Archive for January, 2014

Good News About Alzheimer’s and Dementia

January 28, 2014

About two-thirds of dementia cases are caused by Alzheimer’s. The next most common form is vascular dementia, which is caused by deterioration of the brain’s blood vessels and often involving minor strokes. There are some other subtypes and an increasing belief that dementia at very old ages typically involves different forms of disease. Good news about Alzheimer’s and dementia. How can this be? Well, according to research1 reported in the New Scientist, there is some good news.

The good news comes from two studies published in the medical journal, The Lancet. One study compared two surveys of dementia numbers in the United Kingdom done 20 years apart. A 1994 study led to the conclusion that there were about 650,000 people with the condition. Given the increase in average age of the population over the intervening years, using exactly the same tests and definitions, should have found 900,000 people dementia, but the count came up over 200,000 people short.

The other study examined the health of two groups of Danish people in their mid-90s, born a decade apart in 1905 and 1915. Although the two groups had similar physical health, those born in 1915 markedly outperformed the earlier group in cognitive tests. This second group was not stronger, but they were smarter.

So how can this be? The conjecture is that long term trends of rising prosperity, education, and better health are good for the brain. Special attention should be paid to higher education levels. They support the notion of a cognitive reserve that keeps the brain functioning at a high level despite mild physical deterioration.

These results, while good, should not be misinterpreted. Alzheimer’s and dementia still represent significant threats that need to be addressed. The good news is a relative one. That is, matters are not as bad as they were thought to be, but they are still pretty bad.

Moreover, the conjecture as to why there has been this improvement, points to activities and practices advocated by the healthymemory blog. Good physical health and diet are definitely important. The recommended diet is the heart healthy, or Mediterranean diet, rich in fruit and vegetables, with plenty of fish and not too much red meat or high calorie junk food. An unfortunate trend which is working against this good trend is the increase in obesity with the concomitant increase in diabetes. Some have spoken of Alzheimer’s as being a form of brain diabetes.

It should be understood that formal education is not required to build a cognitive reserve. An effort to grow the mind continually by having new experiences, learning new things through reading, technology and by interacting with fellow humans all serve to build a cognitive reserve. The healthymemory blog is dedicated to these activities.

1Drew, L. (2014). Down with dementia. New Scientist, 11 january, 32-35.

© Douglas Griffith and healthymemory.wordpress.com, 2014. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

Mindfulness Training Improves Working Memory Capacity and GRE Performance

January 25, 2014

An important experiment demonstrated that mindfulness training improves working memory capacity and Graduate Record Examination (GRE) performance while reducing mind wandering.1 Forty-eight undergraduates were randomly assigned to either a mindfulness class or a nutrition task. The mindfulness class emphasized physical posture and mental strategies of focused-attention meditation. It required participants to integrate mindfulness into their daily activities and to complete 10 minutes of daily meditation outside of class. Classes met four times a week for 45 minutes for two weeks. During class, participants sat on cushions in a circle. Each class included 10 to 20 minutes of mindfulness exercises requiring focused attention to some aspect of sensory experience (sensations of breathing, tastes of a piece of fruit, or sounds of an audio recording. Participants shared their experiences with the class and received personalized feedback from the instructor. Class content was designed to provide a clear set of strategies for and a conceptual understanding of how to practice mindfulness, Classes focused on sitting in an upright posture with legs crossed and gaze lowered, distinguishing between naturally arising thoughts and elaborated thinking, minimizing the distracting quality of past and future concerns by reframing them as mental projections occurring in the present, using the breath as an anchor for attention during meditation, repeatedly counting up to 21 consecutive exhalations, and allowing the mind to rest naturally rather than trying to suppress the occurrence of thoughts.

The nutrition class served as a control group so that an equal amount of time would be spent training, but on an unrelated topic. Participants in the nutrition class were required to log their daily food intake.

The working memory capacity (WMC) task was the operation scan test mentioned in the immediately preceding post. A 20 minute verbal reasoning section was excerpted from the GRE that assessed reading comprehension. Mind wandering was measured during the performance of these tasks using the same scale for task unrelated thoughts (TUT) that was described in the immediately preceding post. These tests were administered both before the classes started, and after the classes were completed.

