 |
|
How the brain copes with shifty eyeballs
April 19, 2007Neurobiologists have pinpointed brain regions critical to one of the brain's more remarkable feats—piecing together a continuous view of the world by integrating snippets of visual input from constantly moving eyes. Since the eyeball has only a narrow field of clear view, it must continually make tiny shifts to sample the visual world. And during these shifts, which last thousandths of a second, people are essentially blind.
Marvin Chun of Yale University and colleagues published their studies in the April 19, 2007 issue of the journal Neuron, published by Cell Press.
The researchers' experiments with human volunteers used an illusion known as "boundary extension" to establish brain regions involved in piecing together scenes. In boundary extension, the brain tends to perceive more of a visual scene than is actually presented—a critical ability if the brain is to stitch together a continuous visual world from discontinuous snippets of a scene transmitted from the eyes.
The boundary extension illusion means that if people are presented with a close-up view of a scene followed by a wider view, they will not notice the difference. Their brains have already "assumed" the wider view, and they falsely remember it. On the other hand, people shown a wider view first will readily notice the appearance of the close-up view.
In their experiments, the researchers showed subjects paired scenes in which a close-up view was followed by a wider view, or in which a wider view was followed by a close-up view. They also showed the subjects paired scenes in which the same close and wider views were presented twice. The repeated pairs acted as controls to test whether only presentation of scenes would cause a response.
As the subjects were viewing the scenes, their brains were scanned using functional magnetic resonance imaging. In this technique, harmless radio waves and magnetic fields are used to image blood flow in brain regions, which reflects brain activity.
The researchers concentrated on two brain areas known to process visual information in scenes—the "parahippocampal place area" (PPA) in the medial temporal lobe and the "retrosplenial cortex" (RSC) in the cerebral cortex.
If these two areas are involved in extrapolating scenes, the researchers reasoned, they should see an attenuation of activity in these regions when subjects were presented with close-wide pairs, indicating that these brain areas were initially performing a boundary extension such that the close view was "remembered" as the wide view. In contrast, the PPA and RSC should show no attenuation of activity when presented with wide-close pairs. The researchers found that the two brain regions, indeed, showed activity patterns consistent with their involvement in the brain's process of "extending" the scenes.
In contrast, another area of the brain involved in processing images of objects showed attenuation of activity in response to all of the scene pairs. That finding, said the researchers, showed that the processing of scenes does not extend to other brain areas responsible for processing objects or surfaces.
Chun and colleagues concluded that their findings "provide novel evidence that high-level visual mechanisms extrapolate spatial layout beyond the confines of a given view." They wrote that "Extrapolation of layout may thus provide a means by which the visual system can integrate discrete samples of surrounding space that are drawn from successive movements of the eyes and head, enabling perception of a richly detailed and continuous world."
Cell Press
The boundary extension illusion means that if people are presented with a close-up view of a scene followed by a wider view, they will not notice the difference. Their brains have already "assumed" the wider view, and they falsely remember it. On the other hand, people shown a wider view first will readily notice the appearance of the close-up view.
In their experiments, the researchers showed subjects paired scenes in which a close-up view was followed by a wider view, or in which a wider view was followed by a close-up view. They also showed the subjects paired scenes in which the same close and wider views were presented twice. The repeated pairs acted as controls to test whether only presentation of scenes would cause a response.
As the subjects were viewing the scenes, their brains were scanned using functional magnetic resonance imaging. In this technique, harmless radio waves and magnetic fields are used to image blood flow in brain regions, which reflects brain activity.
The researchers concentrated on two brain areas known to process visual information in scenes—the "parahippocampal place area" (PPA) in the medial temporal lobe and the "retrosplenial cortex" (RSC) in the cerebral cortex.
If these two areas are involved in extrapolating scenes, the researchers reasoned, they should see an attenuation of activity in these regions when subjects were presented with close-wide pairs, indicating that these brain areas were initially performing a boundary extension such that the close view was "remembered" as the wide view. In contrast, the PPA and RSC should show no attenuation of activity when presented with wide-close pairs. The researchers found that the two brain regions, indeed, showed activity patterns consistent with their involvement in the brain's process of "extending" the scenes.
In contrast, another area of the brain involved in processing images of objects showed attenuation of activity in response to all of the scene pairs. That finding, said the researchers, showed that the processing of scenes does not extend to other brain areas responsible for processing objects or surfaces.
Chun and colleagues concluded that their findings "provide novel evidence that high-level visual mechanisms extrapolate spatial layout beyond the confines of a given view." They wrote that "Extrapolation of layout may thus provide a means by which the visual system can integrate discrete samples of surrounding space that are drawn from successive movements of the eyes and head, enabling perception of a richly detailed and continuous world."
