Posts tagged psychology
Articles and news from the latest research reports.
Battling back from a brain injury
Much of the recent attention on traumatic brain injury has focused on the increased risk of neurodegenerative diseases doctors think recurrent injuries may lead to. But transportation accidents and falls, particularly among the elderly, are leading causes of TBI, and one serious head injury can be devastating. Karl Weisgraber is a retired biochemist who worked on cardiovascular and Alzheimer’s research at the Gladstone Institutes in San Francisco. In October of last year, he was on a ladder doing work on the side of his house when he fell and smacked his head on a rock, suffering a severe traumatic brain injury. The 71-year-old Walnut Creek man spent three weeks in a coma and, through therapy, had to relearn how to walk, read and write. He is greatly appreciative of the staffs at San Francisco General and California Pacific Medical Center who worked with him, and of his wife, Judi.
The Connectome Debate: Is Mapping the Mind of a Worm Worth It?
In the 1970s biologist Sydney Brenner and his colleagues began preserving tiny hermaphroditic roundworms known as Caenorhabditis elegans in agar and osmium fixative, slicing up their bodies like pepperoni and photographing their cells through a powerful electron microscope. The goal was to create a wiring diagram—a map of all 302 neurons in the C. elegans nervous system as well as all the 7,000 connections, or synapses, between those neurons. In 1986 the scientists published a near complete draft of the diagram. More than 20 years later, Dmitri Chklovskii of Janelia Farm Research Campus and his collaborators published an even more comprehensive version. Today, scientists call such diagrams “connectomes.”
So far, C. elegans is the only organism that boasts a complete connectome. Researchers are also working on connectomes for the fruit fly nervous system and the mouse brain. In recent years some neuroscientists have proposed creating a connectome for the entire human brain—or at least big chunks of it. Perhaps the most famous proponent of connectomics is Sebastian Seung of the Massachusetts Institute of Technology, whose impressive credentials, TED talk, popular book, charisma and distinctive fashion sense (he is known to wear gold sneakers) have made him a veritable neuroscience rock star.
New research model to aid search for degenerative disease cures
Efforts to treat disorders like Lou Gehrig’s disease, Paget’s disease, inclusion body myopathy and dementiawill receive a considerable boost from a new research model created by UC Irvine scientists.
The team, led by pediatrician Dr. Virginia Kimonis, has developed a genetically modified mouse that exhibits many of the clinical features of human diseases largely triggered by mutations in the valosin-containing protein.
The mouse model will let researchers study how these now-incurable, degenerative disorders progress in vivo and will provide a platform for translational studies that could lead to lifesaving treatments.
“Currently, there are no effective therapies for VCP-associated diseases and related neurodegenerative disorders,” said Kimonis, a professor of pediatrics who specializes in genetics and metabolism. “This model will significantly spark new approaches to research directed toward the creation of novel treatment strategies.”
She and her team reported their discovery Sept. 28 online in PLOS ONE, a peer-reviewed, open-access journal.
The UCI researchers – from pediatrics, neurology, pathology and radiological sciences – specifically bred the first-ever “knock-in” mouse in which the normal VCP gene was substituted with one containing the common R155H mutation seen in humans with VCP-linked diseases. Subsequently, these mice exhibited the same muscle, brain and spinal cord pathology and bone abnormalities as these patients.
VCP is part of a system that maintains cell health by breaking down and clearing away old and damaged proteins that are no longer necessary. Mutations in the VCP gene disrupt the demolition process, and, as a result, excess and abnormal proteins may build up in muscle, bone and brain cells. These proteins form clumps that interfere with the cells’ normal functions and can lead to a range of disorders.
Another study carried out by members of this group – and published in August in the journal Cell Death & Disease – made use of these genetically altered mice to examine the development of Lou Gehrig’s disease, or ALS. The researchers, led by Dr. Hong Yin and Dr. John Weiss in UCI’s Department of Neurology, documented slow, extensive pathological changes in the spinal cord remarkably similar to changes observed in other animal models of ALS as well as in human patients. ALS research is currently limited by a paucity of animal models in which disease processes can be studied.
