News reports of research into memory July 2004

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July 2004

Intelligence based on the volume of gray matter in certain brain regions

Confirming earlier suggestions, the most comprehensive structural brain-scan study of intelligence to date supports an association between general intelligence and the volume of gray matter tissue in certain regions of the brain. Because these regions are located throughout the brain, a single "intelligence center" is unlikely. It is likely that a person's mental strengths and weaknesses depend in large part on the individual pattern of gray matter across his or her brain. Although gray matter amounts are vital to intelligence levels, only about 6% of the brain’s gray matter appears related to IQ — intelligence seems related to an efficient use of relatively few structures. The structures that are important for intelligence are the same ones implicated in memory, attention and language. There are also age differences: in middle age, more of the frontal and parietal lobes are related to IQ; less frontal and more temporal areas are related to IQ in the younger adults. Previous research has shown the regional distribution of gray matter in humans is highly heritable. The findings also challenge the recent view that intelligence may be a reflection of more subtle characteristics of the brain, such as the speed at which nerve impulses travel in the brain, or the number of neuronal connections present. It may of course be that all of these are factors.
The study appears in the online edition of NeuroImage. Full reference
http://www.sciencedaily.com/releases/2004/07/040720090419.htm
http://www.eurekalert.org/pub_releases/2004-07/uoc--hid071904.php

Social status influences brain structure

A rat study has found that dominant rats have more new nerve cells in the hippocampus than their subordinates, suggesting that social hierarchies can influence brain structure. Seven colonies of 6 rats (4 male and 2 female) established their pecking order within three days, and were tested two weeks later. The dominant males had some 30% more neurons in their dentate gyrus than both the subordinate rats and controls. The increase seems to be because the new cells constantly being born in this area of the brain (most of which usually die within a week) were surviving longer. Hippocampal neurons have already been shown to be responsive to negative factors such as stress, and positive factors such as exercise and environmental enrichment. The increase in neurons was maintained when the rats were removed from the social setting.
The results were published in the July 28 issue of the Journal of Neuroscience.
http://www.nature.com/news/2004/040802/full/040802-18.html Full reference

Time really does fly when you’re busy

We all know that time goes faster when we’re busy, but though scientists have long tried to prove a link between attention and time estimation, it has been difficult to design an experimental manipulation that only manipulates attention and not other, potentially confounding variables. But now, it seems, two researchers have managed to do it – and the finding is clear. Results showed that an attentionally demanding search task produced a large underestimation of time, and that as the amount of attention increased, so did the underestimation of time. Note that the study involved prospective estimates of time (participants knew in advance that they would be asked how long the task took), rather than retrospective.
The study was published in the July issue of Brain and Cognition. Full reference
http://www.eurekalert.org/pub_releases/2004-08/uoa-spt080604.php

Early music instruction raises child’s IQ

A new study confirms earlier research supporting the benefits of early music instruction. The study involved 144 children, 6 years old at the start of the study. They were given free weekly voice or piano lessons at the Royal Conservatory of Music. Another group of 6-year-olds was given free training in weekly drama classes, while a fourth group received no extra classes during the study period. Before any classes were given, all the children were tested using the full Weschler intelligence test. At the end of the school year (their first school year), the children were retested. All had an IQ increase of at least 4.3 points on average (a consequence of going to school). Children who took drama lessons scored no higher than those who had no extra lessons, but those who took music lessons scored on average 2.7 points higher than the children who did not take music lessons. Those in the drama group did however show substantial improvement in adaptive social behavior.
The study was published in the August issue of Psychological Science. Full reference
http://www.sciencentral.com/articles/view.htm3?article_id=218392326 http://abcnews.go.com/sections/living/Healthology/Music_IQ_kids_healthday_040716.html?CMP=IL23417

Preschool storytelling ability linked to later mathematical ability

A new study suggests that preschool children's early storytelling abilities are predictive of their mathematical ability two years later. In the study, three-and four-year-old children were shown a book that contained only pictures and were asked to tell the story to a puppet. Their abilities were measured in a variety of ways. Two years later, the children were given a number of tests of academic achievement, including a test of mathematical achievement. It was found was that those children who scored highly on the mathematics test had also scored highly on certain measures of their storytelling ability two years earlier. "Most strongly predictive of children's mathematical performance was their ability to relate all the different events in the story, to shift clearly from the actions of one character to another, and to adopt the perspective of different characters and talk about what they were feeling or thinking." This study suggests that building strong storytelling skills early in the preschool years may be helpful in preparing children for learning mathematics when they enter school.
The study was published in the June issue of First Language. Full reference
http://www.eurekalert.org/pub_releases/2004-07/nsae-url072904.php

