Posts tagged brain connections
Articles and news from the latest research reports.
Size, wiring of brain structures in kids predict benefit from math tutoring
Why do some children learn math more easily than others? Research from the Stanford University School of Medicine has yielded an unexpected new answer.
In a study of third-graders’ responses to math tutoring, Stanford scientists found that the size and wiring of specific brain structures predicted how much an individual child would benefit from math tutoring. However, traditional intelligence measures, such as children’s IQs and their scores on tests of mathematical ability, did not predict improvements from tutoring.
The research is the first to use brain scans to look for a link between math-learning abilities and brain structure or function, and also the first to compare neural and cognitive predictors of kids’ responses to tutoring. In addition, it provides information on the differences between how children and adults learn math, and could help researchers understand the origins of math-learning disabilities.
The study was published online April 29 in Proceedings of the National Academy of Sciences.
"What was really surprising was that intrinsic brain measures can predict change - we can actually predict how much a child is going to learn during eight weeks of math tutoring based on measures of brain structure and connectivity," said Vinod Menon, PhD, the study’s senior author and a professor of psychiatry and behavioral sciences. Menon is also a member of the Child Health Research Institute at Lucile Packard Children’s Hospital.
"The results are a significant step toward the development of targeted learning programs based on a child’s current as well as predicted learning trajectory," said the study’s lead author, Kaustubh Supekar, PhD, postdoctoral scholar in psychiatry and behavioral sciences.
Menon’s team focused on third-grade students ages 8 and 9 because these children are at a critical stage for acquiring basic arithmetic skills. The study included 24 third-graders who participated in a well-validated program of 15 to 20 hours of individualized math tutoring over eight weeks. The tutors explained new concepts to children and also got them to practice math skills with an emphasis on speed, and the sessions were tailored to each child’s level of understanding.
Before tutoring began, the children were given several standard neuropsychological assessments, including tests of IQ, working memory, reading and math-problem-solving abilities. Both before and after the eight-week tutoring period, children’s arithmetic performance was tested, and all children had structural and functional magnetic resonance imaging scans performed on their brains. To control for the effects of math instruction the children received at school (rather than during tutoring), a comparison group of 16 third-grade children who did not receive tutoring, but who had the same testing and brain scans before and after an eight-week interval, was also included in the study.
All 24 children receiving tutoring improved their arithmetic performance. Their performance efficiency, a composite measure of accuracy and speed of problem solving, improved an average of 67 percent after tutoring. But individual gains varied widely, ranging from 8 percent to 198 percent improvement. The children who did not receive tutoring did not show any change in arithmetic performance during the study.
When the researchers analyzed the children’s structural brain scans, they found that larger gray matter volume in three brain structures predicted greater ability to benefit from math tutoring. (The predictions were generated with a machine learning algorithm, the same type of data-analysis tool used to create movie recommendations for users of websites like Netflix, for example.) Of the three structures, the best predictor of improvement with tutoring was a larger hippocampus, a structure traditionally considered one of the brain’s most important memory centers. Functional connections between the hippocampus and several other brain regions, especially the prefrontal cortex and basal ganglia, also predicted ability to benefit from tutoring. These regions are important for forming long-term memories.
"The part of the brain that is recruited in memories for places and events also plays a pivotal role in determining how much and how well a child learns math," Supekar said.
None of the neuropsychological assessment scores, such as IQ or tests of working memory, could predict how much an individual child would benefit from tutoring.
The brain systems highlighted by this study - including the hippocampus, basal ganglia and prefrontal cortex - are different from those previously implicated for math learning in adults, the researchers noted. When solving math problems, adults rely on brain regions that are specialized for representing complex visual objects and processing spatial information.
And the findings suggest that the tutoring approach used, which was tailored to each child’s level of understanding and included lots of repetitive, high-speed arithmetic practice to help cement facts in children’s heads, works because it is compatible with the way their brains encode facts. “Memory resources provided by the hippocampal system create a scaffold for learning math in the developing brain,” Menon said. “Our findings suggest that, while conceptual knowledge about numbers is necessary for math learning, repeated, speeded practice and testing of simple number combinations is also needed to encode facts and encourage children’s reliance on retrieval - the most efficient strategy for answering simple arithmetic problems.” Once kids are able to pull up answers to basic arithmetic problems automatically from memory, their brains can tackle more complex problems.
