Latest Research News

A study involving 236 persons with multiple sclerosis has found that only 7% of those with secondary-progressive MS showed sufficient vitamin D in their blood, compared to 18.3% of patients with the less severe relapsing-remitting type, and that higher levels of vitamin D3 and its byproducts were associated with better scores on cognitive tests (especially reasoning and planning), and less brain atrophy and fewer brain lesions. Lower-than-normal vitamin D status is known to be associated with a higher risk of developing MS

A five-year study involving 214 children born to healthy, non-smoking Caucasian women in Krakow, Poland, has found that those prenatally exposed to high levels of polycyclic aromatic hydrocarbons (PAHs) had a significant reduction in scores on a standardized test of reasoning ability and intelligence at age 5 (an estimated average decrease of 3.8 IQ points). The mothers wore small backpack personal air monitors for 48 hours during pregnancy to estimate their babies' PAH exposure.

Great news for those who crave the benefits of meditation but find the thought a bit intimidating! While a number of studies have demonstrated that long-term mindfulness meditation practice promotes executive functioning and the ability to sustain attention, now a small study involving 49 students has found that as little as four sessions of 20 minutes produced a significant improvement in critical cognitive skills, compared to those who spent an equal amount of time listening to Tolkien's The Hobbit being read aloud.

A six-week study got a lot of press last month. The study involved some 11,000 viewers of the BBC's science show "Bang Goes the Theory", and supposedly showed that playing online brain games makes you no smarter than surfing the Internet to answer general knowledge questions. In fact, the main problem was the media coverage.

In other words, what's important is the time of day you hear/see/read something, not when you try and remember it.

  • information learned in the morning shows better immediate retention, but worse long-term retention
  • short-term memory appears to improve as arousal levels fall

Three experiments investigated whether the time of day had an effect on short-term or long-term memory.

Folkard, S. & Monk, T.H. (1978). Time of day effects in immediate and delayed memory. In M. M. Gruneberg, P. E. Morris & R.N. Sykes (eds.). Practical aspects of memory. London: Academic Press.

Despite the popularity of brainstorming as a strategy for producing ideas and new perspectives, it appears that participation in a group actually reduces the number of ideas produced (compared to the number of ideas that would be produced if the participants thought independently)1.

Three possible explanations have been investigated:

Basden, B.H., Basden, D.R., Bryner, S. & Thomas, R.L. III (1997). A comparison of group and individual remembering: Does collaboration disrupt retrieval strategies? Journal of Experimental Psychology: Learning, Memory and Cognition, 23, 1176-1189.

It is common for people to feel as they get older that they more frequently experience occasions when they cannot immediately retrieve a word they know perfectly well ("it's on the tip of my tongue").

Burke, D.M., MacKay, D.G., Worthley, J.S. & Wade, E. (1991). On the tip of the tongue: What causes word finding failures in young and older adults. Journal of Memory and Language, 30, 542-579.

Although we initially tend to pay attention to obvious features such as hair, it has been long established that familiar faces are recognized better from their inner (eyes, nose, mouth) rather than their outer (hair, hairline, jaw, ears) parts1. Studies have shown that this advantage of inner features does not occur in children until they’re around 10—11 years old. Children younger than this tend to use outer features to recognize people they know2.

Campbell, Ruth, Coleman, Michael, Walker, Jane, Benson, Philip J., Wallace, Simon, Michelotti, Joanne & Baron-Cohen, Simon. 1999. When does the inner-face advantage in familiar face recognition arise and why? Visual Cognition, 6(2), 197-216.

It has been well-established that, compared to younger adults, older adults require more practice to achieve the same level of performance1. Sometimes, indeed, they may need twice as much2.

In the present study, two groups of adult subjects were given paired items to learn during multiple study-test trials. During each trial items were presented at the subject's pace. Afterwards the subjects were asked to judge how likely they were to be able to recall each item in a test.

Dunlosky, J. & Connor, L.T. (1997). Age differences in the allocation of study time account for age differences in memory performance. Memory and Cognition, 25, 691-700.

The effect of smell on learning and memory was investigated in an experiment that used three different ambient odors (osmanthus, peppermint, and pine).

Osmanthus was used to see whether there was a difference in performance depending on whether the smell was novel or familiar. Peppermint and pine were used to see whether the appropriateness or inappropriateness of the smell made a difference to memory.

Herz, R.S. (1997). The effects of cue distinctiveness on odor-based context dependent memory. Memory and Cognition, 25, 375-380.

