News reports of research into memory June 2003

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June 2003

More evidence that mental exercise helps prevent or postpone dementia

Another study provides support for the idea that mentally demanding activities can help stave off dementia. The study involved 469 people aged 75 and older. Over the course of the study, dementia developed in 124 of the participants (Alzheimer's disease in 61,vascular dementia in 30, mixed dementia in 25, and other types of dementia in 8). Those who participated at least twice weekly in reading, playing games (chess, checkers, backgammon or cards), playing musical instruments, and dancing were significantly less likely to develop dementia. Although the evidence on crossword puzzles was not quite statistically significant, those who did crossword puzzles four days a week had a much lower risk of dementia than those who did one puzzle a week. Most physical activities, like group exercise or team games, had no significant impact. The only exception - ballroom dancing - possibly occurred because of the mental demands of remembering dance steps, responding to music and coordinating with a partner. Although the study was careful to include only those who showed no signs of dementia at the start, it cannot be ruled out that people in pre-clinical stages of dementia may be less likely to participate in mentally demanding activities.
The study was published in the June 19 issue of the New England Journal of Medicine. Full reference
http://www.nytimes.com/2003/06/24/opinion/24TUE4.html?th

Effects of Alzheimer's disease may be influenced by education

New findings from the Religious Orders Study (ROS), a long-running prospective study of aging and cognitive function in Catholic clergy, provides evidence that formal education may provide a cognitive reserve or a "neuroplasticity" that can reduce the effect of AD brain abnormalities on cognitive function in later life. A post-mortem study of the brains of 130 participants who had all undergone cognitive testing some months before death, found that the relationship between cognitive performance and the number of amyloid plaques in the brain (characteristic of Alzheimer’s) changed with level of formal education. The more years education you had, the less effect the same number of plaques had on actual cognitive performance. For example, an 84-year-old woman in the most highly educated group (postgraduate work after college) might score 98.1 (on a scale where the average participant scores 100) in the absence of any plaques. The same age woman with the least education (some college attendance) would score 96.8. In the presence of about 18 plaques (more than the number required for a diagnosis of Alzheimer’s), the more highly educated woman's score would drop about two points, to 96.2, while the score of the woman with less formal education would drop more than 14 points, to 82. It’s worth noting that this considerable difference was observed in a population where even the least educated had some college attendance; presumably the difference would be even more marked in the general population.
The research was published in the June 24 issue of Neurology. Full reference
http://www.eurekalert.org/pub_releases/2003-06/rpsl-rrf062303.php

How memory helps make life pleasant

Surveys consistently show that people are generally happy with their lives. A review of research into autobiographical memory suggests why - human memory is biased toward happiness. Across 12 studies conducted by five different research teams, people of different racial and ethnic backgrounds and of different ages consistently reported experiencing more positive events in their lives than negative events, suggesting that pleasant events do in fact outnumber unpleasant events because people seek out positive experiences and avoid negative ones. Our memory also treats pleasant emotions differently from unpleasant emotions. Pleasant emotions appear to fade more slowly from our memory than unpleasant emotions. This is not repression; people do remember negative events, they just remember them less negatively. Among those with mild depression, however, unpleasant and pleasant emotions tend to fade evenly.
The findings are published in the June issue of Review of General Psychology. Full reference
Full text of the article is available at http://www.apa.org/journals/gpr/press_releases/june_2003/gpr72203.html
http://www.eurekalert.org/pub_releases/2003-06/apa-rtg060203.php

Older adults better at forgetting negative images

It seems that this general tendency, to remember the good, and let the bad fade, gets stronger as we age. Following recent research suggesting that older people tend to regulate their emotions more effectively than younger people, by maintaining positive feelings and lowering negative feelings, researchers examined age differences in recall of positive, negative and neutral images of people, animals, nature scenes and inanimate objects. The first study tested 144 participants aged 18-29, 41-53 and 65-80. Older adults recalled fewer negative images relative to positive and neutral images. For the older adults, recognition memory also decreased for negative pictures. As a result, the younger adults remembered the negative pictures better. Preliminary brain research suggests that in older adults, the amygdala is activated equally to positive and negative images, whereas in younger adults, it is activated more to negative images. This suggests that older adults encode less information about negative images, which in turn would diminish recall.
The findings appear in the June issue of the Journal of Experimental Psychology: General. Full reference
Full text of the article is available at http://www.apa.org/journals/xge/press_releases/june_2003/xge1322310.html
http://www.apa.org/releases/aging_memory.html

