News reports of research into memory June 2006

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June 2006

Alzheimer's pathology related to episodic memory loss in those without dementia

A study of 134 participants from the Religious Orders Study or the Memory and Aging Project has found that, although they didn't have cognitive impairment at the time of their death, more than a third of the participants (50) met criteria for a pathologic diagnosis of Alzheimer's disease. This group also scored significantly lower on tests for episodic memory, such as recalling stories and word lists. The results provide further support for the idea that a ‘cognitive reserve’ can allow people to tolerate a significant amount of Alzheimer's pathology without manifesting obvious dementia. It also raises the question whether we should accept any minor episodic memory loss in older adults as 'normal'.
The study was published in the June 27 issue of Neurology. Full reference
http://www.eurekalert.org/pub_releases/2006-06/aaon-apr062006.php

Brain function not impaired by tight diabetes control and hypoglycemia

Previous research had indicated that tight blood glucose control -- achieved by taking three or more insulin injections daily – meant type 1 diabetics were three times as likely to suffer episodes of severe hypoglycemia, raising the fear that it might lead to a long-term loss of cognitive ability. Now a follow-up study provides the reassuring news that there was no link between multiple severe hypoglycemic reactions and impaired cognitive function in people with type 1 diabetes.
The study was presented at the American Diabetes Association's 66th Annual Scientific Sessions held in Washington, D.C, June 9—13. Full reference
http://www.eurekalert.org/pub_releases/2006-06/jdc-lss060806.php

Why are uniforms uniform? Because color helps us track objects

Laboratory tests have revealed that humans can pay attention to only 3 objects at a time. Yet there are instances in the real world — for example, in watching a soccer match — when we certainly think we are paying attention to more than 3 objects. Are we wrong? No. Anew study shows how we do it — it’s all in the color coding. People can focus on more than three items at a time if those items share a common color. But, logically enough, no more than 3 color sets.
The study was reported in the July issue of Psychological Science. Full reference
http://www.eurekalert.org/pub_releases/2006-06/jhu-wau062106.php

Talking on a cellphone while driving as bad as drinking

Yet another study has come out rubbing it in that multitasking comes with a cost, and most particularly, that you shouldn’t do anything else while driving. This study demonstrates — shockingly — that drivers are actually worse off when using a cell phone than when legally drunk. The study had 40 volunteers use a driving simulator under 4 different conditions: once while legally intoxicated, once while talking on a hands-free cell phone, once while talking on a hand-held cell phone, and once with no distractions. There were differences in behavior —drunk drivers were more aggressive, tailgated more, and hit the brake pedal harder; cell phone drivers (whether hands-free and hand-held ) took longer to hit the brakes, and got in more accidents. But in both cases drivers were significantly impaired.
The research was published in the summer issue of Human Factors. Full reference
http://www.sciencentral.com/articles/view.htm3?article_id=218392815
http://www.eurekalert.org/pub_releases/2006-06/uou-doc062306.php
http://www.guardian.co.uk/mobile/article/0,,1809549,00.html

People remember prices more easily if they have fewer syllables

The phonological loop — an important component of working memory —can only hold 1.5 to 2 seconds of spoken information. For that reason, faster speakers have an advantage over slower speakers. Now a consumer study reveals that every extra syllable in a product's price decreases its chances of being remembered by 20%. Thus, people who shorten the number of syllables (e.g. read 5,325 as 'five three two five' as opposed to 'five thousand three hundred and twenty five') have better recall. However, since we store information both verbally and visually, it’s also the case that unusual looking prices, such as $8.88, are recalled better than typical looking prices.
The study will appear in the September issue of the Journal of Consumer Research. Full reference
http://www.sciencedaily.com/releases/2006/06/060623001231.htm
http://www.eurekalert.org/pub_releases/2006-06/uocp-prp062206.php

Increasing consumer preferences by manipulating memory

In two experiments, people who had to solve an anagram before seeing a target brand, they were more likely to claim to have seen the brand before, and to prefer it over competing brands.
The study was published online 29 June in Applied Cognitive Psychology. Full reference
http://www.eurekalert.org/pub_releases/2006-06/jws-icp062606.php

Language affects how math is done?

