News reports of research into memory June 2005

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June 2005

Drinking for just eight weeks impairs learning and memory in mice

It’s well established that chronic alcohol consumption can produce deficits in learning and memory. A new rodent study, however, is the first to show that continuous drinking for as little as eight weeks can produce deficits in learning and memory that last at least 12 weeks after drinking stopped — “equivalent to a human that drank six to eight beers or one bottle of wine a day every day for six years experiencing learning and memory deficits up to nine years after they stopped drinking alcohol." These deficits were global — that is, they affected long-term memory for every type of task tested. Short-term memory was not affected. Rats who drank for only four weeks did not experience the same effects.
The study appeared in the June issue of Alcoholism: Clinical & Experimental Research. Full reference
http://www.eurekalert.org/pub_releases/2005-06/ace-dfj060605.php

How sleep improves memory

While previous research has been conflicting, it does now seem clear that sleep consolidates learning of motor skills in particular. A new imaging study involving 12 young adults taught a sequence of skilled finger movements has found a dramatic shift in activity pattern when doing the task in those who were allowed to sleep during the 12 hour period before testing. Increased activity was found in the right primary motor cortex, medial prefrontal lobe, hippocampus and left cerebellum — this is assumed to support faster and more accurate motor output. Decreased activity was found in the parietal cortices, the left insular cortex, temporal pole and fronto-polar region — these are assumed to reflect less anxiety and a reduced need for conscious spatial monitoring. It’s suggested that this is one reason why infants need so much sleep — motor skill learning is a high priority at this age. The findings may also have implications for stroke patients and others who have suffered brain injuries.
The findings were reported in the June 30 issue of Neuroscience. Full reference http://www.eurekalert.org/pub_releases/2005-06/bidm-ssh062805.php

Aircraft noise may affect children's reading and memory

A large study involving 2844 children aged 9-10 has found exposure to aircraft noise impaired reading comprehension. The children were selected from primary schools located near three major airports — Schiphol in the Netherlands, Barajas in Spain, and Heathrow in the UK. Reading age in children exposed to high levels of aircraft noise was delayed by up to 2 months in the UK and by up to 1 month in the Netherlands for each 5 decibel change in noise exposure. On the other hand, road traffic noise did not have an effect on reading and indeed was unexpectedly found to improve recall memory. An earlier German study found children attending schools near the old Munich airport improved their reading scores and cognitive memory performance when the airport shut down, while children going to school near the new airport experienced a decrease in testing scores.
The study was published in the June 4 issue of The Lancet. Full reference
http://www.eurekalert.org/pub_releases/2005-06/l-eta060105.php

Possible treatment found for 'chemobrain'

A common consequence of chemotherapy is memory problems, confusion and difficulty in concentrating ("chemobrain"). While nearly all breast and ovarian cancer patients receiving chemotherapy or radiation treatments seem to suffer chemobrain, 61% continue to experience memory problems long after their cancer treatment has stopped. A new study involving 154 cancer survivors suggests a possible new treatment using the drug dexmethyphenidate (d-MPH). The drug significantly reduced fatigue and improved memory.
Results of the study were presented to the annual meeting of the American Society of Clinical Oncology.
http://www.eurekalert.org/pub_releases/2005-06/uoc-ptf060705.php

Post-concussion migraine may signal greater neurocognitive impairment

Another study suggesting sports’ concussions should be taken more seriously. The study found that young athletes who experienced migraine headache symptoms (even one week after concussion) were likely to have increased neurocognitive impairment. Headaches are reported in as many as 86% of such injuries; the researchers suggest that athletes should not be allowed to return to play before the headache resolves.
The study was published in the May issue of the Journal of Neurosurgery. Full reference
http://www.eurekalert.org/pub_releases/2005-06/uopm-yap062105.php

Why premature brains improve over time

A new study explains why premature babies often develop better than expected. A mouse study has found that infants born prematurely and with hypoxia (inadequate oxygen to the blood) are able to recover some cells, volume and weight in the brain after oxygen supply is restored, by a process of neurogenesis.
The report was available online 23 May in Experimental Neurology. Full reference
http://www.eurekalert.org/pub_releases/2005-06/yu-gsh062705.php

Interestingly, another recent study, following up an earlier study when premature infants with respiratory distress syndrome were given inhaled nitric oxide (decreasing the risk of death or chronic lung disease), has found that the treatment also improve neurodevelopmental outcomes. 24% of those given nitric oxide had abnormal neurodevelopmental outcomes at two years of age compared to 46% in the placebo group.
The study appeared in the July 7 issue of The New England Journal of Medicine. Full reference

Correlation between brain volume and intelligence

An analysis of 26 previous international studies involving brain volume and intelligence has found that, on average, intelligence (as measured by standardized intelligence tests) increases with increasing brain volume. The correlation was higher for females than males, and for adults compared to children.
The study was published online June 16 in Intelligence. Full reference
A copy of the study is available at http://www.vcu.edu/uns/Releases/2005/june/McDaniel-Big%20Brain.pdf
http://www.eurekalert.org/pub_releases/2005-06/vcu-vss061705.php
http://www.vcu.edu/uns/Releases/2005/june/061705.html