There is a pervasive myth that every detail of every experience we've ever had is recorded in memory. It is interesting to note therefore, that even very familiar objects, such as coins, are rarely remembered in accurate detail1.

We see coins every day, but we don't see them. What we remember about coins are global attributes, such as size and color, not the little details, such as which way the head is pointing, what words are written on it, etc. Such details are apparently noted only if the person's attention is specifically drawn to them.

Modigliani, V., Loverock, D.S. & Kirson, S.R. (1998). Encoding features of complex and unfamiliar objects. American Journal Of Psychology, 111, 215-239.

When we tell people about things that have happened to us, we shape the stories to our audience and our purpose. The amount of detail we give and the slant we give to it depends on our perceptions of our audience and what we think they want to hear. Does this change our memory for the event? Certainly we are all familiar with the confusion we get after we have been telling a particular story for years — we’re no longer sure what really happened and what we’ve added or subtracted to make a better story.

Tversky, Barbara & Marsh, Elizabeth J. 2000. Biased retellings of events yield biased memories. Cognitive Psychology, 40, 1-38.

A number of studies have demonstrated the effectiveness of the keyword mnemonic for short-term recall, for example:

Wang, A.Y. & Thomas, M.H. (1995). Effect of keywords on long-term retention: help or hindrance? Journal of Educational Psychology, 87, 468-475.

When a group of people work together to remember an event, the group do appear to recall more than an individual working alone, but do they recall more than the sum of the memories each individual recalls?

Studies have found that "brainstorming" groups actually produce fewer ideas than groups that are groups in name only1. And in many tasks, from rope-pulling to vigilance tasks, it has been found that people contribute less when they are part of a group than when they are working alone2.

Weldon, M.S. & Bellinger, K.D. (1997). Collective and individual processes in remembering. Journal of Experimental Psychology: Learning, Memory and Cognition, 23, 1160-1175.

It has long been known that spacing practice (reviewing learning or practicing a skill at spaced intervals) is far more effective than massed practice (in one heavy session). It is also well-known that people commonly over-estimate the value of massed practice, and tend not to give due recognition to the value of spacing practice, despite the fact that most memory improvement and study programs advise it.

Landauer, T.K. & Ross, B.H. (1977). Can simple instructions to use spaced practice improve ability to remember a fact? An experimental test using telephone numbers. Bulletin of the Psychonomic Society, 10, 215-218.

Seventh graders given 20 mg zinc, five days per week, for 10 to 12 weeks showed improvement in cognitive performance, responding more quickly and accurately on memory tasks and with more sustained attention, than classmates who received no additional zinc. Those who received only 10mg a day did not improve their performance. Previous studies have linked zinc nutrition to motor, cognitive and psychosocial function in very young children and adults, but this is the first study of its effect in adolescents.

A preliminary study suggests that a regime of high doses of folic acid, B12 and B6 reduces levels of homocysteine in people with mild to moderate Alzheimer’s. A larger study, recruiting 400 participants from all over the U.S., is to be undertaken to assess whether such a vitamin regime can slow the progression of Alzheimer's disease. In the meantime, it is not advised that people take high doses of these vitamins, as there are possible side-effects, including peripheral nerve damage.

A study of over 3,100 older men (49-71) from across Europe has found that men with higher levels of vitamin D performed consistently better in an attention and speed of processing task. There was no difference on visual memory tasks. Although previous studies have suggested low vitamin D levels may be associated with poorer cognitive performance, findings have been inconsistent. Vitamin D is primarily synthesised from sun exposure but is also found in certain foods such as oily fish.

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.

A chemical called methionine (an amino acid found in beta-amyloid) may be the source of the toxic free radicals produced by the amyloid-beta peptide. Recent studies have demonstrated that higher than normal doses of vitamin E may slow the advance of Alzheimer's in some people with late stages of the disease. The current study provides a possible explanation for this link. Vitamin E, an antioxidant, appears to work by destroying free radicals (oxidants) produced by amyloid.

Two studies have come out in favor of a diet rich in foods containing vitamin E to help protect against Alzheimer's disease. One study involved 815 Chicago residents age 65 and older with no initial symptoms of mental decline, who were questioned about their eating habits and followed for an average of about four years. When factors like age and education were taken into account, those eating the most vitamin E-rich foods had a lower risk of developing Alzheimer’s, provided they did not have the ApoE e4 allele. This was not true when vitamin E was taken as a supplement.