A comparison of activity in the brains of Chinese and English participants doing simple arithmetic using Arabic numbers has found that, although both groups utilised the inferior parietal cortex (an area connected to quantity representation and reading), English speakers displayed more activity in the language processing area of the brain, while Chinese speakers used the area of the brain that deals with processing visual information. There was no significant difference in the reaction time and accuracy of the Chinese and English-speaking volunteers. However, an earlier study comparing Canadian and Chinese students found that the latter were better at complex maths. The findings suggest that our native language, or different teaching methods, may influence the way we solve equations.
The report appeared online before print on June 30 in Proceedings of the National Academy of Sciences. Full reference
http://www.scenta.co.uk/scenta/news.cfm?cit_id=903050&FAArea1=widgets.content_view_1
http://www.newscientist.com/article/dn9422?DCMP=NLC-nletter&nsref=dn9422

Language center executive organizer of action plans

Broca's area is the region in the brain traditionally known as the ‘language center’, however recent research has broadened that understanding. The most recent study reveals that this region, and its counterpart in the right hemisphere, becomes active when people are asked to organize plans of action — an activity that we must now distinguish from a simple action sequence, which didn’t require these regions. These regions appear to implement a specialized executive system controlling the selection and nesting of action segments in a hierarchical structure of behavioral plans. This general executive function may explain Broca’s key role in language production.
The report appeared in the June 15 issue of Neuron. Full reference
http://www.eurekalert.org/pub_releases/2006-06/cp-wtb060806.php

Fat hormone linked to learning and memory

A new study reveals why obese patients who have diabetes also may have problems with their long-term memory. Leptin — the so-called ‘fat’ hormone — doesn't cross into the brain to help regulate appetite in obese people. Leptin also acts in the hippocampus, suggesting that leptin plays a role in learning and memory. The new study supports this by demonstrating that mice navigated a maze better after they received leptin. Moreover, mice with elevated levels of amyloid-beta plaques (characteristic of Alzheimer's) were particularly sensitive to leptin.
The research appeared in the June issue of Peptides. Full reference
http://www.sciencedaily.com/releases/2006/06/060614090511.htm
http://www.eurekalert.org/pub_releases/2006-06/slu-alb061306.php

Face blindness is a common hereditary disorder

A German study has found 17 cases of the supposedly rare disorder prosopagnosia (face blindness) among 689 subjects recruited from local secondary schools and a medical school. Of the 14 subjects who consented to further interfamilial testing, all of them had at least one first degree relative who also had it. Because of the compensation strategies that sufferers learn to utilize at an early age, many of them do not realize that it is an actual disorder or even realize that other members of their family have it — which may explain why it has been thought to be so rare. The disorder is one of the few cognitive dysfunctions that has only one symptom and is inherited. It is apparently controlled by a defect in a single gene.
The study was published online June 30, 2006 in American Journal of Medical Genetics Part A. Full reference
http://www.sciencedaily.com/releases/2006/07/060707151549.htm

Prevalence of combat-related PTSD

Two large independent studies funded by the US government have assessed the impact of the Vietnam War on the prevalence of PTSD in US veterans. The National Vietnam Veterans Readjustment Study (NVVRS) estimated prevalence to be 15.2% while the Vietnam Experience Study (VES) estimated the prevalence to be 2.2%. A new study explains this discrepancy by reanalyzing both data sets using varying criteria. Prevalence estimates for combat-related PTSD of 2.5% and 2.9% for the VES and the NVVRS, respectively, were found when a narrow and specific set of criteria were used, while prevalence estimates 12.2% and 15.8% for the VES and NVVRS, respectively, were found when broader and more sensitive criteria were used.
The study was available online 2 May in BMC Psychiatry (Open Access) Full reference
http://www.biomedcentral.com/1471-244X/6/19