The researchers’ next steps will include comparing brain structure and wiring in children with and without math learning disabilities, analyzing how the wiring of the brain changes in response to tutoring and examining whether lower-performing children’s brains can be exercised to help them learn math. “We’re pushing a very ecologically relevant model of learning,” Menon said. “Academic instruction should rely on validated instructional principles while incorporating individualized training to provide feedback on whether students are right or wrong, how they’re wrong and how they can improve their math skills.”
(Source: med.stanford.edu)
Do you obsess over your appearance? Your brain might be wired abnormally
Body dysmorphic disorder is a disabling but often misunderstood psychiatric condition in which people perceive themselves to be disfigured and ugly, even though they look normal to others. New research at UCLA shows that these individuals have abnormalities in the underlying connections in their brains.
Dr. Jamie Feusner, the study’s senior author and a UCLA associate professor of psychiatry, and his colleagues report that individuals with BDD have, in essence, global “bad wiring” in their brains — that is, there are abnormal network-wiring patterns across the brain as a whole.
And in line with earlier UCLA research showing that people with BDD process visual information abnormally, the study discovered abnormal connections between regions of the brain involved in visual and emotional processing.
The findings, published in the May edition of the journal Neuropsychopharmacology, suggest that these patterns in the brain may relate to impaired information processing.
"We found a strong correlation between low efficiency of connections across the whole brain and the severity of BDD," Feusner said. "The less efficient patients’ brain connections, the worse the symptoms, particularly for compulsive behaviors, such as checking mirrors."
People suffering from BDD tend to fixate on minute details, such as a single blemish on their face or body, rather than viewing themselves in their entirety. They become so distressed with their appearance that they often can’t lead normal lives, are fearful of leaving their homes and occasionally even commit suicide. Patients frequently have to be hospitalized. BDD affects approximately 2 percent of the population and is more prevalent than schizophrenia or bipolar disorder. Despite its prevalence and severity, scientists know relatively little about the neurobiology of BDD.
In the current study, Feusner and his colleagues performed brain scans of 14 adults diagnosed with BDD and 16 healthy controls. The goal of the study was to map the brain’s connections to examine how the white-matter networks are organized. White matter is made up of nerve cells that carry impulses from one part of the brain to another.
To do this, they used a sensitive form of brain imaging called diffusion tensor imaging, or DTI. DTI is a variant of magnetic resonance imaging that can measure the structural integrity of the brain’s white matter. From these scans, they were able to create whole brain “maps” of reconstructed white-matter tracks. Next, they used a form of advanced analysis called graph theory to characterize the patterns of connections throughout the brains of people with BDD and then compared them with those of healthy controls.
The researchers found people with BDD had a pattern of abnormally high network “clustering” across the entire brain. This suggests that these individuals may have imbalances in how they process “local” or detailed information. The researchers also discovered specific abnormal connections between areas involved in processing visual input and those involved in recognizing emotions.
"How their brain regions are connected in order to communicate about what they see and how they feel is disturbed," said Feusner, who also directs the Adult Obsessive-Compulsive Disorder Program and the Body Dysmorphic Disorder Research Program at UCLA.
"Their brains seem to be fine-tuned to be very sensitive to process minute details, but this pattern may not allow their brains to be well-synchronized across regions with different functions," he said. "This could affect how they perceive their physical appearance and may also result in them getting caught up in the details of other thoughts and cognitive processes."
The study, Feusner noted, advances the understanding of BDD by providing evidence that the “hard wiring” of patients’ brain networks is abnormal.
"These abnormal brain networks could relate to how they perceive, feel and behave," he said. "This is significant because it could possibly lead to us being able to identify early on if someone is predisposed to developing this problem."
'Network' analysis of the brain may explain features of autism
A look at how the brain processes information finds a distinct pattern in children with autism spectrum disorders. Using EEGs to track the brain’s electrical cross-talk, researchers from Boston Children’s Hospital have found a structural difference in brain connections. Compared with neurotypical children, those with autism have multiple redundant connections between neighboring brain areas at the expense of long-distance links.
The study, using a “network analysis” like that used to study airlines or electrical grids, may help in understanding some classic behaviors in autism. It was published February 27 in BioMed Central’s open access journal BMC Medicine, accompanied by a commentary.
"We examined brain networks as a whole in terms of their capacity to transfer and process information," says Jurriaan Peters, MD, of the Department of Neurology at Boston Children’s Hospital, who is co-first author of the paper with Maxime Taquet, a PhD student in Boston Children’s Computational Radiology Laboratory. "What we found may well change the way we look at the brains of autistic children."
