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(Anatomy) Brain and Central Nervous System
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adedios
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PostPosted: Mon Nov 28, 2005 1:50 pm    Post subject: (Anatomy) Brain and Central Nervous System Reply with quote






Key to a Good Memory: Predict What You Need to Remember
By LiveScience Staff
posted: 28 November 2005
10:30 am ET

It's one thing to stuff a lot of facts into your brain. Marking them as important is a whole other talent.

Yet this predictive ability is a key to having a good memory, a new brain-imaging study suggests.

While one part of the brain was very active when study subjects were memorizing something, a separate area lit up when they were predicting if they'd need to recall the information later, the images revealed.

Study skill

Predicting is an important part of successful learning because it allows us to judge whether we've studied enough or need to review more, explained lead researcher John Gabrieli of MIT.

"We've known through psychological studies that the brain performs these two functions, encoding the memory and predicting whether the information will be later recalled,"Gabrieli said. "This is our first insight into the different brain mechanisms for memory and prediction, what psychologists call judgments of learning."

The memory encoding region lies in the medial temporal lobe (MTL) near the ear. The predicting region lies in the ventromedial prefrontal cortex (VMPFC) above the eyes. The two regions communicate with each other, the researchers say.

Room for improvement

In essence, Gabrieli and his colleagues say, the mind seems to monitor the brain, telling you if you need to review some information again or if you know it cold.

Writing in the December issue of the journal Nature Neuroscience, Gabrieli and colleagues conclude that people who make more accurate prediction are better learners. Some people can intuitively judge their own memory, the scientists say, while others must learn the skill.

Learning more about the mechanics of this introspection might help people become better learners, Gabrieli said.

*************************************************************

Questions to explore further this topic:

Here is an introduction to neuroscience:

The Central Nervous System
http://faculty.washington.edu/.....e.html#cns

The Peripheral Nervous System
http://faculty.washington.edu/.....e.html#pns

The Divisions of the Nervous System and Brain Structure
http://faculty.washington.edu/.....e.html#div

The Parts of the Brain
http://faculty.washington.edu/chudler/phylo.html

The Lobes of the Brain
http://faculty.washington.edu/chudler/lobe.html

Functional Divisions of the Brain
http://faculty.washington.edu/.....ional.html

How to take care of your brain

http://faculty.washington.edu/.....infit.html

Is the brain a computer in your head?

http://faculty.washington.edu/.....puter.html

How does your brain compare to those of other animals?

http://faculty.washington.edu/chudler/facts.html

How good is your memory?

http://faculty.washington.edu/.....emory.html

How does one improve memory?

http://www.exploratorium.edu/m.....mes_2.html

GAMES

http://faculty.washington.edu/chudler/chgames.html
http://www.brainsrule.com/kids/games/index.htm


Last edited by adedios on Sat Jan 27, 2007 4:34 pm; edited 2 times in total
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PostPosted: Sat Jan 21, 2006 2:55 pm    Post subject: Mobile Phone Use Not Linked To Increased Risk of Brain Tumor Reply with quote

Source: BMJ-British Medical Journal
Date: 2006-01-20
URL: http://www.sciencedaily.com/re.....232625.htm

--------------------------------------------------------------------------------

Mobile Phone Use Not Linked To Increased Risk Of Glioma Brain Tumors, According To New Study

Mobile phones are not associated with an increased risk of the most common type of brain tumour, finds the first UK study of the relationship between mobile phone use and risk of glioma. The results are published online by the British Medical Journal.

The four year study by the Universities of Leeds, Nottingham and Manchester and the Institute of Cancer Research, London found those who had regularly used a mobile phone were not at a greater overall risk of developing this type of tumour.

There was no relationship for risk of glioma and time since first use of a mobile phone, lifetime years of use and cumulative number of calls and hours of use. Risk was not associated with phone use in rural areas which was found to be associated with an increased risk in an earlier Swedish study.

A significantly increased risk was found for tumours which developed on the same side of the head as the phone was reported to have been held but this was mirrored by a decrease in the risk on the opposite side of the head making it difficult to interpret as a real effect.

This finding may be due to people with glioma brain tumours linking mobile phone use to the side of the tumour and therefore over reporting the use of a phone on the same side as their tumour. This results in under reporting use on the opposite side of the head, say the authors.

Mobile phones have been available in the UK since 1985, but widespread use did not begin until the late 1990s making the number of long term users (over 10 years) quite small. This study had limited numbers for estimating the risk of using a phone over a long period.

Early mobile phones were designed to use analogue signals and emitted higher power than current digital phones but the study showed no increased risk of glioma brain tumours with the use of analogue phones.

Notes to Editors: There are over 4,000 new cases of brain tumours per year of which glioma is the most common type. Early symptoms include headaches and feelings of nausea. The causes of these tumours are currently unknown.

The study was conducted between 1 December 2000 and 29 February 2004 and included people living in the Thames region, southern Scotland, Trent, the West Midlands and West Yorkshire.

966 people with glioma brain tumours (cases) and 1716 healthy volunteers (controls) were interviewed about their previous mobile phone use history including how long they had used mobile phones, the number and duration of the calls they made and what make and model of phone they had used.
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PostPosted: Sat Jan 21, 2006 2:58 pm    Post subject: Working Memory Retains Visual Details Despite Distractions Reply with quote

Source: Association for Research in Vision and Ophthalmology
Date: 2006-01-20
URL: http://www.sciencedaily.com/re.....231614.htm

--------------------------------------------------------------------------------

Working Memory Retains Visual Details Despite Distractions

The ability to retain memory about the details of a natural scene is unaffected by the distraction of another activity and this information is retained in "working memory" according to a study recently published in Journal of Vision, an online, free access publication of the Association for Research in Vision and Ophthalmology (ARVO). These results reinforce the notion that humans maintain useful information about previous fixations in long-term working memory rather than the limited capacity of visual short-term memory (VSTM).

Memory has traditionally been divided into VSTM and long-term memory (LTM). VSTM usually involves the retention of about four objects at a time. This is followed by either information loss or the transfer of this information into LTM. This study provides further evidence that an intermediary "working memory" better describes the nature of information retained while engaged in a particular task.

In the study conducted by Oxford Brookes University Professor David Melcher, participants were asked to view a photograph of a natural scene for 10 seconds. Following the initial viewing, they were asked to silently read a paragraph for 60 seconds, repeating if necessary, or view an image with five colored square for 60 seconds. The participants were then asked questions about the first scene they had viewed. The results show that the addition of the reading task had no measurable influence on the average performance for either color, shape or location questions compared to other trials which involved just a 10-second delay between the viewing and the testing.

According to Melcher, "These results provide further evidence that visual scenes are special and that memory for real scenes involves a system with different properties than that used for words or simple shapes. We are currently examining how this memory system develops in children, how it is affected by aging and how it interacts with attention and disorders of attention."



###
This research was supported by grants from the British Academy and the Royal Society.

You can read this article online in Journal of Vision at http://www.journalofvision.org/6/1/2. Journal of Vision is published by ARVO, the Association for Research in Vision and Ophthalmology. All articles are free and open to anyone.

Established in 1928, The Association for Research in Vision and Ophthalmology, Inc. (ARVO) is a membership organization of more than 11,300 eye and vision researchers from over 70 countries. The Association encourages and assists its members and others in research, training, publication and dissemination of knowledge in vision and ophthalmology. ARVO's headquarters are located in Rockville, Md. The Association's Web site is www.arvo.org.
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PostPosted: Fri Jan 27, 2006 7:15 pm    Post subject: 'To Be Or, Or ... Um ... Line!' Reply with quote

Source: American Psychological Society
Date: 2006-01-27
URL: http://www.sciencedaily.com/re.....194917.htm

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'To Be Or, Or ... Um ... Line!' -- Research Puts Actors' Memory On Center Stage

"How do you learn all those lines?" It is the question most asked of actors and their art. The ability to remember and effortlessly deliver large quantities of dialogue verbatim amazes non-thespians. Most people imagine that learning a script involves hours, days, and even months of rote memorization. But actors seldom work that way; in fact, they often don't consciously try to memorize lines at all. And they seldom consider memorization as defining what they do.

