News reports of research into memory November 2005

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November 2005

'Sharp' older brains are not the same as younger brains

We know that many older adults still retain the mental sharpness of younger people, but studies comparing brain activity in older and younger adults suggest they perform differently. A rat study has now found the first solid evidence that still "sharp" older brains do indeed store and encode memories differently than younger brains. Comparison of those older rats who had retained their cognitive abilities with those who had not, also revealed that those with impaired cognition had lost the ability to modify the strength of the communications between synapses (synaptic communication is the means by which memories are encoded and stored). But the competent seniors also differed from the younger rats in the mechanism most used to bring about synaptic change.
The findings were reported online November 13 in Nature Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2005-11/jhu-ob110905.php

Common cholesterol-lowering drug reverses learning disabilities in mice

Following their discovery that neurofibromatosis 1 (NF1) — the leading genetic cause of learning disabilities — is linked to dysfunction in a protein called Ras, researchers have successfully used a commonly prescribed cholesterol-lowering statin drug (lovastatin) to reverse the learning deficits in mice. Clinical trials with humans are being planned.
The report appeared in the November 8 issue of Current Biology. Full reference
http://www.eurekalert.org/pub_releases/2005-11/uoc--rf110405.php
http://www.newscientist.com/channel/health/dn8276

Use of heart pump during bypass surgery not implicated in cognitive decline

A study involving 380 individuals has found that those patients undergoing coronary artery bypass grafting (CABG) surgery that used a cardiopulmonary heart pump had no significant differences in their mental functions compared to CABG patients whose surgery did not involve a heart pump. Patients with coronary heart disease all performed lower on cognitive tests than healthy controls, prior to surgery. By three months, both cardiac patients who had undergone surgery (with or without use of a heart pump) and those who had not, had improved cognitive function.
The study was published in the issue of Neurology. Full reference
http://www.eurekalert.org/pub_releases/2005-11/jhmi-hsf110905.php

Smarter kids may live longer

A prospective study that recruited 897 individuals who scored 135 or higher on the Stanford-Binet IQ test in 1922 has found that higher IQs were associated with longevity, with the survival advantage leveling off after a childhood IQ of 163. The association was independent of childhood social position (as measured by father’s occupation). The study confirms earlier research suggesting an association between IQ and mortality, and provides the new finding of where the cut-off point (when high IQ no longer brought additional health benefits) appears — the cutoff of 163 was much higher than expected. Suggested reasons for the association (all of which may well be valid) include: greater tendency to adopt healthy habits and avoid bad ones; increased probability of better jobs; better skills for managing their health and the health-care system.
The findings were reported in the November issue of the American Journal of Epidemiology. Full reference
http://health.yahoo.com/news/126478

Early gaze-following associated with early language

The ability to detect the direction of another's glance has been recognized as a crucial component of human social interaction for some time. New research now reveals that babies start to follow the movement of another person’s head at around 9 months, and by 10-11 months they follow the head and eyes. Sometimes they will make sounds as they follow the gaze. Those who simultaneously followed the eyes of the researcher and made vocalizations when they were 10 or 11 months old understood an average of 337 words at 18 months old while the other babies understood an average of only 195 words.
The study appeared in the November issue of Developmental Science. Full reference
http://www.eurekalert.org/pub_releases/2005-11/uow-wic110905.php

Early cognitive tests of premature babies predict later development

A number of studies have shown that premature birth increases a child's risk of learning and other cognitive disabilities, including lower IQ, language delay, poorer school achievement and learning disabilities. A new study has now found that early cognitive deficits apparent at 7 months (such as poorer attention, slower processing speed and poorer recognition memory) fully account for lower cognitive scores of 2- and 3-year-olds. This suggests that cognitive difficulties can be identified early, with the hope of successful intervention.
The study was published in the November/December issue of Child Development. Full reference
http://www.eurekalert.org/pub_releases/2005-11/sfri-ort110805.php

Breakdown of myelin insulation in brain's wiring implicated in childhood developmental disorders

Previous research has suggested that the production of myelin (a fatty insulation coating the brain's internal wiring) is a key component of brain development through childhood and well into middle age, when development peaks and deterioration begins, and that midlife breakdown of myelin is implicated to onset of Alzheimer's disease later in life. Now new research suggests the disruption of myelination is a key neurobiological component behind childhood developmental disorders, such as autism and attention deficit/hyperactivity disorder, and addictive behaviors. The analysis also suggests that alcohol and other drugs of abuse have toxic effects on the myelination process in some adolescents.
The paper will be published in the annual publication Adolescent Psychiatry (The Analytic Press). Reference
http://www.eurekalert.org/pub_releases/2005-11/uoc--bom111405.php

