Posts tagged brain
Articles and news from the latest research reports.
Brain imaging alone cannot diagnose autism
In a column appearing in the current issue of the journal Nature, McLean Hospital biostatistician Nicholas Lange, ScD, cautions against heralding the use of brain imaging scans to diagnose autism and urges greater focus on conducting large, long-term multicenter studies to identify the biological basis of the disorder.
"Several studies in the past two years have claimed that brain scans can diagnose autism, but this assertion is deeply flawed," said Lange, an associate professor of Psychiatry and Biostatistics at Harvard Medical School. "To diagnose autism reliably, we need to better understand what goes awry in people with the disorder. Until its solid biological basis is found, any attempt to use brain imaging to diagnose autism will be futile."
While cautioning against current use of brain imaging as a diagnostic tool, he is a strong proponent of using this technology to help scientists better understand autism. Through the use of various brain imaging techniques, including functional magnetic resonance imaging (MRI), positron emission tomography (PET), and volumetric MRI, Lange points out that researchers have made important discoveries related to early brain enlargement in the disorder, how those with autism focus during social interaction and the role of serotonin in someone with autism.
"Brain scans have led to these extremely valuable advances, and, with each discovery, we are getting closer to solving the autism pathology puzzle," said Lange. "What individuals with autism and their parents urgently need is for us to carry out large-scale studies that lead us to find reliable, sensitive and specific biological markers of autism with high predictive value that allow clinicians to identify interventions that will improve the lives of people with the disorder."
Autism and autism spectrum disorder (ASD) are terms regularly used to describe a group of complex disorders of brain development. This spectrum characterized, in varying degrees, by difficulties in social interaction, verbal and nonverbal communication, and repetitive behaviors, whose criteria have been revised in the newly proposed Diagnostic and Statistical Manual of Mental Disorders (DSM-5). The prevalence of ASD in the United States has increased 78 percent in the last decade, with the Centers for Disease Control estimating that one in 88 children has ASD.
(Source: eurekalert.org)
Simulations improve predictability of aneurysm development
Using new computer models of blood flow in the vicinity of cerebral aneurysms (dilated sections of blood vessels in the brain), it is now possible to calculate every detail of the patient-specific situation. This has resulted in powerful new techniques for predicting a further weakening or even rupture of the blood vessel’s wall, and for effective intervention. Julia Mikhal was awarded a PhD on this topic by the University of Twente.
Bacteria yield clues about why proteins go bad in ALS and Alzheimer’s
Scientists are unsure why proteins form improperly and cluster together in bunches, a hallmark of neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), Alzheimer’s and Mad Cow Disease. In the Nov. 1 issue of the journal Molecular Cell, Yale scientists shed light on protein aggregate formation by studying the process in bacteria.
“The question we are all asking is what happens when protein synthesis goes wrong?” said Jesse Rinehart, assistant professor of cellular and molecular physiology at Yale’s West Campus and co-senior author of the paper.
Proteins are created from instructions encoded in DNA and assembled in ribosomes within the cells. However, sometimes they are not assembled correctly, and these misfolded proteins tend to aggregate, a process typified by the plaques that form in the brains of Alzheimer’s patients.
The Yale team — led by Rinehart and Dieter Söll, Sterling Professor of Molecular Biophysics and Biochemistry and professor of chemistry — showed that the antibiotic streptomycin can trigger protein aggregations in the bacterium E. coli. Using large-scale proteomics and genetic screens, they analyzed the aggregates and searched for bacterial proteins that make E. coli cells resistant to antibiotics and other threats. The researchers discovered how one of these proteins protecting the bacteria from hydrogen peroxide also suppressed the aggregation of proteins triggered by streptomycin.
Making a Game Out of Improving the ‘Sticky’ Brain
UCSF neuroscientists have found that by training on attention tests, people young and old can improve brain performance and multitasking skills.
Anyone who tries to perform two tasks at once is likely to do worse on both. Why that is so at the neurological level has largely been terra incognita. But research now is starting to reveal the impact of multitasking on short-term memory and attention.
Adam Gazzaley, MD, PhD, associate professor of neurology, physiology and psychiatry, and researchers at the UCSF Neuroscience Imaging Center use EEG, MRI and other non-invasive tools to study cognitive processes while people try their best on drills that test short-term memory.
UCSB Scientists Report ‘New Beginning’ in Split-Brain Research, Using New Analytical Tools
UC Santa Barbara has reported an important discovery in the interdisciplinary study of split-brain research. The findings uncover dynamic changes in brain coordination patterns between left and right hemispheres.
