News reports of research into memory September 2006

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September 2006

Anticipation strengthens memory

An imaging study has revealed that the amygdala and the hippocampus become activated when a person is anticipating a difficult situation (some type of gruesome picture). Moreover, the higher the level of activation during this anticipation, the better the pictures were remembered two weeks later. The study demonstrates how expectancy can affect long-term memory formation, and suggests that the greater our anxiety about a situation, the better we’ll remember that situation. If it’s an unpleasant one, this will only reinforce the anxiety, setting up a vicious cycle. The study has important implications for the treatment of psychological conditions such as post-traumatic stress disorder and social anxiety.
The study appeared in the September 19 issue of the Proceedings of the National Academy of Sciences. Full reference
http://www.eurekalert.org/pub_releases/2006-09/uow-apa090106.php

Long-term lead exposure linked to cognitive decline in older adults

A study of nearly a thousand randomly selected Baltimore residents, all between 50 and 70 years old and consequently exposed to higher levels of lead prior to the 1980s when lead was used extensively in commercial products, has revealed higher lead levels in the bone were consistently associated with worse cognitive performance on tests, equivalent to two to six years of aging. Blood lead levels were not associated with a difference in cognitive performance. The study also found bone lead levels were significantly higher in African Americans compared to Caucasians.
The study was published online on September 13 in Neurology. Full reference
http://www.eurekalert.org/pub_releases/2006-09/aaon-lle091306.php

Elevated testosterone kills nerve cells

Testosterone is the main male hormone and plays a crucial role in neuronal function. However, a new study has found that high levels of testosterone triggered programmed cell death in nerve cells in culture. Increased loss of brain cells has been associated with several neurological illnesses, such as Alzheimer disease and Huntington disease. The findings point to another potential danger of steroid use.
The findings were reported in the September issue of the Journal of Biological Chemistry. Full reference
http://www.eurekalert.org/pub_releases/2006-09/yu-etk092606.php

Anemia linked to impaired thinking in older adults

For older adults, anemia has long been linked to fatigue, muscle weakness and other physical ailments. But a new study suggests it may also be an independent risk factor for executive-function impairment. The study examined 364 women between 70 and 80 years old, of whom some 10% had mild anemia. Those with anemia were four to five times more likely to perform worst on the executive function tests.
The study was reported in the September issue of The Journal of the American Geriatrics Society. Full reference
http://www.eurekalert.org/pub_releases/2006-09/jhmi-aab091306.php

Senior’s memory complaints should be taken seriously

A study involving 120 people over 60 found those who complained of significant memory problems who still performed normally on memory tests had a 3% reduction in gray matter density in their brains. This compares to 4% in those diagnosed with mild cognitive impairment. This suggests that significant memory loss complaints may indicate a very early "pre-MCI" stage of dementia for some people.
The study was published in the September 12 issue of Neurology. Full reference
http://www.eurekalert.org/pub_releases/2006-09/aaon-fym090506.php

Evidence musical training affects brain development

A study that examined 12 young children (4—6 year olds) over the course of a year found measurable cognitive differences in those taking Suzuki music lessons compared to those having no musical training outside school. The Suzuki children not only showed greater improvement over the year in melody, harmony and rhythm processing but also in general memory skills such as literacy, verbal memory, visuospatial processing, mathematics and IQ, suggesting that musical training is having an effect on how the brain gets wired for general cognitive functioning related to memory and attention. Brain activity showed greater development consistent with establishing a neural network associated with sound categorization and/or involuntary attention.
The findings were published online ahead of print on 20 September in Brain. Full reference
http://www.sciencedaily.com/releases/2006/09/060920093024.htm
http://www.eurekalert.org/pub_releases/2006-09/oup-fet091906.php

Drug for teen drivers with ADHD

A comparison of the effects of OROS methylphenidate (Concerta), a controlled-release stimulant, and extended release amphetamine salts (Adderall XR) on driving performance in teens with ADHD has found that treatments with Concerta led to fewer inattentive driving errors and less hyperactive or impulsive driving errors, such as speeding and inappropriate braking, compared with Adderall XR and placebo.
The report appears in the September issue of Pediatrics. Full reference
http://www.sciencedaily.com/releases/2006/09/060905225503.htm
http://www.eurekalert.org/pub_releases/2006-09/uovh-rfn090506.php

Drug improves memory loss for traumatic brain injury patients

A study involving 157 men and women with traumatic brain injury found attention and verbal memory test scores significantly improved among those with moderate to severe memory impairment who took rivastigmine for 12 weeks. However, the drug was not effective for patients with less severe memory loss. Rivastigmine, a drug used to treat Alzheimer’s, is thought to enhance the function of acetylcholine, a neurotransmitter involved in memory and learning.
The study was published in the September 12 issue of Neurology. Full reference
http://www.eurekalert.org/pub_releases/2006-09/aaon-dim090506.php

More support that sleep helps consolidate learning

An experiment involving fruitflies has found that those in a social environment with at least 30 other flies slept four times as long during their daytime naps as flies in isolation. There was no difference in night-time sleep. The length of the nap increased with the size of the group they socialized with. Confirming that this effect was due to an increase in social interactions, rather than, for example, physical exhaustion from flying around more, flies deprived of their sight and sense of smell (meaning they could still fly around but could not socialize) showed no difference in daytime sleep patterns. Of 49 genes known to be involved in learning and memory, switching off seventeen (all related to long-term memory) made the flies sleep equally long regardless of whether they were social or not.
The study was reported in the September 22 issue of Science. Full reference
http://www.nature.com/news/2006/060918/full/060918-9.html
http://www.livescience.com/humanbiology/060921_flies_sleep.html

Human study supports value of daytime napping for learning

REM sleep, when most dreaming occurs, has been shown in a number of studies to be important in consolidating procedural (skill) learning, while non-REM (slow-wave) sleep seems to be more important for declarative (knowledge-based) learning. However, because normal sleep contains both REM and non-REM cycles, research hasn’t been able to clearly distinguish the effects. Now a new study using brief daytime napping confirms the role of non-REM sleep for declarative learning. Volunteers who memorized pairs of words and practiced tracing images in a mirror test scored 15% better in the word test if they had been allowed a nap in the six hour period before being tested. However, they did no better at the action test.
The report appeared in the September issue of Neurobiology of Learning and Memory. Full reference
http://www.newscientist.com/article/mg19125704.800?DCMP=NLC-nletter&nsref=mg19125704.800

A cognitive strategy shared by human infants and our great-ape kin

There are two basic strategies for remembering the location of something: either remembering the features of the item (it was a tree, a stone, etc.), or knowing the spatial placement (left, right, middle, etc.). All animal species tested so far seem to employ both strategies, but some species (e.g. fish, rats and dogs) have a preference for locational strategies, while others (e.g. toads, chickens and children) favor those which use distinctive features. A comparison of the cognitive strategies of humans, chimpanzees, bonobos, gorillas, and orangutans, has revealed that all non-human great apes and 1-year-old human infants prefer a locational strategy, even when an object strategy would be more efficient. This suggests that the common ancestor of all great apes enacted a similar strategy preference in employing spatial memory. However, 3-year-old human children in these circumstances chose the more efficient strategy.
The findings were reported in the September 5 issue of Current Biology. Full reference
http://www.eurekalert.org/pub_releases/2006-09/cp-acs083006.php
http://www.eurekalert.org/pub_releases/2006-09/m-hdo090606.php