News reports of research into memory February 2007

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February 2007

Vitamin B12, folate, and cognitive function

Confirming earlier studies, a large epidemiological study has found that older people with normal vitamin B12 status and high levels of folate had higher scores on a test of cognitive function. The study clarifies some inconsistencies in earlier research by disentangling the interaction between these factors. It appears seniors with normal levels of vitamin B12 perform better if folate level is high, but when vitamin B12 is low, high levels of folate are associated with poor cognitive performance, as well as a greater probability of anemia. There are also indications that the combination might be a factor in some other diseases.
The study appeared in the January issue of the American Journal of Clinical Nutrition. Full reference
http://www.eurekalert.org/pub_releases/2007-02/tu-fab020907.php

Students who believe intelligence can be developed perform better

Research with 12-year-olds has found that, although all students began the study with equivalent achievement levels in math, over a two year period, those who believed that intelligence was malleable increasingly did better than those who believed their intelligence was fixed. Another study found that, when students showing declines in their math grades were taught that intelligence could be increased, they reversed their decline and showed significantly higher math grades than others who weren’t taught that.
The research was published in the January/February 2007 issue of Child Development. Full reference
http://www.eurekalert.org/pub_releases/2007-02/sfri-swb013107.php

Implicit stereotypes and gender identification may affect female math performance

Relatedly, another study has come out showing that women enrolled in an introductory calculus course who possessed strong implicit gender stereotypes, (for example, automatically associating "male" more than "female" with math ability and math professions) and were likely to identify themselves as feminine, performed worse relative to their female counterparts who did not possess such stereotypes and who were less likely to identify with traditionally female characteristics. Strikingly, a majority of the women participating in the study explicitly expressed disagreement with the idea that men have superior math ability, suggesting that even when consciously disavowing stereotypes, female math students are still susceptible to negative perceptions of their ability.
The article was published in the January issue of Psychological Science. Full reference
http://www.eurekalert.org/pub_releases/2007-01/afps-isa012407.php

Reducing the racial achievement gap

And staying with the same theme, a study that came out six months ago, and recently reviewed on the excellent new Scientific American Mind Matters blog, revealed that a single, 15-minute intervention erased almost half the racial achievement gap between African American and white students. The intervention involved writing a brief paragraph about which value, from a list of values, was most important to them and why. The intervention improved subsequent academic performance for some 70% of the African American students, but none of the Caucasians. The study was repeated the following year with the same results. It is thought that the effect of the intervention was to protect against the negative stereotypes regarding the intelligence and academic capabilities of African Americans.
The research appeared in the September 1 issue of Science. Full reference
http://blog.sciam.com/index.htm?title=closing_the_racial_achievement_gap&more=1&c=1&tb=1&pb=1

Highly accomplished people more prone to failure than others when under stress

One important difference between those who do well academically and those who don’t is often working memory capacity. Those with a high working memory capacity find it easier to read and understand and reason, than those with a smaller capacity. However, a new study suggests there is a downside. Such people tend to heavily rely on their abundant supply of working memory and are therefore disadvantaged when challenged to solve difficult problems, such as mathematical ones, under pressure — because the distraction caused by stress consumes their working memory. They then fall back on the less accurate short-cuts that people with less adequate supplies of working memory tend to use, such as guessing and estimation. Such methods are not made any worse by working under pressure. In the study involving 100 undergraduates, performance of students with strong working memory declined to the same level as those with more limited working memory, when the students were put under pressure. Those with more limited working memory performed as well under added pressure as they did without the stress.
The findings were presented February 17 at the annual meeting of the American Association for the Advancement of Science.
http://www.eurekalert.org/pub_releases/2007-02/uoc-hap021607.php

African-American and poor children more affected by sleep problems

A study involving 166 8- and 9-year-old African-American and European-American children from varying socioeconomic backgrounds has found that sleep disruption has greater effects on cognitive performance for children from lower-income homes and African-American children. When socioeconomic status was taken into consideration, African-American and European-American children's performance on cognitive tests was similar when they slept well. But when sleep was disrupted, African-American children's performance was worse. Similarly, children from lower and higher socioeconomic backgrounds performed similarly on tests when they slept well and their sleep schedules were consistent. But when their sleep was disrupted, children from higher-income homes did better than children from lower-income homes.
The study was published in the January/February 2007 issue of Child Development. Full reference
http://www.eurekalert.org/pub_releases/2007-02/sfri-csp013107.php

Size of brain areas does matter -- but bigger isn't necessarily better

In a fascinating mouse study that overturns our simplistic notion that, when it comes to the brain, bigger is better, researchers have found that there is an optimal size for regions within the brain. The study found that if areas of the cortex involved in body sensations and motor control are either smaller or larger than normal, mice couldn’t run an obstacle course, keep from falling off a rotating rod, or perform other tactile and motor behaviors that require balance and coordination as well as mice with normal-sized areas could. It now seems that the best size in one that is best tuned to the context of the neural system within which that area functions — which is not really so surprising when you consider that every brain region acts as part of a network, in conjunction with other regions. This study builds upon a previous discovery by the same researchers, that a gene controls how the cortex in mice is divided during embryonic development into its functionally specialized areas. Different levels of the protein expressed by this gene changes the size of the sensorimotor areas of the cortex. It is known that significant variability in cortical area size exists in humans, and this may explain at least in part variability in human performance.
The findings appeared online before print February 27 in the Proceedings of the National Academy of Sciences. Full reference
Full text is available at http://tinyurl.com/2tpyhe
http://www.physorg.com/news92051236.html

