Posts tagged science
Articles and news from the latest research reports.
The Road to Language Learning Is Iconic
Languages are highly complex systems and yet most children seem to acquire language easily, even in the absence of formal instruction. New research on young children’s use of British Sign Language (BSL) sheds light on one mechanism – iconicity – that may play an important role in children’s ability to learn language.
For spoken and written language, the arbitrary relationship between a word’s form – how it sounds or how it looks on paper – and its meaning is a particularly challenging feature of language acquisition. But one of the first things people notice about sign languages is that signs often represent aspects of meaning in their form. For example, in BSL the sign EAT involves bringing the hand to the mouth just as you would if you were bringing food to the mouth to eat it.
In fact, a high proportion of signs across the world’s sign languages are similarly iconic, connecting human experience to linguistic form.
Robin Thompson and colleagues David Vison, Bencie Woll, and Gabriella Vigliocco at the Deafness, Cognition and Language Research Centre (DCAL) at University College London in the United Kingdom wanted to examine whether this kind of iconicity might provide a key to understanding how children come to link words to their meaning.
Their findings are published in Psychological Science, a journal of the Association for Psychological Science.
(Photo: David Levene)
For brain tumors, origins matter
Cancers arise when a normal cell acquires a mutation in a gene that regulates cellular growth or survival. But the particular cell this mutation happens in—the cell of origin—can have an enormous impact on the behavior of the tumor, and on the strategies used to treat it.
Robert Wechsler-Reya, Ph.D., professor and director of the Tumor Development Program in Sanford-Burnham’s NCI-designated Cancer Center, and his team study medulloblastoma, the most common malignant brain cancer in children. A few years ago, they made an important discovery: medulloblastoma can originate from one of two cell types: 1) stem cells, which can make all the different cell types in the brain or 2) neuronal progenitor cells, which can only make neurons.
Stem cells and progenitor cells are regulated by different growth factors. So, Wechsler-Reya thought, maybe the tumors arising from these cells respond differently to different therapies…
In a study published recently in the journal Oncogene, he and his team show that this is indeed the case. They looked at one growth factor in particular—basic fibroblast growth factor (bFGF)—and found that while it induces stem cell growth, it also inhibits neuronal progenitor cell growth.
What’s more, the researchers discovered that bFGF also blocks the growth of tumors that originate from progenitors. When they treated a mouse model of medulloblastoma with bFGF, it dramatically inhibited tumor growth.
Hormone Combination Effective and Safe for Treating Obesity in Mice
Scientists at Indiana University and international collaborators have found a way to link two hormones into a single molecule, producing a more effective therapy with fewer side effects for potential use as treatment for obesity and related medical conditions.
The studies were carried out in the laboratories of Richard DiMarchi, the Standiford H. Cox Distinguished Professor of Chemistry and the Linda & Jack Gill Chair in Biomolecular Sciences in the IU Bloomington College of Arts and Sciences, and of Matthias Tschöp, professor of medicine and director of the Institute of Diabetes and Obesity, Helmholtz Center Munich, Germany. Results were published online this week by the journal Nature Medicine.
Researchers combined a peptide hormone from the digestive system, GLP-1, with the hormone estrogen and administered it to obese laboratory mice. While both GLP-1 and estrogen have demonstrated efficacy as therapy for obesity and adult-onset diabetes, the combination was more effective in producing weight loss and other beneficial results than using either compound on its own. And it produced fewer adverse effects, such as excessive tissue growth linked to tumor formation.
"We find that combining the hormones as a single molecule dramatically enhanced their efficacy and their safety," DiMarchi said. "The combination improves the ability to lower body weight and the ability to manage glucose, and it does so without showing the hallmark toxicities associated with estrogen."
In a world of chronic pain, individual treatment possible
An investigation into the molecular causes of a debilitating condition known as “Man on Fire Syndrome” has led Yale researchers to develop a strategy that may lead to personalized pain therapy and predict which chronic pain patients will respond to treatment.
More than a quarter of Americans suffer from chronic pain and nearly 40 percent do not get effective relief from existing drugs. In many common conditions such as diabetic neuropathy, no clear source of pain is found.
The new study published in the Nov. 13 issue of Nature Communications used sophisticated atomic modeling techniques to search for mutations found in a rare, agonizing, and previously untreatable form of chronic pain called erythromelagia, commonly referred to as “Man on Fire Syndrome.” Researchers discovered that one of those mutations seem to predicted whether a patient would respond positively to drug treatment.
“Hopefully we can use this knowledge to help chronic pain patients in more systematic ways, and not depend upon trial and error,” said Yang Yang, postdoctoral research associate in the Department of Neurology and lead author of the paper.
Hormone affects distance men keep from unknown women they find attractive
Men in committed relationships choose to keep a greater distance between themselves and an unknown woman they find attractive when given the hormone oxytocin, according to new research in the November 14 issue of The Journal of Neuroscience. The findings suggest oxytocin may help promote fidelity within monogamous relationships.
Oxytocin plays a vital role in triggering childbirth and facilitating nursing. The hormone, which is produced in a region of the brain called the hypothalamus, is also involved in the formation of social bonds. In humans and other animals, this brain chemical is known to promote bonds between parents and children, and between couples. Additionally, previous studies have shown oxytocin increases trust among people. However, scientists had yet to determine what, if any, role oxytocin played in maintaining monogamous human relationships.
In the current study, led by René Hurlemann, MD, PhD, of the University of Bonn, researchers found that men in committed relationships who were given oxytocin kept a greater distance when approaching or being approached by an unknown woman they found attractive compared with those given a placebo. In contrast, oxytocin had no effect on single men.
“Previous animal research in prairie voles identified oxytocin as major key for monogamous fidelity in animals,” Hurlemann said. “Here, we provide the first evidence that oxytocin may have a similar role for humans.”