Skills related to early language learning

A study of more than 120 children aged 21 months — a peak time for language learning — has found a link between language learning and several motor and cognitive skills. Children who were poor at moving their mouths (for example not being able to lick their lips, or blow bubbles) were particularly weak at language skills, while those who were good at these movements had a range of language abilities. Children who were good at pretending that one object is another, such as using a block for a car, or a box for a doll's bed, or giving a doll a tea party, were also better at language, but there was no relationship with more general thinking skills, such as doing puzzles. Children who could say new words an adult asked them to repeat, were best at language. Being able to listen to a new word or a funny sound and work out which picture it went with also distinguished between children with advanced and not so strong abilities.
The study was funded by the Economic and Social Research Council (ESRC). Reference
http://www.sciencedaily.com/releases/2006/06/060628095606.htm
Report available at http://tinyurl.com/qssx7

How does the bilingual brain distinguish between languages?

Studies of bilingual people have found that the same brain regions, particularly parts of the left temporal cortex, are similarly activated by both languages. But there must be some part of the brain that knows one language from another. A new imaging study reveals that this region is the left caudate — a finding supported by case studies of bilingual patients with damage to the left caudate, who are prone to switch languages involuntarily.
The study appeared in the June 9 issue of Science. Full reference
http://sciencenow.sciencemag.org/cgi/content/full/2006/608/2?etoc

Asymmetrical brains let fish multitask

A fish study provides support for a theory that lateralized brains allow animals to better handle multiple activities, explaining why vertebrate brains evolved to function asymmetrically. The minnow study found that nonlateralized minnows were as good as those bred to be lateralized (enabling it to favor one or other eye) at catching shrimp. However, when the minnows also had to look out for a sunfish (a minnow predator), the nonlateralized minnows took nearly twice as long to catch 10 shrimp as the lateralized fish.
The research was reported online 19 June in Animal Behaviour. Full reference
http://sciencenow.sciencemag.org/cgi/content/full/2006/623/2?etoc

Primates take weather into account when searching for fruits

In recent times, a popular hypothesis for why primates, and especially humans, have more strongly developed cognitive skills than other mammals, is that they result from the need for complex social skills. There is quite a lot of support for this argument. But it is not the only possibility and a recent study has looked at an alternative: that it evolved to deal with ecological problems, such as foraging for food. Researchers followed a group of wild gray-cheeked mangabeys from dawn to dusk over 210 days in their natural rainforest habitat, obtaining an almost complete record of their foraging decisions in relation to their preferred food, figs. The findings are consistent with the idea that monkeys make foraging decisions on the basis of episodic ("event-based") memories of whether or not a tree previously carried fruit, combined with knowledge of recent and present weather conditions and a more generalized understanding of the relationship between temperature and solar radiation and the maturation rate of fruit and insect larvae.
The report appeared in the June 20th issue of Current Biology. Full reference
http://www.eurekalert.org/pub_releases/2006-06/cp-ptw061406.php

Connections between neurons act as information filters in the brain

Synapses — the connections between brain cells — have long been known to be important in information-processing, but the exact nature of their role has not been clear. Are they a crucial part of the processing itself, or simply part of the transport system? Worryingly, research has suggested that synapses drop up to 90% of all incoming signals — an unreliability difficult to reconcile with the fact that brain as a whole is very reliable. A new study has cast new light on synaptic activity. It turns out that synaptic transmission is highly temperature-dependent. Previous studies had studied isolated groups of neurons at room temperature; the present study recorded data at wormer conditions — almost body temperature. And revealed that excitatory and inhibitory synapses, previously thought to always work against each other, in fact act in concert to identify patterns carrying relevant information in an incoming signal. As a result, meaningful patterns are amplified, and stray noise is discarded. This provides the experimental confirmation needed, for the view that synapses act to filter the “noise” and makes the information processing reliable.
The report appeared in PLoS Biology. Full reference
http://www.eurekalert.org/pub_releases/2006-06/si-cbn060906.php
Full text available at: http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pbio.0040207

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