large or as well organized as the Japanese effort.” © 2014 Nature Publishing Group,
|By Nathan Collins Step aside, huge magnets and radioactive tracers—soon some brain activity will be revealed by simply training dozens of red lights on the scalp. A new study in Nature Photonics finds this optical technique can replicate functional MRI experiments, and it is more comfortable, more portable and less expensive. The method is an enhancement of diffuse optical tomography (DOT), in which a device shines tiny points of red light at a subject's scalp and analyzes the light that bounces back. The red light reflects off red hemoglobin in the blood but does not interact as much with tissues of other colors, which allows researchers to recover an fMRI-like image of changing blood flow in the brain at work. For years researchers attempting to use DOT have been limited by the difficulty of packing many heavy light sources and detectors into the small area around the head. They also needed better techniques for analyzing the flood of data that the detectors collected. Now researchers at Washington University in St. Louis and the University of Birmingham in England report they have solved those problems and made the first high-density DOT (HD-DOT) brain scans. The team first engineered a “double halo” structure to support the weight of 96 lights and 92 detectors, more than double the number in earlier arrays. The investigators also dealt with the computing challenges associated with that many lights—for example, they figured out how to filter out interference from blood flow in the scalp and other tissues. The team then used HD-DOT to successfully replicate fMRI studies of vision and language processing—a task impossible for other fMRI alternatives, such as functional near-infrared spectroscopy or electroencephalography, which do not cover a large enough swath of the brain or have sufficient resolution to pinpoint active brain areas. Finally, the team scanned the brains of people who have implanted electrodes for Parkinson's disease—something fMRI can never do because the machine generates electromagnetic waves that can destroy electronic devices such as pacemakers. © 2014 Scientific American
Keyword: Brain imaging
Link ID: 20151 - Posted: 10.02.2014
Michael Häusser Use light to read out and control neural activity! This idea, so easily expressed and understood, has fired the imagination of neuroscientists for decades. The advantages of using light as an effector are obvious1: it is noninvasive, can be precisely targeted with exquisite spatial and temporal precision, can be used simultaneously at multiple wavelengths and locations, and can report the presence or activity of specific molecules. However, despite early progress2 and encouragement3, it is only recently that widely usable approaches for optical readout and manipulation of specific neurons have become available. These new approaches rely on genetically encoded proteins that can be targeted to specific neuronal subtypes, giving birth to the term 'optogenetics' to signal the combination of genetic targeting and optical interrogation4. On the readout side, highly sensitive probes have been developed for imaging synaptic release, intracellular calcium (a proxy for neural activity) and membrane voltage. On the manipulation side, a palette of proteins for both activation and inactivation of neurons with millisecond precision using different wavelengths of light have been identified and optimized. The extraordinary versatility and power of these new optogenetic tools are spurring a revolution in neuroscience research, and they have rapidly become part of the standard toolkit of thousands of research labs around the world. Although optogenetics may not yet be a household word (though try it on your mother; she may surprise you), there can be no better proof that optogenetics has become part of the scientific mainstream than the 2013 Brain Prize being awarded to the sextet that pioneered optogenetic manipulation (http://www.thebrainprize.org/flx/prize_winners/prize_winners_2013/) and the incorporation of optogenetics as a central plank in the US National Institutes of Health BRAIN Initiative5. Moreover, there is growing optimism about the prospect of using optogenetic probes not only to understand mechanisms of disease in animal models but also to treat disease in humans, particularly in more accessible parts of the brain such as the retina6. © 2014 Macmillan Publishers Limited
Keyword: Brain imaging
Link ID: 20142 - Posted: 10.01.2014
By Larry Greenemeier Former Grateful Dead percussionist Mickey Hart takes pride in his brain. Large, anatomically realistic 3-D animations representing the inner workings of his gray and white matter have graced video screens at several science and technology conferences. These “Glass Brain” visualizations use imaging and advanced computing systems to depict in colorful detail the fiber pathways that make Hart’s brain tick. The researchers behind the project hope it will also form the basis of a new type of tool for the diagnosis and treatment of neurological disorders. Each Glass Brain animation overlays electroencephalography (EEG) data collected in real time atop a magnetic resonance imaging (MRI) scan—in this case Hart’s—to illustrate how different brain areas communicate with each other. Special algorithms coded into software digitally reconstruct this activity within the brain. The result is a tour of the brain that captures both the timing and location of brain signals. Hart demonstrated the Glass Brain at a computer conference in San Jose, Calif., this past March by playing a video game called NeuroDrummer on stage. The drummer is working with the Studio Bee digital animation house in San Francisco as well as the Glass Brain’s creators to develop NeuroDrummer into a tool that can determine whether teaching someone to keep a drumbeat might help improve the neural signals responsible for cognition, memory and other functions. The Glass Brain’s brain trust includes the University of California, San Francisco’s Neuroscape Lab as well as the University of California, San Diego’s Swartz Center for Computational Neuroscience, EEG maker Cognionics, Inc. and NVIDIA, a maker of extremely fast graphics processing unit (GPU) computer chips and host of the conference where Hart performed. © 2014 Scientific American,
Keyword: Brain imaging
Link ID: 20137 - Posted: 09.30.2014
