News reports of research into memory April 2008

Related topics

For index of all headlines, go to News & Views main page

To look at research reports sorted by subject go to Research Reports

For news about Alzheimer's research go directly to the Alzheimer's page

You can find links to the journals referred to on this site here: Journal links

April 2008

Brain-training to improve working memory boosts fluid intelligence

General intelligence is often separated into "fluid" and "crystalline" components, of which fluid intelligence is considered more reflective of “pure” intelligence (for more on this, see my article at http://www.memory-key.com/NatureofMemory/wm_iq.htm ), and largely resistant to training and learning effects. However, in a new study in which participants were given a series of training exercises designed to improve their working memory, fluid intelligence was found to have significantly improved, with the amount of improvement increasing with time spent training. The small study contradicts decades of research showing that improving on one kind of cognitive task does not improve performance on other kinds, so has been regarded with some skepticism by other researchers. More research is definitely needed, but the memory task did differ from previous studies, engaging executive functions such as those that inhibit irrelevant items, monitor performance, manage two tasks simultaneously, and update memory.
The research was published online April 28 ahead of print in the Proceedings of the National Academy of Sciences (PNAS). Full reference
http://www.physorg.com/news128699895.html
http://www.sciam.com/article.cfm?id=study-shows-brain-power-can-be-bolstered

Intelligence and rhythmic accuracy go hand in hand

And in another perspective on the nature of intelligence, a new study has demonstrated a correlation between general intelligence and the ability to tap out a simple regular rhythm. The correlation between high intelligence and a good ability to keep time, was also linked to a high volume of white matter in the parts of the frontal lobes involved in problem solving, planning and managing time. The finding suggests that the long-established correlation of general intelligence with the mean and variability of reaction time in elementary cognitive tasks, as well as with performance on temporal judgment and discrimination tasks, is a bottom-up connection, stemming from connectivity in the prefrontal regions.
The findings appeared online April 16 in the Journal of Neuroscience. Full reference
http://www.physorg.com/news127561553.html
http://www.eurekalert.org/pub_releases/2008-04/ki-iar041608.php

Working memory has a fixed number of 'slots'

A study that showed volunteers a pattern of colored squares for a tenth of a second, and then asked them to recall the color of one of the squares by clicking on a color wheel, has found that working memory acts like a high-resolution camera, retaining three or four features in high detail. Unlike a digital camera, however, it appears that you can’t increase the number of images you can store by lowering the resolution. The resolution appears to be constant for a given individual. However, individuals do differ in the resolution of each feature and the number of features that can be stored.
The paper was published online April 2 inl Nature. Full reference
http://www.physorg.com/news126432902.html
http://www.eurekalert.org/pub_releases/2008-04/uoc--wmh040208.php

And another study of working memory has attempted to overcome the difficulties involved in measuring a person’s working memory capacity (ensuring that no ‘chunking’ of information takes place), and concluded that people do indeed have a fixed number of ‘slots’ in their working memory. In the study, participants were shown two, five or eight small, scattered, different-colored squares in an array, which was then replaced by an array of the same squares without the colors, after which the participant was shown a single color in one location and asked to indicate whether the color in that spot had changed from the original array.
The study was published in the April 22 issue of Proceedings of the National Academy of Sciences. Full reference
http://www.eurekalert.org/pub_releases/2008-04/uom-mpd042308.php

Dull tasks dull the mind

Confirming something we’ve probably all experienced, an imaging study has revealed that monotonous tasks really do numb the brain — that is, after a while blood flows into the part of the brain which is more active in states of rest. By monitoring that area of the brain, researchers were able to predict when someone was about to make a mistake about 30 seconds before they made it.
The study was published in the April 22 issue of the Proceedings of the National Academy of Sciences. Full reference
Full text available at http://www.pnas.org/cgi/content/short/105/16/6173
http://www.physorg.com/news128015347.html

Vitamin D important in brain development and function

A review described as “definitive” has concluded that there is ample biological evidence to suggest an important role for vitamin D in brain development and function, and that supplementation for groups chronically low in vitamin D is warranted. Vitamin D has long been known to promote healthy bones, but more recently has been found to have a much broader role — over 900 different genes are now known to be able to bind the vitamin D receptor. Evidence for vitamin D's involvement in brain function includes the wide distribution of vitamin D receptors throughout the brain, as well as its ability to affect proteins in the brain known to be directly involved in learning and memory and motor control. Because we receive most of our Vitamin D from sunlight (UV from the sun converts a biochemical in the skin to vitamin D), those with darker skin living in northern latitudes are particularly at risk of vitamin D deficiency. Nursing infants and the elderly are also particularly vulnerable. It has also argued that current recommendations set the recommended level of vitamin D too low. This review is the fourth in a series that critically evaluate scientific evidence linking deficiencies in micronutrients to brain function. Earlier reviews have looked at DHA, choline, and iron.
The review was published on April 22 in the Federation of American Societies for Experimental Biology (FASEB) Journal. Full reference
http://www.eurekalert.org/pub_releases/2008-04/chr-vdi041808.php

Mild cognitive impairment more likely in men

A study involving over 2000 people between 70 and 89 years old, found 15% had mild cognitive impairment, and men were one-and-a-half times more likely to have MCI than women.
The research was presented at the American Academy of Neurology Annual Meeting in Chicago, April 12–19.
http://www.eurekalert.org/pub_releases/2008-04/aaon-mml040208.php

