Latest Research News

A special supplement in the Journal of Alzheimer's Disease focuses on the effects of caffeine on dementia and age-related cognitive decline. Here are the highlights:

A mouse study has found memory restoration and lower levels of amyloid-beta in Alzheimer’s mice following only 1-2 months of caffeine treatment. The researchers talk of “ a surprising ability of moderate caffeine intake to protect against or treat AD”, and define moderate intake as around 5 cups of coffee a day(!).

Studies on the roundworm C. elegans have revealed that the molecules required for learning and memory are the same from C. elegans to mammals, suggesting that the basic mechanisms underlying learning and memory are ancient, and that this animal can serve as a testing ground for treatments for age-related memory loss. Intriguingly, a comparison of two known regulators of longevity — reducing calorie intake and reducing activity in the insulin-signaling pathway (achieved through genetic manipulation) — has found that these two treatments produce very different effects on memory.

A study comparing the brains 32 adult women with Anorexia Nervosa and 21 healthy women has revealed that when the women with anorexia were in a state of starvation they had less brain tissue (especially in grey matter) compared to the healthy women. Those who had the illness the longest had the greatest reductions in brain volume when underweight. Happily, these deficits began to reverse after several weeks of weight gain.

Data from more than 20,000 18-year-old Israeli men has revealed that IQ scores are lower in male adolescents who smoke compared to non-smokers, and in twin brothers who smoke compared to their non-smoking brothers. The average IQ for a non-smoker was about 101, while the smokers' average was about 94, with those who smoked more than a pack a day being lower still, at about 90. 28% of the sample smoked one or more cigarettes a day, 3% identified as ex-smokers, and 68% said they never smoked.

A study in which nearly 50 participants consumed either alcohol (.4 or .8 g/kg, around 2 or 4 glasses of wine) or a placebo drink, performed a memory task, then were shown a video of serious road traffic accidents, has found that those given the smaller amount of alcohol experienced more flashbacks during the next week than those given the larger amount of alcohol, and those given no alcohol.

It’s well established that we are better at recognizing faces of our own racial group, but a new study shows that this ability disappears when we’re mildly intoxicated. The study tested about 140 university students of Western European and east-Asian descent and found that recognition of different-race faces was unaffected by alcohol, yet both groups showed impaired recognition of own-race faces, bringing it down to about the same level of accuracy as for different-race faces. Those given a placebo drink were unaffected.

The largest ever trial of fish oil supplements has found no evidence that they offer benefits for cognitive function in older people. The British study enrolled 867 participants aged 70-80 years, and lasted two years. After two years, those receiving fish oil capsules had significantly higher levels of omega-3 fatty acids in their blood than those receiving placebo capsules. However, cognitive function did not decline in either group over the period. The researchers caution that it may be that more time is needed for benefits to show.

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.

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.

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.

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