What gives actors their seemingly effortless memory capabilities? Could acting teach us something about memory and cognition, and could acting principles help those with memory problems?

These are the questions that cognitive psychologist Helga Noice (Elmhurst College) and her husband, cognitive researcher, actor, and director Tony Noice (Indiana State University) have set out to answer in nearly two decades of psychological studies of actors. The Noices have not only described a learning principle that can be taught to non-actors but they have also tested acting-based interventions to counter cognitive decline in older people. They review their research in the February issue of Current Directions in Psychological Science.

According to the researchers, the secret of actors' memories is, well, acting. An actor acquires lines readily by focusing not on the words of the script, but on those words' meaning -- the moment-to-moment motivations of the character saying them -- as well as on the physical and emotional dimensions of their performance.

To get inside the character, an actor will break a script down into a series of logically connected "beats" or intentions. Good actors don't think about their lines, but feel their character's intention in reaction to what the other actors do, causing their lines to come spontaneously and naturally. The researchers quote the great British actor Michael Caine: "You must be able to stand there not thinking of that line. You take it off the other actor's face."

The key, the researchers have found, is a process called active experiencing, which they say uses "all physical, mental, and emotional channels to communicate the meaning of material to another person." It is a principle that can be applied off-stage as well as on. For example, students who studied material by imagining conveying its meaning to somebody else who needed the information showed higher retention than those who tried to memorize the material by rote.

The active-experiencing principle was also found to be effective against cognitive decline in old age. A group of older adults who received a four-week course in acting showed significantly improved word-recall and problem-solving abilities compared to both a group that received a visual-arts course and a control group. The gains persisted four months afterward, as did a significant improvement in the seniors' perceived quality of life.

Some of the Noices' findings confirm those of other researchers on memory. Memory is heavily reliant on emotion, action, and perception. In their work with actors, the Noices' have found, for example, that memory is aided by physical movement. In one study, lines learned while making an appropriate motion -- e.g., walking across a stage -- were more readily remembered by actors later than were lines unaccompanied by action. The physical motion didn't need to be repeated at the time of recall.

###
Current Directions in Psychological Science, a journal of the Association for Psychological Science (previously the American Psychological Society), publishes concise reviews spanning all of scientific psychology and its applications.
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PostPosted: Fri Feb 03, 2006 7:12 am    Post subject: A Single Memory in Three Separate Parts of the Brain Reply with quote

Source: University Of California, Irvine

Posted: February 2, 2006

Researchers Prove A Single Memory Is Processed In Three Separate Parts Of The Brain

UCI researchers have found that a single brief memory is actually processed differently in separate areas of the brain – an idea that until now scientists have only suspected to be true. The finding will influence how researchers examine the brain and could have implications for the treatment of memory disorders caused by disease or injury.

The results were published this week in the early online edition of the Proceedings of the National Academy of Sciences.

In a study using rats, researchers Emily L. Malin and James L. McGaugh of UCI’s Center for the Neurobiology of Learning and Memory demonstrate that while one part of the brain, the hippocampus, is involved in processing memory for context, the anterior cingulate cortex, a part of the cerebral cortex, is responsible for retaining memories involving unpleasant stimuli. A third area, the amygdala, located in the temporal lobe, consolidates memories more broadly and influences the storage of both contextual and unpleasant information.

“These results are highly intriguing,” said McGaugh, a member of the National Academy of Sciences who pioneered the study of drug and stress-hormone influences on memory. “It is the first time we have found this fragmentation in the brain of what we would think of as a single experience. For example, different aspects of an experience, such as a car accident, would be processed by different parts of the brain. The experience is fragmented in our brain, even though we think of it as one event.”

According to Thomas J. Carew, Donald Bren Professor and chair of UCI’s Department of Neurobiology and Behavior, understanding which parts of the brain process which types of memories gives scientists a better grasp on why particular types of memory impairment can occur and why, for example, different types of strokes might affect different memory systems. “This study is a terrific demonstration of how different components of our neural real estate can be allocated to process different aspects of memory,” said Carew. “The more we know about the specialization of memories, the more we can understand how and why the processing of memory can go awry, which in turn can critically inform clinical problems involving a wide range of cognitive deficits.”

McGaugh’s previous work has shown the key role emotional arousal and the accompanying release of stress hormones play in creating lasting memories. The amygdala has been shown to be activated by the release of these hormones.

ABOUT THE STUDY: In the study, the rats were placed inside a box to familiarize themselves with that context. On the second day, they were confined to a dark compartment of the same box for only a few seconds and given a mild foot shock. The drug oxotremorine, which mimics the neurotransmitter acetylcholine in the brain and enhances memory retention, was injected into the hippocampus, the anterior cingulate cortex or the amygdala immediately after either the contextual training on day one or after the foot-shock training on day two. All the rats were then tested two days later to see how quickly they would return to the chamber where they had received the foot shock, an indication of how well they remembered the previous training.

Rats given oxotremorine in the hippocampus after just the contextual training stayed out of the foot-shock chamber longer, meaning that they remembered the past event. But the injections into the hippocampus after the foot-shock training had no effect on memory retention. This is consistent with evidence that the hippocampus is involved in contextual memory consolidation but not with consolidation of unpleasant information. Likewise, those rats given injections into the anterior cingulate cortex had enhanced memory when the drug was administered after the foot-shock training but not after the contextual experience.

In contrast, the rats with injections in the amygdala showed better memory retention regardless of whether they had received the drug after the context training or the foot-shock training. The results support the hypothesis that the amygdala is involved in overall consolidation of memories of different kinds of experiences.
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PostPosted: Mon Feb 06, 2006 7:03 pm    Post subject: Brain Changes Significantly After Age 18 Reply with quote

Source: Dartmouth College

Posted: February 6, 2006

Brain Changes Significantly After Age 18, Says Dartmouth Research

Two Dartmouth researchers are one step closer to defining exactly when human maturity sets in. In a study aimed at identifying how and when a person's brain reaches adulthood, the scientists have learned that, anatomically, significant changes in brain structure continue after age 18.

Abigail Baird, Assistant Professor of Psychological and Brain Sciences and co-author of the study, explains that their finding is fascinating because the study closely tracked a group of freshman students throughout their first year of college. She says that this research contributes to the growing body of literature devoted to the period of human development between adolescence and adulthood.

"During the first year of college, especially at a residential college, students have many new experiences," says Baird. "They are faced with new cognitive, social, and emotional challenges. We thought it was important to document and learn from the changes taking place in their brains."

For the study, Baird and graduate student Craig Bennett looked at the brains of nineteen 18-year-old Dartmouth students who had moved more than 100 miles to attend college. A control group of 17 older students, ranging in age from 25 to 35, were also studied for comparison.

The results indicate that significant changes took place in the brains of these individuals. The changes were localized to regions of the brain known to integrate emotion and cognition. Specifically, these are areas that take information from our current body state and apply it for use in navigating the world.

"The brain of an 18-year-old college freshman is still far from resembling the brain of someone in their mid-twenties," says Bennett. "When do we reach adulthood? It might be much later than we traditionally think."
The study was funded by a grant from the National Institute of Child Health and Development.
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PostPosted: Mon Feb 13, 2006 2:57 pm    Post subject: Mind Rewind: Brains Run in Reverse Reply with quote

Mind Rewind: Brains Run in Reverse
By Ker Than
LiveScience Staff Writer
posted: 12 February 2006
09:17 pm ET

When faced with a new learning task, our brains replay events in reverse, much like a video on rewind, a new study suggests.

This type of reverse-replay is also used in artificial intelligence research to help computers make decisions. The finding could explain why we learn tasks more easily if we take frequent study breaks: the pauses between sessions give our brains time to review information.

