Posts tagged science
Articles and news from the latest research reports.
A child who suffers a moderate or severe traumatic brain injury (TBI) may still have substantial functional disabilities and reduced quality of life 2 years after the injury. After those first 2 years, further improvement may be minimal. Better interventions are needed to prevent long-lasting consequences of TBI in children conclude the authors of a study published in Journal of Neurotrauma, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers.
Frederick Rivara and colleagues from University of Washington, Seattle, and Mary Bridge Children’s Hospital, Tacoma, WA, and Children’s Hospital of Philadelphia and the University of Pennsylvania, Philadelphia, PA, describe the functional and quality of life outcomes of children who experienced a moderate or severe TBI when they were 0-17 years of age. In the article “Persistence of Disability 24 to 36 Months after Pediatric Traumatic Brain Injury: A Cohort Study” they follow up on a previous report that found improvement in some areas of functioning for up to 24 months. In this expanded study, the authors showed no significant improvement in the children’s ability to function, participate in activities, or in their quality of life between 24 and 36 months post-injury, and they suggest that a plateau is reached in the recovery.
"This important communication by Rivara and colleagues reinforces the concept that pediatric traumatic brain injury is associated with significant enduring morbidity, with recovery plateauing over time," says John T. Povlishock, PhD, Editor-in-Chief of Journal of Neurotrauma and Professor, VCU Neuroscience Center, Medical College of Virginia, Richmond. “This finding also reinforces emerging thought that pediatric traumatic brain injury must be viewed in another context, rather than the current perception that the course of such injury parallels that found in the adult population.”
Imaging the network traffic in our brains
MRI brain scans no longer just show the various regions of brain activity; nowadays the networks in the brain can now be imaged with ever greater precision. This will make functional MRI (fMRI) increasingly powerful in the coming years, leading to tools that can be used in cognitive neuroscience. This is the claim made by Prof. David Norris in his inaugural lecture as Professor of Neuroimaging at the University of Twente on 13 September.
During the twenty years since the invention of fMRI (functional Magnetic Resonance Imaging) developments have come thick and fast, from initially identifying active brain regions to more complex analysis of the connections and hubs in the brain. In his inaugural lecture Norris describes how this has been achieved thanks to not only a growing understanding of the underlying biophysics but also rapid technological developments: scanners with larger magnetic fields, better image-processing techniques and algorithms. His aim is to go beyond merely localizing which parts of the brain are active. The challenge is to answer two questions: How are the various regions interconnected, structurally and functionally? What do the networks in our brains look like?
Faster and more powerful
Back in the 19th century scientists observed increased blood flow in brain regions that are functionally active. fMRI enables the change in oxygen content to be seen. Haemoglobin, the substance that transports oxygen in the blood, can take the form of oxyhaemoglobin (when it is still combined with oxygen) and deoxyhaemoglobin (when the oxygen has been released), each of which has different magnetic properties. One of the complicating factors when interpreting the scans is that various physiological mechanisms are at work simultaneously, causing the deoxyhaemoglobin level to rise and fall. One of the remedies to increase accuracy, Norris explains, has been to increase the magnetic field strength: there are now MRI scanners operating at 7 Tesla. At the same time the speed at which laminae can be imaged has gone up by leaps and bounds: the entire brain can be scanned in three seconds with a precision of 1 millimetre.
Hubs
The functional connections between parts of the brain can be registered by means of blood flow, but MRI also enables the structural and anatomical connections to be seen. This involves measuring the movement of water molecules caused by the ‘white matter’ in nerve fibres. This technology is known as diffusion-weighted imaging (DWI). Combining these technologies provides a wealth of fresh information on the networks in the brain and the places where many connections come together, the ‘hubs’. Not only have ‘known networks’ thus been proven, so have networks that neuroscience posits as plausible but that have never been measured.
Image showing the distribution of connector hubs on the surface of a flattened brain. The top two figures show the medial views of each hemisphere, the bottom two show the external views.
CMI
The new Centre for Medical Imaging that is to come to the University of Twente campus will soon provide extensive facilities for collaborating in the field of fMRI, says Norris, who is also on the staff of the Donders Institute in Nijmegen.
(Source: utwente.nl)
A ‘can do’ attitude is the key to a healthy lifestyle, University of Melbourne economists have determined.