Cell Press
Brain Current Events and Brain News RSSSmoking, but not past alcohol abuse, may impair mental function
Men and women with a history of alcohol abuse may not see long-term negative effects on their memory and thinking, but female smokers do, a new study suggests.
Brain plaques may explain higher risk of Alzheimer's based on mom's history
A family history of Alzheimer's is one of the biggest risk factors for developing the memory-robbing disease, which affects more than 5 million Americans and is the most common form of senile dementia.
Neuroimaging study describes Alzheimer's disease-like changes in elderly people without the disease
The emergence of multiple new brain imaging technologies and the combined application of these new approaches is helping to create new insights into aging and Alzheimer's disease.
Impulsive-Antisocial Personality Traits Linked to a Hypersensitive Brain Reward System
Normal individuals who scored high on a measure of impulsive/antisocial traits display a hypersensitive brain reward system, according to a brain imaging study by researchers at Vanderbilt University.
Exploring status quo bias in the human brain
The more difficult the decision we face, the more likely we are not to act, according to new research by UCL scientists that examines the neural pathways involved in 'status quo bias' in the human brain.
Using New Approach, Mayo Clinic Researchers Find Level of Gene Alters Risk of Alzheimer's Disease
Using sophisticated techniques that scan the genomes of patients, researchers at the Mayo Clinic campus in Florida have found that a gene appears to either help protect against development of Alzheimer's disease, or promote the disorder depending on the level of gene in the brain.
3-D cell culture: Making cells feel right at home
The film "Avatar" isn't the only 3-D blockbuster making a splash this winter. A team of scientists from Houston's Texas Medical Center this week unveiled a new technique for growing 3-D cell cultures, a technological leap from the flat petri dish that could save millions of dollars in drug-testing costs. The research is reported in Nature Nanotechnology.
New study identifies best treatment for childhood epilepsy
One of the oldest available anti-seizure medications, ethosuximide, is the most effective treatment for childhood absence epilepsy, according to initial outcomes published in this week's New England Journal of Medicine.
Psychopaths' brains wired to seek rewards, no matter the consequences
The brains of psychopaths appear to be wired to keep seeking a reward at any cost, new research from Vanderbilt University finds. The research uncovers the role of the brain's reward system in psychopathy and opens a new area of study for understanding what drives these individuals.
Device advances interventional radiology treatment to clear blocked carotid arteries, prevent stroke
An important interventional radiology advancement-the use of a new cerebral protection device in combination with FDA-approved carotid stents in high-surgical-risk patients-provides a minimally invasive, safe and effective way to prevent stroke from occurring during treatment to clear blocked carotid arteries.
More Brain Current Events and Brain News Articles
 |
The Brain That Changes Itself: Stories of Personal Triumph from the Frontiers of Brain Science (James H. Silberman Books) by Norman Doidge (Author) An astonishing new science called neuroplasticity is overthrowing the centuries-old notion that the human brain is immutable. In this revolutionary look at the brain, psychiatrist and psychoanalyst Norman Doidge, M.D., provides an introduction to both the brilliant scientists championing neuroplasticity and the people whose lives they’ve transformed. From stroke patients learning to speak again to the remarkable case of a woman born with half a brain that rewired itself to work as a whole, The Brain That Changes Itself will permanently alter the way we look at our brains, human nature, and human potential. |
 |
The Human Brain Book by Rita Carter (Author) The Human Brain Book is a complete guide to the one organ in the body that makes each of us what we are - unique individuals. It combines the latest findings from the field of neuroscience with expert text and state-of-the-art illustrations and imaging techniques to provide an incomparable insight into every facet of the brain. Layer by layer, it reveals the fascinating details of this remarkable structure, covering all the key anatomy and delving into the inner workings of the mind, unlocking its many mysteries, and helping you to understand what's going on in those millions of little gray and white cells. Tricky concepts are illustrated and explained with clarity and precision, as The Human Brain Book looks at how the brain sends messages to the rest of the body, how we think... |
 |
Learning Resources Brain Anatomy Model by Learning Resources Get a close-up view of the human brain with this detailed model. All of the brain components assemble easily and are displayed on a special stand. Includes facts and assembly instructions. Measures 3.75" tall. |
 |