Kids can remember events even if they can't remember times

How do we remember when an event has occurred? Most of the time we do it by reconstructing the event and inferring the time from details stored. Given that, it should perhaps be no surprise to learn that while children aged 4 through 13 can recall the details of an event fairly well, they are unable to extrapolate further and link those details with a specific time of year, even when it occurs around a major holiday. The finding has implications for legal testimony, where lawyers are inclined to cast doubt on memories if the child is unable to recall when the event occurred.
The study was published in the November/December issue of Child Development. Full reference http://www.eurekalert.org/pub_releases/2005-11/sfri-kcr110805.php

Discovery disproves simple concept of memory as 'storage space'

The idea of memory “capacity” has become more and more eroded over the years, and now a new technique for measuring brainwaves seems to finally knock the idea on the head. Consistent with recent research suggesting that a crucial problem with aging is a growing inability to ignore distracting information, this new study shows that visual working memory depends on your ability to filter out irrelevant information. Individuals have long been characterized as having a “high” working memory capacity or a “low” one — the assumption has been that these people differ in their storage capacity. Now it seems it’s all about a neural mechanism that controls what information gets into awareness. People with high capacity have a much better ability to ignore irrelevant information.
The finding was published in the November 24 issue of Nature. Full reference
http://www.eurekalert.org/pub_releases/2005-11/uoo-dds111805.php

What we perceive is not what we sense

Perceiving a simple touch may depend as much on memory, attention, and expectation as on the stimulus itself. A study involving macaque monkeys has found that the monkeys’ perception of a touch (varied in intensity) was more closely correlated with activity in the medial premotor cortex (MPC), a region of the brain's frontal lobe known to be involved in making decisions about sensory information, than activity in the primary somatosensory cortex (which nevertheless accurately recorded the intensity of the sensation). MPC neurons began to fire before the stimulus even touched the monkeys' fingertips — presumably because the monkey was expecting the stimulus.
The report was published early online on November 6 in Nature Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2005-11/hhmi-tsi110405.php

Preconditioning could prevent injury to dendrites in neurological diseases

New research has revealed a previously unknown mechanism by which brain cells can be damaged during chronic neurodegenerative diseases such as Alzheimer's, multiple sclerosis, Parkinson's and dementia associated with HIV. When inflammation occurs in the brain, nerve impulses can become toxic. Instead of triggering the formation of memories, these impulses can inflict injury on neurons and disrupt neural function. Understanding this mechanism could provide a new path for drugs to treat the diseases, perhaps by chemical preconditioning to induce adaptations in nerve cells that would enable the cells to better withstand toxic attacks, prevent injury, and preserve function.
The report appeared in the November 1 issue of The Journal of Clinical Investigation. Full reference
http://www.eurekalert.org/pub_releases/2005-11/uorm-ssh110305.php

More light on adult neurogenesis; implications for dementia and brain injuries

New research has demonstrated that adult mice produce multi-purpose, or progenitor, cells in the hippocampus, and indicates that the stem cells ultimately responsible for adult hippocampal neurogenesis actually reside outside the hippocampus, producing progenitor cells that migrate into the neurogenic zones and proliferate to produce new neurons and glia. The finding may help in the development of repair mechanisms for people suffering from dementia and acquired brain injury.
The study appeared as the cover story in November 23 issue of the Journal of Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2005-11/ra-nrt112305.php

'Perception' gene tracked humanity's evolution

A gene thought to influence perception and susceptibility to drug dependence is expressed more readily in human beings than in other primates, and this difference coincides with the evolution of our species. The gene encodes prodynorphin, an opium-like protein implicated in the anticipation and experience of pain, social attachment and bonding, as well as learning and memory. Although the protein prodynorphin is identical in humans and chimps, in the gene's promoter sequence (that controls how much of the protein is expressed) some 10% is different (this compares to the overall 1 to 1.5% difference between human and chimpanzee genes). There is high genetic variation in the prodynorphin promoter among humans, but not among other primates. Variants have been tentatively linked to schizophrenia, cocaine addiction, and epilepsy. The report supports a growing consensus among evolutionary anthropologists that hominid divergence from the other great apes was fueled not by the origin of new genes, but by the quickening (or slowing) of the expression of existing genes.
The report was published online 15 November in Public Library of Science Biology. Full reference
Full text available at http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pbio.0030387
http://www.eurekalert.org/pub_releases/2005-11/iu-gt111405.php

