News reports of research into memory September 2003

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September 2003

Estrogen improves verbal memory in postmenopausal women

A study involving 60 postmenopausal women aged 32.8 to 64.9, found those receiving daily estrogen treatment (conjugated equine estrogens — Premarin) showed improved oral reading and verbal memory performance, compared to those receiving a placebo. This is consistent with brain imaging date indicating estrogen produces brain activations in the inferior parietal lobule, a region sensitive to phonological demands and implicated in reading.
The report appeared in the September issue of Menopause. Full reference
http://www.eurekalert.org/pub_releases/2003-09/yu-eis092303.php

Menopause not linked to memory decline

Since 1996, 803 African American and white women aged 40 to 55 have been tested annually for loss of brain function. Performance was compared annually for women in premenopausal, during menopause, and postmenopausal groups. Smallbut significant increases in performance were found over time during the premenopausaland perimenopausal phases, leading the authors to conclude that transition through menopause is not accompaniedby a decline in working memory and perceptual speed.
The study appeared in the September 23 issue of Neurology. Full reference
http://www.eurekalert.org/pub_releases/2003-09/aa-nss091803.php

High blood pressure may be a factor in "senior moments"

An imaging study of seniors (average age 60) found that those with high blood pressure showed reduced blood flow to active brain areas when performing various everyday memory tasks, such as looking up a phone number then walking to another room to pick up the phone and dial the number. The diminished blood flow correlated to slightly worse scores on the memory tests. The differences weren’t large, but may help account for "senior moments" - memory problems commonly associated with age. It’s estimated that as many as a third of those with high blood pressure are not aware they have it.
Reported at the American Heart Association's 57th Annual High Blood Pressure Research Conference, September 23. Reference
http://www.eurekalert.org/pub_releases/2003-09/aha-hbp091703.php
http://www.americanheart.org/presenter.jhtml?identifier=3015552

Effects of high blood pressure on cognition may have been overstated

Epidemiological studies have suggested hypertensive patients perform worse than individuals with normal blood pressure on cognition tests. A new study has investigated performance on specific cognitive tasks (visual and memory search involving computer displays) by those with high blood pressure who were not on medication and had no detectable cardiovascular disease. Participants ranged in age from 20 to 80. Contrary to expectation, high blood pressure slowed performance only in the middle-aged group (40-59), not in those younger or older.
The results were published in the September issue of Aging, Neuropsychology and Cognition. Full reference
http://www.eurekalert.org/pub_releases/2003-09/dumc-hbp092503.php

More learned about how spatial navigation works in humans

Researchers monitored signals from individual brain cells as patients played a computer game in which they drove around a virtual town in a taxi, searching for passengers who appeared in random locations and delivering them to their destinations. Previous research has found specific cells in the brains of rodents that respond to “place”, but until now we haven’t known whether humans have such specific cells. This study identifies place cells (primarily found in the hippocampus), as well as “view” cells (responsive to landmarks; found mainly in the parahippocampal region) and “goal” cells (responsive to goals, found throughout the frontal and temporal lobes). Some cells respond to combinations of place, view and goal — for example, cells that responded to viewing an object only when that object was a goal.
The study was published in the Sept. 11 edition of Nature. Full reference
http://www.eurekalert.org/pub_releases/2003-09/uoc--vgu091003.php

Study of alcoholics reveals connection between cerebellum and prefrontal cortex

Two functions commonly compromised by chronic alcoholism are executive functions (such as problem solving, putting things in order, working memory, doing multiple tasks at once) and balance (the ability to walk a straight line or stand on one foot, especially with eyes closed or in the dark). Executive functions are primarily processed in the prefrontal cortex, while balance and postural stability are functions of the cerebellum. Previous studies have shown that the prefrontal cortex and regions of the cerebellum are especially vulnerable to the effects of chronic alcoholism. Although these areas are spatially far apart (the former in the frontal lobes, the latter in the hindbrain), they are connected in a variety of ways, most particularly through the pons and the thalamus. An imaging study of 25 nonamnesic alcoholic men suggests that these connections may compound the damaging effects of alcohol on these brain regions, and that the cerebellum, through these connections, can exert a significant effect on functions of the prefrontal cortex.
The study was reported in the September issue of Alcoholism: Clinical & Experimental Research. Full reference
http://www.eurekalert.org/pub_releases/2003-09/ace-amc090803.php

Too much exercise may be bad for the brain

Mice bred for 30 generations to display increased voluntary wheel running behavior – an "exercise addiction" – showed much higher amounts of BDNF (brain-derived neurotrophic factor – a chemical involved in protecting and producing neurons in the hippocampus) than normal, sedentary mice. In a related study, it was found that the mice also grow more neurons there as well. However, while BDNF and neurogenesis are good for learning and memory, this doesn’t necessarily mean an exercise addict learns at a faster rate. The “running addict” mice in fact performed much worse than normal mice when attempting to navigate around a maze. It could be that too much BDNF and neuron production may be a bad thing, or it may be that the hyperactive wheel running exercise actually kills or damages neurons in the hippocampus, and the high BDNF production is simply trying to minimize this damage. At the moment, all we can say with surety is that exercise greatly activates the hippocampus.
The first study was published in the 26 September issue of Neuroscience. Full reference
The second in the October edition of Behavioral Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2003-09/ohs-cn092603.php

Cognitive abilities are fairly stable and may be correlated with longevity

The Scottish Mental Survey assessed 87,498 eleven-year-olds in 1932, and another 70,805 in 1947. In a fascinating follow-up to this study, over 1000 of these students have been contacted and re-assessed, on the exact same tests. It was found that, first of all, the seniors did rather better than they had at age 11, and that differences in mental ability remained fairly stable with age. Mental ability at 11 was also found to be significantly correlated with survival — those who scored highly were more likely to have survived, with the exception that men with high ability were more likely to die in active service in World War II. People of lower ability had a greater tendency to lung and stomach cancer. More results from this landmark study are expected.
These preliminary findings were presented by Professor Ian Deary from the Department of Psychology, University of Edinburgh at a symposium on aging at the Australian National University.
http://dsc.discovery.com/news/afp/20030929/aging.html

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