Brain Imaging Study Supports the “Cognitive Reserve” Hypothesis

Individuals with higher education levels appear to score higher on cognitive tests despite having evidence of brain plaques associated with Alzheimer’s disease, according to a report in the November issue of Archives of Neurology, one of the JAMA/Archives journals.

Newswise— Individuals with higher education levels appear to score higher on cognitive tests despite having evidence of brain plaques associated with Alzheimer’s disease, according to a report in the November issue of Archives of Neurology, one of the JAMA/Archives journals.

The cognitive reserve hypothesis holds that individuals with greater cognitive (thinking, learning and memory) abilities are able to delay symptoms of Alzheimer’s disease despite underlying changes in the brain, according to background information in the article. Education is commonly used as a substitute measure of cognitive reserve. “Adjusting for level of Alzheimer disease pathological burden determined at autopsy, greater education has been associated with better cognitive function during life,” the authors write. “Education interacts with Alzheimer disease pathological burden such that a greater pathological burden is required to show an effect on cognition among persons with more education.”

Catherine M. Roe, Ph.D., and colleagues at the Washington University School of Medicine, St. Louis, studied 37 individuals with dementia of the Alzheimer type and 161 individuals without dementia between 2003 and 2008. Participants reported their education history and took cognitive tests. They were injected with a marker known as carbon 11–labeled Pittsburgh Compound B ([11C]PiB) and then underwent a 60-minute positron emission tomography (PET) scan of the brain. Recent studies have shown that [11C]PiB adheres to beta-amyloid brain plaques associated with Alzheimer’s disease, allowing researchers to identify these characteristics of the disease in living patients.

The level of [11C]PiB uptake interacted significantly with years of education in predicting cognitive test scores. Among individuals whose brains took up higher levels of [11C]PiB, indicating the presence of beta-amyloid plaques, performance on the test increased with increasing education levels. Education was not associated with cognitive scores among those with low [11C]PiB uptake, indicating no plaques.

“The results support the hypothesis that cognitive reserve influences the association between Alzheimer disease pathological burden and cognition,” the authors write. “Based on autopsy data, there may be a ceiling effect when extensive beta-amyloid pathological burden is present as in late-stage dementia of the Alzheimer type. Presumably, as the Alzheimer disease pathological burden increases, a greater proportion of highly educated participants reaches the threshold for dementia and the initial advantage provided by cognitive reserve decreases. Longitudinal imaging of beta-amyloid pathology in vivo will soon allow us to determine whether these inferences from cross-sectional studies are accurate.”

Reference: Arch Neurol. 2008;65[11]:1467-1471

Smoking and the Brain

By Gregory Kellett, a cognitive neuroscience researcher at SFSU and UCSF, and science writer for Lumos Labs.

A recent research review to be published in the journal Progress in Neuropsychopharmacology & Biological Psychiatry shows a link between cigarette smoking and adverse changes in the function and physiology of the brain. Summarizing the findings of dozens of experiments, the review indicates that:

• Strokes are more prevalent in smokers than non-smokers.
• Gray matter (made up of brain cells) shrinks in long-term smokers.
• Smoking is associated with less integrity in the white matter connecting brain hemispheres.
• Puffing tobacco can be bad for neurotransmitters.

There are a few factors clouding the picture however. These include the fact that alcohol consumption often accompanies cigarette smoking and has also been shown to have detrimental effects on the brain.

In addition there is the question of which comes first: brain abnormalities or smoking habits. It is possible that preexisting brain abnormalities increase the likelihood of smoking and addiction.  The author suggested more research in order to answer these questions, as well as to determine if these symptoms are reversible after quitting.

References:

Domino, E. (2008). Tobacco Smoking and MRI/MRS Brain Abnormalities Compared to Nonsmokers. Progress in Neuro-Psychopharmacology and Biological Psychiatry, In press.

