Saturday, April 17, 2010

The simultaneous execution of multiple cases "breaks" the brain

The hemispheres of the brain operate independently of each other, when a person is busy with two complex cases at the same time, scientists have found. Each of them performs its task and can not solve a third, according to a paper published in Science. 
"This means that in everyday life, you can easily combine the two things at once, such as cooking and talking on the phone," - said the French scholar of the Medical Center, INSERM Etienne Koechlin. However, she said, when a person tries to do the third task, the cerebral cortex simply ignores it.

Scientists have conducted research on the algorithm of the brain, when he switches from one case to two. To do this they used a group of volunteers, consisting of 16 men and 16 women aged from 19 to 32 years.
Participants of the experiment on the screen in turn saw the letters comprising the word "tablet". They needed to determine whether the previous two letters shown in the same order in which they are in the word. At the same time volunteers were supposed to indicate whether the letters lowercase or uppercase. And their brains scanned for viruses by the method of resonance magnetic imaging.

It turned out that the performance of a problem both hemispheres of the brain were occupied exclusively by it. But as soon as the volunteers were switched on two tasks simultaneously, their brains share the responsibilities between the hemispheres. In this case each half of the brain involved in decision their problems.

Once these two tasks had been added one more - the definition of color letters on the screen - the researchers found that a third simple task simultaneously with the first two brains do not have a state. At the same time, they say, banal reason: he simply is not the third hemisphere. Therefore, volunteers are constantly forget to follow one of the problems, according to Morning.

Nevertheless, some experts about the study of French colleagues were skeptical. "This suggests that there are conditions under which you can not add a third task, but it all depends on the type of problems" - said the American neuroscientist Scott Hyuttel.

For example, he said, people can easily do other things while eating, because motor skills used in the absorption of food, not really intersect with other skills. Nevertheless Hyuttel noted that the study found a lack of knowledge of the cerebral hemispheres.

Meditation may sharpen brain cognition

WINSTON-SALEM, N.C., April 16 (UPI) -- Some look to coffee to sharpen their brain but U.S. researchers suggest a bit of meditation may help improve cognition.

Fadel Zeidan, a post-doctoral researcher at Wake Forest University School of Medicine, and a former doctoral student at the University of North Carolina at Charlotte, where the research was conducted, said the study found that meditation-trained participants showed a significant improvement in their critical cognitive skills after four days of 20-minute training.

"Simply stated, the profound improvements that we found after just four days of meditation training -- are really surprising," Zeidan said in a statement. "It goes to show that the mind is, in fact, easily changeable and highly influenced, especially by meditation."

The experiment involved 63 student volunteers, randomly assigned to two groups. One received meditation training while the other group listened to a book being read aloud. Both groups performed equally at the beginning of the experiment. However, the study found only the group with the meditation training improved cognitive measures.

The research appeared in Consciousness and Cognition and is scheduled to be presented at the Cognitive Neuroscience Society's annual meeting in Montreal.

What Is A Brain Abscess (Cerebral Abscess)?

A brain abscess, also known as a cerebral abscess or CNS abscess, is an abscess within the brain tissue caused by inflammation and collection of immune cells and infected material originating from local or remote infection sources.

A brain abscess is a rare, life-threatening infection of the brain. Local sources may include ear infections, a dental abscess, infection of the paranasal sinuses, or epidural abscess, while remote sources may include infections in the lung, heart or kidney.

A brain abscess may also be the result of a head trauma or surgical procedure. In children cerebral abscesses are usually linked to congenital heart disease.

What are the signs and symptoms of a brain abscess (cerebral abscess)?

What are the causes of a brain abscess (cerebral abscess)?

Diagnosing a brain abscess (cerebral abscess).

What are the treatment options of a brain abscess (cerebral abscess)?
Brain abscesses may affect people of any age, but more commonly occur in people in their 30s and 40s. Traditionally, they were disproportionately diagnosed in young people - changes in vaccination practices, treatment of child infections, and the AIDS pandemic shifted the average age of infection upwards. Males have double the risk of developing a brain abscess compared to females.

