Study reveals natural protection mechanism during stroke

Last updated 17 August 2011
Scientists have discovered how some nerve cells in the brain are resistant to damage during a stroke - a finding that could one day pave the way for new therapies to protect other types of nerve cells.

A research team at the University of Bristol examined two types of nerve cell in the hippocampus - part of the brain that is involved in memory and navigation.

One of the cell types, the CA1 cell, is highly susceptible to stroke-related damage, while the other type, the CA3 cell, is much more resistant.

The researchers found that CA1 cells' susceptibility appears to be linked to the absence of adenosine A3 receptors, which are normally activated by high levels of adenosine during stroke conditions.

Dr Jake Mellor, senior lecturer in the university's School of Physiology and Pharmacology, said: 'We hope that if we can understand why some nerve cells are resistant to stroke damage we may be able to develop strategies to protect those cells that are sensitive.'

The scientist, whose findings are published in the Journal of Neuroscience, noted that stroke's unpredictability and the need to administer drugs within minutes of onset have historically made it difficult to treat.

'These problems will not be overcome by our research but our findings do reveal a natural protection mechanism in some nerve cells, which may be useful in developing treatments to protect other nerve cell types,' he added.

Around 150,000 people in the UK are affected by stroke each year, according to the Stroke Association........ http://bit.ly/qIIqXI

Life After Stroke Audiobook

In this unique and gentle approach to Stroke, learn
everything there is to know about stroke whether a
survivor, friend, family member or caregiver.

This important guide contains information that will:

Educate you about the immediate aftereffects of stroke,
so you know what to expect and how to overcome setbacks
in the early weeks following a stroke.

Teach you how to set goals following a stroke that will
speed the progression of your healing.

Help you understand what rehabilitation is all about,
including what forms of rehabilitation are available
and how they can improve your quality of life and
standard of living,..... http://bit.ly/qsRgOm

Speaking and Listening Share Large Part of Brain Infrastructure

ScienceDaily (Aug. 16, 2011) — What areas of the brain are involved in the linguistic processes underlying speech and listening and are there large differences between these? Neuroscientists from the Donders Institute for Brain, Cognition and Behaviour at Radboud University Nijmegen are the first to have successfully investigated this question using functional magnetic resonance imaging (fMRI). In what may come as a surprise to many scientists, the researchers have established that there is a large degree of overlap between the areas involved.

---

See Also:

Mind & Brain

• Language Acquisition
• Neuroscience
• Perception
• Brain Injury
• Child Development
• Intelligence

Reference

• Functional neuroimaging
• Psycholinguistics
• Learning disability
• Brain damage

The results are published in the journal Psychological Science.
Within the scientific community there is a lot of discussion about whether the brain functions involved in speech production are also involved in the comprehension of speech. In the area of mirror neuron research in particular (a hot topic for the past 15 years), research has viewed the overlap between the areas of the brain involved in speech and listening as reaction and observed action, says neuroscientist Laura Menenti, who is currently working at the University of Glasgow. However, speaking and listening are more than just action and observation. They also involve linguistic processing. Menenti and her colleagues mainly focused on this last aspect:..... http://bit.ly/nXC6tn

FDA panel votes 9-2 in favor of new blood thinner drug

By Dr Ananya Mandal, MD
A new stroke preventer from Bayer and Johnson & Johnson – Xarelto moved one step closer to U.S. approval, but questions remained about restrictions on labeling and the need for more studies.
An Food and Drug Administration (FDA) panel advisory looked at the effectiveness and safety of blood thinner Xarelto compared to standard warfarin in the ROCKET-AF trial. They voted 9-2 on Thursday to recommend approval of the once-a-day anti-clotting pill, called Xarelto. They asked for further studies on how to transition off of Xarelto. FDA decision on the drug is expected by Nov. 4
Xarelto is one of several promising entrants angling to replace warfarin for people with dangerously irregular heart rhythms, called atrial fibrillation (AF). Warfarin is a problematic decades-old clot preventer originally developed as rat poison. AF patients' irregular heartbeats can cause blood to pool, increasing their risk of blood clots and strokes. But many are unwilling to take warfarin, which requires regular blood tests, or are unable to tolerate it.
The study involved 14,264 patients across 1,178 sites in 45 countries. Patients were diagnosed with persistent or paroxysmal AF with additional risk factors for stroke, and were randomly assigned to warfarin (Coumadin, Bristol-Meyers Squibb) or rivaroxaban (Xarelto, Johnson & Johnson). Patients who were assigned to rivaroxaban received a 20mg dose once daily, and warfarin was titrated to a target range of two to three.
Overall, a decreased rate of stroke and non-CNS embolism events were associated with rivaroxaban during treatments vs. warfarin (P=.015). In the intention-to-treat analysis, rivaroxaban was non-inferior to warfarin (P=.117). The rate of bleeding and adverse events was similar between the rivaroxaban and warfarin arms, but rivaroxaban was associated with less intercranial hemorrhage and fatal bleeding.
“I've seen the problems many patients face with warfarin,” said Dr. Philip Sager, a panel member and executive committee member of the Cardiac Safety Research Consortium in San Francisco. “I think there's a tremendous unmet medical need for new therapies.”
Panelists were divided on whether Xarelto, with the clinical name rivaroxaban, was as effective as warfarin. In clinical trials that compared Xarelto to warfarin, panelists and the FDA said the older drug was not always given in the proper dosing, making it more difficult to determine if Xarelto was just as good.
“I've heard nothing that convinces me that rivaroxaban should be first-line treatment for many patients,” said Allan Coukell, the patient representative on the panel and director for medical safety at Pew Health Group, adding that Xarelto's label should reflect that......   