by Elijah Wolfson @elijahwolfson The class was the most difficult of the fall 2013 semester, and J.D. Leadam had missed all but one lecture. His grandfather’s health had worsened, and he left San Jose State, where he was studying for a degree in business, to return home to Los Angeles to help out. Before he knew it, midterm exams had almost arrived. At this point, Leadam had, for a while, been playing around with transcranial direct-current stimulation, or tDCS, an experimental treatment for all sorts of health issues that, at its most basic, involves running a very weak electric current through the brain. When he first came across tDCS, Leadam was immediately intrigued but thought, “There’s no way I’m gonna put electrodes on my head. It’s just not going to happen.” After extensive research, though, he changed his mind. He looked into buying a device online, but there wasn’t much available — just one extremely expensive machine and then a bare-bones $40 device that didn’t even have a switch. So he dug around online and figured he could build one himself. He bought all the pieces he needed and put it together. He tried it a few times, but didn’t notice much, so he put it aside. But now, with the test looming, he picked it back up. The professor had written a book, and Leadam knew all the information he’d be tested on was written in its pages. “But I’m an auditory learner,” he said, “so I knew it wouldn’t work to just read it.” He strapped on the device, turned it on and read the chapters. “Nothing,” he thought. But when he got to the classroom and put pen to paper, he had a revelation. “I could remember concepts down to the exact paragraphs in the textbook,” Leadam said. “I actually ended up getting an A on the test. I couldn’t believe it.”
Keyword: Learning & Memory
Link ID: 20130 - Posted: 09.29.2014
By Melissa Dahl If you are the sort of person who has a hard time just watching TV — if you’ve got to be simultaneously using your iPad or laptop or smartphone — here’s some bad news. New research shows a link between juggling multiple digital devices and a lower-than-usual amount of gray matter, the stuff that’s made up of brain cells, in the region of the brain associated with cognitive and emotional control. More details, via the press release: The researchers at the University of Sussex's Sackler Centre for Consciousness used functional magnetic resonance imaging (fMRI) to look at the brain structures of 75 adults, who had all answered a questionnaire regarding their use and consumption of media devices, including mobile phones and computers, as well as television and print media. They found that, independent of individual personality traits, people who used a higher number of media devices concurrently also had smaller grey matter density in the part of the brain known as the anterior cingulate cortex (ACC), the region notably responsible for cognitive and emotional control functions. But a predilection for using several devices at once isn’t necessarily causing a decrease in gray matter, the authors note — this is a purely correlational finding. As Earl Miller, a neuroscientist at MIT who was not involved in this research, wrote in an email, “It could be (in fact, is possibly more likely) that the relationship is the other way around.” In other words, the people who are least content using just one device at a time may have less gray matter in the first place.
By Alyssa Abkowitz If you’re wary of investing in a certain stock or exchange-traded fund, it could be because of the your brain’s physical composition. In a recent study, 61 participants from the Northeastern U.S. were asked to choose between monetary options that differed in the level of risk. Questions included: “Would you prefer a 50 percent chance of receiving $5 or would you rather take a 13 percent chance of winning $50?” and “Would you prefer $10 for sure or a 50 percent chance of receiving $50?” Researchers found that individuals with more gray matter in a specific part of their brains tend to tolerate more financial risks, says Agnieszka Tymula, an economist at the University of Sydney and co-author of the findings. Most of the participants answered questions while their brains were being scanned, while others received MRIs afterward (the timing doesn’t make a difference because the researchers were looking at brain structure, not brain function). The study involved measuring the volume of gray matter, or the outer layer of the brain, in the right posterior parietal region of the cortex. Thicker gray matter corresponded to riskier responses. Tymula worked with researchers from Yale University, University College London, New York University, and the University of Pennsylvania. Their findings, published in the Journal of Neuroscience this month, dovetail with previous work in which Tymula found that adults become more risk-averse as they age. Other neuroscience research shows that people’s cortexes become thinner as they get older, meaning there could be a link between a thinning cortex and risk aversion. ©2014 Bloomberg L.P
By Neuroskeptic Today, we are thinking – and talking – about the brain more than ever before. It is widely said that neuroscience has much to teach psychiatry, cognitive science, economics, and others. Practical applications of brain science are proposed in the fields of politics, law enforcement and education. The brain is everywhere. This “Neuro Turn” has, however, not always been accompanied by a critical attitude. We ought to be skeptical of any claims regarding the brain because it remains a mystery – we fundamentally do not understand how it works. Yet much neuro-discourse seems to make the assumption that the brain is almost a solved problem already. For example, media stories about neuroscience commonly contain simplistic misunderstandings – such as the tendency to over-interpret neural activation patterns as practical guides to human behavior. For instance, recently we have heard claims that because fMRI finds differences in the brain activity of some violent offenders, this means that their criminal tendencies are innate and unchangeable – with clear implications for rehabilitation. Neuroscientists are well aware of the faults in lay discourse about the brain – and are increasingly challenging them e.g. on social media. Unfortunately, the same misunderstandings also exist within neuroscience itself. For example, I argue, much of cognitive neuroscience is actually based on (or, only makes sense given the assumption that) the popular misunderstanding that brain activity has a psychological ‘meaning’. In fact, we just do not know what a given difference in brain activity means, in the vast majority of cases. Thus, many research studies based on finding differences in fMRI activity maps across groups or across conditions, are not really helping us to understand the brain at all – but only providing us with a canvas to project our misunderstandings onto it.