The finding was detailed in a Feb. 12 online issue of the journal Nature.

Running rats

The researchers measured brain activity in rats as the animals ran back and forth on a linear track. Specifically, they monitored a brain region called the hippocampus, which is known to be important for memory and navigation in both rats and in humans.

When the rats completed a lap, they were given a food reward. After eating, the animals would pause briefly before starting another lap. Outwardly, the rats didn't seem to be doing much during these rest periods. They would fidget, groom or remain still. The brain recordings told a different story, however. During times of rest, a rat's hippocampus was a hotbed of activity.

As the rodents ran up and down the track, hippocampal cells fired in certain patterns. This sequence of firing repeated when the animals rested, but in reverse order. The reverse-replays were repeated several times; each replay took only a few hundred milliseconds.

"In that compressed time, the rat is replaying the entire track from where it currently is all the way back to the very beginning," said study team-member David Foster from the Massachusetts Institute of Technology. "This result suggests that the immediate experience is actually recapitulated several times. The processing going on outside of the original experience may be important for learning."

Opening moves

The finding could help explain how rats solve something called the "temporal credit assignment problem." And because the hippocampus in rats and humans perform many of the same functions, the current study suggests that our brains may work in the same way.

The problem, a classic dilemma in decision-making theory, is this: If an animal has to perform a sequence of actions before it can get a reward, how does it know which actions were ultimately important and which weren't? Actions performed right before the reward was obtained are easy to identify as important, but what about actions performed at the beginning of the sequence? Which of those were important?

Richard Sutton, a computer scientist at the University of Alberta, Canada who was not involved in the study, likens the problem to playing backgammon for the first time.

"How do you evaluate the opening move if you don't know how to play yet?" he said.

In the fields of computer science and artificial intelligence, the temporal credit assignment problem is solved by having the machines work backward, replaying events in reverse and assigning more credit to actions near the end of a sequence than to those at the beginning.

"You know that the final move was the right thing to do, so you can send that information back through the set of actions that were taken leading up to the final state," Foster said in a phone interview.

If reverse replay also takes place in humans, it could explain why cramming hours before a test doesn't typically work. The new finding suggests that our brains learn best when there are frequent pauses between study sessions; during these breaks, our brains unconsciously reviews the new information several times, making it easier to commit to memory when the time comes.

How reverse replay leads to learning

Scientists have long known that the release of the chemical molecule dopamine is an important part of the brain's reward system. The release of this neurotransmitter floods us with feelings of joy and motivates us to perform certain activities.

When this knowledge is paired with the new suggestion that our brains may replay new experiences in reverse, a possible mechanism for learning emerges, Foster said.

The researchers hypothesize the existence of a special "value area" of the brain where dopamine signals and reverse-replay signals are fed become paired together. If the dopamine signal is one that decays over time, meaning that it is stronger at the beginning of transmission than at the end, then the following might happen:

As a reverse replay signal plays out in the brain's value area, it is associated with the beginning of a strong dopamine signal; as the replay continues, the dopamine signal becomes weaker. In this scenario, actions taken near the beginning of a reverse replay event will be more important to an organism than actions taken later.

Hints in psychology

Sutton said he would not be surprised if reverse replay occurred in animals as well as machines. If anything, he said, this mechanism had long been suspected from early psychological experiments, such as Ivan Pavlov's classical conditioning experiments with dogs.

"Pavlov rang the bell and gave the dog the steak and after a while, just ringing the bell was rewarding," Sutton told LiveScience. "So somehow it worked backward from the steak to the bell."

Foster agrees, but added that the current study suggests we make trains of associations going much further back than previously thought.

"It's taking the animals several seconds to run around, so this replay could be sending that information back through several stages and rewarding a long sequence of actions," Foster said. "It's that long sequence that is new."

The current study looked specifically at spatial learning; however, in rats, and probably in humans too, the hippocampus is involved in other types of learning as well.

"So [reverse replay] could very well be a mechanism to deal with a broad variety of information, not just spatial," Foster said.
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PostPosted: Tue Feb 21, 2006 7:57 am    Post subject: Something Fishy: How Humans Got So Smart Reply with quote

Something Fishy: How Humans Got So Smart
By Corey Binns
Special to LiveScience
posted: 20 February 2006
10:20 am ET

ST. LOUIS—Human brains are bigger and better than any of our closest living or dead non-human relatives in relation to body weight. Scientists say we have fish and frogs to thank for this.

When early humans started to fish, they also began feeding their hungry brains.

The arrival of language and tool-making tend get all the credit for the big brain phenomenon. But before language or tools, a healthy diet was a brain's first fertilizer, said Stephen Cunnane, a metabolic physiologist at the University of Sherbrooke in Quebec.

"Something had to start the process of brain expansion and I think it was early humans eating clams, frogs, bird eggs and fish from shoreline environments," Cunnane said.

Cunnane presented his research here Saturday at the annual meeting of the American Association for the Advancement of Science.

Baby food

Three-quarters of a human infant's energy goes straight to the brain.

Given that babies are helpless, that sounds like a lot to spend on an organ that is cognitively useless and does little to ensure a child's survival, Cunnane said.

But human babies have extra energy to feed their brains. Unlike other primates, human newborns are born with baby fat. That lovable chub stores the energy needed to quench a baby's ravenous brain.

The fatter the baby, the healthier its brain, the thinking goes.

A diet that included fish and shellfish—and particularly frogs and eggs—would have provided ancient humans, and their fattening babies, with the best source of nutrients and minerals to foster brain development.

Still today

Even today, many people are dependent on shore-based foods. And it's possible, Cunnane speculates, that diets which aren't based on the ancient tradition put us at grave risk.

Deficiencies in iodine and iron—minerals rich in a fish diet—can lead to cognitive degeneration. That's why companies added iodine to salt starting in the 1920s.

"We're still vulnerable when we're not consuming that vitamin-rich diet," Cunnane told LiveScience. "I think we're seeing it today in neurodegenerative diseases like Alzheimer's. If you take away the fuel, the brain suffers."

So what would happen if we fatten up skinny chimp babies? A natural chimpanzee diet is low in brain food.

If scientists fed them fish, Cunnane said, their brains might grow. However, he added, "We'd never see the results. The experiment would take tens of thousands of years of evolution. But I think there would be a change in chimp brains."
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PostPosted: Thu Feb 23, 2006 6:34 pm    Post subject: Learning and Memory Stimulated by Gut Hormone Reply with quote

Learning and Memory Stimulated by Gut Hormone
Yale School of Medicine
Press Release

New Haven, Conn. — Researchers at Yale School of Medicine have found evidence that a hormone produced in the stomach directly stimulates the higher brain functions of spatial learning and memory development, and further suggests that we may learn best on an empty stomach.

Published in the February 19 online issue of Nature Neuroscience by investigators at Yale and other institutes, the study showed that the hormone ghrelin, produced in the stomach and previously associated with growth hormone release and appetite, has a direct, rapid and powerful influence on the hippocampus, a higher brain region critical for learning and memory.

The team, led by Tamas L. Horvath, chair of the Section of Comparative Medicine at Yale School of Medicine and associate professor of comparative medicine, Obstetrics, Gynecology & Reproductive Sciences, and Neurobiology, first observed that peripheral ghrelin can enter the hippocampus and bind to local neurons promoting alterations in connections between nerve cells in mice and rats. Further study of behavior in the animals showed that these changes in brain circuitry are linked to enhanced learning and memory performance.

Because ghrelin is highest in the circulation during the day and when the stomach is empty, these results also indicate that learning may be most effective before meal-time.

“Based on our observations in animal models, a practical recommendation could be that children may benefit from not overeating at breakfast in order to make the most out of their morning hours at school,” said Horvath. “The current obesity epidemic among American school children, which to some degree has been attributed to bad eating habits in the school environment, has been paralleled by a decline of learning performance. It is however too early to speculate if hormonal links between eating and learning are involved in that phenomenon.”