Genetically modified mice have become important research models in the effort to cure human ailments. Mice bred to exhibit the brain pathology of Alzheimer’s disease, for example, have dramatically sped up the race to advance new treatments – one such model was developed at UCI. And many cancer therapies were created and tested using genetically altered mice.
(Source: today.uci.edu)
Using a high-tech imaging process to measure the thickness of the eye’s retina may one day predict the progression of multiple sclerosis, a new study suggests.
The finding might lead to better ways to judge the effectiveness of treatments because different parts of the retina seem to indicate different aspects of the disease and the toll it takes on different parts of the brain, the researchers said.
The report was published online Oct. 1 in the Archives of Neurology.
Intelligence Is in the Genes, but Where?
You can thank your parents for your smarts—or at least some of them. Psychologists have long known that intelligence, like most other traits, is partly genetic. But a new study led by psychological scientist Christopher Chabris of Union College reveals the surprising fact that most of the specific genes long thought to be linked to intelligence probably have no bearing on one’s IQ. And it may be some time before researchers can identify intelligence’s specific genetic roots.
Chabris and David Laibson, a Harvard economist, led an international team of researchers that analyzed a dozen genes using large data sets that included both intelligence testing and genetic data.
In nearly every case, the researchers found that intelligence could not be linked to the specific genes that were tested. The results are published online in Psychological Science, a journal of the Association for Psychological Science.
“In all of our tests we only found one gene that appeared to be associated with intelligence, and it was a very small effect. This does not mean intelligence does not have a genetic component. It means it’s a lot harder to find the particular genes, or the particular genetic variants, that influence the differences in intelligence,” said Chabris.
New Definition of Autism in Updated Psychiatric Clinical Manual Will Not Exclude Most Children with Autism
Parents should not worry that proposed changes to the medical criteria redefining a diagnosis of autism will leave their children excluded and deemed ineligible for psychiatric and medical care, says a team of researchers led by psychologists at Weill Cornell Medical College.
Their new study, published in the October 1 issue of the American Journal of Psychiatry, is the largest to date that has tried to unpack the differences between the diagnostic criteria for autism spectrum disorders in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) and the proposed revision in the fifth edition (DSM-5), which is expected to be published in May 2013. These manuals provide diagnostic criteria for people seeking mental-health-related medical services.
"I know that parents worry, but I don’t believe there is any substantial reason to fear that children who need to be diagnosed with autism spectrum disorders, and provided with vital services, will not be included in the new criteria in this updated manual," says the study’s senior investigator, Dr. Catherine Lord, director of the Center for Autism and the Developing Brain at NewYork-Presbyterian Hospital’s Westchester campus, along with its affiliated medical schools Weill Cornell Medical College and Columbia University College of Physicians and Surgeons.
At issue is whether DSM-5 will “capture” the same individuals diagnosed with different forms of autism by the DSM-IV. The DSM-5 proposal redefines autism as a single category — autism spectrum disorder (ASD) — whereas DSM-IV had multiple categories and included Autistic Disorder, Asperger’s Disorder, and Pervasive Developmental Disorder, Not Otherwise Specified (PDD-NOS).
Critics have particularly worried that among the excluded will be children now diagnosed with PPD-NOS and Asperger’s disorder. That isn’t the case, says Dr. Lord, who is also a DeWitt Wallace Senior Scholar at Weill Cornell and an attending psychologist at NewYork-Presbyterian Hospital. The study, the largest to date and arguably, the most rigorous, finds that when relying on parent report, 91 percent of the 4,453 children in the sample currently diagnosed with a DSM-IV autism spectrum disorder would be diagnosed with ASD using DSM-V.
Many of the remaining nine percent would likely be reincluded once a clinician can offer input, says Dr. Lord, who is also a member of the American Psychiatric Association’s DSM-5 Neurodevelopmental Disorders Work Group.
