April 2, 2009, 5:15 AM CT

How to improve the working memory?

Psychology experts and neurologists invest considerable effort in the study of working memory. In terms of information retention, there is a difference between long-term memory, which is affected in diseases such as Alzheimer, and short-term or working memory, which allows us to make immediate decisions or structure a discourse. This more ephemeral memory is affected in diseases such as schizophrenia and depression, eventhough a cause-effect relationship has not been established. People with a higher working-memory capacity score higher on intelligence tests and, for this reason, it is thought that it appears to be intimately associated with people's cognitive ability. A study by IDIBAPS uses computational systems neurobiology models and functional magnetic resonance imaging scans to show that there are two parts of the cerebral cortex with highly differentiated roles implicated in this type of memory. The results of the study were reported in the journal Proceedings of the National Academy of Sciences of the United States of America (PNAS), in an article headed by Dr. Albert Compte of the Systems Neuroscience team of the Institut d'Investigacions Biomdiques August Pi i Sunyer (IDIBAPS), and with Fredrik Edin as the first author. This study was carried out in collaboration with two other laboratories of the Karolinska Institute, Stockholm, led by professors Torkel Klingberg and Jesper Tegnr......... Posted by: Daniel      Read more         Source

March 31, 2009, 3:43 PM CT

The limitations of working memory

Scientists at Karolinska Institutet (KI) have constructed a mathematical activity model of the brain´s frontal and parietal parts, to increase the understanding of the capacity of the working memory and of how the billions of neurons in the brain interact. One of the findings they have made with this "model brain" is a mechanism in the brain´s neuronal network that restricts the number of items we can normally store in our working memories at any one time to around two to seven.

Working memory, which is our ability to retain and process information over short periods of time, is essential to most cognitive processes, such as thinking, language and planning. It has long been known that the working memory is subject to limitations, as we can only manage to "juggle" a certain number of mnemonic items at any one time. Functional magnetic resonance imagery (fMRI) has revealed that the frontal and parietal lobes are activated when a sequence of two pictures is to be retained briefly in visual working memory. However, just how the nerve cells work together to handle this task has remained a mystery.

The study, which is reported in the journal PNAS, is based on a multidisciplinary project co-run by two research teams at KI led by professors Torkel Klingberg and Jesper Tegner. Most of the work was conducted by doctors Fredrik Edin and Albert Compte, the latter of whom is currently principal investigator of the theoretical neurobiology group at IDIBAPS in Barcelona......... Posted by: Daniel      Read more         Source

March 31, 2009, 5:21 AM CT

Link Between Schizophrenia And Diabetes

People with schizophrenia are at increased risk for type 2 diabetes, Medical College of Georgia scientists have found.

In a study of 50 people newly-diagnosed with schizophrenia or a related psychotic disorder with no other known risk factors, 16 percent had either diabetes or an abnormal rate of glucose metabolism, says Dr. Brian Kirkpatrick, vice chair of the MCG Department of Psychiatry and Health Behavior. In a similar size control group of people without schizophrenia, none had signs of or had developed the disease.

People with diabetes cannot produce or properly use insulin, a hormone that converts glucose, starches and other food into energy.

"These findings point toward there being some shared environmental factors or genetic factors between the development of schizophrenia and diabetes," he says.

Dr. Kirkpatrick presented his findings at the International Congress on Schizophrenia Research in San Diego March 28-April 1.

Scientists have long suspected that schizophrenia led to an increased risk of diabetes, Dr. Kirkpatrick says.

To find out whether there was a link, he and his colleagues at the University of Barcelona in Spain and the University of Maryland administered a two-hour oral glucose test to patients who had still not been placed on anti-psychotic medication. Catching them before prescriptive therapy was important because scientists already knew that some of the most effective schizophrenia drugs also cause rapid weight gain - a risk factor for type 2 diabetes......... Posted by: JoAnn      Read more         Source

March 26, 2009, 9:56 PM CT

Neurodegeneration in Alzheimer's disease

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Tiny, toxic protein particles severely disrupt neurotransmission and inhibit delivery of key proteins in Alzheimer's disease, two separate studies by Marine Biological Laboratory (MBL) scientists have found.