Bacteria, fungi or viruses may enter brain tissue and cause an abscess - a pus-filled swelling - to develop. The most common reported symptoms include an elevated body temperature, headache, confusion, weakness - and even paralysis on one side of the body. Symptoms vary, depending on where in the brain the abscess is located.

As the inflammation can damage the brain, as well as undermine its oxygen and blood supply, a cerebral abscess may be a very serious condition. If left untreated the patient may die. If the abscess ruptures (bursts) the risk of brain damage and death is even greater. A cerebral abscess is a medical emergency which requires immediate treatment with antibiotics and surgery (to drain the pus or remove the abscess entirely).

The National Institutes of Health (NIH), USA, informs that between 1,500 and 2,500 cases of brain abscesses are reported in the USA each year. According to the National Health Service (NHS), UK, approximately between 2 and 3 people in every million develop an abscess annually in the United Kingdom - it is a very rare infection. The NHS adds that modern diagnostic and surgical techniques have significantly improved the prognosis (outlook) for patients - approximately 10% of patients today die; a much lower figure than a few decades ago. The majority of patients recover completely. However, if the abscess ruptures into the ventricular system, the mortality rate may be 80%.

According to Medilexicon's medical dictionary:

An abscess is

"1. A circumscribed collection of purulent exudate frequently associated with swelling and other signs of inflammation.

2. A cavity formed by liquefactive necrosis within solid tissue."

Written by Christian Nordqvist

* What are the signs and symptoms of a brain abscess (cerebral abscess)?
* What are the causes of a brain abscess (cerebral abscess)?
* Diagnosing a brain abscess (cerebral abscess).
* What are the treatment options of a brain abscess (cerebral abscess)?

Smoking could predispose people to dementia

London: In a new study, researchers have found that lighting a cigarette could predispose people to dementia, not protect them as it has been earlier claimed.
The human brain becomes riddled with amyloid protein plaques and tangles of tau proteins in Alzheimer's disease. Low doses of nicotine have been shown to reduce the number of plaques in rats, but till now little was known about the effect of nicotine on the protein tangles.

In order to find out, Yan-Jiang Wang's team at the Third Military Medical University in Chongqing, China, injected amyloid plaques into the brains of healthy rats and gave some the equivalent of a smoker's daily dose of nicotine for two weeks, while others received nothing, reports New Scientist.

All the rats showed early signs of tau tangles and had difficulty navigating a maze, but the rats that were on nicotine did worse than those that were not.

The study has been published in the European Journal of Pharmacology.

Brain Area That May Delay Need for Gratification Found

THURSDAY, April 15 (HealthDay News) -- A brain circuit that may govern the ability to resist instant gratification to achieve long-term benefit has been pinpointed by German researchers.

"Humans normally prefer larger over smaller rewards, but this situation can change when the larger rewards are associated with delays. Although there is no doubt that humans discount the value of rewards over time, in general, individuals exhibit a particularly significant ability to delay gratification," study author Dr. Jan Peters, of the University Medical Center Hamburg-Eppendorf, said in a news release.

The researchers used functional MRI to monitor the brain activity of volunteers who had to make a series of choices between smaller immediate rewards and larger delayed rewards. The results showed that the degree to which participants chose long-term rewards was predicted by signals in the anterior cingulate cortex (ACC), an area of the brain involved in reward-based decision making, and functional coupling of the ACC with the hippocampus, which is involved in imagining the future.

"Taken together, our results reveal that vividly imagining the future reduced impulsive choice. Our data suggests that the ACC, based on episodic predictions involving the hippocampus, supports the dynamic adjustment of preference functions that enable us to make choices that maximize future payoffs," Peters said.

Helpful tips for an aging brain

MONTREAL ­ Since forgetting names and important dates and losing things are all common problems, clinical neuropsychologist Angela Troyer’s seminar at Toronto’s Baycrest geriatric and academic health science centre offers basic education and practical information when it comes to these matters. Visualizing, repeating, writing things down and making information meaningful (with a song or story) – these are painfully obvious memory tools that most people use to some degree. But when it comes to an aging brain, you must be painfully diligent about obvious things.

Remembering dates and future events. Write them down – but not on sticky notes all over your living space. Put them in a single book or in a digital organizer. “Everything in one place,” Troyer advises. If you are particularly scatterbrained or heavily booked, it might help to have both a book and a digital organizer, as long as you always duplicate the information in both.