The study researchers also concluded that DSM-5 has higher specificity than DSM-IV—in their study, DSM-5 criteria resulted in fewer misclassifications.
(Source: weill.cornell.edu)
University of Miami researchers find that babies’ non-verbal communication skills can help predict outcomes in children at high risk of developing Autism
Approximately 19 percent of children with a sibling diagnosed with Autism Spectrum Disorder (ASD) will develop Autism due to shared genetic and environmental vulnerabilities, according to previous studies. For that reason, University of Miami (UM) psychologists are developing ways to predict the occurrence of ASD in high-risk children, early in life, in hopes that early intervention will lead to better outcomes in the future. Their findings are published in the journal Infancy.
The study is one of the first to show that measures of non-verbal communication in children, as young as eight months of age, predict autism symptoms that become evident by the third year of life. The results suggest that identifying children, who are having difficulties early enough, can enhance the effects of interventions.
The Obese Brain May Thwart Weight Loss
New research by Terry Davidson, director of American University’s Center for Behavioral Neuroscience, indicates that diets that lead to obesity—diets high in saturated fat and refined sugar—may cause changes to the brains of obese people that in turn may fuel overconsumption of those same foods and make weight loss more challenging.
“It is a vicious cycle that may explain why obesity is so difficult to overcome,” said Davidson, also a professor of psychology at AU.
Davidson recently published his research, “The Effects of a High-Energy Diet on Hippocampal-Dependent Discrimination Performance and Blood-Brain Barrier Integrity Differ for Diet-Induced Obese and Diet-Resistant Rats,” in the journal Physiology & Behavior.
Omega-3 Supplements May Slow A Biological Effect of Aging
Taking enough omega-3 fatty acid supplements to change the balance of oils in the diet could slow a key biological process linked to aging, new research suggests.
The study showed that most overweight but healthy middle-aged and older adults who took omega-3 supplements for four months altered a ratio of their fatty acid consumption in a way that helped preserve tiny segments of DNA in their white blood cells.
These segments, called telomeres, are known to shorten over time in many types of cells as a consequence of aging. In the study, lengthening of telomeres in immune system cells was more prevalent in people who substantially improved the ratio of omega-3s to other fatty acids in their diet.
Omega-3 supplementation also reduced oxidative stress, caused by excessive free radicals in the blood, by about 15 percent compared to effects seen in the placebo group.
“The telomere finding is provocative in that it suggests the possibility that a nutritional supplement might actually make a difference in aging,” said Jan Kiecolt-Glaser, professor of psychiatry and psychology at Ohio State and lead author of the study.
Homolog of mammalian neocortex found in bird brain
A seemingly unique part of the human and mammalian brain is the neocortex, a layered structure on the outer surface of the organ where most higher-order processing is thought to occur. But new research at the University of Chicago has found the cells similar to those of the mammalian neocortex in the brains of birds, sitting in a vastly different anatomical structure.
The work, published in Proceedings of the National Academy of Sciences, confirms a 50-year-old hypothesis about the identity of a mysterious structure in the bird brain that has provoked decades of scientific debate. The research also sheds new light on the evolution of the brain and opens up new animal models for studying the neocortex.
"If you want to study motor neurons or dopamine cells, which are biomedically important, you can study them in mammals, in chick embryos, in zebrafish. But for these neurons of the cerebral cortex, we could only do that in mammals before," said Clifton Ragsdale, PhD, associate professor of neurobiology at University of Chicago Biological Sciences and senior author of the study. "Now, we can take advantage of these other experimental systems to ask how they are specified, can they regenerate, and other questions."
Both the mammalian neocortex and a structure in the bird brain called the dorsal ventricular ridge (DVR) originate from an embryonic region called the telencephalon. But the two regions mature into very different shapes, with the neocortex made up of six distinct cortical layers while the DVR contains large clusters of neurons called nuclei.