Posts tagged brain
Articles and news from the latest research reports.
A new study from the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute shows that a two-hour exposure to electronic devices with self-luminous “backlit” displays causes melatonin suppression, which might lead to delayed bedtimes, especially in teens.
The research team, led by Mariana Figueiro, associate professor at Rensselaer and director of the LRC’s Light and Health Program, tested the effects of self-luminous tablets on melatonin suppression. In order to simulate typical usage of these devices, 13 individuals used self-luminous tablets to read, play games, and watch movies.
The actual melatonin suppression values after 60 minutes were very similar to those estimated using a predictive model of human circadian phototransduction for one-hour light exposures. “Based on these results, display manufacturers can use our model to determine how their products could affect circadian system regulation,” said Figueiro.
The results of this study, together with the LRC predictive model of human circadian phototransduction, could urge manufacturers to design more “circadian-friendly” electronic devices that could either increase or decrease circadian stimulation depending on the time of day — reducing circadian stimulation in the evening for a better night’s sleep, and increasing in the morning to encourage alertness.
New Model of Muscular Dystrophy Provides Insight Into Disease Development
ScienceDaily (Aug. 27, 2012) — Muscular dystrophy is a complicated set of genetic diseases in which genetic mutations affect the various proteins that contribute to a complex that is required for a structural bridge between muscle cells and the extracellular matrix (ECM) that provides the physical and chemical environment required for their development and function.
The affects of these genetic mutations in patients vary widely, even when the same gene is affected. In order to develop treatments for this disease, it is important to have an animal model that accurately reflects the course of the disease in humans. In this issue of the Journal of Clinical Investigation, researchers at the University of Iowa report the development of a mouse model of Fukuyama’s muscular dystrophy that copies the pathology seen in the human form of the disease.
By removing the gene fukutin from mouse embryos at various points during development, researchers led by Kevin Campbell were able to determine that fukutin disrupts important modifications of dystrophin that prevent the muscle cells from attaching to the ECM. Disruption of the gene earlier in development led to a more severe form of the disease, suggesting that fukutin is important for muscle maturation. Disruptions in later stages of development caused a less severe form of the disease. In a companion piece, Elizabeth McNally of the University of Chicago discusses the implications of this disease model for the development of new therapies to treat muscular dystrophy.
Source: Science Daily
Vitamin B12 deficiency: Tracking the genetic causes
August 26, 2012
Vitamin B12 is essential to human health. However, some people have inherited conditions that leave them unable to process vitamin B12. As a result they are prone to serious health problems, including developmental delay, psychosis, stroke and dementia. An international research team recently discovered a new genetic disease related to vitamin B12 deficiency by identifying a gene that is vital to the transport of vitamin into the cells of the body. This discovery will help doctors better diagnose this rare genetic disorder and open the door to new treatments. The findings are published in the journal Nature Genetics.
"We found that a second transport protein was involved in the uptake of the vitamin into the cells, thus providing evidence of another cause of hereditary vitamin B12 deficiency", said Dr. David Rosenblatt, one of the study’s co-authors, scientist in medical genetics and genomics at the Research Institute of the McGill University Health Centre (RI MUHC) and Dodd Q. Chu and Family Chair in Medical Genetics and the Chair of the Department of Human Genetics at McGill University. "It is also the first description of a new genetic disease associated with how vitamin B12 is handled by the body".
These results build on previous research by the same team from the RI MUHC and McGill University, with their colleagues in Switzerland, Germany and the United States. In previous work, the researchers discovered that vitamin B12 enters our cells with help from of a specific transport protein. In this study, they were working independently with two patients showing symptoms of the cblF gene defect of vitamin B12 metabolism but without an actual defect in this gene. Their work led to the discovery of a new gene, ABCD4, associated with the transport of B12 and responsible for a new disease called cblJ combined homocystinuria and methylmalonic aciduria (cblJ-Hcy-MMA).