Forgetting to turn off the stove or lock the door. These are typically the result of not paying a lot of attention. “So whenever you do these actions, you have to be mindful – focus attention on it, say it out loud and visualize it. See yourself doing it,” Troyer says.

Forgetting names. This is a common problem at every age, because it takes a lot of effort to commit names to memory. “Most people say it three or four times to themselves,” Troyer says, “but that’s not as useful as spaced repetition.” Spaced repetition involves repeating the name immediately, then a couple of minutes later, then again several minutes later. You can also help make information meaningful by putting it in a song, or relating it to a similar place or person. “So with names like Jonathan, you have to be more creative. Once you put time into it, it’s amazing how often you can do it.”

Where did I park the car? When you park it, remember to say where it is out loud. Repeat it and try to make the information meaningful. Then when looking for the car later, call upon your visual memory for a picture.

Panicking after you’ve forgotten something. It’s usually too late to try to find something after you lose it and freak out. “It’s best to identify problems and memory strategies before they happen,” Troyer says. So if you know you’re horrible at finding things or remembering appointments, try to find a logical solution for your specific problem.

Losing your belongings. Find a logical place to put each item. Put your slippers in the closet or by the front door. For glasses, get a string and leave them around your neck, Troyer says. “Again, these are about habits. They’re hard to make, but once you have them, they’re harder to break. And those are the best memory habits to have.”

Go easy on the distractions. And remember that hours spent watching TV are hours that could be spent on brain-friendlier activities.

Limb Movement Regained Years After Stroke

Study Shows Therapy 5 Years After Stroke Helps Patients Recover Movement of Limbs
Regaining lost movement may be possible many years after suffering a stroke thanks to intensive stroke rehabilitation therapy and help from new robotic aids.

A new study shows people who had lost significant strength in arm movement due to a stroke were able to achieve modest gains in limb movement and function as well as an improved outlook on life after undergoing intensive therapy an average of five years after their stroke.

Researchers say the results provide the best evidence yet that stroke survivors can regain some lost movement long after their stroke. In the U.S., stroke survivors typically receive stroke rehabilitation therapy only during the first six months after a stroke because the conventional wisdom is that lost movement cannot be regained after that point.

"There are about 6.4 million stroke patients in the U.S. with chronic deficits. We've shown that with the right therapy, they can see improvements in movement, everyday function, and quality of life," says researcher Albert Lo, assistant professor of neurology at Brown University, in a news release. "One of the purposes of this study was to upend the conventional dogma that stroke victims can't recover physiological function."
Using Robots to Regain Arm Movement

The study, published in The New England Journal of Medicine, involved 127 veterans who had suffered a stroke at least six months earlier that caused moderate to severe impairment of an arm. On average, the stroke had occurred nearly five years before enrollment in the study.

The participants were divided into three groups: one group received intensive stroke rehabilitation therapy with the use of robotic aids, another did similar exercises with a therapist, and the third group received only general health care and no stroke rehabilitation therapy.

For the first two groups, stroke rehabilitation therapy consisted of 36 one-hour sessions over a period of 12 weeks, during which they performed 1,024 upper-arm movements either with a robotic aid or with a therapist.

In the robot-assisted group, the participants sat at a table with their affected arm attached to the device and followed therapists' instructions or computerized prompts to move a cursor on a screen, like playing a video game. The robotic aid sensed their movements and provided help as needed.

Immediately after the therapy ended, researchers found people who received robot-assisted therapy showed significant improvement in their quality of life (an 8-point improvement on the Stroke Impact Scale) compared to those who received no therapy. No other significant differences were found at 12 weeks between the three groups.

But six months after the study began, the results showed that those who had received either type of intensive stroke rehabilitation therapy had improvements in upper-arm function (an average of a 3-point improvement on a stroke recovery scale).

Both intensive stroke rehabilitation therapy groups also reported improved progress in activities of their everyday life, such as cutting food with a fork and knife, opening jars, and tying shoes.

"We believe that by gaining more function and better control of their affected arms, patients were able to get out and do more, translating their motor benefits into additional meaningful social activity and participation," says Lo.

