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March 13, 2008, 8:48 PM CT

Memory on Trial

Memory on Trial
Research says verbatim trace, i.e. memories of what actually happened, may reduce false memories.
The U.S. legal system has long assumed that all testimony is not equally credible, that some witnesses are more reliable than others. In tough cases with child witnesses, it assumes adult witnesses to be more reliable. But what if the legal system had it wrong?

Scientists Valerie Reyna, human development professor, and Chuck Brainerd, human development and law school professor--both from Cornell University--argue that like the two-headed Roman god Janus, memory is of two minds--that is, memories are captured and recorded separately and differently in two distinct parts of the mind.

They say children depend more heavily on a part of the mind that records, "what actually happened," while adults depend more on another part of the mind that records, "the meaning of what happened." As a result, they say, adults are more susceptible to false memories, which can be extremely problematic in court cases.

Reyna's and Brainerd's research, funded by the National Science Foundation, Arlington, Va., sparked more than 30 follow-up memory studies, a number of of them also funded by NSF. The scientists review the follow-on studies in an upcoming issue of Psychological Bulletin.

Tis research shows that meaning-based memories are largely responsible for false memories, particularly in adult witnesses. Because the ability to extract meaning from experience develops slowly, children are less likely to produce these false memories than adults, and are more likely to give accurate testimony when properly questioned.........

Posted by: JoAnn      Read more         Source


March 13, 2008, 8:23 PM CT

Pain Receptor in Brain and Memory

Pain Receptor in Brain and Memory
Researchers have long known that the nervous system receptor known as TRPV1 can affect sensations of pain in the body. Now a group of Brown University researchers has observed that these receptors - a darling of drug developers - also may play a role in learning and memory in the brain.

In surprising new research, reported in the journal Neuron, Julie Kauer and her team show that activation of TPRV1 receptors can trigger long-term depression, a phenomenon that creates lasting changes in the connections between neurons. These changes in the brain - and the related process of neural reorganization known as long-term potentiation - are thought to bethe cellular basis for memory making.

"We've known that TRPV1 receptors are in the brain, but this is some of the first evidence of what they actually do there," Kauer said. "And the functional role we uncovered is unexpected. No one has previously linked these pain receptors to a cellular mechanism underlying memory. So we may have found a whole new player in brain plasticity".

The study findings have implications for drug development, Kauer said.

The research points out potentially effective new targets for drugs that could prevent memory loss or could possibly treat neural disorders such as epilepsy, Kauer said. The other implication may be cautionary. Drug makers already sell drugs - such as the weight-loss pill rimonabant, which is sold in Europe under the name Acomplia - that can block TRPV1 receptors. Other drugs aimed at reducing pain and inflammation by blocking or activating TRPV1 receptors are in the research pipeline. But drugs that bind to TRPV1 receptors in the central nervous system are likely to influence more than just pain-related functions, Kauer said.........

Posted by: Daniel      Read more         Source


March 12, 2008, 9:31 PM CT

Paradoxical Alzheimer's finding linking memory loss

Paradoxical Alzheimer's finding linking memory loss
Do you remember the seventh song that played on your radio on the way to work yesterday? Most of us dont, thanks to a normal forgetting process that is constantly cleaning house culling inconsequential information from our brains. Scientists at the Buck Institute now think that this normal memory loss is hyper-activated in Alzheimers disease (AD) and that this effect is key to the profound memory loss linked to the incurable neurodegenerative disorder.

Last year, this same group of scientists observed that they could completely prevent Alzheimers disease in mice genetically engineered with a human Alzheimers geneMouzheimersby blocking a single site of cleavage of one molecule, called APP for amyloid precursor protein. Normally, this site on APP is attacked by molecular scissors called caspases, but blocking that process prevented the disease. Now they have studied human brain tissue and observed that, just as expected, patients suffering from AD clearly show more of this cleavage process than people of the same age who do not have the disease. However, when they extended their studies to much younger people without Alzheimers disease, they were astonished to find an apparent paradox: these younger people displayed as much as ten times the amount of the same cleavage event as the AD patients. The scientists now believe they know why.........

Posted by: Daniel      Read more         Source


March 12, 2008, 9:29 PM CT

Ibuprofen Works Against Aspirin

Ibuprofen Works Against Aspirin
Stroke patients who use ibuprofen for arthritis pain or other conditions while taking aspirin to reduce the risk of a second stroke undermine aspirin's ability to act as an anti-platelet agent, scientists at the University at Buffalo have shown.

In a cohort of patients seen by physicians at two offices of the Dent Neurologic Institute, 28 patients were identified as taking both aspirin and ibuprofen (a nonsteroidal anti-inflammatory drug, or NSAID) daily and all were found to have no anti-platelet effect from their daily aspirin.