Horvath said that high ghrelin levels or administration of ghrelin-like drugs could also protect against certain forms of dementia, because aging and obesity are associated with a decline in ghrelin levels and an increased incidence of conditions of memory loss like Alzheimer’s disease.

Other authors on the study were first author Sabrina Diano, Susan A. Farr, Stephen C. Benoit, Ewan C. McNay, Ivaldo da Silva, Balazs Horvath, F. Spencer Gaskin, Naoko Nonaka, Laura B. Jaeger, William A. Banks, John E. Morley, Shirly Pinto, Robert S. Sherwin, Lin Xu, Kelvin A. Yamada, Mark W. Sleeman and Matthias H. Tschop.

The study was supported by several grants from the National Institutes of Health and by a VA Merit Review Grant.

Citation: Nature Neuroscience: Online issue, February 19, 2006

A patent application covering this subject matter has been filed by Yale University. For information regarding licensing, please contact Yale's Office of Cooperative Research.
Last modified: 02/23/2006 18:32:02
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PostPosted: Sat Mar 04, 2006 12:43 pm    Post subject: Buff and Brainy Reply with quote

Exercising the body can benefit the mind
Christen Brownlee

http://www.sciencenews.org/art...../bob10.asp

Eat Smart
Foods may affect the brain as well as the body

Christen Brownlee

http://sciencenews.org/articles/20060304/bob8.asp
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PostPosted: Mon Mar 13, 2006 2:46 pm    Post subject: UCI researchers identify new form of superior memory syndrom Reply with quote

UCI researchers identify new form of superior memory syndrome
University of california, Irvine

Woman displays exceptional recall of her past; case could open new avenues in memory research

Irvine, Calif., March 13, 2006
Researchers at UC Irvine have identified the first known case of a new memory syndrome – a woman with the ability to perfectly and instantly recall details of her past. Her case is the first of its kind to be recorded and chronicled in scientific literature and could open new avenues of research in the study of learning and memory.

Researchers Elizabeth Parker, Larry Cahill and James L. McGaugh spent more than five years studying the case of “AJ,” a 40-year-old woman with incredibly strong memories of her personal past. Given a date, AJ can recall with astonishing accuracy what she was doing on that date and what day of the week it fell on. Because her case is the first one of its kind, the researchers have proposed a name for her syndrome – hyperthymestic syndrome, based on the Greek word thymesis for “remembering” and hyper, meaning “more than normal.”

Their findings are published in the current issue of the journal Neurocase.

AJ first wrote McGaugh with the details of her extraordinary ability in 2000. She wrote that she “can take a date, between 1974 and today, and tell you what day it falls on, what I was doing that day and if anything of importance occurred on that day.” She had been called “the human calendar” for years by her friends and acquaintances.

According to McGaugh, her case is different from others who have been studied in the past with superior memory. Nearly all recorded cases involve people who use mnemonic devices, memory aids such as rhymes or visual imagery to create associations among facts. By using mnemonics, they are able to memorize great amounts of meaningless information. In the most famous case, a man known as “S” started his career in the 1920s as a journalist but eventually became a professional mnemonist and earned his living using his memory to entertain.

“What makes this young woman so remarkable is that she uses no mnemonic devices to help her remember things,” said McGaugh, a National Academy of Sciences member and a pioneer in the field of memory research. “Her recall is instant and deeply personal, related to her own life or to other events that were of interest to her.”

AJ’s powers of recollection can be astonishing. In 2003, she was asked to write down all the Easter dates from 1980 onward. In 10 minutes, and with no advance warning, she wrote all 24 dates and included what she was doing on each of those days. All the dates except for one were accurate. The incorrect one was only two days off. Two years later when she was asked, again without warning, the same question, she quickly responded with all the correct dates and similar information about personal events on those dates.

There are limits to AJ’s memory. While she has nearly perfect recall of what she was doing on any given date and instantly can identify the date and day of the week when an important historical event in her lifetime occurred, she has difficulty with rote memorization and did not always do well in school. She scored perfectly on a formal neuropsychological test to measure her autobiographical memory, but during the testing had difficulty organizing and categorizing information. She refers to her ongoing remembering of her life’s experiences as “a movie in her mind that never stops”.

“AJ is both a warden and a prisoner of her memories,” said Parker, a clinical professor of psychiatry and neurology and lead author of the paper. “They can at times be a burden because they cannot be controlled, but she told us that if she had a choice, she would not want to give them up.”

Researchers do not yet know how many other cases of hyperthymesia may exist. They plan on continuing to work with AJ to better understand the underlying cause of her unusual abilities. Their hope, according to Cahill, is that AJ’s case will open new doors in research involving superior memory, an avenue that has been largely neglected to date.

“To date, the field of memory research has primarily moved forward on two legs – studying subjects with normal memories, or those with memory deficits,” said Cahill, an associate professor of neurobiology and behavior. “This presents the opportunity for a new leg of research, the study of individuals who have exceptionally strong abilities related to memory that do not rely on mnemonic devices, but presumably have more of a genetic basis.”

About the University of California, Irvine: The University of California, Irvine is a top-ranked university dedicated to research, scholarship and community service. Founded in 1965, UCI is among the fastest-growing University of California campuses, with more than 24,000 undergraduate and graduate students and about 1,400 faculty members. The second-largest employer in dynamic Orange County, UCI contributes an annual economic impact of $3.3 billion. For more UCI news, visit www.today.uci.edu
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PostPosted: Mon Mar 13, 2006 4:26 pm    Post subject: Up in Smoke: Marijuana Toasts Memory Reply with quote

Up in Smoke: Marijuana Toasts Memory
By Robert Roy Britt
LiveScience Managing Editor
posted: 13 March 2006
04:01 pm ET

If you can't remember the headline of this article or are already struggling to recall some of the words at the beginning of the story, try hard to recall how much pot you smoked in your youth.

A new study finds those who've used a lot of marijuana have worse memories and don't think as quickly.

It's not the first study to suggest pot hurts memory, but the findings are stark.

In one memory test, long-time uses remembered seven of 15 words, on average. Non-users remembered 12 of 15. On a decision-making test, those who had rarely smoked pot had impaired performance 8 percent of time, while long-term tokers had 70 percent impairment.

The results are detailed in the March 14 issue of the journal Neurology.

The study involved 64 people age 17 to 49 selected from a larger study group. They were split into three groups: those who had smoked four or more joints per week for more than 10 years; those who'd been smoking for five to 10 years; and those who had smoked at least once but not more than 20 times and not at all in the past two years.

The middle group consistently scored in between the other two.

"We found that the longer people used marijuana, the more deterioration they had in these cognitive abilities, especially in the ability to learn and remember new information," said Lambros Messinis of the Department of Neurology at the University Hospital of Patras in Patras, Greece.

A separate study in Neurology last year found higher blood flow velocity in the marijuana users even a month after they stopped smoking. Researchers said the change could help explain other studies that have revealed memory problems in pot smokers.

A Harvard Medical School study in 2003 found lasting memory impairment in people who had started smoking marijuana before age 17, when the brain is still forming.

And research published in November indicated that heavy marijuana use might put adolescents who are genetically predisposed to schizophrenia at greater risk of developing the brain disorder.

Some 3.1 million Americans age 12 and older use marijuana daily or almost daily, according to the National Institute on Drug Abuse. In 2004, 5.6 percent of 12th graders reported daily use of marijuana.
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PostPosted: Mon Mar 20, 2006 8:00 pm    Post subject: New Research Data On The Link Between Learning Results And W Reply with quote

Source: University of Helsinki

Posted: March 20, 2006

New Research Data On The Link Between Learning Results And Working Memory

A research project on the Working Memory and Cognition has reached its conclusion. This three-year project has concentrated on basic research into the essence of memory and learning, and its results can be applied to such things as predicting learning difficulties or successes and understanding their related factors, which within working memory hinder or promote learning at an individual level.

