News reports of research into memory August 2006

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August 2006

Exercise helps sustain mental activity as we age

A review of the research on the effects of exercise on brain functioning supports the view that physical exercise helps people maintain cognitive abilities well into older age. There’s also evidence that fitness training may improve some mental processes even more than moderate activity. The review examined three types of study: epidemiological studies, human intervention studies, and animal studies. All provide support for the benefits of physical activity for the aging brain.
Findings from the review were presented August 11 at the 114th Annual Convention of the American Psychological Association (APA). Full reference
http://www.eurekalert.org/pub_releases/2006-08/apa-ehs080106.php

Copper increases cognitive decline in older adults on high-fat diet

A six-year study involving 3,718 Chicago residents age 65 years and older has found that among the 16% who had high levels of saturated and trans fats in their diets, cognitive function deteriorated more rapidly the more copper they had in their diets. Copper intake wasn’t a factor for the rest of the group. Previous studies have found higher levels of copper in the blood of patients with Alzheimer's disease. The finding will need to be confirmed by further research. The dietary recommended allowance of copper for adults is .9 milligrams per day. Organ meats, such as liver, and shellfish are the foods with the highest copper levels, followed by nuts, seeds, legumes, whole grains, potatoes, chocolate and some fruits.
The report appeared in the August issue of Archives of Neurology. Full reference
http://www.sciencedaily.com/releases/2006/08/060816013125.htm
http://www.eurekalert.org/pub_releases/2006-08/jaaj-hcd081006.php

Novelty aids learning

We’ve long suspected that the human brain is particularly attracted to new information. Research now reveals that the brain region that regulates our levels of motivation and our ability to predict rewards, by releasing dopamine in the frontal and temporal regions of the brain, responds better to novelty than to the familiar. Behavioral experiments also revealed that participants best remembered the images they had been shown when new images were mixed in with slightly familiar images during learning. It’s worth noting that this midbrain area (substantia nigra/ventral tegmentum) responded strongly only to completely new stimuli.
The study was published in the 3 August issue of Neuron. Full reference
http://www.eurekalert.org/pub_releases/2006-08/ucl-nal073106.php

Most of the cognitive deficits associated with alcoholism recoverable

Results of a study involving middle-aged alcoholics who have been sober for six months to 13 years, suggest that long-term abstinent alcoholics can recover most of their neurocognitive deficits. However, deficits in spatial-processing abilities continued. Visuospatial processes are important for many daily activities, including driving, reading a map, assembling things, and performing tasks that require spatial orientation. The study doesn’t however know how much damage had been done when the alcoholics ceased drinking; further studies are exploring the recovery of older abstinent alcoholics who ceased drinking at different ages.
Results are published in the September issue of Alcoholism: Clinical & Experimental Research. Full reference
http://www.eurekalert.org/pub_releases/2006-08/ace-lam082106.php

Morbid obesity in toddlers linked to low IQ

A study of 18 children and adults with early-onset morbid obesity (they weighed at least 150% of their ideal body weight before they were 4), 19 children and adults with Prader-Willi syndrome, and 24 of their normal-weight siblings, has revealed a link between morbid obesity in toddlers and lower IQ scores, cognitive delays and brain lesions similar to those seen in Alzheimer's disease patients. The links between cognitive impairments and Prader-Willi syndrome (a genetic disorder that causes people to eat nonstop and become morbidly obese at a very young age if not supervised) are well-established. But researchers were surprised to find patients with early-onset morbid obesity had an average IQ of 77, compared to an average of 63 for Prader-Willi patients and an average of 106 for the control group of siblings. Scans also revealed white-matter lesions on the brains of many of the Prader-Willi and early-onset morbidly obese patients.
The report was published in the August issue of the Journal of Pediatrics. Full reference
http://www.eurekalert.org/pub_releases/2006-08/uof-ssl083106.php

Childhood sleep apnea linked to brain damage, lower IQ

It’s long been known that sleep apnea, characterized by fragmented sleep, interrupted breathing and oxygen deprivation, harms children's learning ability and school performance. Now a new study involving 19 children with severe obstructive sleep apnea has identified damage in the hippocampus and the right frontal cortex, and linked that to observable deficits in performance on cognitive tests. Children with OSA had an average IQ of 85 compared to 101 in matched controls. They also performed worse on standardized tests measuring executive functions, such as verbal working memory (8 versus 15) and word fluency (9.7 versus 12). Obstructive sleep apnea affects 2% of children in the United States, but it is unclear how many of these suffer from severe apnea.
The report appeared in the August 22 issue of Public Library of Science Medicine. Full reference
Full text available at:
http://medicine.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pmed.0030301
http://www.eurekalert.org/pub_releases/2006-08/jhmi-csa081506.php