Alcohol damages day-to-day memory function

A new study involving 763 participants (465 female, 298 males) used self-report questionnaires: the Prospective Memory Questionnaire (PMQ), the Everyday Memory Questionnaire (EMQ), and the UEL (University of East London) Recreational Drug Use Questionnaire, and found that heavy users of alcohol reported making consistently more errors than those who said that they consumed little or no alcohol. More specifically, those who reported higher levels of alcohol consumption were more likely to miss appointments, forget birthdays and pay bills on time (prospective memory), as well as more problems remembering whether they had done something, like locking the door or switching off the lights or oven, or where they had put items like house keys. The study also found a significant increase in reported memory problems by people who claimed to drink between 10 and 25 units each week in comparison to non-drinkers – this is within the ’safe drinking’ limits suggested by U.K. government guidelines.
The study appeared in the June issue of Alcoholism: Clinical & Experimental Research. Full reference
http://www.eurekalert.org/pub_releases/2003-06/ace-add060903.php

Eating methylmercury contaminated fish causes problems in adults

Pregnant women and children have been warned about eating methylmercury contaminated fish. New research now suggests that all adults should be wary. The study involved 129 men and women living in fishing communities of the Pantanal region of Brazil. About one out of four were found to have mercury levels that exceeded the 'safe' level set by the World Health Organization for women and children. Those individuals fared worse on tests for motor skills, memory and concentration.
The major source of methylmercury is diet, particularly large fish like shark and swordfish.
The research was published in Environmental Health: A Global Access Science Source ( http://www.ehjournal.net/ ).
Full reference
http://www.eurekalert.org/pub_releases/2003-06/bc-fin060403.php
The article is available at http://www.ehjournal.net/content/2/1/8

Malnutrition in early life associated with long-lasting cognitive deficits

Malnutrition in early life has been associated with poor cognitive abilities. A longitudinal study involving 1559 children from the island of Mauritius has now found that children who were malnourished at 3 years of age, still had significant cognitive deficits at age 11.
The report appeared in the June issue of the Archives of Pediatrics & Adolescent Medicine. Full reference

Complex mental tasks interfere with drivers' ability to detect visual targets

The researchers studied 12 adults who drove for about four hours on the highway north from Madrid. During the journey, drivers listened to recorded audio messages with either abstract or concrete information (acquisition task), and later were required to freely generate a reproduction of what they had just listened to (production task). Although the more receptive tasks – listening and learning -- had little or no effect on performance, there were significant differences in almost all of the measures of attention when drivers had to reproduce the content of the audio message they had just heard. Drivers also performed other tasks, either live or by phone. One was mental calculus (mentally changing between Euros and Spanish pesetas) either with an experimenter in the car, talking to the driver, or with the driver speaking by hands-free phone. One was a memory task (giving detailed information about where they were and what they were doing at a given day and time). Both tasks significantly impacted on the driver's ability to detect visual targets. In the experimental variation that examined the impact of hands-free phone conversation, message complexity made the difference. The relative safety of low-demand phone conversation -- if hands-free and voice-operated --appeared to be about the same as that of live conversation. The findings also confirm that the risk of internal distraction (one’s own thoughts) is at least as relevant as external distraction.
These findings appeared in the June issue of the Journal of Experimental Psychology: Applied. Full reference
http://www.eurekalert.org/pub_releases/2003-06/apa-mcm062403.php

New insight into the relationship between recognising faces and recognising expressions

The quest to create a computer that can recognize faces and interpret facial expressions has given new insight into how the human brain does it. A study using faces photographed with four different facial expressions (happy, angry, screaming, and neutral), with different lighting, and with and without different accessories (like sunglasses), tested how long people took to decide if two faces belonged to the same person. Another group were tested to see how fast they could identify the expressions. It was found that people were quicker to recognize faces and facial expressions that involved little muscle movement, and slower to recognize expressions that involved a lot of movement. This supports the idea that recognition of faces and recognition of facial expressions are linked – it appears, through the part of the brain that helps us understand motion.
The report appeared in the April issue of Vision Research. Full reference
http://www.osu.edu/researchnews/archive/compvisn.htm