The particles are minute clumps of amyloid beta, which has long been known to accumulate and form plaques in the brain of Alzheimer's patients.

"These small particles that haven't aggregated into plaquesthese are increasingly being seen as the really toxic species of amyloid beta," says Scott Brady of University of Illinois College of Medicine, who has been an MBL investigator since 1982.

Brady and colleagues observed that these particles inhibit neurons from communicating with each other and with other target cells in the body.

"The disease symptoms for Alzheimer's are associated not with the death of the neurons that is a very late event but with the loss of functional connections. It's when the neuron is no longer talking to its targets that you start to get the memory deficits and dementia linked to the disease," Brady says......... Posted by: Daniel      Read more         Source

March 26, 2009, 9:34 PM CT

Exercise and Migraine

While physical exercise has been shown to trigger migraine headaches among sufferers, a newly released study describes an exercise program that is well tolerated by patients. The findings show that the program decreased the frequency of headaches and improved quality of life. The study is published in Headache: The Journal of Head and Face Pain.

The study used a sample of migraine sufferers who were examined before, during and after an aerobic exercise intervention. The program was based on indoor cycling (for continuous aerobic exercise) and was designed to improve maximal oxygen uptake without worsening the patients' migraines.

After the therapy period, patients' maximum oxygen uptake increased significantly. There was no worsening of migraine status at any time during the study period and, during the last month of therapy, there was a significant decrease in the number of migraine attacks, the number of days with migraine per month, headache intensity and amount of headache medicine used.

Individuals with headache and migraine typically are less physically active than those without headache. Patients with migraine often avoid exercise, resulting in less aerobic endurance and flexibility. Therefore, well designed studies of exercise in patients with migraine are imperative......... Posted by: Daniel      Read more         Source

March 19, 2009, 6:10 AM CT

Why is it difficult to recognize faces on photo negatives?

Humans excel at recognizing faces, but how we do this has been an abiding mystery in neuroscience and psychology. In an effort to explain our success in this area, scientists are taking a closer look at how and why we fail.

A newly released study from MIT looks at a especially striking instance of failure: our impaired ability to recognize faces in photographic negatives. The study, which appears in the Proceedings of the National Academy of Sciences this week, suggests that a large part of the answer might lie in the brain's reliance on a certain kind of image feature.

The work could potentially lead to computer vision systems, for settings as diverse as industrial quality control or object and face detection. On a different front, the results and methodologies could help scientists probe face-perception skills in children with autism, who are often reported to experience difficulties analyzing facial information.

Anyone who remembers the days before digital photography has probably noticed that it's much harder to identify people in photographic negatives than in normal photographs. "You have not taken away any information, but somehow these faces are much harder to recognize," says Pawan Sinha, an associate professor of brain and cognitive sciences and senior author of the PNAS study......... Posted by: Daniel      Read more         Source

March 19, 2009, 5:10 AM CT

How Brain Remembers Single Events

Single events account for a number of of our most vivid memories - a marriage proposal, a wedding toast, a baby's birth. Until a recent UC Irvine discovery, however, researchers knew little about what happens inside the brain that allows you to remember such events.

In a study with rats, neuroscientist John Guzowski and his colleagues observed that a single brief experience was as effective at activating neurons and genes linked to memory as more repetitive activities.

Knowing how the brain remembers one-time events can help researchers design better therapies for diseases such as Alzheimer's in which the ability to form such memories is impaired.

"Most experiences in life are encounters defined by places, people, things and times. They are specific, and they happen once," says Guzowski, UCI neurobiology and behavior assistant professor. "This type of memory is what makes each person unique".

It is well known that a brain structure called the hippocampus is critical to memory and learning, but a number of questions exist about how brief experiences trigger the physical changes necessary for memory. In his study, Guzowski set out to learn how neurons in the hippocampus react to single events - especially in the CA3 region, which is believed to be most critical for single-event memory......... Posted by: Daniel      Read more         Source

March 12, 2009, 9:53 PM CT

How brain records memories

It appears to be possible to "read" a person's memories just by looking at brain activity, as per research carried out by Wellcome Trust scientists. In a study published recently in the journal Current Biology , they show that our memories are recorded in regular patterns, a finding which challenges current scientific thinking.

