News reports of research into memory May 2005

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May 2005

Older adults more likely to "remember" misinformation

In a study involving older adults (average age 75) and younger adults (average age 19), participants studied lists of paired related words, then viewed new lists of paired words, some the same as before, some different, and some with only one of the two words the same. In those cases, the "prime" word, which was presented immediately prior to the test, was plausible but incorrect. The older adults were 10 times more likely than young adults to accept the wrong word and falsely "remember" earlier studying that word. This was true even though older adults had more time to study the list of word pairs and attained a performance level equal to that of the young adults. Additionally, when told they had the option to "pass" when unsure of an answer, older adults rarely used the option. Younger adults did, greatly reducing their false recall. The findings reflect real-world reports of a rising incidence of scams perpetrated on the elderly, which rely on the victim’s poor memory and vulnerability to the power of suggestion.
A full report appeared in the May issue of the Journal of Experimental Psychology (JEP): General. Full reference
Full text of the article is available at http://www.apa.org/journals/releases/xge1342131.pdf.
http://www.eurekalert.org/pub_releases/2005-05/apa-gmc051005.php

Mice brains shrink during winter, impairing spatial memory

A study involving adult male white-footed mice may help us understand seasonal dysfunctions such as seasonal affective disorder. The study found that those mice kept in artificial light conditions mimicking winter (8 hours of light per day) had impaired spatial memory compared to mice kept in “summer” conditions (16 hours per day). They also had, on average, smaller brains, with a proportionally smaller hippocampus, as well as changes in dendritic spine density in that region. Other types of memory did not appear to be affected.
The findings were published in the May 4 issue of the Journal of Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2005-05/osu-mbs051205.php

How estrogen affects the brain

A new study involved cultured rat neurons has revealed how estrogen affects learning and memory. It appears that, in females, estrogen can activate particular glutamate receptors within the hippocampus. Glutamate is the primary excitatory neurotransmitter in the brain, allowing for fast communication between neurons.
The findings appear in the May 18 issue of the Journal of Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2005-05/uom-uom051905.php

Stress bad for the brain

A study of older adults for three to six years has found that those with continuous high levels of the stress hormone cortisol performed poorly on memory tests and had a 14% smaller hippocampus. A further study involving young adults and children between the ages of six and fourteen found that even an acute increase in cortisol can lead to reversible memory impairments in young adults, and that children from low socio-economic status environments had higher cortisol levels than those from high SES homes. Children from low SES homes tended to process positive and negative attributes more negatively than children from high SES homes, and this type of processing was significantly related to basal cortisol levels at ages 10, 12 and 14.
The findings were published in the April issue of Psychoneuroendocrinology. Full reference
http://www.eurekalert.org/pub_releases/2005-05/mu-tst051705.php

Cancer survivors may be at higher risk for cognitive dysfunction

A study involving 702 cancer survivors and their cancer-free twins has found that cancer survivors are twice as likely to develop cognitive problems as individuals who have never been treated for cancer. About 15% of the cancer survivors showed cognitive dysfunction. The study did not involve patients who had tumors involving the central nervous system. A follow-up study is planned, to compare those who received different treatments for their cancer.
The article appeared in the June 1 issue of the Journal of the National Cancer Institute. Full reference
http://www.eurekalert.org/pub_releases/2005-05/uosc-csm052705.php

Brain atrophy occurs faster in women alcoholics

A study of 34 male and 42 female alcoholics has found that, although the women had been alcoholics for just 5.5 years on average, compared to the average 10.4 years for the men, the women had lost as much proportionate brain volume as the men. The findings are consistent with other studies suggesting that women suffer from the effects of alcohol abuse faster.
The results were reported in the May issue of Alcoholism: Clinical and Experimental Research. Full reference
http://www.nature.com/news/2005/050509/full/050509-15.html