How faces become familiar

With faces, familiarity makes a huge difference. Even when pictures are high quality and faces are shown at the same time, we make a surprising number of mistakes when trying to decide if two pictures are of the same person – when the face is unknown to us. On the other hand, even when picture quality is very poor, we’re very good at recognising familiar faces. So how do faces become familiar to us? Recent research led by Vicki Bruce (well-known in this field) showed volunteers video sequences of people, episodes of unfamiliar soap operas, and images of familiar but previously unseen characters from radio's The Archers and voices from The Simpsons. They confirmed previous research suggesting that for unfamiliar faces, memory appears dominated by the 'external' features, but where the face is well-known it is 'internal' features such as the eyes, nose and mouth, that are more important. The shift to internal features occurred rapidly, within minutes. Speed of learning was unaffected by whether the faces were experienced as static or moving images, or with or without accompanying voices, but faces which belonged to well-known, though previously unseen, personal identities were learned more easily.
The report was published by the Economic and Social Research Council as part of Social Science Week 2003. Reference
http://www.eurekalert.org/pub_releases/2003-06/esr-hs061603.php
http://www.esrc.ac.uk/esrccontent/news/june03-5.asp

The reorganization of the visual cortex in congenitally blind people

Studies indicate that congenitally blind people have superior verbal memory abilities than the sighted. A new study helps us understand why this is so. Some 25% of the human brain is devoted to vision. Until now it was assumed that loss of vision rendered these regions useless. Now it appears that in those blind from birth, the part of the occipital cortex usually involved in vision is utilized for other purposes. Extensive regions in the occipital cortex, in particular the primary visual cortex, are activated not only during Braille reading, but also during performances of verbal memory tasks, such as recalling a list of abstract words. No such activation was found in a sighted control group. It also appears that the greater the occipital activation, the higher the scores in the verbal memory tests.
The research appeared on 1 July in the online edition of Nature Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2003-06/huoj-hur061703.php

Chinese herb effective in treating vascular dementia

The herb gastrodine has been used in China for centuries to treat disorders such as dizziness, headache and even ischemic stroke. Now a 12-week, randomized, double-blind trial comparing gastrodine with Duxilâ (a drug used to treat stroke patients in China) has been done in Beijing Dongzhimen Hospital. The trial involved 120 stroke patients who were diagnosed with mild to moderate vascular dementia. Both treatment groups showed similar improvement in memory, orientation, calculation, and language (as measured by the MMSE). The gastrodine group also showed a significant difference in the Blessed Behavioral Scale (BBS) score - including behavior, activities of daily living, and also suffered fewer side effects. Researchers say combined results showed the gastrodine group improvement was 51.43 percent, with 16 of the 70 cases showing much improvement, 20 cases with some improvement, and 34 cases with no change. The improvement rate for patients treated with Duxilâ was 52 percent, with seven of the 50 cases showing much improvement, 19 cases with some improvement, and 24 cases with no change.
The research was presented at the American Heart Association's Second Asia Pacific Scientific Forum in Honolulu on June 10.
http://www.eurekalert.org/pub_releases/2003-06/aha-nhd052303.php

Another step in understanding how memories are formed

The electrical activity of individual neurons in the brains of two adult rhesus monkeys was monitored while the monkeys played a memory-based video game in which an image pops up on the computer screen with four targets—white dots—superimposed on it. The monkeys’ task was to learn which target on which image was associated with a reward (a drop of their favorite fruit juice). Dramatic changes in the activity of some hippocampal neurons, which the scientists called "changing cells", paralleled their learning, indicating that these neurons are involved in the initial formation of new associative memories. In some of the cells, activity continued after the animal had learned the association, suggesting that these cells may participate in the eventual storage of the associations in long-term memory.
The findings are reported in the June 6 issue of Science. Full reference
http://www.eurekalert.org/pub_releases/2003-06/nyu-fir060503.php
http://tinyurl.com/ftob

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