Posts Tagged ‘science’

Brain Training Therapy For Brain Injury

Tuesday, April 20th, 2010

Psychologists in London, England, have shown that brain training can aid recovery from brain injuries.

As reported at the British Psychological Society’s Annual Conference in Stratford-upon-Avon on April 16, 2010, scientists at London’s Metropolitan University, just 15 minutes of daily brain training brought about dramatic memory improvements.

According to Dr Simon Moore – “It is really interesting to find that people with brain injuries both benefited from, and enjoyed these brain training games, and we hope that they can become part of treatment programmes that improve brain injured patients’ independence and self-fulfilment.”

This finding reinforces the anecdotal reports from Mind Sparke customers that Brain Fitness Pro restores cognitive ability lost after brain injury from physical trauma, adverse drug reaction, or depression.

New Brain Cells, Stress, And Learned Behavior

Thursday, April 1st, 2010
Stressed Out Mouse

Stressed Out Mouse

A new study by UT Southwestern scientists (Lagace, Donovan, DeCarolis, Farnbauch, Malhotra, Berton, Nestler, Krishnan and Eisch) sheds some light on the connection between stress and neurogenesis.

Eisch and her colleagues performed two experiments related to stress.

1. They exposed mice to a socially stressful experience — confrontation with a more aggressive mouse (the mouse equivalent of a carjacking), then measured the immediate and long term impact on the generation of new brain cells.

2. They irradiated mice to eliminate neurogenesis before exposing the irradiated mice to the same kind of stressful situation.

The scientists made two important findings:

In the first experiment, the stressful situation reduced neurogenesis temporarily (for a few days), and left the mice more likely to be fearful in similar situations.

In the second experiment the irradiated mice showed less fear when exposed to similar stressful situations.

These findings indicate that neurogenesis is key to forming stress memories. This can be a healthy response, educating us on avoidance. (Common sense.) But in cases of inappropriate or chronic stress response, neurogenesis may be overactive.

See Brain Region, See Other Brain Region Run

Friday, February 26th, 2010

A novel study shows that when learning new words the part of the brain we use depends on whether the words are nouns or verbs.

“Learning nouns activates the left fusiform gyrus, while learning verbs switches on other regions (the left inferior frontal gyrus and part of the left posterior medial temporal gyrus)”, says Catalan researcher Antoni Rodríguez-Fornells, co-author of the study from the Cognition and Brain Plasticity Unit of the University of Barcelona.

He and neurologist Thomas F. Münte from the Otto-von-Guericke University in Magdeburg, in Germany, reported their findings of neural differences in acquiring new nouns and verbs in the journal Neuroimage.

By studying real time scans showing brain activation during a language learning exercise the researchers confirmed prior observations that our brains handle nouns and verbs in different ways.

The scientists inserted nonsense words into otherwise meaningful sentences, and then asked the study participants to derive the meaning of the inserted word – “Joe bought his mom a grimo of flowers for Mother’s day…” for instance, indicates that the word “grimo” means “bunch.”

“This task simulates, at an experimental level, how we acquire part of our vocabulary over the course of our lives, by discovering the meaning of new words in written contexts”, explains Rodríguez-Fornells. “This kind of vocabulary acquisition based on verbal contexts is one of the most important mechanisms for learning new words during childhood and later as adults, because we are constantly learning new terms”.

They measured responses to 80 new nouns and 80 new verbs.

“[The] results suggest that the same regions previously associated with the representation of the meaning of nouns and verbs are also associated with establishing correspondences between these meanings and new words, a process that is necessary for learning a second language”, says Rodríguez-Fornells.

Seeing The Brain Hear

Wednesday, February 3rd, 2010

“The organization of the cortex does not look as pretty as it does in the textbooks,” says Dr. Kanold, Assistant Professor of Biology at the University of Maryland, and lead scientist on a new study of the auditory cortex. “Things are a lot messier than expected.”

Dr. Kanold and his team published their report on auditory processing in the January 31 online edition of Nature Neuroscience.

“[Discrete sampling] is like showing someone who wants to know how America looks, ‘Here is one person from New York City and one person from California.’ You don’t get a very good picture of what the country looks like from that sampling,” says Kanold, originally from Germany.

Kanold’s team employed a new technique to observe all the neurons across a broad swath of the auditory cortex. Using a dye that glows when calcium levels rise, indicating active neurons, the team shone a laser on areas of the cortex and measured the neuronal activity of hundreds of neurons in activated by simple tones at different frequencies.

Left: Dyed Brain Regions; Right: Frequency Response

Left: Dyed Brain Regions; Right: Frequency Response

According to Dr. Andrew King, Professor of Neurophysiology at the University of Oxford, “The functional organization of the auditory cortex has remained unclear and a matter of some controversy, despite the efforts of many labs over a number of years. The approach used by Dr. Kanold and colleagues is an important advance in this field.”

“We discovered that the organization of the cortex does not look as pretty as it does in the textbooks, which surprised us,” explains Kanold. “Things are a lot messier than expected. And we don’t see evidence of the maps previously proposed using less precise techniques.”

This messiness could hint at a brain that is far more adaptable than previously thought. “These results may rewrite our classical views of how cortical circuits are organized and what functions they serve,” suggests Dr. Shihab Shamma, whose own work had used discrete microelectrodes to map  the auditory cortex.

Kanold’s team looked at both how neurons receive sound information (the inputs), and how they process it (the outputs). “Neighboring neurons do their own thing by creating different outputs,” Kanold says, a finding which overturns conventional models. “You can imagine that you and your neighbor both receive water to your houses from the same pipe, but you do different things with it — you might cook with it while your neighbor waters the lawn. You can’t assume that they are doing the same thing just because they are neighbors.”

