News reports of research into memory February 2005

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February 2005

The effects of training and age on the spatial-memory gender gap

A study of 90 adult rhesus monkeys found young-adult males had better spatial memory than females, but peaked early. By old age, male and female monkeys had about the same performance. This finding is consistent with reports suggesting that men show greater age-related cognitive decline relative to women. A second study of 22 rhesus monkeys showed that in young adulthood, simple spatial-memory training did not help males but dramatically helped females, raising their performance to the level of young-adult males and wiping out the gender gap.
The research appeared in the February issue of Behavioral Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2005-02/apa-ima022205.php
http://www.eurekalert.org/pub_releases/2005-02/euhs-npm020905.php
http://www.sciam.com/article.cfm?articleID=000560D5-7252-12B9-9A2C83414B7F0000&sc=I100322

Low cholesterol also associated with impaired cognition

Data from 789 men and 1,105 women from the Framingham Heart Study has found that those who had the lowest total cholesterol performed significantly more poorly on tests of similarities, word fluency, and attention/concentration than patients with higher cholesterol levels. Those in the lowest total cholesterol group (a level of under 200) were 49% more likely to perform poorly and 80% more likely to perform very poorly than were participants in the highest total cholesterol group (240 to 380). The finding should not be taken as a warning against those with high cholesterol taking medication to lower it; the study applies to those with naturally low cholesterol levels, and previous studies have shown that both high and low cholesterol have led to poor cognitive performance.
The study findings were published in the January/February issue of Psychosomatic Medicine. Full reference
http://preventdisease.com/news/articles/021505_low_cholesterol_mental.shtml
http://www.eurekalert.org/pub_releases/2005-03/bu-but032105.php

An advantage of age

A study comparing the ability of young and older adults to indicate which direction a set of bars moved across a computer screen has found that although younger participants were faster when the bars were small or low in contrast, when the bars were large and high in contrast, the older people were faster. The results suggest that the ability of one neuron to inhibit another is reduced as we age (inhibition helps us find objects within clutter, but makes it hard to see the clutter itself). The loss of inhibition as we age has previously been seen in connection with cognition and speech studies, and is reflected in our greater inability to tune out distraction as we age. Now we see the same process in vision.
The study was published in the February 3 issue of Neuron. Full reference
http://psychology.plebius.org/article.htm?article=739
http://www.eurekalert.org/pub_releases/2005-02/mu-opg020305.php

Cell phone users drive like seniors

Another study on the evils of multitasking, in particular, of talking on a cellphone while driving. This one has a nice spin — the study found that when young motorists talk on cell phones, they drive like elderly people, moving and reacting more slowly and increasing their risk of accidents. Specifically, when 18- to 25-year-olds were placed in a driving simulator and talked on a cellular phone, they reacted to brake lights from a car in front of them as slowly as 65- to 74-year-olds who were not using a cell phone. Although elderly drivers became even slower to react to brake lights when they spoke on a cell phone, they were not as badly affected as had been expected. An earlier study by the same researchers found that motorists who talk on cell phones are more impaired than drunken drivers with blood alcohol levels exceeding 0.08.
The study was published in this winter's issue of Human Factors. Full reference
http://www.eurekalert.org/pub_releases/2005-02/uou-cpu020105.php

Anxiety adversely affects those who are most likely to succeed at exams

It has been thought that pressure harms performance on cognitive skills such as mathematical problem-solving by reducing the working memory capacity available for skill execution. However, a new study of 93 students has found that this applies only to those high in working memory. It appears that the advantage of a high working memory capacity disappears when that attention capacity is compromised by anxiety.
The study was published in the February issue of Psychological Science. Full reference
http://www.eurekalert.org/pub_releases/2005-02/bpl-wup020705.php

Positive emotions help people see big picture details

A study involving 89 students, who watched a video designed to induce either joy and laughter, anxiety, or no emotion, found that those who were in a positive mood had a far greater ability to recognize members of another race when briefly shown photos of individuals. In the absence of positive emotions, subjects recognized members of their own race 75% of the time but only recognized members of another race 65% of the time. Their ability to recognize members of their own race was unaffected by their emotional state.
The findings will appear in an upcoming issue of Psychological Science.
http://www.eurekalert.org/pub_releases/2005-02/uom-pes020105.php

Faster neuron transmission in young males

A study of 186 male and 201 female students (aged 18-25) has found that men's brain cells can transmit nerve impulses 4% faster than women's, probably due to the faster increase of white matter in the male brain during adolescence.
The study, available online 12 September 2004, will appear in a forthcoming edition of Intelligence. Full reference
http://www.theaustralian.news.com.au/common/story_page/0,5744,12170249%255E2703,00.html

