Friday, 16 November 2012

Brainy beverage: Study reveals how green tea boosts brain power

It has long been believed that drinking green tea is good for the memory. Now researchers have discovered how the chemical properties of China's favorite drink affect the generation of brain cells, providing benefits for memory and spatial learning.

The research is published in Molecular Nutrition & Food Research.

"Green tea is a popular beverage across the world," said Professor Yun Bai from the Third Military Medical University, Chongqing, China. "There has been plenty of scientific attention on its use in helping prevent cardiovascular diseases, but now there is emerging evidence that its chemical properties may impact cellular mechanisms in the brain."

Professor Bai's team focused on the organic chemical EGCG, (epigallocatechin-3 gallate) a key property of green tea. While EGCG is a known anti-oxidant, the team believed it can also have a beneficial effect against age-related degenerative diseases.

"We proposed that EGCG can improve cognitive function by impacting the generation of neuron cells, a process known as neurogenesis," said Bai. "We focused our research on the hippocampus, the part of the brain which processes information from short-term to long-term memory."

"We have shown that the organic chemical EGCG acts directly to increase the production of neural progenitor cells, both in glass tests and in mice," concluded Bai. "This helps us to understand the potential for EGCG, and green tea which contains it, to help combat degenerative diseases and memory loss."

This paper is published as part of a collection of articles bringing together high quality research on the theme of food science and technology with particular relevance to China. Browse free articles from Wiley's food science and technology publications including the Journal of Food Science, Journal of the Science of Food and Agriculture and Molecular Nutrition & Food Research.

Story Source:
The above story is reprinted from materials provided by Wiley, via AlphaGalileo.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:
Yanyan Wang, Maoquan Li, Xueqing Xu, Min Song, Huansheng Tao, Yun Bai. Green tea epigallocatechin-3-gallate (EGCG) promotes neural progenitor cell proliferation and sonic hedgehog pathway activation during adult hippocampal neurogenesis. Molecular Nutrition & Food Research, 2012; 56 (8): 1292 DOI: 10.1002/mnfr.201200035
Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment.

View the original article here


Enhanced by Zemanta

Monday, 12 November 2012

New Findings reveal brain mechanisms at work during sleep

New findings presented today report the important role sleep plays, and the brain mechanisms at work as sleep shapes memory, learning, and behavior. The findings were presented at Neuroscience 2012, the annual meeting of the Society for Neuroscience and the world's largest source of emerging news about brain science and health.

One in five American adults show signs of chronic sleep deprivation, making the condition a widespread public health problem. Sleeplessness is related to health issues such as obesity, cardiovascular problems, and memory problems.



Today's findings show that:
Sleepiness disrupts the coordinated activity of an important network of brain regions; the impaired function of this network is also implicated in Alzheimer's disease (Andrew Ward, abstract 909.05).Sleeplessness plays havoc with communication between the hippocampus, which is vital for memory, and the brain's "default mode network;" the changes may weaken event recollection (Hengyi Rao, PhD, abstract 626.08).In a mouse model, fearful memories can be intentionally weakened during sleep, indicating new possibilities for treatment of post-traumatic stress disorder (Asya Rolls, abstract 807.06).Loss of less than half a night's sleep can impair memory and alter the normal behavior of brain cells (Ted Abel, PhD, abstract 807.13).

Story Source:
The above story is reprinted from materials provided by Society for Neuroscience.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment.

View the original article here


Enhanced by Zemanta

Friday, 9 November 2012

Learning requires rhythmical activity

The hippocampus represents an important brain structure for learning. Scientists at the Max Planck Institute of Psychiatry in Munich discovered how it filters electrical neuronal signals through an input and output control, thus regulating learning and memory processes.

Accordingly, effective signal transmission needs so-called theta-frequency impulses of the cerebral cortex. With a frequency of three to eight hertz, these impulses generate waves of electrical activity that propagate through the hippocampus. Impulses of a different frequency evoke no transmission, or only a much weaker one. Moreover, signal transmission in other areas of the brain through long-term potentiation (LTP), which is essential for learning, occurs only when the activity waves take place for a certain while. The scientists even have an explanation for why we are mentally more productive after drinking a cup of coffee or in an acute stress situation: in their experiments, caffeine and the stress hormone corticosterone boosted the activity flow.

When we learn and recall something, we have to concentrate on the relevant information and experience it again and again. Electrophysiological experiments in mice now show why this is the case. Scientists belonging to Matthias Eder´s Research Group measured the transmission of electrical impulses between neurons in the mouse hippocampus. Under the fluorescence microscope, they were able to observe in real time how the neurons forward signals.

Jens Stepan, a junior scientist at the Max Planck Institute of Psychiatry in Munich, stimulated the input region of the hippocampus the first time that specifically theta-frequency stimulations produce an effective impulse transmission across the hippocampal CA3/CA1 region. This finding is very important, as it is known from previous studies that theta-rhythmical neuronal activity in the entorhinal cortex always occurs when new information is taken up in a focused manner. With this finding, the researchers demonstrate that the hippocampus highly selectively reacts to the entorhinal signals. Obviously, it can distinguish important and, thus, potentially recollection-worth information from unimportant one and process it in a physiologically specific manner.