Researchers say long-term intensive stroke rehabilitation therapy, with or without robots, takes advantage of the brain's neuroplasticity -- the ability of the brain to "rewire" itself and compensate for lost function after damage.

Molecular Discovery Points to New Therapies for Brain Tumors

DNA modification defines early onset glioblastoma, is prevalent in lower grade gliomas

A class of brain tumor that tends to emerge in younger patients but is less aggressive than others can be identified by examining DNA methylation of a specific set of genes, scientists at The University of Texas M. D. Anderson Cancer Center and colleagues with The Cancer Genome Atlas report today online at Cancer Cell.

The national research group discovered that hypermethylation is a defining aspect of secondary glioblastomas, malignancies that have progressed from lower-grade tumors. Patients with these glioblastomas survive longer after diagnosis than those with other types.

"Discovery of molecular factors that define subgroups of glioblastoma will help us identify new therapeutic options for patients," said study co-senior author Ken Aldape, M.D., professor in the Department of Pathology at M. D. Anderson. "In this case, therapeutically altering the methylation state of the tumor's genes might be a new avenue for treatment."

Altered methylation of DNA in cancer is generally thought to promote tumor development, Aldape said. When methyl groups, consisting of one carbon and three hydrogen atoms, attach to sites called CpG islands in a gene's promoter region, the general result is to shut down the gene, although other factors affect gene regulation. On balance, methylation is thought to have a greater effect in silencing tumor-suppressing genes.

'Remarkably detailed insights into cancer'

Methylation is an epigenetic process; it affects gene expression without damaging or altering the gene's DNA sequence. The Cancer Genome Atlas is a joint initiative of the National Cancer Institute and the National Human Genome Research Institute to increase understanding of cancer genetics.

"Such findings are critical to the detection and treatment of brain cancer based on the genetic or epigenetic profile of each patient's disease," said Francis Collins, M.D., Ph.D., director at the National Institutes of Health. "The depth and breadth of expertise in The Cancer Genome Atlas research network, combined with ever-improving genomic technologies, is generating remarkably detailed insights into cancer."

Gliomas are tumors that form in the astrocytes and glial cells, which support the neurons. They are currently classified by microscopic examination.Glioblastomas, the most aggressive form of brain tumor, account for 50 percent of gliomas and have a median survival time of 15 months.

The team found that 24 of 272 glioblastomas were methylated at CpG islands for the defined gene set, and termed these cases as positive for the CpG island methylator phenotype (CIMP). Subsequent experiments, Aldape said, robustly defined the subgroup by genetic mutation, gene expression pattern and clinical outcome.

Glioblastomas are grouped by several types, or signatures, of gene expression that drive the tumor. Of the 24 methylated tumors, 21 fell in the "proneural" signature in which the genes expressed are associated with neural development. The team found that patients with CpG islandmethylation had a median age at diagnosis of 36, compared with 59 for those without.

Two avenues to new therapies

Among grade IV glioblastoma patients, the median survival for the CIMP-positive group was 150 weeks, compared with 42 weeks for those negative for this epigenetic alteration. CIMP-positivity was more common in low- and intermediate-grade tumors, with a 10-fold increase inmethylation seen in grade II tumors compared with grade IV glioblastomas.

Aldape said study results could lead to better therapies two ways. "First, this alteration could identify glioblastoma patients with outcomes similar to lower grade tumors. Second, since it is so common in lower grade tumors, it represents a new therapeutic target for these patients."

Methylation also was tightly associated with mutation in the IDHI gene in 78 percent of cases. IDHI mutations were recently associated with lower grade gliomas.

The researchers note that a subset of grade IV glioblastoma patients tends to be younger and have a relatively favorable prognosis. These patients might be identified in advance by using biomarkers such as CpG islandmethylation and IDH1 gene mutations. By the same token, the markers could be used to identify patients with low- or intermediate grade gliomas who may have relatively unfavorable prospects for their tumor grade.

They also found that of the 1,520 genes with promoter hypermethylation, only 293 genes, or 19 percent, showed a decrease in expression. "Epigenetics controls expression potential (of genes), rather than expression state," the authors noted.

Hypermethylation might promote tumor development by silencing two tumor-suppressing genes, the team reported, or by silencing others to provide a favorable context for genetic damage to occur.

