News reports of research into memory May 2007

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May 2007

Natural compound and exercise boost memory in mice

The flavanol epicatechin, found in blueberries, tea, grapes, and cocoa, has been found to enhance memory in mice. Moreover, this effect increased when mice also exercised regularly. The combination of exercise and a diet with epicatechin also promoted structural and functional changes in the dentate gyrus.
The findings were published in the May 30 issue of The Journal of Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2007-05/sfn-nca052907.php

Sleep deprivation affects attention and visual short-term memory

A new study indicates that sleep deprivation leads to short-term memory loss not, or not only, because the brain has problems encoding the information, but because people who are sleep deprived can see and take in only a small number of objects at a time. The study involved 30 healthy volunteers who were tested after a regular night's sleep and after 24 hours without sleep. The test involved increasing numbers of colored squares (from 1 to 8) being flashed on a computer screen, with participants asked to remember if a new square displayed on the screen was the same color as any of the earlier squares. When sleep deprived, participants showed deficiencies with visual arrays involving as few as one or two squares. The problem seemed to be caused by a deficit in ability to pay attention. The findings have obvious implications for people such as air traffic controllers.
The study appeared in the May 29 issue of the Proceedings of the National Academy of Sciences. Full reference
Full text available at http://tinyurl.com/2esfhu
http://www.eurekalert.org/pub_releases/2007-05/dumc-fsm052207.php

Sleep deprivation can threaten competent decision-making

An imaging study follows research showing that sleep-deprived participants engaged in a gambling task choose higher-risk decks and exhibit reduced concern for negative consequences. The study reveals that sleep deprived adults asked to make decisions in a gambling task show higher selective activity in the nucleus accumbens (involved with the anticipation of reward), and reduced activity in the insula (involved with evaluating the emotional significance of an event). The findings help explain why we make poorer decisions when sleep deprived.
The study was published in the May 1st issue of SLEEP. Full reference
http://www.eurekalert.org/pub_releases/2007-05/aaos-jss042507.php

Inducing restorative sleep

Researchers have found a way to stimulate the slow brain waves that characterize the deepest stage of sleep using transcranial magnetic stimulation (TMS). Creating slow waves on demand could someday lead to treatments for insomnia, and might also lead to a magnetically stimulated "power nap," which might confer the benefit of eight hours sleep in just a few hours. The technique will also be helpful in sleep research.
The paper was published in the May 15 issue of the Proceedings of the National Academy of Sciences. Full reference
http://www.eurekalert.org/pub_releases/2007-04/uow-spu042707.php

Meditation may improve attentional control

Paying attention to one thing can keep you from noticing something else. When people are shown two visual signals half a second apart, they often miss the second one — this effect is called the attentional blink. In a study involving 40 participants being trained in Vipassana meditation (designed to reduce mental distraction and improve sensory awareness), one group of 17 attended a 3 month retreat during which they meditated for 10–12 hours a day (practitioner group), and 23 simply received a 1-hour meditation class and were asked to meditate for 20 minutes daily for 1 week prior to each testing session (control group). The three months of intense training resulted in a smaller attentional blink and reduced brain activity to the first target (which was still detected with the same level of accuracy. Individuals with the most reduction in activity generally showed the most reduction in attentional blink size. The study demonstrates that mental training can result in increased attentional control.
The study appeared online May 8 in PLoS Biology. Full reference
Full text available at http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pbio.0050138
http://www.physorg.com/news97825611.html
http://www.eurekalert.org/pub_releases/2007-05/uow-mmf050407.php

A first glimpse at healthy brain and behavioral development

Initial data from the National Institutes of Health (NIH) MRI Study of Normal Brain Development, a large, population-based study that began in 1999 and is documenting structural brain development and behavior from birth to young adulthood, has revealed that:

Norms were higher with only healthy children being considered (the study excluded children who had any signs or known risk of serious neurological or psychiatric disorders).
Gender differences were less evident. Boys performed better on perceptual analysis, and girls performed better on processing speed and motor dexterity. The slight advantage girls showed in verbal learning disappeared by adolescence. There was no difference in math ability.
Income predicted IQ and academic achievement, but lower-income children performed better than in previous studies, with the study being restricted to healthy children.
Performance climbed steeply from age 6, but leveled off overall for most tests between 10 and 12 years of age, then improved more slowly or not at all during adolescence.