One possible reaction is the formation of the so-called long-term potentiation (LTP) of signal transmission at CA3-CA1 synapses, which is often essential for learning and memory. The present study documents that this CA1-LTP occurs only when the activity waves through the hippocampus take place for a certain time. Translating this to our learning behavior, to commit for instance an image to memory, we should intently view it for a while, as only then we produce the activity waves described long enough to store the image in our brain.

With this study, Matthias Eder and colleagues succeeded in closing a knowledge gap. "Our investigation on neuronal communication via the hippocampal trisynaptic circuit provides us with a new understanding of learning in the living organism. We are the first to show that long-term potentiation depends on the frequency and persistency of incoming sensory signals in the hippocampus," says Matthias Eder.

Story Source:
The above story is reprinted from materials provided by Max-Planck-Gesellschaft.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:
Jens Stepan, Julien Dine, Thomas Fenzl, Stephanie A. Polta, Gregor von Wolff, Carsten T. Wotjak, Matthias Eder. Entorhinal theta-frequency input to the dentate gyrus trisynaptically evokes hippocampal CA1 LTP. Frontiers in Neural Circuits, 2012; 6 DOI: 10.3389/fncir.2012.00064
Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment.

View the original article here


Enhanced by Zemanta

Monday, 5 November 2012

Omega-3 intake heightens working memory

Omega-3 essential fatty acids found in foods like wild fish and grass-fed livestock are necessary for human body functioning, their effects on the working memory of healthy young adults have not been studied until now.

In the first study of its kind, researchers at the University of Pittsburgh have determined that healthy young adults ages 18-25 can improve their working memory even further by increasing their Omega-3 fatty acid intake. Their findings have been published online in PLOS One
.
Led by Rajesh Narendarn, project principal investigator and associate professor of radiology, the Pitt research team sought healthy young men and women from all ethnicities to boost their Omega-3 intake with supplements for six months. They were monitored monthly through phone calls and outpatient procedures.

Before they began taking the supplements, all participants underwent positron emission tomography (PET) imaging, and their blood samples were analyzed. They were then asked to perform a working memory test in which they were shown a series of letters and numbers. The young adults had to keep track of what appeared one, two, and three times prior, known as a simple "n-back test."

After six months of taking Lovaza an Omega-3 supplement approved by the Federal Drug Administration the participants were asked to complete this series of outpatient procedures again. It was during this last stage, during the working memory test and blood sampling, that the improved working memory of this population was revealed.

Although the effects of Omega-3s on young people were a focus, the Pitt team was also hoping to determine the brain mechanism associated with Omega-3 regulation. Previous rodent studies suggested that removing Omega-3 from the diet might reduce dopamine storage (the neurotransmitter associated with mood as well as working memory) and decrease density in the striatal vesicular monoamine transporter type 2 (commonly referred to as VMAT2, a protein associated with decision making). Therefore, the Pitt researchers posited that increasing VMAT2 protein was the mechanism of action that boosted cognitive performance. Unfortunately, PET imaging revealed this was not the case.

"It is really interesting that diets enriched with Omega-3 fatty acid can enhance cognition in highly functional young individuals," said Narendarn. "Nevertheless, it was a bit disappointing that our imaging studies were unable to clarify the mechanisms by which it enhances working memory."

Ongoing animal modeling studies in the Moghaddam lab indicate that brain mechanisms that are affected by Omega-3s may be differently influenced in adolescents and young adults than they are in older adults. With this in mind, the Pitt team will continue to evaluate the effect of Omega-3 fatty acids in this younger population to find the mechanism that improves cognition.

Other Pitt researchers involved in the project include William G. Frankle, professor of psychiatry, and Neal S. Mason, research assistant professor of radiology.

Story Source:


The above story is reprinted from materials provided by University of Pittsburgh.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:
Rajesh Narendran, William G. Frankle, Neale S. Mason, Matthew F. Muldoon, Bita Moghaddam. Improved Working Memory but No Effect on Striatal Vesicular Monoamine Transporter Type 2 after Omega-3 Polyunsaturated Fatty Acid Supplementation. PLoS ONE, 2012; 7 (10): e46832 DOI: 10.1371/journal.pone.0046832
Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. View the original article here


Enhanced by Zemanta

Thursday, 1 November 2012

Self-directed learning can it be effective?

Educators have come to focus more and more on the importance of lab-based experimentation, hands-on participation, student-led inquiry, and the use of "manipulables" in the classroom. The underlying rationale seems to be that students are better able to learn when they can control the flow of their experience, or when their learning is "self-directed."

While the benefits of self-directed learning are widely acknowledged, the reasons why a sense of control leads to better acquisition of material are poorly understood.

Some researchers have highlighted the motivational component of self-directed learning, arguing that this kind of learning is effective because it makes students more willing and more motivated to learn. But few researchers have examined how self-directed learning might influence cognitive processes, such as those involved in attention and memory.

But we're not always optimal self-directed learners. The many cognitive biases and heuristics that we rely on to help us make decisions can also influence what information we pay attention to and, ultimately, learn.