Demis Hassabis and Professor Eleanor Maguire at the Wellcome Trust Centre for Neuroimaging at UCL (University College London) have previously studied the role of a small area of the brain known as the hippocampus which is crucial for navigation, memory recall and imagining future events. Now, the scientists have shown how the hippocampus records memory.

When we move around, nerve cells (neurons) known as "place cells", which are located in the hippocampus, activate to tell us where we are. Hassabis, Maguire and his colleagues used an fMRI scanner, which measures changes in blood flow within the brain, to examine the activity of these places cells as a volunteer navigated around a virtual reality environment. The data were then analysed by a computer algorithm developed by Demis Hassabis.

"We asked whether we could see any interesting patterns in the neural activity that could tell us what the participants were thinking, or in this case where they were," explains Professor Maguire, a Wellcome Trust Senior Research Fellow. "Surprisingly, just by looking at the brain data we could predict exactly where they were in the virtual reality environment. In other words, we could 'read' their spatial memories"......... Posted by: Daniel      Read more         Source

March 10, 2009, 10:56 PM CT

Migraines, pregnancy and risk of stroke

Women who suffer migraines are at an increased risk of stroke during pregnancy as well as other vascular conditions such as heart disease, hypertension and blood clots, concludes a study published on bmj.com today.

Migraine headache occurs in up to 26% of women of childbearing age and around one third of women aged between 35 and 39. Eventhough it is very common in this age group, little is known about the prevalence of migraine during pregnancy.

So in the largest study of its kind, scientists in the United States set out to test the association between migraine and vascular diseases during pregnancy.

Using a national database of over 18 million hospital discharge records, they identified 33,956 pregnancy related discharges with a diagnosis of migraine from 2000 to 2003.

Older women (40 years of age or more) were 2.4 times more likely to have a diagnosis of migraines than women under 20 years of age, and white women were more likely to have a diagnosis of migraines than any other race or ethnicity.

Migraines during pregnancy were associated with a 15-fold increased risk of stroke. Migraines also tripled the risk of blood clots in the veins and doubled the risk of heart disease. Vascular risk factors were also strongly linked to migraines. These included diabetes, hypertension and cigarette smoking......... Posted by: Daniel      Read more         Source

March 6, 2009, 9:37 PM CT

New breakthrough therapy for brain cancer

The combination of two drugs produces a critical improvement in the therapy of certain brain tumours. This has been demonstrated by scientists at Bonn University working in co-operation with German and Swiss colleagues in a current study. They treated 39 patients who had been diagnosed with a so-called gliablastoma. The patients survived on average 23 months; with the standard treatment the mean would have been 14.6 months. Glioblastomas are the most aggressive and the commonest brain tumours. Left untreated, they prove fatal within just a few weeks. The study has been reported in the Journal of Clinical Oncology (doi: 10.1200/JCO.2008.19.2195).

Even today, glioblastomas are untreatable something which even the new combination treatment cannot change. Nevertheless, Professor Dr. Ulrich Herrlinger of Bonn Universitys Schwerpunkt Klinische Neuroonkologie speaks of an outstanding success: "This uncommonly manifest extension of the survival time has surprised even us. Our results offer the opportunity to improve our grip on this aggressive form of cancer. Now, further investigations involving a larger number of patients are needed to optimise this treatment. Planning for this is already in hand in Bonn".

Up to now, doctors have treated glioblastomas using radiotherapy with concomitant chemotherapy. The "gold standard" for this for the last few years has been the active agent temozolomide. This is still celebrated as the most important breakthrough in the therapy of glioblastomas. The scientists combined this preparation with the drug lomustine. At the same time, the patients were given radiotherapy. The 39 patients thus treated survived the tumour for an average of 23.1 months. With the standard treatment, this time is over one third shorter. Seven patients even survived for over four years......... Posted by: Janet      Read more         Source