For more information see http://www.brain-child.org/.
These findings were published online May 18 in the Journal of the International Neuropsychological Society. Full reference
http://www.eurekalert.org/pub_releases/2007-05/chb-afg051607.php
http://www.eurekalert.org/pub_releases/2007-05/nion-nst051507.php
http://www.physorg.com/news98692796.html
http://sciam.com/article.cfm?articleID=A15FAD05-E7F2-99DF-34B5A1856E790722&chanID=sa003

Frequent TV viewing during adolescence linked with risk of attention and learning difficulties

A long-running study of 678 families in upstate New York, surveyed children at 14, 16 and 22 years old (averages), and again when the children in the study had reached an average age of 33. At age 14, 225 (33.2%) of the teens reported that they watched three or more hours of television per day. Those who watched 1 or more hours of television per day at mean age 14 years were at higher risk of poor homework completion, negative attitudes toward school, poor grades, and long-term academic failure. Those who watched 3 or more hours of television per day were most likely to experience these outcomes, and moreover were at higher risk of subsequent attention problems and were the least likely to receive postsecondary education. Analysis of the data also indicated that television watching contributes to learning difficulties and not vice versa.
The findings were reported in the May issue of Archives of Pediatrics & Adolescent Medicine. Full reference
http://www.eurekalert.org/pub_releases/2007-05/jaaj-ftv050307.php

Young children can add and subtract without arithmetic

We knew infants can judge simple mathematical relationships, such as being able to tell when there are more objects in one group compared to another. Now a new study shows that children can apply that ability to Arabic numerals after learning to count but before they learned to add and subtract. When given such problems as, "Sarah has 15 candies and she gets 19 more; John has 51 candies. Who has more?", five- and six-year-old children answered correctly 64—73% of the time. The research suggests ways to improve children’s engagement with formal arithmetic.
The study appeared in the May 31 issue of Nature. Full reference
http://www.sciam.com/article.cfm?chanID=sa017&ref=feedburner&articleId=D98DB8BB-E7F2-99DF-3B57177BA445AF65

Stereotype-induced math anxiety robs women's working memory

Another study finds evidence that being told men are better at mathematics undermines women's math performance, and extends it by demonstrating that the anxiety induced by the stereotype mainly reduced the verbal part of working memory, and that this carried over to subsequent (non-math-related) tasks. The accuracy of women exposed to the stereotype was reduced from nearly 90% in a pretest to about 80% after being told men do better in mathematics. Among women not receiving that message, performance actually improved slightly.
The results appeared in the May issue of the Journal of Experimental Psychology: General. Full reference
http://www.physorg.com/news99239898.html
http://www.eurekalert.org/pub_releases/2007-05/uoc-sma052107.php

Female alcoholics can develop cognitive problems more rapidly than male alcoholics

It is known that women, compared to men, seem to become more "damaged" by chronic alcohol abuse within a shorter period of drinking and with less overall consumption. A new study shows that female alcoholics may also sustain greater cognitive damage than male alcoholics.
Results were published in the May issue of Alcoholism: Clinical & Experimental Research. Full reference
http://www.eurekalert.org/pub_releases/2007-04/ace-fac041607.php
http://www.sciencedaily.com/releases/2007/04/070423185702.htm

Tight diabetes control does not impact cognitive ability in type 1 diabetes

A long-running study involving 1,441 type 1 diabetics, aged 13 to 39, has demonstrated that multiple episodes of severe hypoglycaemia, though they can cause confusion, irrational behavior, convulsions and unconsciousness, do not lead to long-term loss of cognitive ability.
The findings were published in the May 3 issue of the New England Journal of Medicine. Full reference
http://www.eurekalert.org/pub_releases/2007-05/jdc-sst050107.php

Inflammatory system genes linked to cognitive decline after heart surgery

The finding that people with variants of two genes involved in the inflammatory system appear to be protected from suffering a decline in mental function following heart surgery raises the possibility that therapy involving drugs known to dampen the inflammatory response may be effective in preventing cognitive decline after heart surgery. The specific genes involved were those for C-reactive protein (which plays an important role in the body’s initial response to injury) and P-selectin (which helps recruit circulating white blood cells to the site of an injury). Patients with the variation of the C-reactive protein gene were 20.6% less likely to suffer mental decline, and patients with the P-selectin variant had a 15.2% risk reduction. The risk of cognitive decline for those with both gene variants was only 17% compared to 43% for patients who had neither variant.
The findings were published online May 1 in the Journal of the American College of Cardiology. Full reference
http://www.eurekalert.org/pub_releases/2007-05/dumc-isg043007.php

Adult neurogenesis more important for learning than thought

A mouse study reveals that adult neurogenesis briefly gives adult brains similar plasticity to that seen in infant brains. It seems new neurons about four weeks of age have a two week window during which they show increased adaptability to stimuli, similar to what occurs in newborn animals. Researchers were surprised both by the timing of the plasticity and the similarity of new neurons in adults to neurons in newborns. The findings suggest that new neurons are more involved than their mature neighbors in memory formation, and that plasticity depends more on the age of the neurons than the age of the brain.
The report appeared in the May 24 issue of Neuron. Full reference
http://www.the-scientist.com/news/home/53238/
http://www.physorg.com/news99142458.html
http://www.eurekalert.org/pub_releases/2007-05/cp-nab051807.php
http://www.eurekalert.org/pub_releases/2007-05/jhmi-abc052307.php
http://www.sciam.com/article.cfm?chanID=sa017&ref=feedburner&articleId=BAB80AA1-E7F2-99DF-3A640AF2C3600666
http://www.newscientist.com/channel/health/mg19426053.300?DCMP=NLC-nletter&nsref=mg19426053.300