Researchers from the Melbourne Institute of Applied Economic and Social Research analysed data on the diet, exercise and personality type of more than 7,000 people. The study found those who believe their life can be changed by their own actions ate healthier food, exercised more, smoked less and avoided binge drinking.
Professor Deborah Cobb-Clark, Director of the Melbourne Institute of Applied Economic and Social Research, said those who have a greater faith in ‘luck’ or ‘fate’ are more likely to live an unhealthy life. “Our research shows a direct link between the type of personality a person has and a healthy lifestyle,“ she said.
Professor Cobb-Clark hoped the study would help inform public health policies on conditions such as obesity. “The main policy response to the obesity epidemic has been the provision of better information, but information alone is insufficient to change people’s eating habits,” she said.
“Understanding the psychological underpinning of a person’s eating patterns and exercise habits is central to understanding obesity.” The study also found men and women hold different views on the benefits of a healthy lifestyle.
Men wanted physical results from their healthy choices, while women were more receptive to the everyday enjoyment of leading a healthy lifestyle. Professor Cobb-Clarke said the research demonstrated the need for more targeted policy responses. “What works well for women may not work well for men,” she said. “Gender specific policy initiatives which respond to these objectives may be particularly helpful in promoting healthy lifestyles.”
CAMH illuminates roles of novel epigenetic chemical in the brain
Researchers from the Centre for Addiction and Mental Health (CAMH) have identified a new role of a chemical involved in controlling the genes underlying memory and learning.
"The brain is a plastic tissue, and we know that learning and memory require various genes to be expressed,” says CAMH Senior Scientist Dr. Art Petronis, who is a senior author on the new study. “Our research has identified how the chemical 5-hmC may be involved in the epigenetic processes allowing this plasticity.” Dr. Petronis is head of the Krembil Family Epigenetics Laboratory in CAMH’s Campbell Family Mental Health Research Institute.
5-hmC is an epigenetic modification of DNA, and was discovered in humans and mice in 2009. DNA modifications are chemical changes to DNA. They flag genes to be turned “on” - signalling the genome to make a protein - or turned “off.” As the overwhelming majority of cells in an individual contain the same genetic code, this pattern of flags is what allows a neuron to use the same genome as a blood or liver cell, but create a completely different and specialized cellular environment.
The research, published online in Nature Structural & Molecular Biology, sheds light on the role of 5-hmC. Intriguingly, it is more abundant in the brain than in other tissues in the body, for reasons not clear to date.
The CAMH team of scientists examined DNA from a variety of tissues, including the mouse and human brain, and looked at where 5-hmC was found in the genome. They detected that 5-hmC had a unique distribution in the brain: it was highly enriched in genes related to the synapse, the dynamic tips of brain cells. Growth and change in the synapse allow different brain cells to “wire” together, which allows learning and memory.
"This enrichment of 5-hmC in synapse-related genes suggests a role for this epigenetic modification in learning and memory," says Dr. Petronis.
The team further showed that 5-hmC had a special distribution even within the gene. The code for one gene can be edited and “spliced” to create several different proteins. Dr. Petronis found that 5-hmC is located at “splice junctions,” the points where the gene is cut before splicing.
"5-hmC may signal the cell’s splicing machinery to generate the diverse proteins that, in turn, give rise to the unprecedented complexity of the brain," he says.
The research team is continuing to investigate the role of 5-hmC in more detail, and to determine whether 5-hmC function is different in people with bipolar disorder and schizophrenia compared to people without these diagnoses.
This research was funded by the U.S National Institutes of Health, the Canadian Institutes of Health Research, and the Tapscott Chair in Schizophrenia Studies at the University of Toronto.
The Centre for Addiction and Mental Health (CAMH) is Canada’s largest mental health and addiction teaching hospital, as well as one of the world’s leading research centres in the area of addiction and mental health. CAMH combines clinical care, research, education, policy development and health promotion to help transform the lives of people affected by mental health and addiction issues.
(Source: Yahoo!)
By studying how birds master songs used in courtship, scientists at Duke University have found that regions of the brain involved in planning and controlling complex vocal sequences may also be necessary for memorizing sounds that serve as models for vocal imitation.
In a paper appearing in the September 2012 issue of the journal Nature Neuroscience, researchers at Duke and Harvard universities observed the imitative vocal learning habits of male zebra finches to pinpoint which circuits in the birds’ brains are necessary for learning their songs.