Using anti-cholinergic drugs may increase cognitive decline

The Religious Orders Study has thrown up more data, this time on the subject of anticholinergic medication. Over an eight year period, 679 of the 870 elderly participants took at least one medication with anticholinergic properties. The study found those people who took anticholinergic drugs saw their rate of cognitive function decline 1.5 times as fast as those people who did not take the drugs. Anticholinergic properties are found in many medicines, such as medicines for stomach cramps, ulcers, motion sickness, and urinary incontinence.
The research was presented at the American Academy of Neurology Annual Meeting in Chicago, April 12–19.
http://www.eurekalert.org/pub_releases/2008-04/aaon-uad040208.php

Chemotherapy may not affect memory in breast cancer patients

A study that tested 30 women with breast cancer repeatedly before each cycle of chemotherapy and one month after the final cycle, comparing them to healthy controls, found the women with breast cancer had slight problems in attention and learning skills before chemotherapy started. Only three women (10%) developed cognitive problems during chemotherapy, and interestingly, these were not the women who reported that they had problems.

Another study compared 40 women with breast cancer not yet treated, 27 women who had recently had a breast biopsy that was not cancerous, and 20 breast cancer survivors who had completed treatment at least one year before. On tests of working memory and spatial learning, the women recently diagnosed with breast cancer performed about the same as the women with the recent benign biopsy, but both groups were slower and less accurate than the breast cancer survivors. The results suggest the cognitive difficulties may be related to stress as a result of the diagnosis and other quality-of-life factors.
The studies were presented at the American Academy of Neurology Annual Meeting in Chicago, April 12–19.
http://www.eurekalert.org/pub_releases/2008-04/aaon-cmn040208.php

Chemotherapy's damage to the brain identified

On the other hand, studies have shown that upwards of 82% of breast cancer patients report that they suffer from some form of cognitive impairment, and that a significant proportion of these (reports range from 15-20% to 50%) have lingering cognitive problems a year or more after treatment. And following their demonstration that three common chemotherapy drugs used to treat a wide range of cancers are more toxic to healthy brain cells than the cancer cells they were intended to treat, researchers have now found in cell and mouse studies that the widely used chemotherapy drug 5-fluorouracil (5-FU) is associated with a progressing collapse of support cells that are responsible for producing myelin. The next step will be to find out why some patients are vulnerable to this, and others not.
The study was published 22 April in the open-access Journal of Biology. Full reference
Full text available at http://jbiol.com/content/7/4/12
http://www.eurekalert.org/pub_releases/2008-04/uorm-rdc041708.php

How blueberries help the aging brain

An animal study has found that supplementing the regular diet of older animal with blueberries over a 12-week period, produced improvements in spatial working memory tasks within three weeks. This improvement was associated with the activation of the protein CREB and increases in the level of BDNF in the hippocampus. Blueberries are a major source of flavonoids, in particular anthocyanins and flavanols.
The study was published online 17 April in Free Radical Biology and Medicine. Full reference
http://www.eurekalert.org/pub_releases/2008-04/tpco-gft041008.php

How chronic exposure to solvents can impair the brain

Chronic occupational exposure to organic solvents, found in materials such as paints, printing and dry cleaning agents, has been linked to long-term cognitive impairment, but chronic solvent-induced encephalopathy (CSE) is still a controversial diagnosis. An imaging study of 10 CSE patients who had been exposed to solvents and had mild to severe cognitive impairment, 10 participants who had been exposed to solvents but had no CSE symptoms, and 11 participants who were not exposed to solvents and had no symptoms, has now found impairment in the frontal-striatal-thalamic (FST) circuitry of CSE patients. The disturbances are predictive of the clinical findings — impaired psychomotor speed and attention — and were also linked to exposure severity.
The study was published online April 15 in Annals of Neurology. Full reference
http://www.eurekalert.org/pub_releases/2008-04/w-dib041508.php

Chinese and English dyslexias stem from different brain abnormalities.

Dyslexia involves impairment in connecting the sight and sound of a word. In English, this is commonly seen in transpositions of letters, while in Chinese, the problem can affect how a person converts a symbol into both sound and meaning. Following an earlier study in which the brain areas involved in dyslexia were found to be different for English and Chinese readers, a new technique has confirmed and clarified the results. Chinese children with dyslexia had a significantly smaller left middle frontal gyrus than did Chinese children without the disorder, even though both groups had the same overall volume of gray matter. Intriguingly, this area is not associated with symbol recognition, but with working memory. Earlier research has found English-speaking dyslexics have less gray matter in the left parietal region. The findings also suggest that dyslexics in one language will probably not be dyslexic in the other.
The study was published in the April 8 issue of the Proceedings of the National Academy of Sciences. Full reference
http://www.nature.com/news/2008/080407/full/news.2008.739.html
http://sciencenow.sciencemag.org/cgi/content/full/2008/408/1?etoc

Costs and benefits of a larger brain

A study of key benchmarks in the development of 28 different primate species, from humans living in South American jungles to lemurs in Madagascar, has concluded that larger brain sizes produce extended lives and delayed maturity. Growth rates are much slower, thus delaying reproduction, because it takes longer to grow a bigger brain. But the larger brain grants the adult caretakers greater skills, thus allowing them to live longer, thus extending their reproductive lives. Earlier studies have produced contradictory results, because they mixed wild and captive animals, but the present study included only wild animals.
The report was posted online ahead of its publication in the May issue of the Journal of Human Evolution. Full reference
http://www.physorg.com/news127568456.html