Dr. Kanold, an expert in neuroplasticity, sees a benefit to this randomness. “Each individual neuron is getting inputs from a wide range of frequencies, and by selecting which frequencies they are strongly responding to, they might be very easily able to shift their function,” he says. This might help explain how we are quickly able to tune in to different auditory information (paying attention at one moment to the car radio, and at the next to a question from the back seat).

Strength Training for Brain Sharpness

Friday, January 29th, 2010
Weight A Minute!

Weight A Minute!

In a study of women aged 65 to 75, strength training produced 10 to 12% increases on tests of executive function over the course of a year. A control group who trained on balance and toning did not show increases.

Teresa Liu-Ambrose, researcher at the Center for Hip Health and Mobility at Vancouver General Hospital was the lead author of the paper, which appears in the Jan. 25 issue of Archives of Internal Medicine.

The Phrenology of Fear

Thursday, January 28th, 2010
Mortified Mouse

Mortified Mouse

Scientists at Emory University, extending the work of others scientists who have identified the amygdala (an almond-shaped brain region) as key to our fear response, have shown that the prelimbic cortex plays a role, too.

Kerry Ressler, MD, PhD, and his team found that without a critical growth factor in the prelimbic cortex mice become less prone to remember a previously frightening experience. This finding could benefit the diagnosis and treatment for anxiety disorders such as post-traumatic stress disorder and phobias.

BDNF (brain-derived neurotrophic factor) has been called Miracle-Gro for brain cells. The protein protects cells from stress and stimulates them to forge new connections. Previous studies had shown that blocking BDNF’s action in the amygdala made it more difficult for fear memories to take hold.

“The prelimbic cortex is part of the medial prefrontal cortex, which appears to be important for emotional regulation in rodents as well as humans,” Ressler says. “Evidence is building that these regions may be dysregulated or even over-active in fear and anxiety disorders in humans.”

“This work is important for extending our understanding of how BDNF is important for neuronal plasticity, learning and memory,” Ressler says. “Together with our previous work, these data suggest that preventing neural plasticity in very precise, but critical brain regions, can have vastly different effects on emotional memory.

“It is becoming increasingly clear that these prefrontal cortex regions are functionally associated with regions of the brain known for a long time to be involved in emotion, such as the amygdala and hippocampus,” he adds. “Understanding the molecular and cellular mechanisms of these connections in rodent models will provide scientists a better understanding of how these similar areas are functioning in humans.”

See the report in Science Codex

Nanotechnology Approximates A Brain Cell

Saturday, January 23rd, 2010

Here’s a fascinating report on how French technologists have created an organic nanoparticle that responds somewhat like a neuron.

“In the nervous system, a synapse is the junction between two neurons, enabling the transmission of electric messages from one neuron to another and the adaptation of the message as a function of the nature of the incoming signal (plasticity). For example, if the synapse receives very closely packed pulses of incoming signals, it will transmit a more intense action potential. Conversely, if the pulses are spaced farther apart, the action potential will be weaker.

“It is this plasticity that the researchers have succeeding in mimicking with the NOMFET.”

Commenters on this report point out that it is poorly reported and misleading – but still interesting in my opinion.

Read more…

Adaptive Plasticity Clue To Schizophrenia

Friday, November 20th, 2009

UCSF scientists have found a gene in fruit flies whose human equivalent may play a critical role in schizophrenia.

The mutated form of the human gene – one of three associated with schizophrenia – mildly disrupts brain cell signaling.

The gene the study honed in on plays a role in “adaptive plasticity,” the process by which connected cells tolerate wide variations in communication signals. If one cell functions abnormally, the surrounding cells work around it, keeping brain function stable overall.

The team screened 276 mutated, or disabled, fly genes to see whether they affected adaptive plasticity — one, called dysbindin, did.

As reported in the November 20, 2009 issue of Science, senior author of the study, Graeme Davis, PhD, Albert Bowers Endowed Professor and Chair of the Department of Biochemistry and Biophysics at UCSF is quoted as saying:

“Mutation of the gene completely prevented the capacity of the neural circuitry to respond to an experimental perturbation, to be adaptive. The dysbindin mutation was one of very few gene mutations that had this effect,” he says. “The gene’s unique function suggests to us that impaired adaptive plasticity may have particular relevance to the cause or progression of schizophrenia.”

Davis theorizes that normal developmental changes in late teens and early twenties pose considerable stress to ongoing, stable neural function. The capacity of the brain to respond to these normal developmental changes – which reveal themselves as functional variations – may be impaired in people who become schizophrenic.

“The next question the researchers will ask,” he says, “is whether absence of the dysbindin gene causes a blockade of adaptive plasticity in mice and whether other genes linked to schizophrenia cause a similar block of adaptive plasticity.”

The study also ruled out any role in adaptive plasticity of various other genes.

“We tested numerous mutations that alter neural function, and most showed perfectly fine adaptive plasticity.” he says, “This suggests that there are distinct roles for genes at the synapse, some support normal neural function while a small subset control adaptive plasticity.”

“It’s become clear that the nervous system is remarkably stable, but not as one might suspect,” says Davis. “It is continuously responsive to a changing environment, which allows us to learn and remember and to respond to environmental change. There probably are many processes that are sensing the environment, continually updating neural function and neural structure in order to keep the brain stable. If we can understand how stability is maintained in the nervous system, perhaps we could understand what happens when stability is lost and disease ensues.”

“These are big questions that reach far beyond our current understanding of brain function,” he says. “This is the power and importance of basic science. By studying fundamental questions, you can discover unexpected phenomenon and also create new perspectives for understanding existing diseases, even if the human genes are known.” The new finding, he says, “may add a new dimension to the conversation about the origins of schizophrenia.”

UCSF is a leading university dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care.

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