The 27 co-authors on the project are from eight academic institutions and one biotechnology company. "Complex problems, such as defining clinically relevant molecular changes in human cancer, require cooperation among many individuals with complementary expertise and therefore require a 'team science' approach," Aldape said.

Research funding was provided by grants from the National Cancer Institute, the Brain Tumor Funders' Collaborative, the V Foundation, M. D. Anderson's Center for Cancer Epigenetics, the Rose Foundation, and M. D. Anderson's Specialized Program in Research Excellence for brain tumors.

M. D. Anderson co-authors with Aldape were Kristin Diefes and Krishna Bhat, Ph.D., of the Department of Pathology; and Christopher Pelloski, M.D., and Erik Sulman, M.D., Ph.D., of the Department of Radiation Oncology. Co-senior and corresponding author was Peter Laird, Ph.D., of the University of Southern California Epigenome Center. Other collaborating institutions were Johns Hopkins School of Medicine; Washington University School of Medicine; Linebarger Comprehensive Cancer Center at the University of North Carolina; University of California, Berkeley; Dana-Farber Cancer Institute; Broad Institute of Massachusetts Institute of Technology and Harvard University; and Genentech, Inc. 04/15/10

Brain Limits Capacity for Multitasking, Report Finds

French scientists have discovered the brain's construction limits the ability of humans to make more than two choices at the same time.

While some people may think their ability to multitask comes easily, a report published in the current issue of Science magazine suggests the brain’s two lobes automatically divides the ability to do two tasks in half, and the report warned overloading the brain with several tasks simultaneously reduces its ability to function as effectively. The study was authored by Sylvain Charron and Etienne Koechlin of the Institut National de la Santé and Ecole Normale Superieure, respectively.

The report noted the brain’s anterior prefrontal cortex (APC) gives humans the ability to simultaneously pursue several goals. Koechlin and Charron set out to find how the brain’s motivational system, including the medial frontal cortex (MFC), drives the pursuit of these concurrent goals. Using brain imaging, they observed that the left and right MFC, which jointly drive single-task performance, divide under dual-task conditions. “While the left MFC encodes the rewards driving one task, the right MFC concurrently encodes those driving the other task,” an abstract of the report explained. “The same dichotomy was observed in the lateral frontal cortex, whereas the APC combined the rewards driving both tasks. The two frontal lobes thus divide for representing simultaneously two concurrent goals coordinated by the APC. The human frontal function seems limited to driving the pursuit of two concurrent goals simultaneously.”

In an interview with BusinessWeek, Koechlin said while dual-tasking is fine, tackling three tasks at the same time would overwhelm the brain’s frontal function capacity. "Human higher cognition is dual in essence, which can explain why people like binary choice and have difficulties in multiple choices [people can easily switch back and forth between two options before making a decision, but not across three alternatives]," he told the news outlet. "This finding…suggests that the frontal function cannot keep track of more than two goals/tasks at the same time."

This research may help explain the results of a report published in August 2009 from researchers at Stanford University. Scientists there found those likely to experience rigorous daily multitasking are negatively impacting their cognitive state. The report, “Cognitive Control in Media Multitaskers,” claimed heavy media multitaskers performed worse on a test of task-switching ability than a group of users who multitasked lightly. The results suggested media multitasking, a rapidly growing societal trend, is “associated with a distinct approach to fundamental information processing.”

The research team conducted tests of 262 college undergraduates, dividing them into two groups. Results showed that heavy media multitaskers are more susceptible to interference from irrelevant environmental stimuli and from irrelevant representations in memory. This led to the unexpected result that heavy media multitaskers performed worse on a test of task-switching ability, which researchers concluded was likely due to reduced ability to filter out interference from the irrelevant task set.

While evidence suggests reducing the need for multiple tasks is a health benefit, cutting back on multitasking may not be an easy option for small business owners. A July survey by online payroll specialist SurePayroll found small to medium-size businesses (SMBs) are being forced to do more with less in a constrictive economy, but an increase in multitasking is hurting the quality of service at some midmarket companies. The survey found 88 percent of small business owners think multitasking is now a key component in running a successful business that business owners should embrace.