Change Your Brain, Change Your Life: The Breakthrough Program for Conquering Anxiety, Depression, Obsessiveness, Anger, and Impulsiveness by Daniel G. Amen (Author) BRAIN PRESCRIPTIONS THAT REALLY WORK In this breakthrough bestseller, you'll see scientific evidence that your anxiety, depression, anger, obsessiveness, or impulsiveness could be related to how specific structures in your brain work. You're not stuck with the brain you're born with. Here are just a few of neuropsychiatrist Dr. Daniel Amen's surprising--and effective--"brain prescriptions" that can help heal your brain and change your life: To Quell Anxiety and Panic: ¸ Use simple breathing techniques to immediately calm inner turmoil To Fight Depression: ¸ Learn how to kill ANTs (automatic negative thoughts) To Curb Anger: ¸ Follow the Amen anti-anger diet and learn the nutrients that calm rage To Conquer Impulsiveness and Learn to Focus: ¸ ... |
 |
Brain Rules: 12 Principles for Surviving and Thriving at Work, Home, and School by John Medina (Author) See how the brain works while using it in the process of reading this book! Most of us have no idea what's really going on inside our heads. Yet brain scientists have uncovered details every business leader, parent, and teacher should know - like that physical activity boosts your brain power.How do we learn? What exactly do sleep and stress do to our brains? Why is multi-tasking a myth? Why is it so easy to forget - and so important to repeat new information? Is it true that men and women have different brains?In "Brain Rules", Dr. John Medina, a molecular biologist, shares his lifelong interest in how the brain sciences might influence the way we teach our children and the way we work. In each chapter, he describes a brain rule - what scientists know for sure about how our brains work -... |
 |
The Brain Starring: ~ Directed By: Richard Vagg THE BRAIN is an astonishing voyage of discovery into our last biological frontier. Although today s computers can make calculations in one-100th of a second and technology can transport us outside the bonds of Earth, only now are we beginning to understand the most complex machine in the universe. Using simple analogies, real-life case studies, and state-of-the-art CGI, this special shows how the brain works, explains the frequent battle between instinct and reason, and unravels the mysteries of memory and decision-making. It takes us inside the mind of a soldier under fire to see how decisions are made in extreme situations, examines how an autistic person like Rain Man develops remarkable skills, and takes on the age-old question of what makes one person good and another... |
 |
Change Your Brain, Change Your Body: Use Your Brain to Get and Keep the Body You Have Always Wanted by Daniel G. Amen M.D. (Author) THE KEY TO A BETTER BODY—in shape, energized, and youthful—is a healthy brain. Based on the latest medical research, as well as on Dr. Amen’s two decades of clinical practice at the renowned Amen Clinics, where Dr. Amen and his associates pioneered the use of the most advanced brain imaging technology, Change Your Brain, Change Your Body shows you how to take the very best care of your brain. With fifteen practical, easy-to-implement solutions involving nutritious foods, natural supplements and vitamins, positive-thinking habits, and, when necessary, highly targeted medications, Dr. Amen shows you how to: * Reach and maintain your ideal weight * Soothe and smooth your skin at any age * Reduce the stress that can impair your immune system * Sharpen your... |
 |
Learning Resources Cross Section Human Brain Model by Learning Resources Learning about the complexities of the human brain is easy with this labeled cross-section model. One half is labeled with the parts of the brain, and the other has letters only for testing purposes. An Activity Guide is included with detailed information about the human brain and how it functions. Model measures 5" in diameter. |
 |
Making a Good Brain Great: The Amen Clinic Program for Achieving and Sustaining Optimal Mental Performance by Daniel G. Amen (Author) Daniel Amen, M.D., one of the world’s foremost authorities on the brain, has news for you: your brain is involved in everything you do—learn to care for it properly, and you will be smarter, healthier, and happier in as little as 15 days! You probably run, lift weights, or do yoga to keep your body in great shape; you put on sunscreen and lotions to protect your skin; but chances are you simply ignore your brain and trust it to do its job. People unknowingly endanger or injure their brains, stress them by working at a frenzied pace and not getting enough sleep, pollute them with caffeine, alcohol, and drugs, and deprive them of proper nutrients. Brain dysfunction is the number one reason people fail at school, work, and relationships. The brain is the organ of learning,... |
 |
Brain: The Complete Mind by Michael S. Sweeney (Author), Richard Restak (Foreword) Did you know that listening to music tunes up your brain? Or that certain foods can help maintain mental fitness? Or that exercise can keep both body and mind in good shape? Delving into the science behind these strategies, Brain goes even deeper to reveal the brain’s inner workings. Overseen by distinguished neuropsychiatrist Dr. Richard Restak, Brainis both a practical owner’s manual and a complete guide to the brain’s development and function. Its pages explore not only the brain’s physical formits 100 billion nerve cells and near-infinite network of synapsesbut also its interactions that regulate every thought and action. Brainfeatures the latest discoveries about improving and optimizing mental acuity right alongside sidebars on breakthrough moments in... |
| © 2010 BrightSurf.com |