Ingredient commonly found in shampoos may inhibit brain development

An ingredient found in many shampoos and other personal care products (Diethanolamine (DEA)) appears to interfere with normal brain development in baby mice when applied to the skin of their pregnant mothers. DEA appears to block the body's ability to absorb the nutrient choline, which is essential for normal development of the brain. Whether the amounts most people absorb from personal care products would cause harm remains unclear. A list of some products that contain DEA can be found at http://householdproducts.nlm.nih.gov/index.htm.
The study is featured as the cover story in the August issue of the Federation of American Societies for Experimental Biology Journal. Full reference
http://www.eurekalert.org/pub_releases/2006-08/uonc-uss080306.php

Drug erases long-term memory

A rat study has succeeded in erasing memory without damaging the brain. The study found that if rats were given an inhibitor for an atypical enzyme, protein kinase M zeta (PKMzeta), after being trained in a shock-avoidance task, they had no memory of the training. They could however learn the task once the drug cleared their system. Moreover, the inhibitor even caused the memory of the task to vanish if it was given 30 days after the training. Earlier this year, PKMzeta was found to be bound up in the tangles of Alzheimer's disease.
The report appeared in the August 25 issue of Science. Full reference
http://www.sciencedaily.com/releases/2006/08/060830204206.htm
http://www.eurekalert.org/pub_releases/2006-08/sdmc-sds083006.php
http://www.the-scientist.com/news/daily/24375/

Restoring flexibility to old brains

Researchers have identified a protein, PirB, that stops new neural connections forming in adult brains, possibly explaining why older brains become less adaptable. The study found that the brains of adult mice that lacked PirB retained the same rewiring ability of much younger brains. Without PirB to hold them back, the old mice were, in effect, able to learn new tricks. The findings could offer hope for victims of brain injury and strokes.
The findings were published online August 17 in Science Express. Full reference
http://www.timesonline.co.uk/article/0,,11069-2319339,00.html
http://www.sciencedaily.com/releases/2006/08/060818012553.htm

No specialized face area

Another study has come out casting doubt on the idea that there is an area of the brain specialized for faces. The fusiform gyrus has been dubbed the "fusiform face area", but a detailed imaging study has revealed that different patches of neurons respond to different images. However, twice as many of the patches are predisposed to faces versus inanimate objects (cars and abstract sculptures), and patches that respond to faces outnumber those that respond to four-legged animals by 50%. But patches that respond to the same images are not physically connected, implying a "face area" may not even exist.
The study was published online 6 August and will be published in the September issue of Nature Neuroscience. Full reference
http://www.sciencedaily.com/releases/2006/08/060830005949.htm

Genetic variations that may be key to the evolution of the human brain

It has been thought that most genetic variations between people and between species are due to small changes in the sequence of DNA lettering, but a new idea that’s becoming popular is that the number of copies of genes is an important source of variation that may be driving evolution. Comparison of the DNA sequences of humans, chimpanzees and monkeys, has now revealed that a gene that codes for a piece of protein called DUF1220 exists in 212 copies in humans, but only 37 in chimpanzees and 30 in monkeys. Mice and rats have only one. The protein is found in the heart, spleen, skeletal muscle, and small intestine, and particularly in brain regions associated with higher cognitive function.
The report appeared in the 1 September issue of Science. Full reference
http://www.nature.com/news/2006/060828/full/060828-5.html
http://sciencenow.sciencemag.org/cgi/content/full/2006/831/4?etoc

An exploration of those 49 areas of the genome that have changed most between human and chimpanzee has revealed one area that's changed dramatically in a relatively short period of time. The gene is found only in mammals and birds, and hasn’t changed much in other animals — between a chimp and a chicken, there are only two differences in the 118 letters of DNA code that make up HAR1 (human accelerated region 1). But there are 18 differences in that one gene between human and chimp. That is a lot of change to happen in five million years. HAR1 is part of two overlapping genes -- both the rare RNA genes, not genes that code for proteins -- one of which (HAR1F) is active in nerve cells that appear early in embryonic development and play a critical role in the formation of the layered structure of the human cerebral cortex. The other also appears to be involved in cortical development.
The study was published on August 16 as an advance online publication in Nature. Full reference
http://news.yahoo.com/s/ap/20060817/ap_on_sc/brain_evolution
http://www.newscientist.com/article/dn9767?DCMP=NLC-nletter&nsref=dn9767
http://www.sciencedaily.com/releases/2006/08/060817102730.htm