News reports of research into memory July 2008

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July 2008

Passive learning imprints on the brain just like active learning

New research adds to other recent studies showing that observation can act like actual practice in acquiring new motor skills. In a study where participants played a video game in which they had to move in a particular sequence to match the position of arrows on the screen (similar to the popular Dance Dance Revolution game), it was found that brain activity in the Action Observance Network (mostly in the inferior parietal and premotor cortices) was similar for dance sequences that were actively rehearsed daily for five days, and a different set of sequences that were passively observed for an equivalent amount of time, but declined for unfamiliar sequences.
The findings were published in the May issue of Cerebral Cortex. Full reference
http://www.eurekalert.org/pub_releases/2008-07/dc-drr071408.php

How alliteration helps memory

Previous studies have shown that alliteration can act as a better tool for memory than both imagery and meaning. Now a series of experiments explains why and demonstrates the effect occurs whether you read aloud or silently, and whether the text is poetry or prose. The memory-enhancing property of alliteration appears to occur because the alliterative cues reactivated readers' memories for earlier words that were similar sounding. Alliteration, then, is most powerful when the same alliterative sounds are repeated throughout the text.
The findings were reported in the July issue of Psychological Science. Full reference
http://www.physorg.com/news136632182.html
http://www.eurekalert.org/pub_releases/2008-07/afps-tpo073008.php

Changes in gray matter induced by learning

Three months of training in three-ball cascade juggling was found to be associated with a transient and highly selective increase in gray matter in the occipito-temporal cortex. A follow-up study involving 20 adults confirmed this finding and found that the change in grey matter occurred after only 7 days of training. Neither performance nor exercise alone could explain these changes, and the increase receded when training stopped. The researchers suggest that learning a new task is more critical for the brain to change its structure than continued training of an already-learned task.
The report appeared July 23 in the open access journal PLoS One. Full reference
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0002669

How food affects the brain

I’ve reported on quite a lot of studies finding beneficial effects of one food or another on the brain. Now a researcher has analyzed more than 160 studies about food's effect on the brain, and here’s the bottom line. He comes out for omega-3 fatty acids, as both improving synaptic plasticity and the expression of several molecules proteins to learning and memory, as well as protecting against attention-deficit disorder, dyslexia, dementia, depression, bipolar disorder and schizophrenia. He suggests it’s better to get it from food than supplements (which is always recommended). Salmon, walnuts and kiwi fruit are all good sources. They’re still working out which fatty acids are most important, but one is definitely docosahexaenoic acid, or DHA — which like vitamin C we’re not good at making for ourselves; we have to ingest it. He also concludes that diets high in trans fats and saturated fats are bad for cognition.
Studies also support the need for folic acid (found in spinach, orange juice and yeast), which is essential for brain function, and appears to reduce age-related cognitive decline and dementia. And BDNF, important for learning and memory as well as metabolic regulation (so there’s a connection there with obesity), is helped by omega-3 fatty acids and the curry spice curcumin, and also, it seems, smaller food portions.
The results appeared in the July issue of Nature Reviews Neuroscience. Full reference
Full text is available online at www.nature.com/nrn/journal/v9/n7/abs/nrn2421.html
http://www.eurekalert.org/pub_releases/2008-07/uoc--slh070908.php

Early-life nutrition may be associated with adult intellectual functioning

A study in Guatemala has revealed the importance of early nutrition for lifetime cognition. Between 1969 and 1977, Guatemalan children in four villages participated in a trial of nutritional supplementation. Some consumed atole—a protein-rich enhanced nutritional supplement—and others fresco, a sugar-sweetened beverage. Cognitive testing of participants in 2002-4, who were an average of 32 years old, found that those exposed to atole in the first two years of life scored higher on intellectual tests of reading comprehension and cognitive functioning in adulthood than those not exposed to atole or exposed to it at other ages. The association was stronger for females, and occurred irrespective of education.
The report appeared in the July issue of Archives of Pediatrics & Adolescent Medicine. Full reference
http://www.eurekalert.org/pub_releases/2008-07/jaaj-enm070308.php