Where tunes get stuck in your head

An imaging study has added to our understanding of how tunes get “stuck” in our head. Participants in the study listened to familiar and unfamiliar pieces of music in which snippets of the music had been removed. Imaging revealed that, for familiar songs, brain activity continued in the auditory cortex during the silent gaps. Participants confirmed that during this time they continued to mentally “hear” the music. Different parts of the auditory cortex were active, depending on whether the section was purely instrumental, or had lyrics. Instrumental music seemed to require deeper searching, further back into the auditory processing stream, suggesting that lyrics (processed in more advanced parts of the processing stream) might be the focus of the memory. The findings support other recent research indicating that sensory-specific memories are stored in the brain regions that were involved in processing that information in the first place.
The report was published in the March 10 issue of Nature. Full reference
http://news.bbc.co.uk/1/hi/health/4332771.stm
http://www.eurekalert.org/pub_releases/2005-03/dc-drf030705.php

Why traumatic memories have the power they do

In the first imaging study to look at retrieval of emotional memories after a long period (one year after encoding), researchers found that people did recall emotional images, both pleasant and unpleasant, better than emotionally-neutral images. This recall was associated with higher activity in both the amygdala and the hippocampus. The synchronicity of activity between these two regions suggested that each region triggers the other, creating a self-reinforcing "memory loop" in which an emotional cue might trigger recall of the event, which then loops back to a re-experiencing of the emotion of the event. The findings suggest why people subject to traumatic events may be trapped in a cycle of emotion and recall that aggravates post-traumatic stress disorder, and may also suggest why therapies in which people relive such memories and reshape perspective to make it less traumatic can help people cope with such memories.
The paper was published online February 9 in the Proceedings of the National Academy of Sciences. Full reference
http://www.eurekalert.org/pub_releases/2005-03/du-ems030805.php

Are language and math processed separately by the brain?

Challenging the view that mathematics and language use common cognitive resources, a recent study provides support for the view that the functions of math and language are separate in the human brain. The study involved three men with severe agrammatic aphasia, which means they're unable to understand or form sentences due to brain damage. They didn't understand a reversible sentence - for example, the difference between 'John kissed Kate' and 'Kate kissed John', but they were able to understand that 5 - 2 is different from 2 – 5 (but not when it was expressed in words: two minus five). The researcher takes the results as a demonstration that we can have cognition without language, however, because the men were all normal until they sustained brain damage, it doesn’t answer the question of whether sophisticated cognition could arise without language.
The research is published in the March 1 issue of the Proceedings of the National Academy of Sciences. Full reference
http://education.guardian.co.uk/egweekly/story/0,,1427167,00.html
http://news.bbc.co.uk/1/hi/sci/tech/4265763.stm
http://www.nature.com/news/2005/050214/full/050214-3.html

Mother's work schedule may impact her child's cognitive development

A new study suggests that a mother who works nonstandard hours, such as evenings, nights or rotating shifts, may significantly affect her young child's intellectual development. The study used information from the National Institute of Child Health Development's (NICHD) Study of Early Child Care, which tracked 1,364 children from 10 sites around the country from birth in 1991 through 36 months. Her study focused on 900 children whose mothers had worked in the first three years of their child's life. About half the working mothers worked at nonstandard hours during this time. Even after controlling for the quality of the home environment and child care, maternal depression, and the mother's sensitivity towards her children, researchers found that the children of mothers who worked nonstandard work schedules during their first three years of life performed much worse on cognitive tests, particularly if these schedules began in the 1st year, and particularly for measures of cognitive development at 24 months and expressive language at 36 months. It’s suggested that one reason may be the type of care children receive when their mothers work such hours.
The study was published in the January/February issue of Child Development. Full reference
http://www.eurekalert.org/pub_releases/2005-02/sfri-mws020105.php

Smoking associated with working memory impairment in adolescents

A study of 41 adolescent daily smokers and 32 nonsmokers has revealed that adolescent smokers had impairments in accuracy of working memory performance. Male adolescents as a group begin smoking at an earlier age than female smokers and were significantly more impaired during tests of selective and divided attention. All of the adolescent smokers also showed further disruption of working memory when they stopped smoking.
The study was reported in the January issue of Biological Psychiatry. Full reference
http://www.eurekalert.org/pub_releases/2005-02/yu-scc020105.php