Using next generation sequencing of the patients’ genetic information, the scientists identified two mutations in the same ABCD4 gene, in both patients. “We were also able to compensate for the genetic mutation by adding an intact ABCD4 protein to the patients’ cells, thus allowing the vitamin to be properly integrated into the cells,” explained Dr. Matthias Baumgartner, senior author of the study and a Professor of metabolic diseases at Zurich’s University Children’s Hospital.
Vitamin B12, or cobalamin, is essential for healthy functioning of the human nervous system and red blood cell synthesis. Unable to produce the vitamin itself, the human body has to obtain it from animal-based foods such as milk products, eggs, red meat, chicken, fish, and shellfish – or vitamin supplements. Vitamin B12 is not found in vegetables.
"This discovery will lead to the early diagnosis of this serious genetic disorder and has given us new paths to explore treatment options. It also helps explain how vitamin B12 functions in the body, even for those without the disorder," said Dr. Rosenblatt who is the director of one of only two referral laboratories in the world for patients suspected of having this genetic inability to absorb vitamin B12. Dr. Rosenblatt points out that the study of patients with rare diseases is essential to the advancement of our knowledge of human biology.
Source: medicalxpress.com
SOLITAIRE, which was approved by the U.S. Food and Drug Administration in March, is among an entirely new generation of devices designed to remove blood clots from blocked brain arteries in patients experiencing an ischemic stroke. It has a self-expanding, stent-like design, and once inserted into a blocked artery using a thin catheter tube, it compresses and traps the clot. The clot is then removed by withdrawing the device, reopening the blocked blood vessel.
People who carry a “G” instead of an “A” at a specific spot in their genetic code have roughly a six-fold higher risk of developing certain types of brain tumors, a Mayo Clinic and University of California, San Francisco study has found. The findings, published online in the journal Nature Genetics, could help researchers identify people at risk of developing certain subtypes of gliomas which account for about 20 percent of new brain cancers diagnosed annually in the U.S. and may lead to better surveillance, diagnosis and treatment.
Researchers still have to confirm whether the spot is the source of tumors, but if it’s not, “it is pretty close,” says senior author Robert Jenkins, M.D., Ph.D., a pathologist at the Mayo Clinic Cancer Center. “Based on our findings, we are already starting to think about clinical tests that can tell patients with abnormal brain scans what kind of tumor they have, just by testing their blood.”
How to learn in your sleep
26 August 2012 by Mo Costandi
Subjects trained to sniff pleasant smells while asleep retain the conditioning when they wake up.
It sounds like every student’s dream: research published today in Nature Neuroscience shows that we can learn entirely new information while we snooze.
TIPS/Photoshot
Anat Arzi of the Weizmann Institute of Science in Rehovot, Israel, and her colleagues used a simple form of learning called classical conditioning to teach 55 healthy participants to associate odours with sounds as they slept.
They repeatedly exposed the sleeping participants to pleasant odours, such as deodorant and shampoo, and unpleasant odours such as rotting fish and meat, and played a specific sound to accompany each scent.
It is well known that sleep has an important role in strengthening existing memories, and this conditioning was already known to alter sniffing behaviour in people who are awake. The subjects sniff strongly when they hear a tone associated with a pleasant smell, but only weakly in response to a tone associated with an unpleasant one.
But the latest research shows that the sleep conditioning persists even after they wake up, causing them to sniff strongly or weakly on hearing the relevant tone — even if there was no odour. The participants were completely unaware that they had learned the relationship between smells and sounds. The effect was seen regardless of when the conditioning was done during the sleep cycle. However, the sniffing responses were slightly more pronounced in those participants who learned the association during the rapid eye movement (REM) stage, which typically occurs during the second half of a night’s sleep.
Pillow power
Arzi thinks that we could probably learn more complex information while we sleep. “This does not imply that you can place your homework under the pillow and know it in the morning,” she says. “There will be clear limits on what we can learn in sleep, but I speculate that they will be beyond what we have demonstrated.”
In 2009, Tristan Bekinschtein, a neuroscientist at the UK Medical Research Council’s Cognition and Brain Sciences Unit in Cambridge, and his colleagues reported that some patients who are minimally conscious or in a vegetative state can be classically conditioned to blink in response to air puffed into their eyes. Conditioned responses such as these could eventually help clinicians to diagnose these neurological conditions, and to predict which patients might subsequently recover. “It remains to be seen if the neural networks involved in sleep learning are similar to the ones recruited during wakefulness,” says Bekinschtein.
