News reports of research into memory July 2006

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July 2006

Brain Imaging Identifies Best Memorization Strategies

Why do some people remember things better than others? An imaging study has revealed that the brain regions activated when learning vary depending on the strategy adopted. The study involved 29 right-handed, healthy young adults, ages 18-31, all of whom had normal or corrected-to-normal vision and reported no significant neurological history. Participants were given interacting object pair images (such as a turkey seated atop a horse and a banana positioned in the back of a dump truck) and told to study them in anticipation of a memory test. Earlier studies had indicated that while individuals use a variety of strategies to help them memorize new information, the following four strategies were the main strategies:

1) A visual inspection strategy in which participants carefully studied the visual appearance of objects.

2) A verbal elaboration strategy in which individuals constructed sentences about the objects to remember them.

3) A mental imagery strategy in which participants formed interactive mental images of the objects.

4) A memory retrieval strategy in which they thought about the meaning of the objects and/or personal memories associated with the objects.

Both visual inspection and verbal elaboration resulted in improved recall. Imaging revealed that people who often used verbal elaboration had greater activity in a network of regions that included prefrontal regions associated with controlled verbal processing compared to people who used this strategy less frequently. People who often used a visual inspection strategy had greater activity in a network of regions that included an extrastriate region associated with object processing compared to people who used this strategy less frequently.
The findings were published in the July 20 issue of Neuron. Full reference
http://www.sciencedaily.com/releases/2006/08/060809082610.htm

Curry helps older brains

Turmeric, an ingredient of curry, contains curcumin, which is a powerful antioxidant and anti-inflammatory that may inhibit the build-up of amyloid plaques in people with Alzheimer's. Now an investigation of 1010 older Asians (between 60 and 93 years) has found that those who ate curry "occasionally" (once or more in 6 months but less than once a month) and "often" (more than once a month) performed better on a standard test of cognitive function than those who only ate curry "never or rarely".
The report was published online on July 26 in the American Journal of Epidemiology. Full reference
http://www.newscientist.com/article/mg19125635.500?DCMP=NLC-nletter&nsref=mg19125635.500

Vigorous exercise helps children's grades

214 sixth graders were divided into two groups — one group took a general physical education class in the first semester, then a non-physical education course in the next semester. The other group did the classes in the other order. There was no difference in performance in academic classes between those taking the physical education course and those taking the non-physical. However, students who took part in more vigorous physical activities at least three times a week (such as soccer, skateboarding) did better in academic subjects (by around 10%). It’s worth noting that PE classes only averaged 19 minutes of moderate or vigorous activity; activity outside the classroom was assessed in 30 minute blocks. Only vigorous activity impacted academic performance.
The research was published in the August issue of Medicine & Science in Sports & Exercise. Full reference
http://www.sciencedaily.com/releases/2006/08/060803181914.htm

Drug reverses aging effect on memory process

Rat studies suggest that a drug made to enhance memory triggers a natural mechanism in the brain that fully reverses age-related memory loss, even after the drug itself has left the body. In middle-aged rats given ampakines twice a day for four days, there was a significant increase in the production of brain-derived neurotrophic factor (BDNF), a protein known to play a key role in memory formation, and in long-term potentiation (LTP), the process by which the connection between the brain cells is enhanced and memory is encoded. Deficits in LTP occur with age. This restoration of LTP was found in the brains even after the ampakines had been cleared from the animals' bodies.
The study appears in the August issue of the Journal of Neurophysiology. Full reference
http://www.sciencedaily.com/releases/2006/07/060727154900.htm

How multitasking impedes learning

A number of studies have come out in recent years demonstrating that the human brain can’t really do two things at once, and that when we do attempt to do so, performance is impaired. A new imaging study provides evidence that we tend to use a less efficient means of learning when distracted by another task. In the study, 14 younger adults (in their twenties) learned a simple classification task by trial-and-error. For one set of the cards, they also had to keep a running mental count of high tones that they heard while learning the classification task. Imaging revealed that different brain regions were used for learning depending on whether the participants were distracted by the other task or not — the hippocampus was involved in the single-task learning, but not in the dual-task, when the striatum (a region implicated in procedural and habit learning) was active. Although the ability of the participants to learn didn’t appear to be affected at the time, the distraction did reduce the participants' subsequent knowledge about the task during a follow-up session. In particular, on the task learned with the distraction, participants could not extrapolate from what they had learned.
The study was reported in the August 1 issue of Proceedings of the National Academy of Sciences. Full reference
http://www.boston.com/news/science/articles/2006/07/25/study_distractions_impede_learning/
http://www.chicagotribune.com/entertainment/tv/chi-0607250144jul25,1,7810233.story?coll=chi-ent_tv-hed&ctrack=1&cset=true
http://www.sciencedaily.com/releases/2006/07/060726083302.htm