http://bit.ly/n2z5qA

Interfacing Your Brain with Computers

Big Think Editors on April 17, 2011, 9:36 AM

What's the Most Recent Development?
Renowned scientist and professor of neurology at Brown University, John Donoghue has made incredible advances in interfacing the human brain with computers, allowing paralyzed people to move objects by simply using their imagination. A small chip implanted in the brain picks up the right neural signals and beams them into a computer where they are translated into moving a cursor or controlling a computer keyboard. "By this means, paralysed people can move a robot arm or drive their own wheelchair, just by thinking about it."
What's the Big Idea?
The implications of a brain-computer interface are formidable, from transferring human consciousness onto a computer—in other words, immortality—to using the technology to read people's minds. Military establishments are interested in Dr. Donoghue's research in order to enhance interrogations methods. Were interrogators able to interface the mind of a prisoner with a computer, perhaps information could be extracted they could use to prevent criminal acts and save lives. It seems the next phase of evolution will be synthetic, rather than purely biological. more read...

Connectomics: Mapping The Brain's Complexity

Scientists say they have moved a step closer to developing a computer model of the brain after finding a way to map both the connections and functions of nerve cells in the brain together for the first time.
In a study in the journal Nature on Sunday, researchers from Britain's University College London (UCL) described a technique developed in mice which enabled them to combine information about the function of neurons with details of their connections.
The study is part of an emerging area of neuroscience research known as 'connectomics'. A little like genomics, which maps our genetic make-up, connectomics aims to map the brain's connections, known as synapses.
By untangling and being able to map these connections -- and deciphering how information flows through the brain's circuits -- scientists hope to understand how thoughts and perceptions are generated in the brain and how these functions go wrong in diseases such as Alzheimer's, schizophrenia and stroke.
"We are beginning to untangle the complexity of the brain," said Tom Mrsic-Flogel, who led the study.
"Once we understand the function and connectivity of nerve cells spanning different layers of the brain, we can begin to develop a computer simulation of how this remarkable organ works."

Story continues below

Advertisement

But he said would take many years of work among scientists and huge computer processing power before that could be done.
In a report of his research, Mrsic-Flogel explained how mapping the brain's connections is no small feat: There are an estimated one hundred billion nerve cells, or neurons, in the brain, each connected to thousands of other nerve cells, he said, making an estimated 150 trillion synapses.
"How do we figure out how the brain's neural circuitry works? We first need to understand the function of each neuron and find out to which other brain cells it connects," he said.
In this study, Mrsic-Flogel's team focused on vision and looked into the visual cortex of the mouse brain, which contains thousands of neurons and millions of different connections.
Using high resolution imaging, they were able to detect which of these neurons responded to a particular stimulus.
Taking a slice of the same tissue, the scientists then applied small currents to subsets of neurons to see which other neurons responded and which of them were synaptically connected.
By repeating this technique many times, they were able to trace the function and connectivity of hundreds of nerve cells in visual cortex.
Using this method, the team hopes to begin generating a wiring diagram of a brain area with a particular function, such as the visual cortex. The technique should also help them map the wiring of regions that underpin touch, hearing and movement.
John Williams, head of neuroscience and mental health at the Wellcome Trust medical charity, which helped fund the study, said understanding the brain's inner workings was one of science's "ultimate goals."
"This important study presents neuroscientists with one of the key tools that will help them begin to navigate and survey the landscape of the brain," he said. more read....

Brain boffins in cortex mapping breakthrough

Brain boffins at University College London have made a major breakthrough in the ongoing effort to bridge the gap between man and machine.
The UCL research team has developed a technique for mapping both the connections and functions of nerve cells in the brain, as revealed by UCL News.

"We are beginning to untangle the complexity of the brain," reads a statement from UCL research fellow Tom Mrsic-Flogel. "Once we understand the function and connectivity of nerve cells spanning different layers of the brain, we can begin to develop a computer simulation of how this remarkable organ works."  more read...