Knowing which brain circuits are involved in learning by imitation could have broader implications for diagnosing and treating human developmental disorders, the researchers said. The finding shows that the same circuitry used for vocal control also participates in auditory learning, raising the possibility that vocal circuits in our own brain also help encode auditory experience important to speech and language learning.
EnChroma glasses designed to compensate for color-blindness
While many people may think that being color blind means seeing everything in black-and-white, such a condition is in fact quite rare. Instead, the majority of people who are classified as color blind are capable of color vision, but they have difficulty distinguishing red and green as distinct colors. EnChroma’s Cx sunglasses are designed to help in these cases, by selectively reducing the transmission of given wavelengths of light, thus allowing red and green to stand out.
The key to the sunglasses’ performance is a proprietary coating on the lenses. Said to be harder and more scratch-resistant than glass, it can be tweaked in production to filter certain wavelengths that cause “color confusion.” The result is an improved signal-to-noise ratio in the perception of colors, in which red and green don’t just appear as variations of yellowy-brown – as an example.
Depending on their specific type of red-green color vision deficiency, users can choose between two different models of the sunglasses, designed to filter different wavelengths of light. There are also models that simply boost the intensity of all colors (for use by normally-sighted users), and that boost colors while also blocking UV rays.
People who are completely incapable of seeing any colors will unfortunately not be helped by any of the models. Also, because they are sunglasses, their color correction feature only works in bright light.
EnChroma’s Cx sunglasses should be available as of the middle of next month. Expect to pay at least US$800 for a complete set of glasses, or $700 for the lenses alone.
The first detailed and complete picture of a protein complex that is tied to human birth defects as well as the progression of many forms of cancer has been obtained by an international team of researchers led by scientists with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab). Knowing the architecture of this protein, PRC2, for Polycomb Repressive Complex 2, should be a boon to its future use in the development of new and improved therapeutic drugs.
'Maternal gene' identified in mice
Researchers from The Rockefeller University in New York found that mice engineered to suppress the gene spent less time licking, nursing and retrieving their pups compared with a control group.
The findings, published in the Proceedings of the National Academy of Sciences, suggest the single gene could be responsible for motivating mothers to protect, feed and raise their young, the scientists said.
Previous studies have found that a brain region called the medial preoptic area controls aggression, sexual receptivity and maternal care in mice. In the new study, scientists artificially lowered the levels of the chemical in the medial preoptic area of female mice, to examine how they functioned without it.
They found that the mice spent less time caring for their pups but that their levels of aggression remained unchanged. Dr Ana Ribiero, who led the study, said: “The main finding of this paper is manipulation of a specific gene in a specific group of neurons (nerve cells) can drastically alter the expression of a complete, biologically crucial behaviour.” The effects were “remarkably specific” to maternal care because even related behaviours, such as aggression, remained unchanged, she added.
Kids who get migraine headaches are much more likely than other children to also have behavioral difficulties, including social and attention issues, and anxiety and depression. The more frequent the headaches, the greater the effect, according to research out now in the journal Cephalagia, published by SAGE.
Marco Arruda, director of the Glia Institute in São Paulo, Brazil, together with Marcelo Bigal of the Albert Einstein College of Medicine in New York studied 1,856 Brazilian children aged 5 to 11. The authors say that this is the first large, community based study of its kind to look at how children’s behavioural and emotional symptoms correlate with migraine and tension-type headaches (TTH), and to incorporate data on headache frequency.
Researchers from ETH Zurich have quite literally created a “cell phone”: they have reprogrammed mammalian cells in such a way that they can “phone” each other via chemical signals.
Telephoning is a mutual exchange of information: A phones B and they both agree what B should do. Once this is done, Party B phones Party A to let him or her know. A no longer phones B. During this two-way communication, electrical signals are sent, and for their transmission suitable devices are necessary.
Based on this formula, a team of bioengineers headed by Martin Fussenegger and Jörg Stelling at ETH Zurich’s Department of Biosystems Science and Engineering in Basel has programmed mammalian cells in such a way that two cells can communicate via chemical signals. The scientists have thus incorporated a synthetic two-way communication system into mammalian cells for the first time that also responds to concentration differences in the signal molecules. The researchers used suitable signal molecules and constructed “devices” out of biological components that receive, process and respond accordingly to the signals. The devices consist of suitable genes and their products, proteins, which are linked to each other logically.