'Cocktail' for improved memory

Reinforcing that, a study has found that gerbils given a ‘cocktail’ of DHA, uridine and choline performed significantly better on learning and memory tests than untreated gerbils, and their brains had up to 70% more phosphatides (a type of molecule that forms cell membranes) than controls, suggesting that new synapses are forming. Some of the gerbils received all three compounds and some received only two; the improvements were greatest in those given all three. An earlier study had found that the treatment improved function in rats with cognitive impairment. Omega-3 fatty acids are found in fish, eggs, flaxseed and meat from grass-fed animals. Choline is found in meats, nuts and eggs. Uridine cannot be obtained from food sources, but is a component of human breast milk and can be produced in the body.
The findings appeared online July 7 in the Journal of FASEB. Full reference
http://www.eurekalert.org/pub_releases/2008-07/miot-spt070808.php

Aging impairs the 'replay' of memories during sleep

During sleep, the hippocampus repeatedly "replays" brain activity from recent experiences, in a process believed to be important for memory consolidation. A new rat study has found reduced replay activity during sleep in old compared to young rats, and rats with the least replay activity performed the worst in tests of spatial memory. The best old rats were also the ones that showed the best sleep replay. Indeed, the animals who more faithfully replayed the sequence of neural activity recorded during their earlier learning experience were the ones who performed better on the spatial memory task, regardless of age. The replay activity occurs during slow-wave sleep.
The research was reported in the July 30 issue of The Journal of Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2008-07/sfn-ait072408.php

Heart disease linked to worse cognition

Another report has come out from the large Whitehall study, this time on the subject of coronary heart disease and cognition. The study found that coronary heart disease was associated with a worse performance in mental processes such as reasoning, vocabulary and verbal fluency, and that the longer ago the heart disease had been diagnosed, the worse was the person's cognitive performance. This effect was particularly marked in men. Although there has been quite a lot of research on cardiovascular disease and impaired cognition, this is the first, large study to specifically examine the association between coronary heart disease and cognition. The major risk factors for coronary heart disease are all modifiable: cigarette smoking, diabetes, high cholesterol levels and high blood pressure. The findings also support the growing view that it is events happening in earlier life that have an impact on whether or not dementia develops in older age.
The study was published online 22 July in the European Heart Journal. Full reference
http://www.eurekalert.org/pub_releases/2008-07/esoc-hdi072108.php

New 'everyday cognition' scale tracks how older adults function in daily life

A new, carefully validated questionnaire called Everyday Cognition (ECog) has been developed by seven psychologists. The 39-question screening tool is designed to enable mild functional problems in older adults to be quickly and easily identified. The questionnaire needs to be filled out by someone who knows an older adult well, such as a spouse, adult child, or close friend. It looks at everyday function in seven key cognitive domains: memory, language, semantic (factual) knowledge, visuospatial abilities, planning, organization and divided attention. The test has been shown to be sensitive to early changes present in Mild Cognitive Impairment, and unlike other cognitive tests, does not appear to be strongly influenced by education level. The test even differentiated between people diagnosed with mild impairment in memory only and those mildly impaired in several areas.
The report appeared in the July issue of Neuropsychology. Full reference
Full text of the article is available at http://www.apa.org/journals/releases/neu224531.pdf
http://www.eurekalert.org/pub_releases/2008-07/apa-nc062408.php

Memory impairment associated with sound processing disorder

Central auditory processing dysfunction refers to the situation where hearing in quiet settings is normal or near normal but is substantially impaired in the presence of competing noise or in other difficult listening situations. Such a problem is not helped by amplification and requires alternative rehabilitation strategies. Central auditory processing has been found to be impaired in those with dementia. Now a study comparing individuals with dementia, those with mild memory impairment but without a dementia diagnosis, and those without memory loss, has found that scores on central auditory processing tests were significantly lower in both the group with dementia and in the group with mild memory impairment, compared to controls.
The report appeared in the July issue of Archives of Otolaryngology–Head & Neck Surgery. Full reference
http://www.eurekalert.org/pub_releases/2008-07/jaaj-mia071708.php