Musicians, Creativity and Balanced Brain Use

By Gregory Kellett, a cognitive neuroscience researcher at SFSU and UCSF, and science writer for Lumos Labs.

Research just published in the journal Brain and Cognition suggests that musical training can lead to more creative thinking and more symmetrical brain activity. The investigators, based out of Vanderbilt University in Nashville Tennessee, ran two experiments both comparing 20 musicians (with a minimum of 8 years of musical experience) with 20 non-musicians.

The first looked at potential differences in creative abilities by asking participants to come up with as many novel uses of common household items as possible, followed by their completing a word association task.

The second study monitored brain blood flow via near infrared spectroscopy (NIRS) while participants again generated as many novel uses of everyday objects as possible.

The data indicated that:

• On average the musicians were able to generate about 13 more examples of how to use common objects than non-musicians.
• The musicians performed better on the word association task, producing an average of approximately 9 more correct responses than their non-musical counter parts.
• Overall, during the creative tasks, musicians showed more symmetrical brain blood flow between the hemispheres than the non-musicians.

Although it is always possible that creative people tend to be more drawn to the world of music than non-creative people, the authors suggest that the results might be due to the ability of certain aspects of music training, such as improvisation and song creation, to enhance cognitive and neural mechanisms of the creative process.

References:

Gibson, C., Folley, B. S., & Park, S. (2008). Enhanced divergent thinking and creativity in musicians: A behavioral and near-infrared spectroscopy study. Brain and Cognition.

Surgical Gaming

By Gregory Kellett, a cognitive neuroscience researcher at SFSU and UCSF, and science writer for Lumos Labs.

Video game play seems to be related to better surgical skills according to research showcased at the recent Annual Convention of the American Psychological Association.

Iowa State University psychologist Douglas Gentile, PhD, ran an experiment looking at the video game experience of 33 budding surgeons and how this related to performance during surgical training.

The numbers showed that:

• Past video game play in excess of 3 hrs/wk correlated with 37% fewer errors and a 27% increase in speed (over non-video-game players) during training exercises.

• Video game skill (as measured by high scores) were a significant predictor of demonstrated surgical skills.

Although this doesn’t necessarily translate as cause and effect, it seems plausible that exercising fine motor control, visual attention processing, reaction time, hand-eye coordination and 2-dimensional depth perception might just improve one’s ability to wield a scalpel.

References:

Rosser, J. C., Lynch, P. J., Cuddihy, L., Gentile, D. A., Klonsky, J., & Merrell, R. (2007). The Impact of Video Games on Training Surgeons in the 21st Century. Arch Surg, 142(2), 181-186.

Dorval, M., & Pépin, M. (1986). Effect of playing a video game on a measure of spatial visualization. Perceptual and Motor Skills, 62(1), 159-62.

Intelligence training

By Gregory Kellett, a cognitive neuroscience researcher at SFSU and UCSF, and science writer for Lumos Labs.

A study conducted by Martin Buschkuehl and Susanne Jaeggi in John Jonides’ lab at the University of Michigan indicates that it is possible to improve on measures of fluid intelligence by training one’s working memory.

The concept of fluid intelligence (gF) as defined by its founder Raymond Cattell is “…the ability to perceive relationships independent of previous specific practice or instruction concerning those relationships.” Fluid intelligence contributes to abilities like learning and problem solving. It is distinct from its counterpart, crystallized intelligence (cF) which involves  “…abilities that have obviously been acquired, such as verbal and numerical ability, mechanical aptitude, social skills, and so on.”

Fluid intelligence tests usually entail completing visual patterns of some kind.  Performance on such tests typically declines after reaching a peak in early adulthood.  This study, however, offers evidence that it’s possible to improve fluid intelligence, at least temporarily.

The researchers used a computer-based working memory task called the “dual n-back” to simultaneously administer auditory and visual stimuli in sequence.  A response was required whenever one of the presented stimuli (visual or auditory) matched a previously presented stimulus n positions back in the sequence.  Four groups trained daily for either 8, 12, 17 or 19 days, with each group being matched by a control group that did not have training.  Pre and post tests of fluid intelligence were given to all groups.