The project was headed by Elisabet Service, a docent at the Department of Psychology at the University of Helsinki. Other members of the group were Jarmo Herkman, Virpi Kalakoski, Emilia Luotoniemi and Sini Maury, researchers from the Department of Psychology. The research is divided into two primary areas: the essence of language-related memory processes and the impact of expertise in working memory tasks concerning music.

Poor short-term memory reveals an ineffective language learning process

It has long been known that effective language learning is correlated with the efficient storing of linguistic material in short-term memory. Those who can repeat long series of numbers or multisyllabic nonsense words without making errors, are typically good at learning languages. Recent studies indicate that this is not a causal relationship. It would seem that a good short-term memory is not a prerequisite for long-term learning, rather, it is the case that both short-term and long-term memory tasks tap the same ability of the nervous system to create representations of sufficient quality to support the maintenance of several of them at once.

The project also studied those factors that result in the heaviest working memory loads, that is to say, lead to overlapping and interfering representations. This type of basic research in applicable in teaching. For example, when studying a foreign language, it is important to present material which reinforces the long-term representations of new sounds and sound clusters. By systematic teaching, one can also practice difficult things, such as the correct recognition of unstressed syllables. In this project, which has now reached its conclusion, these studies were carried out by Emilia Luotoniemi, Sini Maury and Elisabet Service.

Jarmo Herkman studied the relationship between the understanding of metaphorical expression and working memory. The key question in this field of research is whether or not the processing of metaphoric language differs from the processing of literal language. His results support the view that the understanding of symbolic language differs from that of literal language. Metaphoric language often puts greater stress on working memory and so is harder to process than literal language.

The group also collaborated with the Cognitive-Clinical Neuroscience Unit led by Professor John Connolly, as well as with Professor Kimmo Alho and researcher Anu Kujala of the Department of Psychology at the University of Helsinki, and Professor Riitta Salmelin and researcher Päivi Helenius of the Brain Research Unit at the Low Temperature Laboratory at Helsinki University of Technology.

Does an expert have a better memory than an amateur?

The project also studied the roles of concept formation in the information processing of an expert, one object of research being the processing of musical knowledge. Researcher Sini Maury studied the ability of musicians to compare separate intervals and melodies formed of several tones.

The ability to recognise a tone in an interval as belonging to a certain tone category can help to distinguish it from other tones. Intervals, whose critical tones belong to the same class, are more difficult to distinguish from each other than intervals, which contain tones belonging to different classes, when the acoustic differences between the tone pairs of intervals are equally large. This phenomenon is known as categorical perception. In her experiments, Sini Maury observed that the significance of categorical perception is more pronounced when the load on working memory in a sorting task grows, for example, when a tone interval is included in a four-tone melody. The interpretation of such a result can be that it is a memory phenomenon in which the representation of an established tone category is used to fill in an imperfect auditory memory trace. The same kind of mechanism can influence memory for linguistic stimuli. The words of an unknown language are difficult, when their sounds cannot be classified into categories familiar from one's mother tongue.

Virpi Kalakoski studied differences between the abilities of musicians and persons who did not have music as an active hobby to remember series of notes presented in succession on a computer screen. She developed a test paradigm, by which it is possible to follow the combining of stimuli into a pattern. Kalakoski's results show how expertise makes it possible to apparently bypass working memory limits, even when the memory items cannot be grouped into simple categories.
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PostPosted: Thu May 25, 2006 3:52 pm    Post subject: If the chemistry is right … you might remember this Reply with quote

Children's Medical Research Institute
24 May 2006

If the chemistry is right … you might remember this

New findings in nerve communication
If the chemistry is right … you might remember this
A young Australian scientist has made an important discovery about how brain cells communicate. This finding is central to understanding all brain function – from laying down memory to being able to walk

The groundbreaking research has been published in the latest edition of world-leading journal Nature Neuroscience.

Victor Anggono, a PhD student at the Children's Medical Research Institute (CMRI), set out to identify the molecular partners of a key protein called dynamin, and how their partnership allows neurons to send messages .

The result was astounding. A protein called syndapin, previously thought to have no major role in nerve communication, was proven to be the molecule that simultaneously works with dynamin to allow the transmission of messages between nerve cells.

The brain functions by sending chemical messages between nerves. The messages, or neurotranmsitters, are held in tiny packages at the nerve terminal where they are released to send a signal. The packages then return to the cell and are re-filled so that brain function can continue.

In collaboration with researchers from the University of Edinburgh further studies have revealed that by blocking the interaction of these two proteins nerve communication shuts down.

'The partnership between dynamin and syndapin is crucial for the continous cycle of neurotransmission. This makes syndpain a very specific target for medicines that could treat conditions where there is an overload of nerve activity, such as during a seizures,' said Dr Phil Robinson leader of the research at the CMRI.

The relationship between dynamin and syndapin is also crucial to understanding other processes where there is a high level of brain activity and nerve transmission, such as when forming memories and during learning.

Dr Robinson says, 'A discovery like this will be vital for future research into many neurological disorders, such as epilepsy, conditions of memory loss and schizophrenia. It is only through research like this, that medical science can now target specific problems and develop improved treatments.'


###
This research was funded through a grant from the National Health & Medical Research Council (NHMRC) and a scholarship from the University of Sydney as well as funds from the community donated to Jeans for Genes – the major fundraising event of the CMRI.
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PostPosted: Mon Jul 17, 2006 7:08 pm    Post subject: Decline in concentration, decision-making and problem-solvin Reply with quote

Public release date: 17-Jul-2006

Mayo Clinic

Decline in concentration, decision-making and problem-solving

Rochester, Minn. -- A new Mayo Clinic study finds that after memory begins to decline, executive function is the next brain function to deteriorate in the progression from mild cognitive impairment, a pre-Alzheimer's disease condition, to Alzheimer's disease. Findings will be presented July 17 at the Alzheimer's Association International Conference on Alzheimer's Disease and Related Disorders in Madrid, Spain.

Ron Petersen, M.D., Ph.D., Mayo Clinic neurologist and senior study investigator, says executive function includes concentration, decision making, and higher-order problem solving.

"If someone with mild cognitive impairment starts having trouble staying on task, concentrating, multitasking, making decisions or paying attention to several things at once, that would mean they are progressing toward dementia," he says. "A decline in executive function will cause people to become more impaired in their daily activities, as it is pretty important in daily function."

Dr. Petersen says that awareness of the typical progression to Alzheimer's will be useful for patients, their families and their doctors. In order to convert from mild cognitive impairment to Alzheimer's disease, patients must have impairment in memory and one other aspect of brain function.

"Knowing what area of cognitive function is likely to become impaired after memory helps us as we try to keep our eyes out for people when they are worsening," he says.

Awareness of a patient's functional decline informs neurologists what areas of the brain are being affected as mild cognitive impairment progresses to Alzheimer's: the medial temporal lobe is affected as memory declines, and then the frontal regions of the brain are affected as executive function worsens, according to Dr. Petersen. The lessening of these abilities indicates the buildup of more plaques and tangles in the brain. The buildup results from abnormal protein accumulation inside the cells and the deposit of abnormal material outside the cells in the brain, leading to a slowly degenerating neuron death and shrinkage of the affected brain regions.

No one knows why mild cognitive impairment affects the memory then spreads to executive function as the disease moves toward Alzheimer's, says Dr. Petersen.

In future studies of mild cognitive impairment, measuring whether a patient has moved from memory impairment alone to weakened executive function could help determine whether a particular drug is successful in slowing or stopping the disease, he says.

If patients or their families notice progress from memory decline to problems with executive function, they should inform their physicians and consider medication to potentially slow the patient's deterioration, if they have not already done so, says Dr. Petersen.