Language cues help visual learning in children

A study of 4-year-old children has found that language, in the form of specific kinds of sentences spoken aloud, helped them remember mirror image visual patterns. The children were shown cards bearing red and green vertical, horizontal and diagonal patterns that were mirror images of one another. When asked to choose the card that matched the one previously seen, the children tended to mistake the original card for its mirror image, showing how difficult it was for them to remember both color and location. However, if they were told, when viewing the original card, a mnemonic cue such as ‘The red part is on the left’, they performed “reliably better”.
The paper was presented by a graduate student at the 17th annual meeting of the American Psychological Society, held May 26-29 in Los Angeles.
http://www.eurekalert.org/pub_releases/2005-05/jhu-lc051705.php

New evidence for the cause of dyslexia

A new study casts new light on the cause of dyslexia. Recent research has tended to focus on the magnocellular (M) pathway, one of two visual pathways in the brain that processes motion and brightness. The other visual channel, the parvocellular (P) pathway, processes detail and color. Although some studies have implicated an impaired M channel, showing that dyslexic children have trouble seeing rapidly changing or moving stimuli, results have been inconsistent. A new study suggests that the problem is rather a more general problem in basic sensory perception — an inability to shut out “noise”, that is, the sounds and patterns surrounding the target information.
The report appeared in the May 29 issue of Nature Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2005-05/uow-sso052505.php

Language learning declines after second year of life

A study involving 96 deaf children who had received cochlear implants during their first four years of life has found that the rate of language learning was greatest for those given implants before they turned two. Children given implants at three or four years of age acquired language skills more slowly. The finding supports the idea that there is a 'sensitive period' for language learning, and suggests that deaf children should get cochlear implants sooner (it is still relatively rare for them to be given to children younger than two).
The findings were presented on 16 May at the Acoustical Society of America conference in Vancouver, Canada.
http://www.nature.com/news/2005/050516/full/050516-1.html

Teen's ability to multi-task develops late in adolescence

A study involving adolescents between 9 and 20 years old has found that the ability to multi-task continues to develop through adolescence. The ability to use recall-guided action to remember single pieces of spatial information (such as looking at the location of a dot on a computer screen, then, after a delay, indicating where the dot had been) developed until ages 11 to 12, while the ability to remember multiple units of information in the correct sequence developed until ages 13 to 15. Tasks in which participants had to search for hidden items in a manner requiring a high level of multi-tasking and strategic thinking continued to develop until ages 16 to 17. "These findings have important implications for parents and teachers who might expect too much in the way of strategic or self-organized thinking, especially from older teenagers."
The research was published in the May/June issue of Child Development. Full reference
http://www.eurekalert.org/pub_releases/2005-05/sfri-tat051205.php

Too much knowledge can be bad for some types of memory

Following on from an earlier study reported last year, in which children were found to have better memories than adults in certain circumstances, researchers have found that adults did better remembering pictures of imaginary animals than they did remembering pictures of real cats. The reason has to do with the effects of categorization. While categorization is often vital, it can lead people to ignore individual details. The trick is to know when it’s important to categorize and when it’s better to note specific details. The new study added to the earlier findings by showing that there is a gradual decrease in recognition memory from children to adults, rather than an abrupt change in the way people see the world. Moreover, the difference in how adults and children perceive and remember objects is not a developmental difference, but one caused by differences in knowledge. Adults performed like children when shown imaginary animals.
The research was published in the May/June 2005 issue of Child Development. Full reference
http://www.eurekalert.org/pub_releases/2005-05/osu-tmk051005.php

Long-term storage of autobiographical memories

By studying in detail the ability of patients with selective brain damage to recall events in their past, researchers have helped settle a long-standing controversy about whether long-term memory of one's personal experiences continue to be stored in the medial temporal lobe, or whether they gradually become independent of this area. The evidence from this new study suggests that autobiographical memories gradually become distributed throughout the neocortex.
The research was published in the June 2 issue of Neuron. Full reference
http://www.eurekalert.org/pub_releases/2005-06/cp-wlm052605.php