Thirteen of these patients were being seen because they had a second stroke/TIA while taking aspirin and a NSAID, and were platelet non-responsive to aspirin (aspirin resistant) at the time of that stroke.

The scientists observed that when 18 of the 28 patients returned for a second neurological visit after discontinuing NSAID use and were tested again, all had regained their aspirin sensitivity and its ability to prevent blood platelets from aggregating and blocking arteries.

The study is the first to show the clinical consequences of the aspirin/NSAID interaction in patients being treated for prevention of a second stroke, and presents a possible explanation of the mechanism of action.

The Food and Drug Administration currently warns that ibuprofen might make aspirin less effective, but states that the clinical implications of the interaction have not been reviewed.........

Posted by: Daniel      Read more         Source


March 11, 2008, 7:51 PM CT

New nerve cells originate from neural stem cells

New nerve cells originate from neural stem cells
Most cells in the human brain are not nerve cells, but supporting cells (glial cells). They serve as a framework for nerve cells and play an important role in the wound reaction that occurs with injuries to the brain. However, what these reactive glial cells in the brains of mice and men originate from, and which cells they evolve into was hitherto unknown.

Now, the study group of Prof. Dr. Magdalena Gtz is able to show that after injury, these reactive glial cells in the brains of mice restart their cell division. They then become stem cells from which nerve cells can form yet again under favourable cell culture conditions.

With this came the ground-breaking proof that, in an injured region of the brain, adult neural stem cells exist that could later serve as a source of new nerve cells.

In her study group, the stem cell expert, Magdalena Gtz, examines the molecular bases of cerebral development, in particular in the cerebral cortex. Gtz proved in earlier investigations that glial brain cells can act as stem cells, and nerve cells emerge from glial cells. She also pointed out which factors play a role in the cross-over from glial to neural cells. Now, thanks to these results, the distant goal of being able to use the processes therapeutically is getting a little closer stresses Gtz.........

Posted by: Daniel      Read more         Source


March 5, 2008, 9:28 PM CT

Earlier, More Accurate Diagnosis of Alzheimer's Disease

Earlier, More Accurate Diagnosis of Alzheimer's Disease
Scientists involved in a large, multi-institutional study using positron emission tomography (PET) imaging with the radiotracer fluorodeoxyglucose (FDG) were able to classify different types of dementia with very high rates of success, raising hopes that dementia diagnoses may one day be made at earlier stages.

"Previously, researchers have been able to look only at the surface of the brain to differentiate various types of dementia," said Lisa Mosconi, Ph.D., assistant professor of psychiatry at the New York University School of Medicine. "With FDG PET, we were able to develop standardized disease-specific patterns from which we could correctly classify dementia more than 94 percent of the time."

The study, which was published in the recent issue of the Journal of Nuclear Medicine, measured the cerebral metabolic rate of glucose (CMRglc)-the amount of sugar the brain uses to fuel its activities-in various areas of the organ. A decrease in this rate is indicative of a loss of nerve cells and of dysfunction linked to dementia. Because FDG behaves like glucose when injected into the body, its location in the PET scans pinpointed the specific area where glucose utilization had fallen below normal levels as in comparison to an age-appropriate control group.

"Each type of dementia examined-Alzheimer's disease (AD), frontotemporal dementia (FTD), and dementia with Lewy bodies (DLB)-affects a different area of the brain. Based on where in the brain this decrease occurred, we were able to determine which type of dementia a patient had," Mosconi explained.........

Posted by: Daniel      Read more         Source


March 4, 2008, 4:25 PM CT

Links Betweenarts Education And Cognitive Development

Links Betweenarts Education And Cognitive Development
Learning, Arts, and the Brain, a study three years in the making, is the result of research by cognitive neuroresearchers from seven leading universities across the United States. In the Dana Consortium study, released recently at a news conference at the Dana Foundation's Washington, DC headquarters, scientists grappled with a fundamental question: Are smart people drawn to the arts or does arts training make people smarter?

For the first time, coordinated, multi-university scientific research brings us closer to answering that question. Learning, Arts, and the Brain advances our understanding of the effects of music, dance, and drama education on other types of learning. Children motivated in the arts develop attention skills and strategies for memory retrieval that also apply to other subject areas.

The research was led by Dr. Michael S. Gazzaniga of the University of California at Santa Barbara. "A life-affirming dimension is opening up in neuroscience," said Dr. Gazzaniga, "to discover how the performance and appreciation of the arts enlarge cognitive capacities will be a long step forward in learning how better to learn and more enjoyably and productively to live. The consortium's new findings and conceptual advances have clarified what now needs to be done".........