Meditation skills of Buddhist monks yield clues to brain's regulation of attention

Recent research has suggested that skilled meditation can alter certain aspects of the brain's neural activity. A new study has now found evidence that certain types of trained meditative practice can influence the conscious experience of visual perceptual rivalry, a phenomenon thought to involve brain mechanisms that regulate attention and conscious awareness. Perceptual rivalry arises normally when two different images are presented to each eye, and it is manifested as a fluctuation in the "dominant" image that is consciously perceived. The study involved 76 Tibetan Buddhist monks with training ranging from 5 to 54 years. Tested during the practice of two types of meditation: a "compassion"-oriented meditation (contemplation of suffering within the world), and "one-point" meditation (involving the maintained focus of attention on a single object or thought). Major increases in the durations of perceptual dominance were experienced by monks practicing one-point meditation, but not during compassion-oriented meditation. Additionally, under normal conditions the monks showed longer stable perception (average 4.1 seconds compared to 2.6 seconds for meditation-naïve control subjects). The findings suggest that processes particularly associated with one-point meditation can considerably alter the normal fluctuations in conscious state that are induced by perceptual rivalry.
The study was reported in the June 7 issue of Current Biology. Full reference
http://www.eurekalert.org/pub_releases/2005-06/cp-mso060205.php

New light on speech evolution in humans

A new monkey study challenges thinking that speech developed as a result of new structures that evolved in the human brain. A distinct brain region that controls jaw movements in macaque monkeys has been found in the same area and with the same anatomical characteristics as Broca's area. The discovery suggests that this area of the brain evolved originally to perform high-order control over the mouth and the jaw, and that as humans evolved this area came to control the movements necessary for speech.
The study was published in the 30 June issue of Nature. Full reference
http://www.eurekalert.org/pub_releases/2005-06/mu-nrp062905.php

Practice makes an expert

A comparison of expert video game players and non-players has found that gamers showed a 20% reduction in response times on a visual search test (meaning that, on average, gamers were some 100 milliseconds faster than non-gamers). Analysis showed that expert game players did not show differences in normal visual search patterns; they had simply become faster through practice.
The report was published in the June issue of Acta Psychologica. Full reference
http://www.eurekalert.org/pub_releases/2005-06/wuis-gbn060905.php

Cognitive therapy for ADHD

A researcher that has previously demonstrated that working memory capacity can be increased through training, has now reported that the training software has produced significant improvement in children with ADHD — a disability that is associated with deficits in working memory. The study involved 53 children with ADHD, aged 7-12, who were not on medication for their disability. 44 of these met the criterion of more than 20 days of training. Half the participants were assigned to the working memory training program and the other half to a comparison program. 60% of those who underwent the wm training program no longer met the clinical criteria for ADHD after five weeks of training. The children were tested on visual-spatial memory, which has the strongest link to inattention and ADHD. Further research is needed to show that training improves ability on a wider range of tasks.
The study appeared in the February issue of the Journal of the American Academy of Child & Adolescent Psychiatry.
Full reference
http://www.sciam.com/article.cfm?articleID=000560D5-7252-12B9-9A2C83414B7F0000&sc=I100322

Effect of pregnancy on cognition depends on fetal gender

An intriguing new study may shed light on the conflicting results reported regarding the effect of pregnancy on cognition. The study, which tracked women throughout pregnancy through to postnatal resumption of menstruation, found that there was a significant effect of the sex of the baby on working memory and spatial ability. Women pregnant with boys consistently outperformed women pregnant with girls on these tests.
The findings were reported in the May 12 issue of Neuroreport. Full reference

Single cell recognition research finds specific neurons for concepts

An intriguing study surprises cognitive researchers by showing that individual neurons in the medial temporal lobe are able to recognize specific people and objects. It’s long been thought that concepts such as these require a network of cells, and this doesn’t deny that many cells are involved. However, this new study points to the importance of a single brain cell. The study of 8 epileptic subjects found variable responses from subjects, but within subjects, individuals showed remarkably specific responses to concepts. For example, a single neuron in the left posterior hippocampus of one subject responded to all pictures of actress Jennifer Aniston, and also to Lisa Kudrow, her co-star on the TV hit "Friends", but not to pictures of Jennifer Aniston together with actor Brad Pitt, and not, or only very weakly, to other famous and non-famous faces, landmarks, animals or objects. In another patient, pictures of actress Halle Berry activated a neuron in the right anterior hippocampus, as did a caricature of the actress, images of her in the lead role of the film "Catwoman," and a letter sequence spelling her name. The results suggest an invariant, sparse and explicit code, which might be important in the transformation of complex visual percepts into long-term and more abstract memories.
The findings were reported in the June 23 edition of Nature. Full reference
http://www.eurekalert.org/pub_releases/2005-06/uoc--scr062005.php