Children outperform adults in memory study

An example of the perils of knowing too much! — under specific conditions, young children can beat most adults on a recognition memory test. The study compared young children (average age 5 years) with college students. Without being told what was being tested, participants were shown pictures of cats, bears and birds. Some of them were first shown a picture of a cat, and told that it had “beta cells inside its body”. They were then shown other pictures, and asked whether these animals also had beta cells. After this, they were shown other pictures, and asked whether they had been shown them before. The children were accurate on average 31% of the time; the college students only 7% of the time. The researchers suggested the reason was because the children used similarity-based induction: when asked whether each pictured animal had "beta cells", they looked carefully to see if the animal looked similar to the original cat. On the other hand, the adults used category-based induction: once they determined whether the animal pictured was a cat or not, they paid no more attention. Thus, when they were tested later, the adults didn't know the pictures as well as the children. A subsequent study taught the children to use category-based induction. Their performance then dropped to the level of the adults. Another study in which participants were simply shown the pictures of the 30 animals and told to remember them for a recognition test, found adults were accurate 42% of the time, compared to only 27% for the children.
The research will appear in the August edition of Psychological Science.Full reference
http://tinyurl.com/55r4n
http://www.eurekalert.org/pub_releases/2004-07/osu-cch072104.php

Saving the most vulnerable brain cells in stroke

New research reveals why particular neurons in the hippocampus are most vulnerable to death from oxygen starvation during a stroke, and may lead to drugs that selectively protect those cells, leaving other brain cells unaffected. The findings could also lead to drugs that protect vulnerable brain cells in sufferers of amyotrophic lateral sclerosis, or Lou Gehrig's disease.
The research was published in the July 8 issue of Neuron. Full reference
http://www.eurekalert.org/pub_releases/2004-07/cp-stm070204.php

Imaging reveals a biological basis for autism

An imaging study has found numerous abnormalities in the activity of brains of people with normal IQs who have autism. The new findings indicate a deficiency in the coordination among brain areas. The results converge with previous findings of white matter abnormalities in autism. The researchers have proposed a new theory, called underconnectivity theory, which holds that autism is a system-wide brain disorder that limits the coordination and integration among brain areas. The study produced two important new findings that help make sense of previous mysteries: The autistic participants had an opposite distribution of activation (compared to the control group) in the brain's two main language areas — specifically, in the autistic brains, there was much less activity in Broca’s area, which is an integrating center for language, while Wernicke’s area, which does the processing of individual words, was more active. There was also less synchronization of activation among key brain areas. It is suggested that the brain may adapt to the diminished inter-area communication (a consequence of the white-matter abnormalities) by developing more independent, free-standing abilities in each brain center. If so, then a cognitive behavioral therapy might be developed to stimulate the development of connections in these higher order systems, focusing on the emergence of conceptual connections, interpretive language and so on.
The study will be published in the August edition of Brain. Full reference
http://www.eurekalert.org/pub_releases/2004-07/cmu-cma072904.php

New tool to image brain function at the cellular level

A new tool has been developed which will enable scientists to study individual neurons in a living animal. The tool is a genetically modified mouse that couples a green fluorescent protein (GFP) with a gene (c-fos) that turns on when nerve cells are activated. The coupling of these two means that neurons glow when activated, enabling researchers to see the specific neurons that have been activated by particular stimuli. Previous techniques to detect c-fos expression have been more intrusive, disrupting membranes and disturbing connections. The fosGFP mice should be extremely helpful in helping researchers discover precisely which neurons are active in different neurological diseases.
The research is described in the July 21 issue of The Journal of Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2004-07/cmu-cmn063004.php

Closing in on the genes involved in context learning

A study involving the worm C. elegans (whose genome has been completely sequenced) has demonstrated that even such simple animals demonstrate memory that is sensitive to context. In the study, the worms were trained in a salt medium to associate a particular smell with starvation. When placed in a different salt medium, the worms didn’t respond to the smell, but showed distaste when experiencing the smell in the context of the salt medium in which they were trained. More importantly, use of this animal has enabled the researchers to identify a genetic mutation that affects this type of memory. The next step will be to identify the specific gene involved in processing environmental cues.
The study was published in the July 27 issue of Current Biology. Full reference
http://www.eurekalert.org/pub_releases/2004-07/uot-eil072704.php

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