A theory that changes in fat metabolism in the membranes of nerve cells play a role in Alzheimer's has been supported in a recent study. The study found significantly higher levels of ceramide and cholesterol in the middle frontal gyrus of Alzheimer's patients. The researchers suggest that alterations in fats (especially cholesterol and ceramide) may contribute to a "neurodegenerative cascade" that destroys neurons in Alzheimer's, and that the accumulation of ceramide and cholesterol is triggered by the oxidative stress brought on by the presence of the toxic beta amyloid peptide.

A study involving 4,740 elderly (65 years or older) found the greatest reduction in both prevalence and incidence of Alzheimer's in those who used individual vitamin E and C supplements in combination, with or without an additional multivitamin. There was no significant benefit in using vitamin C alone, vitamin E alone, or vitamin C and multivitamins in combination.

A guinea pig study has found that newborn guinea pigs subjected to moderate vitamin C deficiency had 30% fewer hippocampal neurons and markedly worse spatial memory than guinea pigs given a normal diet. For several reasons the neonatal brain is thought to be particularly vulnerable to even a slight lowering of the vitamin C level. Vitamin C deficiency is very common in some parts of the world, and even in wealthy nations occurs in an estimated 5-10% of the adult population.

The nutrient choline is known to play a critical role in memory and brain function by positively affecting the brain's physical development through increased production of stem cells (the parents of brain cells). New research demonstrates that this occurs through the effect of choline on the expression of particular genes. The important finding is that diet during pregnancy turns on or turns off division of stem cells that form the memory areas of the brain. Developing babies get choline from their mothers during pregnancy and from breast milk after they are born.

A "cocktail" of dietary supplements (omega-3 fatty acids, uridine and choline) has been found to dramatically increase the amount of membranes that form brain cell synapses in gerbils. The treatment is now in human clinical trials. It is hoped that such treatment may significantly delay Alzheimer's disease. The treatment offers a different approach from the traditional tactic of targeting amyloid plaques and tangles. Choline can be found in meats, nuts and eggs, and omega-3 fatty acids are found in a variety of sources, including fish, eggs, flaxseed and meat from grass-fed animals.

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.

A mouse study has found that the diet of a pregnant mother, especially in regards to choline, can change the epigenetic switches that control brain development in the fetus. Pregnant mice received different diets during the period when a fetus develops its

A rat study has found that increased levels of magnesium in the brain improved many aspects of learning and memory in both young and old rats. Because it is difficult to boost brain magnesium levels with traditional oral supplements, the researchers developed a new magnesium compound, magnesium-L-threonate (MgT).

In this study, subjects were shown two sets of 12 color photographs of people’s faces (24 in total). Five minutes after seeing the last one, the subjects were then shown another 48 faces (one by one, as before) and had to say whether or not they had seen the face earlier. If so, they were asked whether they saw it in the first or second set of photographs. Half the subjects had been deprived of sleep for the previous 35 hours. Some of these had been given significant amounts of caffeine to offset their sleepiness.

Harrison, Yvonne & Horne, James A. 2000. Sleep loss and temporal memory. The Quarterly Journal of Experimental Psychology, 53A (1), 271-279.

A study of 20 flight attendants suggests that people who undergo repeated, frequent episodes of jet lag without sufficient recovery time between trips may develop actual tissue changes in the brain in an area that's involved in spatial orientation and related aspects of cognitive function. The extent to which this is due to sleep deprivation rather than time shifts per se is unknown. These findings may also be relevant to shift workers, medical trainees and others who work long hours.

A study involving adult male white-footed mice may help us understand seasonal dysfunctions such as seasonal affective disorder. The study found that those mice kept in artificial light conditions mimicking winter (8 hours of light per day) had impaired spatial memory compared to mice kept in “summer” conditions (16 hours per day). They also had, on average, smaller brains, with a proportionally smaller hippocampus, as well as changes in dendritic spine density in that region. Other types of memory did not appear to be affected.

A survey of 824 undergraduate students has found that those who were evening types had lower average grades than those who were morning types.

We know circadian rhythm affects learning and memory in that we find it easier to learn at certain times of day than others, but now a study involving Siberian hamsters has revealed that having a functioning circadian system is in itself critical to being able to remember. The finding has implications for disorders such as Down syndrome and Alzheimer's disease. The critical factor appears to be the amount of the neurotransmitter GABA, which acts to inhibit brain activity.

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