Mindfulness training improved both the GRE reading-comprehension scores and working memory capacity while simultaneously reducing the occurrence of distracting thoughts during completion of the GRE and the measure of working memory. Improvements in performance following mindfulness training were mediated by reduced mind-wandering among participants who were prone to distraction at pretesting.

The authors concluded that their results suggest that cultivating mindfulness is an effective and efficient technique for improving cognitive function, with wide-reaching consequences. I certainly agree, and I am impressed that these effects were achieved with so little training.

The descriptions of the mindfulness training are limited by the description provided in the research paper. More information on mindfulness and mindfulness techniques can be found by entering “mindfulness” or “meditation” in the healthymemory blog search box.

1Mrazek, M.D., Franklin M.S., Phillips, D.T., Baird, B., & Schooler, J.W. (2013). Mindfulness training improves working memory capacity and Graduate Record Examination performance while reducing mind wandering. Psychological Science, 24, 776.

© Douglas Griffith and healthymemory.wordpress.com, 2014. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

How Mind Wandering Affects Performance on Aptitude Tests

January 21, 2014

Our minds wander quite frequently and we are quite aware of it, and concentration is important to our performance on mental tests. So a reasonable question is whether our mind wandering affects our performance on these aptitude tests. Several experiments1 have addressed this question. In the first experiment 115 undergraduates completed automated versions of memory span tasks, the operation span task, the reading span task, and the symmetry span task. At unpredicted intervals during each span task participants were asked to indicate to what extent their attention was on-task or on task unrelated concerns using the following scale (1=completely on task, 2=mostly on task, 3=both on the task and task unrelated concerns, 4=mostly on unrelated concerns, and 5=completely on unrelated concerns). This provided a measure of task unrelated thoughts (TUTs). Statistically significant negative correlations were found between performance on the memory tasks and the TUTs, indicating that more mind wandering was correlated with lower performance on the memory span tests.

The second experiment examined how mind wandering was related to the performance on specific memory span trials. This time ratings were obtained for each trial of the operation span task. Sixty-seven undergraduates participated in this task. Accurate memory span trials were associated with less mind wandering, fewer TUTs..

It should be well known that correlations do not prove causation. So the question is whether mind wandering causes poorer memory span performance. Prior research2 has shown that financial incentives improve complex task performance. In the third experiment half of the research participants were informed that they could earn as much as $5 for their performance on the operation span task. The other half served as the no financial incentive control group. The financial incentives group performed better on the operation span task and indicated more TUTs, providing evidence that the task performance was mediated by the mind wandering.

The fourth experiment embedded thought sampling ratings into tests of both working memory capacity (WMC) using the operation span task and measures of fluid intelligence, gF (using Raven’s progressive matrices). The hypotheses were that mind wandering would be (a) associated with worse task performance, (b) predict performance on the SAT taken by the participants 1-3 years earlier, and (c) be strongly associated with a latent variable capturing the shared variance between these measures of general aptitude. All three hypotheses were confirmed.

So the ability to control one’s attention is important on the performance on these tests. The next blog post will address the question of better controlling one’s attention to improve performance.

1Mrazek, M.D., Smallwood, J., Franklin, M.S., Chin. J.M., Baird, B., & Schooler, J.W. (2012). The Role of Mind Wandering in Measurements of General Aptitude. Journal of Experimental Psychology: General, 141, 788-798.

2Heitz, R.P., Schrock, J.C., Payne, T.W., & Engle, R.W. (2008).

The Amygdala and the Problem of Reverse Inference

January 18, 2014

This blog post is based on the book Brainwashed: The Seductive Appeal of Mindless Neuroscience by Sally Satel and Scott O. Lillenfeld. Please bear with me as this is just the third post that I’ve written based on a source viewed on my Kindle.