Although previously neurologists have speculated that executive function may be next to wane following memory as one develops Alzheimer's, this study represents a systematic demonstration of the progression of impairment.


###

To conduct this study, the researchers identified 354 patients with amnestic mild cognitive impairment, a pre-Alzheimer's disease condition, and followed them for an average of 3.1 years, assessing them for impairment in the brain's executive function, and visuospatial and language abilities. Early in the course of mild cognitive impairment, the patients' attention capacity began to diminish. Executive function continued to decline steadily over the course of follow-up.

Other Mayo Clinic researchers involved in this study include: Selam Negash, Ph.D.; Yonas Geda, M.D.; Shane Pankratz, Ph.D.; David Knopman, M.D.; Bradley Boeve, M.D.; Glenn Smith, Ph.D.; Robert Ivnik, Ph.D.; and Tiffani Slusser.

This research is sponsored by the National Institute on Aging and the Mayo Clinic Robert H. and Clarice R. Smith and Abigail Van Buren Alzheimer's Disease Research Program.

To obtain the latest news releases from Mayo Clinic, go to www.mayoclinic.org/news

MayoClinic.com (www.mayoclinic.com) is available as a resource for your health stories.
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PostPosted: Mon Jul 24, 2006 4:17 pm    Post subject: 'Friend' protein keeps nerve signals in check Reply with quote

24 July 2006
University of Illinois at Chicago

'Friend' protein keeps nerve signals in check

Among the many thousands of proteins in the cell, some are essential players while some are "hangers-on." The neuronal protein syntaxin is essential. Without it, you die. A more recently discovered protein called tomosyn hangs on, or binds, to syntaxin. Its Japanese discoverers named it tomosyn by combining tomo -- "friend" in Japanese -- with "syn" for syntaxin, to mean "friend of syntaxin."

Now a U.S.-based research team reports this friendly protein appears to play a key role in regulating the synaptic release of neurotransmitter chemicals, which suggests that it may also play a role in learning and memory.

Better understanding of the neurological function of this protein may lead to a better understanding of how synapses get stronger or weaker, and how that, in turn, affects memory formation and loss, says Janet Richmond, associate professor of biological sciences at the University of Illinois at Chicago.

"It's amazing we remember things from as far back as our early childhood with the constant protein turnover going on in our brains," said Richmond. "So understanding how proteins function to control synaptic strength is really important."

Richmond and her colleagues used the soil nematode worm Caenorhabditis elegans to study the function of tomosyn using a recording technique she developed to understand how synaptic proteins affect release of neurotransmitters at the nerve cell junctions. The lab's ability to study synaptic transmission was recently improved with the addition of high pressure freeze electron microscopy and immuno-gold staining, which together provide a clearer picture of where neurotransmitter-containing synaptic vesicles and proteins cluster.

Mutant worms lacking tomosyn were compared to normal worms to determine what effect, if any, the protein had on neuronal transmission. The observed effect is substantial -- the protein helps put a limit on the number of synaptic vesicles that become competent to fuse at synapses, thereby regulating the amount of neurotransmitter released.

"If you remove tomosyn, you get exuberant neurotransmitter release," said Richmond. "This suggests tomosyn is a negative regulator of release. In other words, it dampens down the system, regulating the efficiency and strength of the synapse."

Because the nematode C. elegans uses proteins in its nervous system comparable to those in humans, Richmond suspects that forthcoming experiments involving tomosyn in mammals such as laboratory mice will show similar results.


###
The findings were reported online July 24 in PLoS Biology, the Public Library of Science. Funding was provided by the National Institutes of Health.

Co-authors of the paper include Elena Gracheva, Anna Burdina, Martine Berthelot-Grosjean and Brian Ackley of UIC, Robby Weimer of Cold Stream Harbor Laboratory, Andrea Holgado of Loyola University Chicago, and Gayla Hadwiger and Michael Nonet of Washington University in St. Louis.
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PostPosted: Tue Oct 24, 2006 7:52 am    Post subject: Researchers add to understanding of how brain cells communic Reply with quote

University of Pittsburgh
23 October 2006

Researchers add to understanding of how brain cells communicate

In Journal of Neuroscience paper, Johnson and Qian describe subtypes of NMDA receptors, involved in memory formation and diseases like schizophrenia and Alzheimer's
An hour from now, will you remember reading this? It all depends on proteins in your brain called NMDA receptors, which allow your neurons to communicate with each other.

Jon W. Johnson, University of Pittsburgh associate professor of neuroscience, and former Pitt graduate student Anqi Qian, now of Carnegie Mellon University in Qatar, have discovered how different types of NMDA (N-methyl-d-aspartate) receptors perform varied functions. Their findings are published in the current issue of the Journal of Neuroscience in a paper titled "Permeant Ion Effects on External Mg2+ Block of NR1/2D NMDA Receptors."

Communication between cells in the brain depends on specialized molecular receptors that conduct charged particles, or ions, between the outside and inside of cells. Ions also modify how receptors work. In this paper, Johnson and Qian studied the effects of ions on receptors and found them to vary between different types of receptor molecules. They used computer modeling to show that variation in how ions interact with receptors combined with variation in the structure of receptors is responsible for specialization of receptor function.

"This research helps explain how evolution accomplished a critical goal: producing receptor proteins with finely tuned properties that help optimize brain function," said Johnson.

NR1/2D receptors may be the least-studied of the major NMDA receptor subtypes, but there is increasing evidence that they play important roles in the brain, including the process of long-term depression (which, like long-term potentiation, is thought to be essential for learning and memory) and disease. A better understanding of how NMDA receptors work could lead to better treatments for schizophrenia, Alzheimer's disease, and stroke, said Johnson.

Memories are formed by strengthening the connections between brain cells, known as synapses. If you touch a hot stove, the pain signal from your hand and the visual signal from your eyes reach the brain at about the same time, forging a memory. Specifically, memory requires the coordinated activation of many types of receptors at synapses. The flow of calcium ions through a channel in NMDA receptors plays a central role.

Neurons "talk" to each other by releasing glutamate at a synapse that binds to NMDA receptors on the surface of the "listening" neuron. If the listening neuron is strongly excited, magnesium ions are expelled from the channel of NR1/2A receptors, one NMDA receptor subtype. Calcium ions then can flow through the open channel into the listening neuron at the synapse, causing the synapse to be strengthened and you to remember that "hot stove = pain."

Another type of NMDA receptor that is thought to help sculpt memories is called NR1/2D. Although NR1/2A receptors require strong excitation to let calcium ions flow across the membrane, NR1/2D receptors respond even to weak inputs.

In this paper, Johnson and Qian further elucidate how NR1/2D receptors do this. Johnson was most surprised to find that the magnesium ion, which strongly blocks the channels of NR1/2A receptors, flows much more easily in NR1/2D receptors. In those receptors, magnesium acts more like a "permeant" ion, which means it can flow through the channel without getting stuck in the middle.

In addition to computer modeling, the researchers used the technique of patch clamp recording, which takes a tiny piece of cell membrane and measures the charge that flows through one open channel. They were able to use the remarkable precision of the patch clamp to see exactly when the magnesium ion entered and exited the ion channel.

"Because of our currently limited understanding of NR1/2D receptors, drawing a direct link to human disease and memory is speculative, but I am confident that the links will become firmer as research progresses," Johnson said.


###
This research was funded by the National Institutes of Mental Health.
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PostPosted: Fri Jan 26, 2007 1:52 pm    Post subject: Thinking on Spinal Cord Function Turned on its Head Reply with quote

Thinking on Spinal Cord Function Turned on its Head

By Charles Q. Choi
Special to LiveScience
posted: 26 January 2007
08:56 am ET

A new study reveals that the spinal cord seethes with a tug of war between electrical signals, overturning thinking on how it works.

Intriguingly, these conflicting signals could help animals respond more rapidly. And the findings could shed light on how our brains evolved, researchers said.