Conference papers

Coffee jump-starts short-term memory

An imaging study of 15 males aged 26-47 has found that after consuming caffeine, all showed improved reaction times, and increased activity in part of the frontal lobe and in the anterior cingulate cortex. The findings are consistent with earlier research showing caffeine improves attention.
The study was presented at the annual meeting of the Radiological Society of North America in Chicago. Reference
http://www.eurekalert.org/pub_releases/2005-11/rson-cjs112005.php

Estrogen levels affect hippocampal wiring

Many studies have established the role of estrogen in female cognition. A rat study has now revealed the reason. It appears that the "wiring" in the hippocampus expands and retracts in relation to the amount of estrogen present during the estrous/menstrual cycle. The findings also suggest that “the brain's capacity for growth is well beyond anything we considered in the past”.
The study was presented at the 2005 Society for Neuroscience Meeting in Washington, D.C. Reference
http://www.eurekalert.org/pub_releases/2005-11/nu-bma111405.php

Carotid artery stenting improves thought process

Around a quarter of strokes are caused by a narrowing of the carotid arteries. A less invasive technique — carotid artery stenting — is increasingly taking the place of surgery to treat this problem. A study involving 26 patients who had undergone the procedure has tested their cognitive function at least 24 hours before and three months after the stenting procedure. The results showed that cognitive speed increased significantly after stenting, regardless of the patient's age or the severity of the stenosis, and an increase in memory function in patients with decreased blood flow in the brain.
The research was presented at the annual meeting of the Radiological Society of North America. Reference
http://www.eurekalert.org/pub_releases/2005-11/rson-cas112005.php

Lifelong mild exercise decreases cellular aging in the brain

A rat study has provided evidence that regular, light exercise (say a daily 30-minute walk or a light 1-mile run) decreases cellular aging in the brain. Those rats who had had access to an exercise wheel during their lives showed fewer byproducts of oxidative stress in their brains, and their DNA at two years resembled that of their 6 month old counterparts.
The research was presented at the Society for Neuroscience's 35th annual meeting in Washington, D.C.
http://www.eurekalert.org/pub_releases/2005-11/uof-lea110905.htm

New 'eye movement' test may help treat fetal alcohol syndrome

At present there are no objective diagnostic tools that can be used to distinguish between children with Fetal Alcohol Spectrum Disorder (FASD) and those with other developmental disorders such as Attention-Deficit Hyperactivity Disorder (ADHD). Many of the behavioural tests used to assess children with FASD are geared to white, middle-class English-speaking people. Now a pilot study involving 25 children aged 8-12 has found that the specific brain abnormalities associated with FASD can be identified using a simple test that measures eye movement.
The findings were presented at the annual meeting of the international Society for Neuroscience in Washington, D.C. Reference
http://www.eurekalert.org/pub_releases/2005-11/qu-nm111105.php

Stress interferes with problem-solving; Beta-blocker may help

New research suggests that an experience as simple as watching graphically violent or emotional scenes in a movie can induce enough stress to interfere with problem-solving abilities, and that a beta-blocker medication could promote the ability to think flexibly under stressful conditions. Neither the stress nor the beta-blocker affected memory. The research not only has implications for understanding the range of effects of stress on thinking, but could also have broader clinical implications for patients with anxiety disorders or substance abuse problems.
The research was presented at the annual Society for Neuroscience meeting in Washington, D.C. Reference
http://www.eurekalert.org/pub_releases/2005-11/osu-siw110905.php

Playing music helps the understanding of language

A study involving adult musicians and non-musicians matched by age, sex, general language ability and intelligence found that musicians could make the rapid auditory distinctions necessary to distinguish similar word syllables (like "da" and "ba") more accurately and quickly than non-musicians. This is the first study to demonstrate that musical training improves how the brain processes the spoken word. The researchers suggest the finding could lead to improving the reading ability of children who have dyslexia and other reading problems.
The research was presented at the Society for Neuroscience's annual meeting in Washington, D.C. It will be published in the Annals of the New York Academy of Sciences in December. Reference
http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2005/11/17/MNGQ9FPODP1.DTL

ADDERALL XR significantly improves driving performance, attention in young adults with ADHD

ADDERALL XR® significantly improved driving performance, cognitive function and attention in young adults with attention-deficit/hyperactivity disorder (ADHD) in a controlled driving simulator study. An earlier study found that adults with ADHD had a significant higher incidence of traffic violations, and license suspensions than patients without ADHD — ADHD patients were five times more likely than non-ADHD patients to have five or more speeding tickets and three times more likely to have had three or more vehicular crashes.
The findings werepresented at the 18th Annual U.S. Psychiatric & Mental Health Congress in Las Vegas, NV. Reference
http://www.eurekalert.org/pub_releases/2005-11/pn-axs110805.php

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