Split-brain research has been conducted for decades, and scientists have long ago shown that language processing is largely located in the left side of the brain. When words appear only in the left visual field –– an area processed by the right side of the brain –– the right brain must transfer that information to the left brain, in order to interpret it. The new study at UCSB shows that healthy test subjects respond less accurately when information is shown only to the right brain.
While hemispheric specialization is considered accurate, the new study sheds light on the highly complex interplay –– with neurons firing back and forth between distinct areas in each half of the brain. The findings rely on extremely sensitive neuroscience equipment and analysis techniques from network science, a fast-growing field that draws on insights from sociology, mathematics, and physics to understand complex systems composed of many interacting parts. These tools can be applied to systems as diverse as earthquakes and brains.
Fifty years ago, UC Santa Barbara neuroscientist Michael S. Gazzaniga moved the field forward when he was a graduate student at the California Institute of Technology and first author of a groundbreaking report on split-brain patients. The study, which became world-renowned, was published in the Proceedings of the National Academy of Sciences (PNAS) in August 1962. This week, in the very same journal, Gazzaniga and his team announced major new findings in split-brain research. The report is an example of the interdisciplinary science for which UCSB is well known.
"The occasion of this paper is on the 50th anniversary of the first report on human split-brain research reported in PNAS," said Gazzaniga. "That study showed how surgically dividing the two hemispheres of the human brain –– in an attempt to control epilepsy –– allowed for studying how each isolated half-brain was specialized for cognitive function.
"In the present study, new techniques –– not present 50 years ago –– begin to allow for an understanding of how the normal, undivided brain integrates the special functions of each half brain. It is a new beginning and very exciting," said Gazzaniga, professor of psychology in UCSB’s Department of Psychological and Brain Sciences, and director of UCSB’s SAGE Center for the Study of Mind.
(Source: ia.ucsb.edu)
Brain’s Code for Visual Working Memory Deciphered in Monkeys
The brain holds in mind what has just been seen by synchronizing brain waves in a working memory circuit, an animal study supported by the National Institutes of Health suggests. The more in-sync such electrical signals of neurons were in two key hubs of the circuit, the more those cells held the short-term memory of a just-seen object.
Charles Gray, Ph.D., of Montana State University, Bozeman, a grantee of NIH’s National Institute of Mental Health (NIMH), and colleagues, report their findings Nov. 1, 2012, online, in the journal Science Express.
“This work demonstrates, for the first time, that there is information about short term memories reflected in in-sync brainwaves,” explained Gray.
“The Holy Grail of neuroscience has been to understand how and where information is encoded in the brain. This study provides more evidence that large scale electrical oscillations across distant brain regions may carry information for visual memories,” said NIMH director Thomas R. Insel, M.D.
Prior to the study, scientists had observed synchronous patterns of electrical activity between the two circuit hubs after a monkey saw an object, but weren’t sure if the signals actually represent such short-term visual memories in the brain. Rather, it was thought that such neural oscillations might play the role of a traffic cop, directing information along brain highways.
LSUHSC research identifies new therapeutic target for Alzheimer’s disease
Research led by Chu Chen, PhD, Associate Professor of Neuroscience at LSU Health Sciences Center New Orleans, has identified an enzyme called Monoacylglycerol lipase (MAGL) as a new therapeutic target to treat or prevent Alzheimer’s disease. The study was published online November 1, 2012 in the Online Now section of the journal Cell Reports.
The research team found that inactivation of MAGL, best known for its role in degrading a cannabinoid produced in the brain, reduced the production and accumulation of beta amyloid plaques, a pathological hallmark of Alzheimer’s disease. Inhibition of this enzyme also decreased neuroinflammation and neurodegeneration, and improved plasticity of the brain, learning and memory.
"Our results suggest that MAGL contributes to the cause and development of Alzheimer’s disease and that blocking MAGL represents a promising therapeutic target," notes Dr. Chu Chen, who is also a member of the Department of Otolaryngology at LSU Health Sciences Center New Orleans.
The researchers blocked MAGL with a highly selective and potent inhibitor in mice using different dosing regimens and found that inactivation of MAGL for eight weeks was sufficient to decrease production and deposition of beta amyloid plaques and the function of a gene involved in making beta amyloid toxic to brain cells. They also measured indicators of neuroinflammation and neurodegeneration and found them suppressed when MAGL was inhibited. The team discovered that not only did the integrity of the structure and function of synapses associated with cognition remain intact in treated mice, but MAGL inactivation appeared to promote spatial learning and memory, measured with behavioral testing.