The core components of brains and spinal cords are cells known as neurons, which flicker with electrical activity. The spinal cord helps control thousands of "motor neurons," the cells that directly operate the muscles of the body based on instructions from the brain.

For the full article:

http://www.livescience.com/hum.....brain.html
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PostPosted: Thu Feb 22, 2007 8:08 am    Post subject: Boosting brain power — with chocolate Reply with quote

Boosting brain power — with chocolate
February 19 2007
University of Nottingham

Eating chocolate could help to sharpen up the mind and give a short-term boost to cognitive skills, a University of Nottingham expert has found.


A study led by Professor Ian Macdonald found that consumption of a cocoa drink rich in flavanols — a key ingredient of dark chocolate — boosts blood flow to key areas of the brain for two to three hours.

Increased blood flow to these areas of the brain may help to increase performance in specific tasks and boost general alertness over a short period.

The findings, unveiled at one of the biggest scientific conferences in America, also raise the prospect of ingredients in chocolate being used to treat vascular impairment, including dementia and strokes, and thus for maintaining cardiovascular health.

The study also suggests that the cocoa flavanols found in chocolate could be useful in enhancing brain function for people fighting fatigue, sleep deprivation, and even the effects of ageing.

Ian Macdonald, professor of metabolic physiology at The University of Nottingham, used magnetic resonance imaging (MRI) to detect increased activity in specific areas of the brain in individuals who had consumed a single drink of flavanol-rich cocoa. The effect is linked to dilation of cerebral blood vessels, allowing more blood — and therefore more oxygen — to reach key areas of the brain.

Flavanols are not only found in chocolate with a high cocoa content — they are also present in other substances such as red wine, green tea and blueberries.

He presented his research at the annual meeting of the American Association for the Advancement of Science (AAAS), one of the biggest annual gatherings of scientists from all over the world. This year's meeting takes place in San Francisco from February 15–19.

Professor Macdonald said: “Acute consumption of this particular flavanol-rich cocoa beverage was associated with increased grey matter flow for two to three hours.

“The demonstration of an effect of consuming this particular beverage on cerebral blood flow raises the possibility that certain food ingredients may be beneficial in increasing brain blood flow and enhancing brain function, in situations where individuals are cognitively impaired such as fatigue, sleep deprivation, or possibly ageing.”

He emphasised that the level of cocoa flavanol used in the study is not available commercially. The cocoa-rich flavanol beverage was specially formulated for the purpose of the study.

Co-authors on the research were Dr Susan Francis, research associate Kay Head, and Professor Peter Morris, all from The University of Nottingham's School of Physics and Astronomy.

Professor Macdonald is a member of the Food Standards Agency's Scientific Advisory Committee on Nutrition, and is President-Elect of the UK Nutrition Society. His main research interests are concerned with the functional consequences of metabolic and nutritional disturbances in health and disease, with specific interests in obesity, diabetes, cardiovascular disease and exercise.

The AAAS, founded in 1848, is the world's largest general scientific society and publisher of the prestigious international journal Science. Its annual conference draws up to 10,000 attendees.
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PostPosted: Wed Feb 28, 2007 8:20 am    Post subject: New Study: The Brain is Chaotic Reply with quote

New Study: The Brain is Chaotic

By Sara Goudarzi
LiveScience Staff Writer
posted: 27 February 2007
03:26 pm ET

The inner workings of the brain aren’t as organized as once thought. According to a new study, it’s mayhem up there.

It’s long been believed that information is passed on from one neuron to another at junctions where two neurons, or a neuron and a muscle, meet. Neurons are nervous system cells that process and relay information.

At the junction of two neurons, also known as a synapse, one neuron releases a chemical messenger—neurotransmitter—to excite the other neuron. This is done by diffusing the neurotransmitter to the branches (dendrites) of the transmitting neuron.

For the full article:

http://www.livescience.com/hum.....chaos.html
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PostPosted: Tue Mar 06, 2007 7:27 am    Post subject: Brown Scientists Explain Inception of Perception in the Brai Reply with quote

The Sensational Brain
Brown University
7 March 2007

Brown Scientists Explain Inception of Perception in the Brain

All of human sensation – sight, sound, taste – begins in the brain when information moves from the thalamus to the neocortex. In Nature Neuroscience, Brown University researchers explain how cortical cells get activated during this critical transfer. The findings shed light on the inner workings of the cortex, the biggest part of the brain, and may help explain some forms of irregular electrical brain activity such as epileptic seizures.

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http://www.brown.edu/Administr.....6-112.html
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PostPosted: Thu Mar 15, 2007 7:12 am    Post subject: Controversial New Idea: Nerves Transmit Sound, Not Electrici Reply with quote

Controversial New Idea: Nerves Transmit Sound, Not Electricity

By Robert Roy Britt
LiveScience Managing Editor
posted: 14 March, 2007
1:00 pm ET

Nerves transmit sound waves through your body, not electrical pulses, according to a controversial new study that tries to explain the longstanding mystery of how anesthetics work.

Textbooks say nerves use electrical impulses to transmit signals from the brain to the point of action, be it to wag a finger or blink an eye.

"But for us as physicists, this cannot be the explanation," says Thomas Heimburg, a Copenhagen University researcher whose expertise is in the intersection of biology and physics. "The physical laws of thermodynamics tell us that electrical impulses must produce heat as they travel along the nerve, but experiments find that no such heat is produced."

The textbooks are not likely to be rewritten anytime soon, however.

Roderic Eckenhoff, a researcher in the Department of Anesthesiology and Critical Care at the University of Pennsylvania School of Medicine, called the sound pulse idea interesting. "But an enormous burden of proof exists and they have a very long way to go to beat electricity," he said.

For the full article:

http://www.livescience.com/hum....._work.html
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PostPosted: Thu Apr 12, 2007 9:58 am    Post subject: New Images Reveal Development of Brain Folds Reply with quote

New Images Reveal Development of Brain Folds

By LiveScience Staff

posted: 12 April 2007
09:02 am ET

Just why the outermost surface of our brains is covered in folds and wrinkles is a mystery to scientists, but a new tool is helping researchers see how these folds develop.

Scientists used computer graphic techniques to track and measure the development of folds in brain images taken by magnetic resonance imaging (MRI).

“We can’t open the brain and see by eye,” said the paper’s first author Peng Yu, a Harvard graduate student. “But the cool thing we can do now is see through the MR machine.”

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http://www.livescience.com/hum.....folds.html
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PostPosted: Wed Apr 18, 2007 7:59 pm    Post subject: Racing neurons control whether we stop or go Reply with quote

Vanderbilt University
18 April 2007

Racing neurons control whether we stop or go

New research offers insight into cause of ADHD
In the children’s game "red light green light," winners are able to stop, and take off running again, more quickly than their comrades. New research reveals that a similar race goes on in our brains, with impulse control being the big winner.

"The research provides new insights into how the brain controls movements, which helps explain the impulsivity of people with attention deficit and hyperactivity disorder," study co-author Jeffrey Schall, E. Bronson Professor of Neuroscience at Vanderbilt University, said. "It also shows how mathematical models can be used to discover how the brain produces thought and action."

Vanderbilt psychologists Leanne Boucher, Thomas Palmeri, Gordon Logan and Schall published the findings in the April issue of Psychological Review.

The new paper uses physiological data collected in Schall’s laboratory to show how a theoretical model Logan developed more than 20 years ago is implemented by the brain.

"I developed the race model to explain behavior on a task called the stop signal task with a friend of mine, William Cowan, who is a theoretical physicist, in the 1980s," Logan, Centennial Professor of Psychology, said. Stop signal tasks measure an individual’s ability to stop a planned action, like pressing a key on a keyboard or looking at a target, in response to a signal. "Our race model proposed that two independent processes were underway, one telling us to ‘go’ and one telling us to ‘stop’ in response to the stop signal.

"Applying the model to children’s behavior revealed that stop signal task times are significantly longer in children with attention deficit and hyperactivity disorders than in other children," he said.