Gureckis and Markant note that computational models commonly used in machine learning research can provide a framework for studying how people evaluate different sources of information and decide about the information they seek out and attend to. Work in machine learning can also help identify the benefits -- and weaknesses -- of independent exploration and the situations in which such exploration will confer the greatest benefit for learners.

Drawing together research from cognitive and computational perspectives will provide researchers with a better understanding of the processes that underlie self-directed learning and can help bridge the gap between basic cognitive research and applied educational research. Gureckis and Markant hope that this integration will help researchers to develop assistive training methods that can be used to tailor learning experiences that account for the specific demands of the situation and characteristics of the individual learner.

Story Source:


The above story is reprinted from materials provided by Association for Psychological Science.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:
T. M. Gureckis, D. B. Markant. Self-Directed Learning: A Cognitive and Computational Perspective. Perspectives on Psychological Science, 2012; 7 (5): 464 DOI: 10.1177/1745691612454304
Note: If no author is given, the source is cited instead.

View the original article here
Enhanced by Zemanta

Saturday, 27 October 2012

Your memory is like the telephone game

A chimpanzee brain at the Science Museum London
A chimpanzee brain at the Science Museum London (Photo credit: Wikipedia)
Remember the telephone game where people take turns whispering a message into the ear of the next person in line? By the time the last person speaks it out loud, the message has radically changed. It's been altered with each retelling.

Turns out your memory is a lot like the telephone game, according to a new Northwestern Medicine study.

Every time you remember an event from the past, your brain networks change in ways that can alter the later recall of the event. Thus, the next time you remember it, you might recall not the original event but what you remembered the previous time. The Northwestern study is the first to show this.

"A memory is not simply an image produced by time traveling back to the original event -- it can be an image that is somewhat distorted because of the prior times you remembered it," said Donna Bridge, a postdoctoral fellow at Northwestern University Feinberg School of Medicine and lead author of the paper on the study recently published in the Journal of Neuroscience
. "Your memory of an event can grow less precise even to the point of being totally false with each retrieval."
Bridge did the research while she was a doctoral student in lab of Ken Paller, a professor of psychology at Northwestern in the Weinberg College of Arts and Sciences.

The findings have implications for witnesses giving testimony in criminal trials, Bridge noted.

"Maybe a witness remembers something fairly accurately the first time because his memories aren't that distorted," she said. "After that it keeps going downhill."

The published study reports on Bridge's work with 12 participants, but she has run several variations of the study with a total of 70 people. "Every single person has shown this effect," she said. "It's really huge."

"When someone tells me they are sure they remember exactly the way something happened, I just laugh," Bridge said.

The reason for the distortion, Bridge said, is the fact that human memories are always adapting.

"Memories aren't static," she noted. "If you remember something in the context of a new environment and time, or if you are even in a different mood, your memories might integrate the new information."

For the study, people were asked to recall the location of objects on a grid in three sessions over three consecutive days. On the first day during a two-hour session, participants learned a series of 180 unique object-location associations on a computer screen. The next day in session two, participants were given a recall test in which they viewed a subset of those objects individually in a central location on the grid and were asked to move them to their original location. Then the following day in session three, participants returned for a final recall test.

The results showed improved recall accuracy on the final test for objects that were tested on day two compared to those not tested on day two. However, people never recalled exactly the right location. Most importantly, in session three they tended to place the object closer to the incorrect location they recalled during day two rather than the correct location from day one.

"Our findings show that incorrect recollection of the object's location on day two influenced how people remembered the object's location on day three," Bridge explained. "Retrieving the memory didn't simply reinforce the original association. Rather, it altered memory storage to reinforce the location that was recalled at session two."

Bridge's findings also were supported when she measured participants' neural signals --the electrical activity of the brain -- during session two. She wanted to see if the neural signals during session two predicted anything about how people remembered the object's location during session three.

The results revealed a particular electrical signal when people were recalling an object location during session two. This signal was greater when -- the next day -- the object was placed close to that location recalled during session two. When the electrical signal was weaker, recall of the object location was likely to be less distorted.

"The strong signal seems to indicate that a new memory was being laid down," Bridge said, "and the new memory caused a bias to make the same mistake again."

"This study shows how memories normally change over time, sometimes becoming distorted," Paller noted. "When you think back to an event that happened to you long ago -- say your first day at school -- you actually may be recalling information you retrieved about that event at some later time, not the original event."

The research was supported by National Science Foundation grant BCS1025697 and National Institute of Neurological Disorders and Stroke of the National Institutes of Health grant T32 NS047987.
Share this story on Facebook, Twitter, and Google:
Other social bookmarking and sharing tools:

Story Source:


The above story is reprinted from materials provided by Northwestern University. The original article was written by Marla Paul.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.




Journal Reference:
D. J. Bridge, K. A. Paller. Neural Correlates of Reactivation and Retrieval-Induced Distortion. Journal of Neuroscience, 2012; 32 (35): 12144 DOI: 10.1523/JNEUROSCI.1378-12.2012
Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment.

View the original article here
Enhanced by Zemanta