After nearly 10 years of follow-up of study participants who experienced migraines and who had brain lesions indentified via magnetic resonance imaging, women with migraines had a higher prevalence and greater increase of deep white matter hyperintensities (brain lesions) than women without migraines, although the number, frequency, and severity of migraines were not associated with lesion progression, according to a study appearing in the November 14 issue of JAMA. Also, increase in deep white matter hyperintensity volume was not significantly associated with poorer cognitive performance at follow-up.
Migraine affects up to 15 percent of the general population. “A previous cross-sectional study showed an association of migraine with a higher prevalence of magnetic resonance imaging (MRI)-measured ischemic lesions in the brain,” according to background information in the article. White matter hyperintensities are associated with atherosclerotic disease risk factors, increased risk of ischemic stroke, and cognitive decline.
Teenagers’ brains affected by preterm birth
New research at the University of Adelaide has demonstrated that teenagers born prematurely may suffer brain development problems that directly affect their memory and learning abilities.
The research, conducted by Dr Julia Pitcher and Dr Michael Ridding from the University of Adelaide’s Robinson Institute, shows reduced ‘plasticity’ in the brains of teenagers who were born preterm (at or before 37 weeks gestation).
The results of the research are published in the Journal of Neuroscience.
"Plasticity in the brain is vital for learning and memory throughout life," Dr Pitcher says. "It enables the brain to reorganise itself, responding to changes in environment, behaviour and stimuli by modifying the number and strength of connections between neurons and different brain areas. Plasticity is also important for recovery from brain damage.
"We know from past research that preterm-born children often experience motor, cognitive and learning difficulties. The growth of the brain is rapid between 20 and 37 weeks gestation, and being born even mildly preterm appears to subtly but significantly alter brain microstructure, neural connectivity and neurochemistry.
"However, the mechanisms that link this altered brain physiology with behavioural outcomes - such as memory and learning problems - have remained unknown," Dr Pitcher says.
Alzheimer gene may boost young brains but contributes to ‘burnout’ in later years
A gene that confers a higher risk for dementia in old age could also promote better-than-average memory and verbal skills in youth, according to a new University of Sussex-led study.
Neuroscientists tested the cognitive abilities of those with a particular gene variant, known as ‘APOE e4’, found in approximately 25 per cent of the population, against those without it. They also looked at the brain structure and brain activities of both groups during the tasks.
They found that young people with the e4 variant performed better in attention tests (one involving episodic memory of words, the other requiring participants to spot number sequences), which correlated with increased task-related brain activation as detected by MRI scans. The researchers also noticed subtle differences in the white matter of the brains of those with the variant.
Lead researcher Professor Jennifer Rusted said: “Earlier studies suggested that those with the e4 variant outperform those without it in tasks such as memory, speed of processing, mental arithmetic and verbal fluency.
But it is also well-established that this gene is a risk factor for Alzheimer’s disease. The suggestion is that while this confers cognitive advantages in early life, leading to higher achievement, it may also increase susceptibility to memory failure as we enter old age.
“Our study is the first to show that subtle differences in the structure and activation of the brain during cognitive tasks in APOE e4 carriers are linked to their cognitive performance. It is possible that the brain over-activations that we see in youth have negative effects over the longer term and contribute to a kind of ‘burnout’ in older adulthood.”
‘APOE e4 polymorphism in young adults is associated with improved attention andindexed by distinct neural signatures’, by Professor Jennifer Rusted, Dr Simon Evans and Dr Sarah King in the School of Psychology, Dr Nick Dowell and Professor Paul Tofts in the Clinical Imaging Sciences Centre at the Brighton and Sussex Medical School (BSMS), and Dr Najo Tabet in the BSMS Institute of Postgraduate Medicine, is published in NeuroImage.
(Source: sussex.ac.uk)
Why do we get older? When do we die and why? Is there a life without ageing? For centuries, science has been fascinated by these questions. Now researchers from Kiel (Germany) have examined why the polyp Hydra is immortal – and unexpectedly discovered a link to ageing in humans. The study carried out by Kiel University together with the University Medical Center Schleswig-Holstein (UKSH) will be published this week in the Proceedings of the National Academy of Sciences of the United States of America (PNAS). It was funded by the German Research Foundation DFG.
Wired for Harmony?
Many creatures, such as human babies, chimpanzees, and chicks, react negatively to dissonance—harsh, unstable, grating sounds. Since the days of the ancient Greeks, scientists have wondered why the ear prefers harmony. Now, scientists suggest that the reason may go deeper than an aversion to the way clashing notes abrade auditory nerves; instead, it may lie in the very structure of the ear and brain, which are designed to respond to the elegantly spaced structure of a harmonious sound.
"Over the past century, researchers have tried to relate the perception of dissonance to the underlying acoustics of the signals," says psychoacoustician Marion Cousineau of the University of Montreal in Canada. In a musical chord, for example, several notes combine to produce a sound wave containing all of the individual frequencies of each tone. Specifically, the wave contains the base, or "fundamental," frequency for each note plus multiples of that frequency known as harmonics. Upon reaching the ear, these frequencies are carried by the auditory nerve to the brain. If the chord is harmonic, or "consonant," the notes are spaced neatly enough so that the individual fibers of the auditory nerve carry specific frequencies to the brain. By perceiving both the parts and the harmonious whole, the brain responds to what scientists call harmonicity.
In a dissonant chord, however, some of the notes and their harmonics are so close together that two notes will stimulate the same set of auditory nerve fibers. This clash gives the sound a rough quality known as beating, in which the almost-equal frequencies interfere to create a warbling sound. Most researchers thought that phenomenon accounted for the unpleasantness of a dissonance.