The model has been widely accepted and has also been used to explain cognitive problems in people with obsessive-compulsive disorder, schizophrenia and Parkinson’s disease.

"We think of people who are impulsive as acting too quickly," Logan said. "Kids with ADHD are actually slower on the ‘go’ task than the control kids. It’s not that they go too quickly; they stop too slowly."

In the race model, "go" and "stop" processes independently race one another – whichever one crosses the finish line first determines whether a movement is made or not. Though the model accurately explains behavior, it left neuroscientists scratching their heads. Their work found that "go" and "stop" processes are produced through a complex network of interacting neurons. If so, then how could "go" and "stop’ be acting independently as required by the race model?

"The model proposes that there are two processes happening in our brain, one making us ‘go’ and another making us ‘stop,’" Boucher, a postdoctoral fellow, said. "However, as neurophysiologists, we know these processes are intricately linked, not independent. Our goal with this paper was to resolve that paradox."

To answer this question, the researchers applied the independent race model to existing data from experiments that monitored brain activity in monkeys while they were performing a visual stop signal task. In those experiments, the monkeys were taught to look at a visual target unless a stop signal came on, in which case they were supposed to refrain from looking at the target.

"We knew that the neurons responsible for the ‘go’ and ‘stop’ actions were located in the parts of the brain that control movements," Boucher said. "Each trial began with the illumination of a target in the periphery that the subject was supposed to look at. This is when the ‘go’ unit was activated. Sometimes a ‘stop’ signal came on and the subject had to inhibit their eye movement. This is when the ‘stop’ unit was activated."

The researchers found that the results predicted by the model and those shown by the neural activity matched.

"For most of the race, ‘stop’ and ‘go’ act independently. ‘Stop’ interacts with ‘go’ very briefly—it basically has one chance to knock ‘go’ out of the race. It needs to react strongly and rapidly after the stop signal is given," Schall said. "If it is successful, the subject stops his or her planned movement. If it is unsuccessful, the subject goes ahead. In individuals with impulse control problems, ‘stop’ more often loses the race."

The findings are some of the first to bridge cognitive research and neurophysiology—making the connection between the mind and the brain.

"For years, one group of researchers was looking at what neurons are doing, and a different group of researchers was looking at what people are doing," Palmeri, associate professor of psychology, said. "Now there is a point of contact between decades of important research in neurophysiology and decades of important research in cognitive modeling. Research that has very different histories and approaches is really starting to come together."

"You develop a model to explain behavior and in many ways it’s just made up," Logan said. "But then you find out that it says something about what the neurons are doing, and that’s exciting."

###
[A multimedia version of this story, with video and photos, is available on Exploration, Vanderbilt’s online research magazine, at http://exploration.vanderbilt.edu]

The research was supported with funding from Robin and Richard Patton through the E. Bronson Ingram Chair in Neuroscience, the National Science Foundation and the National Institutes of Health.

For more Vanderbilt news visit VUCast, www.vanderbilt.edu/news.
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PostPosted: Fri Apr 20, 2007 9:52 am    Post subject: The origin of the brain lies in a worm Reply with quote

The origin of the brain lies in a worm

EMBL
Heidelberg, 20 April 2007 - The rise of the central nervous system
(CNS) in animal evolution has puzzled scientists for centuries.
Vertebrates, insects and worms evolved from the same
ancestor, but their CNSs are different and were thought to have
evolved only after their lineages had split during evolution.
Researchers from the European Molecular Biology Laboratory
(EMBL) in Heidelberg now reveal that the vertebrate nervous system
is probably much older than expected. The study, which is
published in the current issue of Cell, suggests that the last common
ancestor of vertebrates, insects and worms already had a
centralised nervous system resembling that of vertebrates today.
Many animals have evolved complex nervous systems throughout
the course of evolution, but their architectures can differ substantially
between species. While vertebrates have a CNS in the shape
of a spinal cord running along their backs, insects and annelid
worms like the earthworm have a rope-ladder-like chain of nerve
cell clusters on their belly side. Other invertebrates on the other
hand have their nerve cells distributed diffusely over their body.
Yet, all these species descend from a common ancestor called
Urbilateria. If this ancestor already possessed a nervous system,
what it might have looked like and how it gave rise to the diversity
of nervous systems seen in animals today is what Detlev Arendt
and his group study at EMBL. To do so, they investigate the nervous
system of a marine annelid worm called Platynereis dumerilii.
“Platynereis can be considered a living fossil,” says Arendt, “it still
lives in the same environment as the last common ancestors used
to and has preserved many ancestral features, including a prototype
invertebrate CNS.”
Arendt and his group investigated how the developing CNS in
Platynereis embryos gets subdivided into the regions that later on
give rise to the different CNS structures. The regions are defined
by the unique combination of regulatory genes expressed, which
endow every type of neuron with a specific molecular fingerprint.
Comparing the molecular fingerpint of Platynereis nerve cells
with what is known about vertebrates revealed surprising similarities.
“Our findings were overwhelming,” says Alexandru Denes, who
carried out the research in Arendt’s lab. “The molecular anatomy
of the developing CNS turned out to be virtually the same in vertebrates
and Platynereis. Corresponding regions give rise to neuron
types with similar molecular fingerprints and these neurons
also go on to form the same neural structures in annelid worm
and vertebrate.”
“Such a complex arrangement caould not have been invented
twice throughout evolution, it must be the same system,” adds
Gáspár Jékely, a researcher from Arendt’s lab, who contributed
essentially to the study. “It looks like Platynereis and vertebrates
have inherited the organisation of their CNS from their remote
common ancestors.”
The findings provide strong evidence for a theory that was first
put forward by zoologist Anton Dohrn in 1875. It states that vertebrate
and annelid CNS are of common descent and vertebrates
have turned themselves upside down throughout the course of
evolution.
“This explains perfectly why we find the same centralised CNS on
the backside of vertebrates and the bellyside of Platynereis,”
Arendt says. “How the inversion occurred and how other invertebrates
have modified the ancestral CNS throughout evolution
are the next exciting questions for evolutionary biologists.”
The origin of the brain lies in a worm
Researchers discover that the centralised nervous system of vertebrates is
much older than expected
Photo, Marietta Schupp, EMBL
Researchers Detlev Arendt, Alexandru Denes and Gáspár Jékely.
Contact:
Anna-Lynn Wegener, EMBL Press Officer, Heidelberg, Germany

Source Article
A.S. Denes, G. Jékely, D. Arendt et al., Conserved mediolateral molecular architecture of the annelid trunk neuroectoderm reveals
common ancestry of bilaterian nervous system centralisation, Cell, 20 April 2007
Embargoed until Friday, 19 April 2007, 18:00 BST
Press Release
About EMBL
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(Austria, Belgium, Croatia, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Israel, Italy, the Netherlands, Norway,
Portugal, Spain, Sweden, Switzerland and the United Kingdom). Research at EMBL is conducted by approximately 80 independent
groups covering the spectrum of molecular biology. The Laboratory has five units: the main Laboratory in Heidelberg, and Outstations
in Hinxton (the European Bioinformatics Institute), Grenoble, Hamburg, and Monterotondo near Rome. The cornerstones of EMBL’s
mission are: to perform basic research in molecular biology; to train scientists, students and visitors at all levels; to offer vital services
to scientists in the member states; to develop new instruments and methods in the life sciences and to actively engage in technology transfer activities. EMBL’s International PhD Programme has a student body of about 170. The Laboratory also sponsors an active Science and Society programme. Visitors from the press and public are welcome.

Policy regarding use
EMBL press releases may be freely reprinted and distributed via print and electronic media. Text, photographs & graphics are copyrighted by EMBL. They may be freely reprinted and distributed
in conjunction with this news story, provided that proper attribution to authors, photographers and designers is made. High-resolution copies of the images can be downloaded from the EMBL
web site: www.embl.org
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