Alzheimer’s disease is a neurodegenerative disorder characterized by accumulation and deposition of amyloid plaques and neurofibrillary tangles, neuroinflammation, synaptic dysfunction, progressive deterioration of cognitive function and loss of memory in association with widespread nerve cell death. The most common cause of dementia among older people, more than 5.4 million people in the United States and 36 million people worldwide suffer with Alzheimer’s disease in its various stages. Unfortunately, the few drugs that are currently approved by the Food and Drug Administration have demonstrated only modest effects in modifying the clinical symptoms for relatively short periods, and none has shown a clear effect on disease progression or prevention.
"There is a great public health need to discover new therapies to prevent and treat this devastating disorder," Dr. Chen concludes. The research was supported by grants from the National Institutes of Health. In addition to scientists from LSU Health Sciences Center New Orleans, the research team also included investigators from the Massachusetts Institute of Technology.
(Source: eurekalert.org)
Rethinking reading: UI study breaks new ground in reading development research
Many educators have long believed that when words differ on only one sound, early readers can learn the rules of phonics by focusing on what is different between the words. This is thought to be a critical gateway to reading words and sentences.
But scientists at the University of Iowa are turning that thinking on its head. A recent study published in Developmental Psychology shows certain kinds of variation in words may help early readers learn better. When children see the same phonics regularities, embedded in words with more variation, they may learn these crucial early reading skills better. What might appear to make learning a more difficult task—learning about letter-sound relationships from words with more variation—actually leads to better learning.
Doctoral student Keith Apfelbaum and associate professors Bob McMurray and Eliot Hazeltine of the Department of Psychology in the UI College of Liberal Arts and Sciences (CLAS) studied 224 first-grade students in the West Des Moines, Iowa school system over a period of three months. The group used a version of an online supplementary curriculum called Access Code.
Access Code was developed by Foundations in Learning, a company founded by Carolyn Brown and Jerry Zimmermann. Brown and Zimmermann earned their doctorates from and are now adjunct faculty in the Department of Communication Sciences and Disorders, also in CLAS. Based on the Varied Practice Model, which helps children master early reading skills like phonics, the research team used Access Code to conduct the study directly in the classroom.
Scientists Create “Endless Supply” of Myelin-Forming Cells
In a new study appearing this month in the Journal of Neuroscience, researchers have unlocked the complex cellular mechanics that instruct specific brain cells to continue to divide. This discovery overcomes a significant technical hurdle to potential human stem cell therapies; ensuring that an abundant supply of cells is available to study and ultimately treat people with diseases.
“One of the major factors that will determine the viability of stem cell therapies is access to a safe and reliable supply of cells,” said University of Rochester Medical Center (URMC) neurologist Steve Goldman, M.D., Ph.D., lead author of the study. “This study demonstrates that – in the case of certain populations of brain cells – we now understand the cell biology and the mechanisms necessary to control cell division and generate an almost endless supply of cells.”
The study focuses on cells called glial progenitor cells (GPCs) that are found in the white matter of the human brain. These stem cells give rise to two cells found in the central nervous system: oligodendrocytes, which produce myelin, the fatty tissue that insulates the connections between cells; and astrocytes, cells that are critical to the health and signaling function of oligodendrocytes as well as neurons.
Caffeine’s effect on the brain’s adenosine receptors visualized for the first time
Scans allow researchers to study the link between caffeine and neurodegenerative disorders.
Molecular imaging with positron emission tomography (PET) has enabled scientists for the first time to visualize binding sites of caffeine in the living human brain to explore possible positive and negative effects of caffeine consumption. According to research published in the November issue of The Journal of Nuclear Medicine, PET imaging with F-18-8-cyclopentyl-3-(3-fluoropropyl)-1-propylxanthine (F-18-CPFPX) shows that repeated intake of caffeinated beverages throughout a day results in up to 50 percent occupancy of the brain’s A1 adenosine receptors.
"The effects of caffeine to the human body are generally attributed to the cerebral adenosine receptors. In the human brain the A1 adenosine receptor is the most abundant," said David Elmenhorst, MD, lead author of "Caffeine Occupancy of Human Cerebral A1 Adenosine Receptors: In Vivo Quantification with F-18-CPFPX and PET." "In vitro studies have shown that commonly consumed quantities of caffeine have led to a high A1 adenosine occupancy. Our study aimed to measure the A1 adenosine receptor occupancy with in vivo imaging."