What the study found:

• The working memory training significantly improved performance on the fluid intelligence tests.
• Fluid intelligence performance improved in proportion to the amount of training received.
• Working memory (as measured by digit span) also improved significantly.

The authors suggest that the above effects were due primarily to an increased ability to control attention.

References:

Cattell, R. B. (1971). Abilities: Their structure, growth, and action. New York: Houghton Mifflin.

Jaeggi, S., Buschkuehl, M., Jonides, J., Perrig, J. (2008). “Improving fluid intelligence with training on working memory.” PNAS- Proceedings of the National Academy of Sciences

Genetic Component of Alzheimer’s Disease

By Lumos Labs Science Associate, Paul Li, MS Neuroscience.

There is some new evidence that Alzheimer’s disease is much more likely for people whose parents both have the neurodegenerative disorder than if only one parent has it. Researchers examined families in which both parents have Alzheimer’s, and found that their children ended up with the disease 42% of the time.

This finding supports the evidence that genes play an important role in determining whether you end up with Alzheimer’s. One of the genetic components responsible for the disease is known as the gene Apolipoprotein E (ApoE). Fortunately your genes do not entirely determine your fate. Your lifestyle is important too, and although we do not have control of our genetic makeup, we can control how we live. With the proper cognitive and physical exercise, brain food, and even attitude toward life, one can better buffer their brain from later years of cognitive decline and delay the risk of dementia.

The incidence of Alzheimer’s increases with age, and is typically diagnosed after the age of 65. By then, there’s not much you can do to slow the disease. So what can you do earlier to help your chances of preserving cognitive function? For me personally, I have been implementing some of the brain health tips on this blog, as well as training my brain with Lumosity, as part of my daily routine. This is not just to practice what I preach, but rather to address a concern I have when I constantly need to remind my parents about certain things, such as taking their meds. I’d rather start my cognitive training regimen early so that when I someday reach my parents’ age my brain will be in the best condition it can be.

Brain activity across languages

By Lumos Labs Science Associate, Paul Li, MS Neuroscience.

Different languages are represented differently across the brain. This is especially true for languages that are very dissimilar, such as English and Chinese. English is learned from pronouncing its 26-letter alphabet, whereas to learn the Chinese language, one needs to memorize thousands of characters in order to understand a string of pictographs.

Dyslexia, a learning disability that causes difficulty in reading and writing, affects the brain in different ways according to language. Professor Li-Hai Tan, along with his research team from the University of Hong Kong, discovered that Chinese-speaking dyslexics have a different pattern of brain activity than English-speaking dyslexics. Professor Tan told Lumos Labs that “the left middle frontal gyrus, rather than the posterior brain regions, is a perpetrator of reading disorders in Chinese, suggesting the possibility that a person who is dyslexic in Chinese reading would not be in alphabetic language reading, and vice versa.” One implication is that different interventions may be more or less suitable depending on language. 

Berkeley’s Mind Reader

By Lumos Labs Science Associate, Paul Li, MS Neuroscience.

Movies like Being John Malkovich are based on the idea that one might be able to experience what another human’s mind is visualizing. Most would think that such movies are pure fantasy and science fiction, but researchers at U.C. Berkeley are one step closer to making this a reality.

Using a computational model calibrated to each individual subject, Professor Jack Gallant and his research team were able to use brain activity (measured with fMRI) to identify which of a large set of images was seen by a subject. Importantly, none of the images in the set had been previously seen by the subject, demonstrating the ability to generalize to novel situations. Though performance isn’t yet perfect, it’s impressive. Accuracy ranges from 80% when viewing 1,000 images, to 90% accuracy when viewing 120 images.

Dr. Gallant said, “there may theoretically be sufficient information available to decode memory, imagery and dreams some day, but it will likely be many decades before this is really possible.”