Posted by: Daniel      Read more         Source


February 25, 2008, 8:58 PM CT

Many Stroke, Heart Attack Patients May Not Benefit from Aspirin

Many Stroke, Heart Attack Patients May Not Benefit from Aspirin
Up to 20 percent of patients taking aspirin to lower the risk of suffering a second cerebrovascular event do not have an antiplatelet response from aspirin, the effect thought to produce the protective effect, scientists at the University at Buffalo have shown.

"Millions of people use low-dose aspirin either for prevention of a second stroke, second heart attack or second episode of peripheral artery disease," said Francis M. Gengo, Pharm.D., lead researcher on the study.

Gengo is professor of neurology in the UB School of Medicine and Biomedical Sciences and professor of pharmacy practice in the UB School of Pharmacy and Pharmaceutical Sciences.

"In those three indications, it's crystal clear that aspirin reduces the risk of a second heart attack or stroke in most patients. But we have known for years that in some stroke and heart attack patients, aspirin has no preventive effect".

With no definitive data on the frequency of this condition, known as aspirin resistance, physicians were left with a best guess of between 5 and 50 percent, said Gengo.

UB scientists now have confirmed the 20 percent figure through a strictly controlled study conducted over 29 months in 653 consecutive stroke patients seen at Dent Neurologic Institute offices in the Buffalo suburbs Amherst and Orchard Park.........

Posted by: Daniel      Read more         Source


February 14, 2008, 10:09 PM CT

Physicians Pinpoint Cause Of Children's Seizures

Physicians Pinpoint Cause Of Children's Seizures
It was no way for an 11-year-old to live. For a month the boy had endured daily episodes of uncontrollable jerking and foaming at the mouth, and his physicians at Lucile Packard Children's Hospital were concerned that the boy had epilepsy. Before starting the boy on a lifetime of anti-seizure medications, though, they turned to an unconventional diagnostic tool: hypnosis.

"Children are highly suggestible and they have great imaginations," said Packard Children's child psychiatry expert Richard Shaw, MD. "We've observed that if we suggest that they are going to have one of their events while they are in a hypnotic trance, they will commonly have one".

But wait. Aren't physicians supposed to try to STOP seizures rather than searching for new ways to cause them? In a word, yes. But in order to treat seizures effectively, doctors must learn which parts of the brain are causing the trouble. A number of children who seem to be having epileptic seizures are actually having an involuntary physical reaction to psychological stress in their lives. These events require a vastly different therapy than do true epileptic seizures.

The only way to pinpoint the true cause is to monitor the child's brain activity during an event. Connecting a panel of electrodes to a child's scalp is relatively easy and painless. Conducting a "seizure watch" of indefinite length is another matter.........

Posted by: JoAnn      Read more         Source


February 10, 2008, 10:04 PM CT

Moss protein plays role in Alzheimer's Disease

Moss protein plays role in Alzheimer's Disease
A twenty-eight-day old Physcomitrella (left) moss gametophyte has a surprising link to an amyloid plaque, (right) found in brains that have Alzheimer's disease.
Preventing Alzheimer's disease is a goal of Raphael Kopan, Ph.D., professor of molecular biology and pharmacology at the Washington University School of Medicine. The moss plant Physcomitrella patens studied in the laboratory of Ralph S. Quatrano, Ph.D., the Spencer T. Olin Professor and chair of the biology department on WUSTL's Danforth Campus, might inch Kopan toward that goal. Here's how.

The gene presenilin (PS) in mammals provides the catalytic activity for an enzyme called gamma secretase, which cleaves, or cuts, important proteins Notch, Erb4 and the amyloid precursor protein (APP), all key components of communication channels that cells use to arbitrate functions during development. There are two mammalian genes that occur in mammals for which mutations cause an earlier onset of Alzheimer's. One is APP, where a fragment of the protein accumulates in amyloid plaques linked to the disease. Another common site for mutations is found in PS proteins. The enzyme gamma secretase contains PS and works to dispose of proteins stuck in the cellular membrane.

This enzyme, with PS at its core, mediates two cellular decisions. One is to cut APP and, as a byproduct, generate the bad peptide linked to Alzheimer's; the other is to cut the Notch protein in response to specific stimuli. Notch is then free to enter the nucleus of cells where it partakes in regulating normal gene expression. Without Notch activity, a mammal has no chance of living.........

Posted by: Daniel      Read more         Source



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Did you know?
The drug Ativan is better than Valium or Dilantin for controlling severe epileptic seizures, according to a new review of studies.Ativan, or lorazepam, and Valium, or diazepam, are both benzodiazepines, the currently preferred class of drugs for treating severe epileptic seizures. Dilantin, or phenytoin, is an anticonvulsant long used for the treatment of epileptic seizures.

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