The findings by Arzi and her colleagues might also be useful for these purposes, and could lead to ‘sleep therapies’ that help to alter behaviour in conditions such as phobia.
“We are now trying to implement helpful behavioural modification through sleep-learning,” says Arzi. “We also want to investigate the brain mechanisms involved, and the type of learning we use in other states of altered consciousness, such as vegetative state and coma.”
Source: Nature
Nervous System: Facts, Function & Diseases
The nervous system is a complex collection of nerves and specialized cells known as neurons that transmit signals between different parts of the body. Vertebrates — animals with backbones and spinal columns — have central and peripheral nervous systems.
The central nervous system is made up of the brain, spinal cord and retina. The peripheral nervous system consists of sensory neurons, ganglia (clusters of neurons) and nerves that connect to one another and to the central nervous system.
Credit: iDesign, Shutterstock
Description of the nervous system
The nervous system is essentially the body’s electrical wiring. It is composed of nerves, which are cylindrical bundles of fibers that start at the brain and central cord and branch out to every other part of the body.
Neurons send signals to other cells through thin fibers called axons, which cause chemicals known as neurotransmitters to be released at junctions called synapses. A synapse gives a command to the cell and the entire communication process typically takes only a fraction of a millisecond.
Sensory neurons react to physical stimuli such as light, sound and touch and send feedback to the central nervous system about the body’s surrounding environment. Motor neurons, located in the central nervous system or in peripheral ganglia, transmit signals to activate the muscles or glands.
Glial cells, derived from the Greek word for “glue,” support the neurons and hold them in place. Glial cells also feed nutrients to neurons, destroy pathogens, remove dead neurons and act as traffic cops by directing the axons of neurons to their targets. Specific types of glial cells (oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system) generate layers of a fatty substance called myelin that wraps around axons and provides electrical insulation to enable them to rapidly and efficiently transmit signals.
People forget where they have left their keys because their brain is wired to recall emotionally charged events and ignore the mundane, a study has found.
When we see or experience something emotional such as the birth of a child or a traumatic event, our brain interprets it more vividly and stores it with greater clarity. In contrast everyday events are only processed with a minimal level of detail, explaining why we can remember things from our childhood but not what we ate for dinner 24 hours ago, researchers claim.
Rebecca Todd of the University of Toronto, who led the study, said: “We’ve discovered that we see things that are emotionally arousing with greater clarity than those that are more mundane. What’s more, we found that how vividly we perceive something in the first place predicts how vividly we will remember it later on … it is like the flash of a flashbulb that illuminates an event as it’s captured for memory.”
FOOTBALL teams of the future — even high school squads on limited budgets — may someday have a new tool to check players for brain injuries. It’s a special form of headgear, packed with sensors that read the brain waves of athletes after they come off the field, thus detecting changes caused by the trauma of hard knocks.
The compact, portable sensors decipher neural activity by measuring changes in the brain’s tiny magnetic field. These small magnetometers — still in the laboratory and in prototype — have yet to be tried on athletes. But their potential is enormous for brain imaging and for inexpensive monitoring of brain diseases, as well as for many other applications like the control of prosthetics, said Dr. José Luis Contreras-Vidal, a professor of electrical and computer engineering at the University of Houston.
A typical five-month-old infant has hardly figured out how to sit up yet — even crawling may be months away — but there are a few babies who already know how to drive. They’re steering their very own mobile robots.
The robots are designed to allow babies with disabilities to move around independently, at the same age their peers might learn to crawl. Whether they use robots or their own limbs, starting to move may be an important part of baby brain development, some childhood specialists think. Researchers don’t want kids with cerebral palsy or other movement disorders to miss out.
"We think that babies with disabilities are missing an opportunity for learning that typically developing babies have," said Carole Dennis, a professor occupational therapy at Ithaca College in New York.