Alcohol's damaging effects on adolescent brain function

A number of speakers at Symposium speakers at the June 2004 Research Society on Alcoholism meeting in Vancouver, reported on research concerning the vulnerability of the adolescent brain to the damaging effects of alcohol. Some of the findings presented were:

The adolescent brain is more vulnerable than the adult brain to disruption from activities such as binge drinking. Adolescent rats that were exposed to binge drinking appear to have permanent damage in their adult brains.
Subtle but important brain changes occur among adolescents with Alcohol Use Disorder, resulting in a decreased ability in problem solving, verbal and non-verbal retrieval, visuospatial skills, and working memory.
The association between antisocial behavior during adolescence and alcoholism may be explained by abnormalities in the frontal limbic system, which appears to cause "blunted emotional reactivity".
Alcohol-induced memory impairments, such as "blackouts", are particularly common among young drinkers and may be at least in part due to disrupted neural plasticity in the hippocampus, which is centrally involved in the formation of autobiographical memories.

The papers were presented at the June 2004 Research Society on Alcoholism meeting in Vancouver, B.C. Proceedings were published in the February issue of Alcoholism: Clinical & Experimental Research. Full reference
http://www.eurekalert.org/pub_releases/2005-02/ace-ade020705.php

Hormone therapy for prostate cancer can produce temporary cognitive impairment

A new study finds men treated with hormone therapy for prostate cancer may experience temporary cognitive changes in visual memory of figures and recognition speed of numbers. No other cognitive areas were affected. The degree of cognitive change was related to the magnitude of decline in the level of estradiol (a form of estrogen in men).
The study was reported online February 28, and will appear in the April 1 print issue of Cancer. Full reference

Rats infected as newborns vulnerable to memory problems when infected in adulthood

Underscoring the value of good prenatal care, a new rat study has found that rats who experienced a one-time infection as newborns didn't learn as well as adult rats who were not infected as pups, after their immunity was challenged. The findings fit into a growing body of evidence that even a one-time infection can potentially permanently change physiological systems, a phenomenon called "perinatal programming." The findings implicate prenatal infections, as the rats were infected on their 4^th day, a time that corresponds, in terms of brain development, with the 3^rd trimester in humans. It should be noted that adult rats who were not infected as pups did not suffer memory impairment as the result of adult infection, and those who were infected as newborns were completely normal until they received the second immune system challenge in adulthood. It’s suggested that this phenomenon may help explain some of the individual variability in disease susceptibility.
The research appeared in the February issue of Behavioral Neuroscience. Full reference
Full text of the article is available at http://www.apa.org/releases/earlylife_article.pdf
http://www.eurekalert.org/pub_releases/2005-02/apa-ria020105.php

More light on a common developmental disorder

Chromosome 22q11.2 deletion syndrome is the most common genetic deletion syndrome, and causes symptoms such as heart defects, cleft palate, abnormal immune responses and cognitive impairments. Two related studies have recently cast more light on these cognitive impairments. Previously it was known that numerical abilities were impaired more than verbal skills. The new study found children with the chromosome deletion performed more poorly on experiments designed to test visual attention orienting, enumerating, and judging numerical magnitudes. All three tasks relate to how the children mentally represent objects and the spatial relationships among them, supporting previous arguments that such visual-spatial skills are a fundamental foundation to the later learning of counting and mathematics. The second study found that such children had changes in the shape, size and position of the corpus callosum, the main bridge between the two hemispheres.
The first study appeared in the April issue of Cortex. Full reference
The second study appeared in the March issue of NeuroImage. Full reference
http://www.eurekalert.org/pub_releases/2005-03/chop-lbt030205.php

How the brain creates false memories

An imaging study has shed new light on how false memories are formed. The study involved participants watching series of 50 photographic slides that told a story. A little later, the subjects were shown what they thought was the same sequence of slides but in fact containing a misleading item and differing in small ways from the original. Two days later, the subjects’ memories were tested. It was found that, during the original encoding (the 1^st set of slides), activity in the hippocampus and perirhinal cortex was greater for true than for false memories, while during the misinformation phase (2^nd set), the activity there was greater for false memories. In other regions, such as the prefrontal cortex, activity for false memories tended to be greater during the original event. Activity in the prefrontal cortex may be correlated to encoding the source, or context, of the memory. Thus, weak prefrontal cortex activity during the misinformation phase indicates that the details of the second experience were poorly placed in a learning context, and as a result more easily embedded in the context of the first event, creating false memories.
The report appeared in the January issue of Learning & Memory. Full reference
http://www.eurekalert.org/pub_releases/2005-02/cshl-htb012805.php