Keyword: Brain imaging
Link ID: 20082 - Posted: 09.17.2014
by Helen Thomson DON'T mind the gap. A woman has reached the age of 24 without anyone realising she was missing a large part of her brain. The case highlights just how adaptable the organ is. The discovery was made when the woman was admitted to the Chinese PLA General Hospital of Jinan Military Area Command in Shandong Province complaining of dizziness and nausea. She told doctors she'd had problems walking steadily for most of her life, and her mother reported that she hadn't walked until she was 7 and that her speech only became intelligible at the age of 6. Doctors did a CAT scan and immediately identified the source of the problem – her entire cerebellum was missing (see scan, below left). The space where it should be was empty of tissue. Instead it was filled with cerebrospinal fluid, which cushions the brain and provides defence against disease. The cerebellum – sometimes known as the "little brain" – is located underneath the two hemispheres. It looks different from the rest of the brain because it consists of much smaller and more compact folds of tissue. It represents about 10 per cent of the brain's total volume but contains 50 per cent of its neurons. Although it is not unheard of to have part of your brain missing, either congenitally or from surgery, the woman joins an elite club of just nine people who are known to have lived without their entire cerebellum. A detailed description of how the disorder affects a living adult is almost non-existent, say doctors from the Chinese hospital, because most people with the condition die at a young age and the problem is only discovered on autopsy (Brain, doi.org/vh7). © Copyright Reed Business Information Ltd.
By Glendon Mellow University and scientific research center programs are increasingly finding it useful to employ artists and illustrators to help them see things in a new way. Few works of art from the Renaissance have been studied and pored over as meticulously as Michelangelo’s frescoes in the Sistine Chapel. Yet, the Master may still have some surprises hidden for an illustrator-scientist. Biomedical Illustrator Ian Suk (BSc, BMC) and Neurological Surgeon Rafael Tamargo (MD, FACS), both of Johns Hopkins proposed in a 2010 article in the journal Neurosurgery, that the panel above, Dividing Light from the Darkness by Michelangelo actually depicts the brain stem of God. Using a series of comparisons of the unusual shadows and contours on God’s neck to photos of actual brain stems, the evidence seems completely overwhelming that Michelangelo used his own limited anatomical studies to depict the brain stem. It’s unlikely even the educated members of Michelangelo’s audience would recognize it. I encourage you to look over the paper here, and enlarge the images in the slideshow: Suk and Tamargo are utterly convincing. Unlike R. Douglas Fields in this previous blog post from 2010 on Scientific American, I don’t think there’s room to believe this is a case of pareidolia. I imagine the thrill of feeling Michelangelo communicating directly with the authors across the centuries was immense. © 2014 Scientific American,
Keyword: Brain imaging
Link ID: 20067 - Posted: 09.12.2014
People who are obese may be more susceptible to environmental food cues than their lean counterparts due to differences in brain chemistry that make eating more habitual and less rewarding, according to a National Institutes of Health study published in Molecular Psychiatry External Web Site Policy. Researchers at the NIH Clinical Center found that, when examining 43 men and women with varying amounts of body fat, obese participants tended to have greater dopamine activity in the habit-forming region of the brain than lean counterparts, and less activity in the region controlling reward. Those differences could potentially make the obese people more drawn to overeat in response to food triggers and simultaneously making food less rewarding to them. A chemical messenger in the brain, dopamine influences reward, motivation and habit formation. “While we cannot say whether obesity is a cause or an effect of these patterns of dopamine activity, eating based on unconscious habits rather than conscious choices could make it harder to achieve and maintain a healthy weight, especially when appetizing food cues are practically everywhere,” said Kevin D. Hall, Ph.D., lead author and a senior investigator at National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of NIH. “This means that triggers such as the smell of popcorn at a movie theater or a commercial for a favorite food may have a stronger pull for an obese person — and a stronger reaction from their brain chemistry — than for a lean person exposed to the same trigger.” Study participants followed the same eating, sleeping and activity schedule. Tendency to overeat in response to triggers in the environment was determined from a detailed questionnaire. Positron emission tomography (PET) scans evaluated the sites in the brain where dopamine was able to act.