Brain networks change according to cognitive task

Using a newly released method to analyze functional magnetic resonance imaging, researchers have demonstrated that the interconnections between different parts of the brain are dynamic and not static. Moreover, the brain region that performs the integration of information shifts depending on the task being performed. The study involved two language tasks, in which subjects were asked to read individual words and then make a spelling or rhyming judgment. Imaging showed that the lateral temporal cortex (LTC) was active for the rhyming task, while the intraparietal sulcus (IPS) was active for the spelling task. The inferior frontal gyrus (IFG) and the fusiform gyrus (FG) were engaged by both tasks. However, Dynamic Causal Modeling (the new method for analyzing imaging data) revealed that the network took different configurations depending on the goal of the task, with each task preferentially strengthening the influences converging on the task-specific regions (LTC for rhyming, IPS for spelling). This suggests that task specific regions serve as convergence zones that integrate information from other parts of the brain. Additionally, switching between tasks led to changes in the influence of the IFG on the task-specific regions, suggesting the IFG plays a pivotal role in making task-specific regions more or less sensitive. This is consistent with previous studies showing that the IFG is active in many different language tasks and plays a role in integrating brain regions.
The findings were presented in the June 1 issue of the Journal of Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2005-06/nu-bnc060105.php

Brain region for understanding metaphors located

Four righthanded patients with damage to the left angular gyrus provide evidence that the angular gyrus is at least partly responsible for the human ability to understand metaphor. The angular gyrus is disproportionately larger in hominids than other primates, and is strategically located at the crossroads of areas specialized for processing touch, hearing and vision.
The paper was presented at the American Psychological Society annual convention in Los Angeles, May 26-29.
http://www.eurekalert.org/pub_releases/2005-05/uoc--gmu052005.php

How the brain handles sarcasm

A study involving people with prefrontal-lobe damage, people with posterior-lobe damage and healthy controls, found that those with prefrontal damage were impaired in comprehending sarcasm, whereas the people in the other two groups had no such problem. Within the prefrontal group, people with damage in the right ventromedial area had the most trouble in comprehending sarcasm. The researchers suggest that the frontal lobes process the context, identifying the contradiction between the literal meaning and the social/emotional context, while the ventromedial prefrontal cortex integrates the literal meaning with the social/emotional knowledge of the situation and previous situations.
The findings appeared in the May issue of Neuropsychology. Full reference
Full text of the article is available at http://www.apa.org/journals/releases/neu193288.pdf
http://www.eurekalert.org/pub_releases/2005-05/apa-tao051705.php

One gene links neurogenesis with neurodegenerative diseases such as Alzheimer's

It used to be thought that the neurons we were born with (or created soon after birth) were all that we could ever have. Then it was discovered that certain neurons in specific brain regions, could be created in an adult brain (neurogenesis). A recent study has investigated the question of what’s different about these neurons, and to the researchers’ surprise, has discovered that replaceable neurons differed from unreplaceable neurons by having persistently low levels of a particular gene known as UCHL1. Intriguingly, UCHL1, expressed as a protein in high quantities throughout the brain, has also been identified as being deficient in degenerative diseases such as Alzheimer's and Parkinson's. Further research revealed that behavior that increases the chance of new neurons surviving is also associated with increases in the level of UCHL1 in replaceable neurons. The findings suggest that rising levels of UCHL1 may be associated with a reduced risk of neuronal death.
The results appeared in the May 23 Early Edition issue of Proceedings of the National Academy of Sciences. Full reference
http://www.eurekalert.org/pub_releases/2005-05/ru-ogl052005.php

Nanotechnology illuminates brain cells at work

A new technique involving genetic nanotechnology and a process known as fluorescence resonance energy transfer (FRET) has for the first time made it possible to accurately measure the levels of important chemicals in living brain cells in real time and at the level of a single cell.
The research is published in the May 30-June 3 on-line early edition of the Proceedings of the National Academy of Sciences. Full reference
http://www.eurekalert.org/pub_releases/2005-05/ci-rni052605.php

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