Sleep makes memories resistant to interference

It’s pretty clear now that sleep consolidates procedural (skill) learning, but the question of whether or not it helps other types of memory is still very much a matter of debate. However, a new study has found a marked effect of sleep on our ability to remember information. The study involved 60 healthy college-aged adults, who were asked them to memorize 20 pairs of random words. Half were given the words at 9am and tested at 9pm, and the other half were given the words at 9pm and tested at 9am. While the sleepers did perform better (94% recall compared to 82%), it was the introduction of another factor that made the benefits of sleep undeniable. Participants who were given a new set of words to learn just 12 minutes before testing revealed a dramatic difference — sleepers recalled 76% of the original words compared to 32% of the sleepless.
The findings are reported in the July 12 issue of Current Biology. Full reference
http://www.sciencedaily.com/releases/2006/07/060711095912.htm
http://www.sciam.com/article.cfm?chanID=sa003&articleID=0006A257-BBB4-14B2-B8B983414B7F4945

Support for labeling as an aid to memory

A study involving an amnesia-inducing drug has shed light on how we form new memories. Participants in the study participants viewed words, photographs of faces and landscapes, and abstract pictures one at a time on a computer screen. Twenty minutes later, they were shown the words and images again, one at a time. Half of the images they had seen earlier, and half were new. They were then asked whether they recognized each one. For one session they were given midazolam, a drug used to relieve anxiety during surgical procedures that also causes short-term anterograde amnesia, and for one session they were given a placebo.
It was found that the participants' memory while in the placebo condition was best for words, but the worst for abstract images. Midazolam impaired the recognition of words the most, impaired memory for the photos less, and impaired recognition of abstract pictures hardly at all. The finding reinforces the idea that the ability to recollect depends on the ability to link the stimulus to a context, and that unitization increases the chances of this linking occurring. While the words were very concrete and therefore easy to link to the experimental context, the photographs were of unknown people and unknown places and thus hard to distinctively label. The abstract images were also unfamiliar and not unitized into something that could be described with a single word.
The paper was published in the July edition of Psychological Science. Full reference
http://www.sciencedaily.com/releases/2006/07/060719092800.htm

Avoiding predators may be the reason for our large brains

A study of predators in Africa and South America suggests a new theory for why we evolved big brains. Apparently predators prefer prey with smaller brains, suggesting that more smarts help you outwit your enemies. A popular theory has been that the complexities of being social pushed the increase in brain size, and it does seem that this is also a factor, but predation is probably behind this as well — living in a group protects against predators, because group mates help keep an eye out for danger. However, the study found that while predators did prefer less sociable prey, the strongest pattern was for predators to prefer prey with relatively small brains. The researchers suggest that the need for a larger brain was strengthened when our primate ancestors came down out of the trees, and entered a much more dangerous environment.
The study was published online ahead of print in Biology Letters. Full reference
http://www.guardian.co.uk/science/story/0,,1835615,00.html

Bigger brains associated with domain-general intelligence

Analysis of hundreds of studies testing the cognitive abilities of non-human primates provides support for a general intelligence, and confirms that the great apes are more intelligent than monkeys and prosimians. Individual studies have always been criticized for not clearly ensuring that one species wasn’t out-performing another simply because the particular testing situation was more suited to them. However, by looking at so many varied tests, the researchers have overcome this criticism. Although there were a few cases where one species performed better than another one in one task and reversed places in a different task, overall, some species truly outperformed others. The smartest species were clearly the great apes — orangutans, chimpanzees, and gorillas. Moreover, there was no evidence that any species performed especially well within a particular paradigm, contradicting the theory that species differences in intelligence only exist for narrow, specialized skills. Instead, the results argue that some species possess a broad, domain-general type of intelligence that allows them to succeed in a variety of situations.
The study was published online August 1 in Evolutionary Psychology. Full reference
Full-text available at http://human-nature.com/ep/downloads/ep04149196.pdf
http://www.sciencedaily.com/releases/2006/08/060801231359.htm

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