Post-natal choline supplements may reduce cognitive effects associated with prenatal alcohol exposure

A rat study has found that giving choline to rat pups exposed to alcohol during the equivalent of the third trimester, when there’s a spurt in brain growth, significantly reduced the severity of alcohol-related over-activity and spatial learning deficits. The benefits lasted months after choline treatment, suggesting that choline’s effects are long-lasting. Further studies are needed to establish exactly how choline helps and how late in development it can reduce fetal alcohol effects, and then, whether the effects also apply to humans. However, although early postnatal choline may reduce learning deficits and hyperactivity following early alcohol exposure, it doesn’t help reduce motor coordination deficits.
The findings appear in the February issue of Behavioral Neuroscience. Full reference
Full text of the article is available at http://www.apa.org/journals/releases/bne1211120.pdf
http://www.eurekalert.org/pub_releases/2007-02/apa-csp022607.php

Breaking fish advice during pregnancy may benefit babies

Fears of the effects of mercury have led to government warnings to pregnant women to limit their consumption of seafood. However, a study involving nearly 12,000 women has found that children whose mothers ate the least amount of seafood during pregnancy showed the worst performance on tests of social development and verbal IQ, and beneficial effects were evident among children of women who ate more than the recommended guidelines.
The findings appeared in the February 17 issue of The Lancet. Full reference
http://www.newscientist.com/article/dn11193-breaking-fish-advice-during-pregnancy-might-benefit-babies.html

'Off-pump' CABG surgery appears to have no benefit on cognitive or cardiac outcomes at 5 years

A five-year study of 281 cardiac patients, half of whom received off-pump coronary artery bypass surgery and half on-pump surgery, has found that there was no difference in cognitive performance five years after surgery. The findings suggest that factors other than cardiopulmonary bypass may be responsible for cognitive decline, such as anesthesia and the generalized inflammatory response that is associated with major surgical procedures.
The study was reported in the February 21 issue of the Journal of the American Medical Association. Full reference
http://www.eurekalert.org/pub_releases/2007-02/jaaj-cs021507.php

Odor can help memory, in some circumstances

A study in which students played a computer version of a common memory game in which you turn over pairs of cards to find each one's match found that those who played in a rose-scented room and were later exposed to the same scent during slow-wave sleep, remembered the locations of the cards significantly better than people who didn't have that experience (97% vs 86%). Those exposed to the odor during REM sleep, however, saw no memory boost. Imaging revealed the hippocampus was activated when the odor was presented during slow-wave sleep. Having the smell available throughout sleep wouldn’t help, however, because we adapt to smells very quickly. Being exposed to the smell when being tested didn’t help either. Nor did experiencing the odor during slow-wave sleep help when the memory task involved a different type of memory — learning a finger-tapping sequence — probably because procedural memory doesn’t depend on the hippocampus.
The study was published March 9 in Science. Full reference
http://www.physorg.com/news92647884.html
http://www.nature.com/news/2007/070305/full/070305-10.html

Eye movement tasks can be used to assess fetal alcohol spectrum disorders

Fetal alcohol spectrum disorders (FASD) cover a wide array of adverse developmental outcomes in children due to prenatal alcohol exposure and is harder to diagnose than the more severe Fetal Alcohol Syndrome. Now new research indicates than simple eye-movement tasks can be used to assess individuals with FASD.
Results are published in the March issue of Alcoholism: Clinical & Experimental Research. Full reference
http://www.eurekalert.org/pub_releases/2007-02/ace-emt021507.php

A gene that influences intelligence

A study involving more than 2000 people from 200 families has found a link between the gene CHRM2, that activates multiple signaling pathways in the brain involved in learning, memory and other higher brain functions, and performance IQ. Researchers found that several variations within the CHRM2 gene (which is on chromosome 7) could be correlated with slight differences in performance IQ scores, which measure a person's visual-motor coordination, logical and sequential reasoning, spatial perception and abstract problem solving skills, and when people had more than one positive variation in the gene, the improvements in performance IQ were cumulative. Intelligence is a complex attribute that results from a combination of many genetic and environmental factors, so don’t interpret this finding to mean we’ve found a gene for intelligence.
The study's findings were published online December 12, and in the March issue of Behavior Genetics. Full reference
http://www.eurekalert.org/pub_releases/2007-02/wuso-gag022607.php

Common gene version optimizes thinking but carries a risk

On the same subject, another study has found that the most common version of DARPP-32, a gene that shapes and controls a circuit between the striatum and prefrontal cortex, optimizes information filtering by the prefrontal cortex, thus improving working memory capacity and executive control (and thus, intelligence). However, the same version was also more prevalent among people who developed schizophrenia, suggesting that a beneficial gene variant may translate into a disadvantage if the prefrontal cortex is impaired. In other words, one of the things that make humans more intelligent as a species may also make us more vulnerable to schizophrenia.
The study was published online February 8, and in the March 1 issue of the Journal of Clinical Investigation. Full reference
http://www.sciencedaily.com/releases/2007/02/070208230059.htm
http://www.eurekalert.org/pub_releases/2007-02/niom-cgv020707.php