News reports of research into memory July 2005

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July 2005

Study links adolescent IQ/activity levels with risk of dementia

An analysis of high school records and yearbooks from the mid-1940s, and interviews with some 400 of these graduates, now in their 70s, and their family members, has found that those who were more active in high school and who had higher IQ scores, were less likely to have mild memory and thinking problems and dementia as older adults.
The results were published in the July 2005 issue of the Journal of the American Geriatrics Society. Full reference
http://www.eurekalert.org/pub_releases/2005-07/cwru-sla070105.php

TV has negative impact on very young children's learning abilities

Analysis of data involving some 1800 children from The National Longitudinal Survey of Youth 1979 (NLSY-Child) compared scores in mathematics, reading recognition and reading comprehension with the level of television watching before age three and from ages three to five. The analysis revealed a consistent pattern of negative associations between television viewing before age three years and adverse cognitive outcomes at ages six and seven years. Television viewing at ages three to five years, on the other hand, had a more beneficial effect, for reading recognition and short-term memory, although not mathematics or reading comprehension.

Another study in the same issue reported on a New Zealand study that compared television viewing in some 1000 people born in 1972-73 with their educational achievements at 26 years of age. The study found mean time spent watching television during childhood and adolescence was significantly associated with leaving school without qualifications and negatively associated with attaining a university degree. Television viewing during childhood (ages 5-11 years) and adolescence (ages 13 and 15 years) had adverse associations with later educational achievement. However, adolescent viewing was a stronger predictor of leaving school without qualifications, whereas childhood viewing was a stronger predictor of nonattainment of a university degree.

Both studies appeared in the July issue of Archives of Pediatrics & Adolescent Medicine.Full reference 2
http://www.eurekalert.org/pub_releases/2005-07/jaaj-thn062905.php

One hit of crystal meth causes birth defects

A mouse study has found that a single prenatal dose of methamphetamine (speed) can cause long-term neurodevelopmental problems in babies, especially reduced motor coordination.
The study was published in the August issue of Free Radical Biology and Medicine. Full reference
http://www.eurekalert.org/pub_releases/2005-07/uot-oho072605.php

Human cerebellum and cortex age in very different ways

Analysis of gene expression in five different regions of the brain's cortex has found that brain changes with aging were pronounced and consistent across the cortex, but changes in gene expression in the cerebellum were smaller and less coordinated. Researchers were surprised both by the homogeneity of aging within the cortex and by the dramatic differences between cortex and cerebellum. They also found that chimpanzees' brains age very differently from human brains; the findings cast doubt on the effectiveness of using rodents to model various types of neurodegenerative disease.
The study was reported in the open-access journal PLoS Biology. Full reference
http://www.eurekalert.org/pub_releases/2005-08/hu-hca072805.php

Closing in on the genes involved in human intelligence

A genetic study claims to have identified two regions of the human genome that appear to explain variation in IQ. Previous research has suggested that between 40% and 80% of variation in human intelligence (as measured by IQ tests) can be attributed to genetic factors, but research has so far failed to identify these genes. The new study has identified specific locations on Chromosomes 2 and 6 as being highly influential in determining IQ, using data from 634 sibling pairs. The region on Chromosome 2 that shows significant links to performance IQ overlaps a region associated with autism. The region on Chromosome 6 that showed strong links with both full-scale and verbal IQ marginally overlapped a region implicated in reading disability and dyslexia.
The study was published in the July issue of the American Journal of Human Genetics. Full reference
http://www.qimr.edu.au/news/index.html

Varied sensory experience important in childhood

A new baby has far more connections between neurons than necessary; from birth to about age 12 the brain trims 50% of these unnecessary connections while at the same time building new ones through learning and sensory stimulation — in other words, tailoring the brain to its environment. A mouse study has found that without enough sensory stimulation, infant mice lose fewer connections — indicating that connections need to be lost in order for appropriate ones to grow. The findings support the idea that parents should try to expose their children to a variety of sensory experiences.
The research was published in the July 14 issue of Nature. Full reference
http://www.sciencentral.com/articles/view.htm3?article_id=218392607

How trauma triggers long-lasting memories in the brain

A rat study sheds more light on why emotional experiences tend to be better remembered than emotionally neutral events. The study found that emotionally arousing events activated the amygdala, which then increased a specific protein — activity-regulated cytoskeletal protein ("Arc") — in the neurons in the hippocampus. It's thought that Arc helps store these memories by strengthening the synapses.
The study appeared in the July 26 issue of the Proceedings of the National Academy of Sciences. Full reference
http://www.eurekalert.org/pub_releases/2005-07/uoc--nih072505.php

Brain function in schizophrenia can improve with cognitive training

Researchers have long recognized that schizophrenia is associated with a wide range of memory problems, but in view of the more serious problems associated with schizophrenia, these have, until now, tended to be ignored. A new study has demonstrated that people with schizophrenia can be helped to remember things just as well as healthy subjects as long as they are given proper cues and memory aids. Moreover, use of these beneficial strategies not only improves recall, but also seems to trigger a more normal pattern of memory-related brain activities.
The study was published in the July 1 issue of Biological Psychiatry. Full reference
http://www.eurekalert.org/pub_releases/2005-07/wuis-bfi070505.php

Study validates MRI imaging method as research and clinical tool

Validating MRI imaging, a new study has succeeded in showing a direct relationship between functional magnetic resonance imaging signals (fMRI) and actual brain cell electrical activity in humans.
The findings appear in the 5 August edition of Science. Full reference
http://www.eurekalert.org/pub_releases/2005-08/uoc--unf080105.php

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