Fragile X syndrome -- A stimulating environment restores neuronal function in mice

Mice in which the gene that causes Fragile X syndrome —- the most common form of inherited mental retardation — in humans had been knocked out, showed reduced long-term potentiation in neurons due to abnormalities in the channels that regulate the flow of calcium into neurons. Excitingly, exposure to an enriched environment restored normal neuronal plasticity, suggesting that mechanisms for synaptic plasticity are in place, they just require stronger neuronal activity to be triggered.
The findings were published in the May 24 issue of Neuron. Full reference
http://www.physorg.com/news99144459.html
http://www.eurekalert.org/pub_releases/2007-05/cp-fxs051807.php

Chronic pain can impair working memory

A study of 24 patients with chronic pain has found that 2/3 of them showed cognitive impairment on attentional tasks on days when their pain was high (i.e. without receiving a pain-reducing procedure).
The findings were published in the May issue of Anesthesia and Analgesia. Full reference
http://www.sciencedaily.com/releases/2007/05/070517142536.htm
http://www.eurekalert.org/pub_releases/2007-05/uoa-cpc051707.php

Bigger is smarter: brain size predicts intelligence in different species

Animals with larger body sizes generally have larger brains, and it has generally been assumed that larger animals require larger nervous systems to coordinate their larger bodies. Consequently, comparison of brain size across different animal species, as an indirect measurement of intelligence, have controlled for body size. New research however suggests that, although some correction is probably needed, completely controlling for body size is almost certainly a mistake. Both overall brain size and overall neocortex size proved to be good predictors of intelligence in different primate species.
The study is published online in Brain, Behavior, and Evolution. Full reference
http://www.sciencedaily.com/releases/2007/05/070518172103.htm

Gene mutation linked to cognition is found only in humans

A new study has found that a certain form of neuropsin, a protein that plays a role in learning and memory, is expressed only in the central nervous systems of humans and that it originated less than 5 million years ago.
The study was published online ahead of print May 8 in Human Mutation. Full reference
http://www.physorg.com/news97825267.html
http://www.sciencedaily.com/releases/2007/05/070508072829.htm
http://www.eurekalert.org/pub_releases/2007-05/jws-gml050107.php

Conference proceedings

Green tea extract protects against HIV-associated dementia

A compound derived from green tea greatly reduced the neurotoxicity of proteins secreted by the human immunodeficiency virus, suggesting a new approach to the prevention and treatment of HIV-associated dementia.
Brian Giunta reported the findings May 1 at Experimental Biology 2007 in Washington, DC.
http://www.eurekalert.org/pub_releases/2007-05/uosf-gte042707.php

Symptomatic Gulf War veterans show reduced brain volume

Early results from a study of 36 veterans of the first Gulf War (1990-1991) found that those who had more than five symptoms (such as joint pain, fatigue, forgetfulness, headaches, skin rash, nausea, and difficulty concentrating) had significantly reduced brain tissue in two areas compared to those who had five or fewer symptoms. The overall cortex was 5% smaller in those with more symptoms, and the rostral anterior cingulated gyrus was 6% smaller. Those with more symptoms also did not perform as well on tests of learning and memory.
White presented the research in a poster session at the American Academy of Neurology’s 59th Annual Meeting in Boston, April 28 – May 5, 2007.
http://www.eurekalert.org/pub_releases/2007-05/aaon-bso041007.php
http://www.sciam.com/article.cfm?articleID=49D0FABA-E7F2-99DF-344DA265CD9D0B93&sc=I100322

TMS improves neuronal function in mice

Transcranial magnetic stimulation (TMS) — a technique that uses a magnetic coil to induce electric fields in the brain tissue — has been used experimentally to treat a range of brain disorders, including depression and schizophrenia, and to rehabilitate people after a stroke. A mouse study reveals that TMS improves long-term potentiation in neurons by modifying key glutamate receptors so that they stayed active for longer. It also substantially increased stem cells in the dentate gyrus.
Battaglia presented his results at the American Academy of Neurology's 59th Annual Meeting in Boston, April 28 – May 5, 2007.
http://www.guardian.co.uk/science/story/0,,2086759,00.html
http://www.newscientist.com/channel/health/mg19426053.300-magnets-may-make-the-brain-grow-stronger.html

Drinking heavy amounts of alcohol shrinks your brain

A study involving 1,839 people from the Framingham Offspring study, ages 34 to 88, who were classified as non-drinkers, former drinkers, low drinkers (one to seven drinks per week), moderate drinkers (eight to 14 drinks per week), or high drinkers (more than 14 drinks per week), has found that the more alcohol people drink on a regular basis, the lower their brain volume. The relationship was slightly larger in women than in men, and drinking heavy amounts of alcohol seemed to have the biggest negative impact on brain volume for women in their 70s.
Paul presented the research at a poster session at the American Academy of Neurology's 59th Annual Meeting in Boston, April 28 – May 5, 2007.
http://www.eurekalert.org/pub_releases/2007-05/aaon-dha041007.php

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