Peters, Taquet and senior authors Simon Warfield, PhD, of the Computational Radiology Laboratory and Mustafa Sahin, MD, PhD, of Neurology, analyzed EEG recordings from two groups of autistic children: 16 children with classic autism, and 14 children whose autism is part of a genetic syndrome known as tuberous sclerosis complex (TSC). They compared these readings with EEGs from two control groups—46 healthy neurotypical children and 29 children with TSC but not autism.
In both groups with autism, there were more short-range connections within different brain region, but fewer connections linking far-flung areas.
A brain network that favors short-range over long-range connections seems to be consistent with autism’s classic cognitive profile—a child who excels at specific, focused tasks like memorizing streets, but who cannot integrate information across different brain areas into higher-order concepts.
"For example, a child with autism may not understand why a face looks really angry, because his visual brain centers and emotional brain centers have less cross-talk," Peters says. "The brain cannot integrate these areas. It’s doing a lot with the information locally, but it’s not sending it out to the rest of the brain."
Decreased Gene Activity Is Likely Involved in Childhood Risk for Anxiety and Depression
Decreased activity of a group of genes may explain why in young children the “fear center” of the anxious brain can’t learn to distinguish real threats from the imaginary, according to a new University of Wisconsin study.
The study, published this week in the Proceedings of the National Academy of Sciences (PNAS), lays out evidence that young primates with highly anxious temperaments have decreased activity of specific genes within the amygdala, the brain’s fear center.
The authors hypothesize that this may result in over activity of the brain circuit that leads to higher risk for developing disabling anxiety and depression.
This may be particularly important since the genes involved play a major role in forming the brain connections needed for learning about fears. While all children have fears and anxieties, the authors suggest that children with low levels of activity of these genes develop anxious dispositions because they fail to learn to cope by overcoming their early childhood fears.
“Working with my close collaborator and graduate student, Drew Fox, we focused on understanding the function of genes that promote learning and plasticity in the amygdala,” says Dr. Ned H. Kalin, chair of psychiatry at the University of Wisconsin School of Medicine and Public Health, who led the research. “We found reduced activity in key genes that could impair the ability to sculpt the brain, resulting in a failure to develop the capacity to discriminate between real and imaginary fears.”
Kalin says the study helps support the need for early intervention in children identified as excessively shy and anxious. It may also point a way to better treatments aimed at decreasing the likelihood of children developing more severe psychiatric problems. Anxiety in children is quite common and can lead to anxiety and depression in adolescence and often precedes anxiety disorders, depression and substance abuse in adults.
Most small children go through a phase when they’re frightened of many things, including monsters or new social situations, Kalin says, but their maturing brains soon learn to distinguish real threats from the imaginary. But some children do not adapt, generalize their fears to numerous situations, and may later develop serious anxiety and mood disorders. These children tend to be more sensitive to stress, produce more stress hormones and have heightened nervous-system activity.
Kalin, Fox and co-authors wondered whether some differences in the developing amygdala prevent it from learning how to regulate and adapt to anxiety. Kalin’s earlier work identified a subset of young monkeys, similar to extremely shy children, with an inherited anxious disposition. Using brain imaging, the authors showed that high levels of amygdala activity predicted trait-like anxiety in anxious young primates. Like their stable and enduring anxious dispositions, these individuals also had chronically elevated levels of amygdala activity.
“We believe that this pinpoints a critical region in the brain that determines an individual’s level of trait anxiety,’’ Kalin explains.
In examining a specific part of the amygdala, the central nucleus, the researchers analyzed gene expression, which reflects both environmental and inherited influences. Within the central nucleus of the amygdala the authors found that anxious individuals tended to have decreased expression of a gene called neurotrophic tyrosine kinase, receptor, type 3 (NTRK3). Low levels of this gene that encodes for a brain cell surface receptor may be why the amygdala of an anxious monkey or child is chronically overactive and unable to overcome anxiety and fears.
“This is the first demonstration that the early risk to develop anxiety and depression may be related to the underactivity of particular genes in the developing primate amygdala,’’ Kalin says. “These findings have provided the basis for our hypothesis that can explain the early childhood risk to develop anxiety and depression. It also suggests some creative ways to help children with extreme anxiety by developing new treatments focused on increasing the activity of specific genes involved in facilitating the brain development that underlies fear learning and coping.”
(Source: newswise.com)