Attention grabbers snatch lion's share of visual memory

It’s long been thought that when we look at a visually "busy" scene, we are only able to store a very limited number of objects in our visual short-term or working memory. For some time, this figure was believed to be four or five objects, but a recent report suggested it could be as low as two. However, a new study reveals that although it might not be large, it’s more flexible than we thought. Rather than being restricted to a limited number of objects, it can be shared out across the whole image, with more memory allocated for objects of interest and less for background detail. What’s of interest might be something we’ve previously decided on (i.e., we’re searching for), or something that grabs our attention. Eye movements also reveal how brief our visual memory is, and that what our eyes are looking at isn’t necessarily what we’re ‘seeing’ — when people were asked to look at objects in a particular sequence, but the final object disappeared before their eyes moved on to it, it was found that the observers could more accurately recall the location of the object that they were about to look at than the one that they had just been looking at.
The study was published online 8 August in Science. Full reference
http://www.physorg.com/news137337380.html

Positive mood may not help in tasks requiring attention to detail

A series of experiments with different child age groups who had happy or sad moods induced with the aid of music and selected video clips before then being asked to undertake a task that required attention to detail has found that the children induced to feel a sad or neutral mood performed the task better than those induced to feel happy. Other research has found that a positive mood is beneficial in other situations, such as when a task calls for creative thinking.
The findings appeared in the June issue of Developmental Science. Full reference
http://www.eurekalert.org/pub_releases/2008-06/uov-ssc053008.php

Even toddlers can ‘chunk' information for better remembering

We all know it’s easier to remember a long number (say a phone number) when it’s broken into chunks. Now a study has found that we don’t need to be taught this; it appears to come naturally to us. The study showed 14 months old children could track only three hidden objects at once, in the absence of any grouping cues, demonstrating the standard limit of working memory. However, with categorical or spatial cues, the children could remember more. For example, when four toys consisted of two groups of two familiar objects, cats and cars, or when six identical orange balls were grouped in three groups of two.
The research appeared online July 14 in the Proceedings of the National Academy of Sciences. Full reference
Full text available at http://www.pnas.org/content/105/29/9926.abstract?sid=c01302b6-cd8e-4072-842c-7c6fcd40706f
http://www.eurekalert.org/pub_releases/2008-07/jhu-etg071008.php

New genes implicated in autism; support new theory of cause

Research involving 104 large Middle Eastern families has implicated half a dozen new genes in autism, and more importantly, strongly supports the emerging idea that autism stems from disruptions in the brain's ability to form new connections in response to experience – consistent with autism's onset during the first year of life, when many of these connections are normally made. Just over 6% of the 88 families with autistic members showed rare, inherited deletions within DNA regions linked to autism. These affected DNA regions varied among families, further indication of autism's large variety of genetic causes. In all, the technique identified five chromosome deletions affecting at least six identifiable genes. Although the genes discovered are diverse in function, all seem to be part of a fundamental network that orchestrates the refinement and maturation of synapses in response to input from the outside world. The network itself is already known to activate at least 300 genes, so it’s no surprise that there are many ways it can be disrupted, explaining why there might be myriad genetic causes of autism, even though in essence it might be all the same problem: a disruption of the brain's ability to modify its synaptic connections in response to experience. The good news is that in all but one case the chromosome deletions didn’t actually remove a gene, they just turned it off — suggesting a possible ‘cure’ if researchers can figure out how to turn them back on.
The study was the cover article in the July 11 issue of Science. Full reference
http://www.eurekalert.org/pub_releases/2008-07/chb-mef070808.php

Autism's social struggles due to disrupted communication networks in brain

And a timely imaging study has now provided the clearest evidence to date that synchronization in what might be termed the Theory of Mind network is impaired in autistic people. The Theory of Mind network (which includes the medial frontal gyrus, the anterior paracingulate, and the right temporoparietal junction) is responsible for processing the intentions and thoughts of others. In the study 12 high-functioning autistic adults and 12 controls viewed animated interacting geometric figures, and then asked to select the word from several choices that best described the interaction. The control subjects were consistently better at inferring the intention from the action than the participants with autism were. Brain scans revealed that synchronization between the frontal and posterior regions in the network was reliably lower in the group with autism. The autistic participants' brains also showed much lower activation levels in the frontal regions, and an independent assessment of their Theory of Mind abilities found these reliably correlated with activation in the right temporoparietal junction. The findings point to the need to develop interventions that could target this problem, and also indicate a way to measure an intervention’s effectiveness.
The study was reported online 3 July in Social Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2008-07/cmu-ass072308.php

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