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Archive - Aug 28, 2014

New Study Maps the Neural Circuitry of Dyslexia

Dyslexia, the most commonly diagnosed learning disability in the United States, is a neurological reading disability that occurs when the regions of the brain that process written language don't function normally. The use of non-invasive functional neuroimaging tools has helped characterize how brain activity is disrupted in dyslexia. However, most prior work has focused on only a small number of brain regions, leaving a gap in our understanding of how multiple brain regions communicate with one another through networks, called functional connectivity, in persons with dyslexia. This led neuroscience Ph.D. student Emily Finn and her colleagues at the Yale University School of Medicine to conduct a whole-brain functional connectivity analysis of dyslexia using functional magnetic resonance imaging (fMRI). They report their findings in the September 1, 2014 issue of Biological Psychiatry. "In this study, we compared fMRI scans from a large number of both children and young adults with dyslexia to scans of typical readers in the same age groups. Rather than activity in isolated brain regions, we looked at functional connectivity, or coordinated fluctuations between pairs of brain regions over time," explained Ms. Finn. In total, the team recruited and scanned 75 children and 104 adults. Ms. Finn and her colleagues then compared the whole-brain connectivity profiles of the dyslexic readers to the non-impaired readers, which revealed widespread differences. Dyslexic readers showed decreased connectivity within the visual pathway as well as between visual and prefrontal regions, increased right-hemisphere connectivity, reduced connectivity in the visual word-form area, and persistent connectivity to anterior language regions around the inferior frontal gyrus. This altered connectivity profile is consistent with dyslexia-related reading difficulties. Dr.

Protein in "Good Cholesterol" May Be a Key to Treating Pulmonary Hypertension

Oxidized lipids are known to play a key role in inflaming blood vessels and hardening arteries, which causes diseases such as atherosclerosis. A new study at UCLA demonstrates that these oxidized lipids may also contribute to pulmonary hypertension, a serious lung disease that narrows the small blood vessels in the lungs. Using a rodent model, the researchers showed that a peptide mimicking part of the main protein in high-density lipoprotein (HDL), the so-called "good" cholesterol, may help reduce the production of oxidized lipids in pulmonary hypertension. They also found that reducing the amount of oxidized lipids improved the rodents' heart and lung function. The study is published in the August 26, 2014 issue of Circulation. A rare progressive condition, pulmonary hypertension can affect people of all ages. The disease makes it harder for the heart to pump blood through these vital organs, which can lead to heart failure. "Our research helps unravel the mechanisms involved in the development of pulmonary hypertension," said Dr. Mansoureh Eghbali, the study's senior author and an associate professor of anesthesiology at the David Geffen School of Medicine at UCLA. "A key peptide related to HDL cholesterol that can help reduce these oxidized lipids may provide a new target for treatment development." Lipids such as fatty acids become oxidized when they are exposed to free radicals — tiny particles that are produced when the body converts food into energy -- or when they are exposed to pollution, and in numerous other ways. Although researchers have known that oxidized lipids played a role in the development of atherosclerosis and other vascular diseases, the UCLA team discovered higher-than-normal levels of oxidized proteins in rodents with pulmonary hypertension.

Touch Is Key to Symbiosis of Plants with Fungi and Bacteria

The mechanical force that a single fungal cell or bacterial colony exerts on a plant cell may seem vanishingly small, but it plays a key role in setting up some of the most fundamental symbiotic relationships in biology. In fact, it may not be too much of a stretch to say that plants may have never moved onto land without the ability to respond to the touch of beneficial fungi, according to a new study led by Dr. Jean-Michel Ané, a professor of agronomy at the University of Wisconsin-Madison. "Many people have studied how roots progress through the soil, when fairly strong stimuli are applied to the entire growing root," says Dr. Ané, who just published a review of touch in the interaction between plants and microbes in the August 2014 issue of Current Opinion in Plant Biology. "We are looking at much more localized, tiny stimuli on a single cell that is applied by microbes." Specifically, Dr. Ané, Dr. Dhileepkumar Jayaraman, a postdoctoral researcher in agronomy, and Dr. Simon Gilroy, a professor of botany, studied how such a slight mechanical stimulus starts round one of a symbiotic relationship — that is, a win-win relationship between two organisms. It's known that disease-causing fungi build a structure to break through the plant cell wall, "but there is growing evidence that fungi and also bacteria in symbiotic associations use a mechanical stimulation to indicate their presence," says Dr. Ané. "They are knocking on the door, but not breaking it down." After the fungus announces its arrival, the plant builds a tube in which the fungus can grow. "There is clearly a mutual exchange of signals between the plant and the fungus," says Dr. Ané.

Encyclopedia of How Genomes Function Gets Much Bigger

A big step in understanding the mysteries of the human genome was unveiled today (August 28, 2014) in the form of three analyses that provide the most detailed comparison yet of how the genomes of the fruit fly, roundworm, and human function. The research, published in the August 28, 2014 issue of Nature, compares how the information encoded in the three species’ genomes is “read out,” and how their DNA and proteins are organized into chromosomes. The results add billions of entries to a publicly available archive of functional genomic data. Scientists can use this resource to discover common features that apply to all organisms. These fundamental principles will likely offer insights into how the information in the human genome regulates development, and how it is responsible for diseases. The analyses were conducted by two consortia of scientists that include researchers from the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab). Both efforts were funded by the National Institutes of Health’s National Human Genome Research Institute (NHGRI). One of the consortia, the “model organism Encyclopedia of DNA Elements” (modENCODE) project, catalogued the functional genomic elements in the fruit fly and roundworm. Dr. Susan Celniker and Dr. Gary Karpen of Berkeley Lab’s Life Sciences Division led two fruit fly research groups in this consortium. Dr. Ben Brown, also with the Life Sciences Division, participated in another consortium, ENCODE, to identify the functional elements in the human genome. The consortia are addressing one of the big questions in biology today: now that the human genome and many other genomes have been sequenced, how does the information encoded in an organism’s genome make an organism what it is?