The amygdala is a small region on each side of the brain. So we all should have two amygdalae. They are located in the temporal lobes, one in each hemisphere. In popular reports the amygdala has become almost synonymous with the emotional state of fearfulness. This is true. When you experience fear, the amygdala lights up. I have personal experience with research on the amygdala that I conducted when I was a graduate student. This was back in the days before brain imaging. I surgically implanted electrodes in rats placed under anesthesia so that they would electrically stimulate only their amygdalae. They were deprived of water and when placed in the operant chamber, they immediately started drinking. They received a shock after drinking. When they were placed back into the operant chamber they would not drink even if they were thirsty. However, if an electric current had been sent to the amygdalae when they were shocked the memory of the shock would never have been formed, so they would drink without fear when placed back in the operant chamber.

Although the amygdala is involved in fearfulness, it also responds to things that are unexpected, novel, unfamiliar or exciting. “This probably explains its increased activation when men look at pictures of a Ferrari 360 Modena. The amygdala reacts to photos of faces with menacing expressions, but also to photos of friendly, unfamiliar faces. If fearful faces are expected and happy faces unexpected, the amygdala will respond more strongly to the happy faces. The amygdala also helps register the personal relevance of a stimulus at a given moment. For example, one study revealed that hungry subjects manifested more robust amygdala responses to pictures of food than did their nonhungry counterparts.1

This amygdala example illustrates the problem of reverse inference, which is a problem that plagues the popular media. Reverse inference is the common practice of reasoning backward from the neural activation viewed in an image to subjective experience. The problem is that brain structures rarely perform single tasks, so one-to-one mapping between a given region and a particular mental states is highly prone to error. So “When Jeffrey Goldberg views a picture of Mahmoud Ahmadinejad and his ventral striatum lights up like a menorah, some investigators might think, ‘Well we know that the mental striatum is involved with processing reward, so this subject, with his activated mental striatum is experiencing positive feelings for the dictator’”2 This would be true only if the ventral striatum exclusively processed the experience of pleasure. But novelty can also stimulate the ventral striatum.

1ibid

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© Douglas Griffith and healthymemory.wordpress.com, 2013. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

The Complexity of the Brain and Neuroimaging

January 14, 2014

This blog post is based on the book Brainwashed: The Seductive Appeal of Mindless Neuroscience by Sally Satel and Scott O. Lillenfeld. Please bear with me as this is the second post that I’ve written based on a source viewed on my Kindle.

The notion that a specific area in the brain is solely responsible for a given mental function is intuitively appealing, and it would definitely simplify matters. Unfortunately that is rarely the case. Mental activities do not map neatly onto discrete brain regions. At one time a specific area of the brain, Broca’s area was believed to be the brain’s one and only language-production center. Subsequent research has found it to be one of the key nodes, or convergence centers, for the pathways that process language. Similarly, there is no one designated site in charge of speech comprehension as it also relies on patterns of connectivity across multiple brain regions. “Although neuroscientists regard a few cortical regions as being highly specialized for particular operations—such as the perception of faces, places, body parts, ascribing mental states to others (“theory of mind”) and processing visually presented words—most neural real estate is zoned for mixed-use development.”1 This is most fortunate as the brain can rewire itself and allows the newly discovered remarkable plasticity of the brain. So when the brain is damaged it can rewire itself to regain its lost functionality. This rewiring might partially account for those individuals whose autopsies revealed the neurofibrillary tangles and amyloid plaques of Alzheimer’s, but who never exhibited the symptoms. People who are born blind are able to use their visual cortex to perceive touch and learn to read braille letters.

This complexity of the brain should be kept in mind both when viewing images and when reading reports that draw conclusions from neuroimages. As will be seen many reports are overstated, incorrect, or only partially correct.

1Satel, S. & Lillenfold, S.L. (2013) Brainwashed: The Seductive Appeal of Mindless Neuroscience

© Douglas Griffith and healthymemory.wordpress.com, 2013. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

What Is fMRI?

January 11, 2014

This blog post is based on the book Brainwashed: The Seductive Appeal of Mindless Neuroscience by Sally Satel and Scott O. Lillenfeld. Please bear with me as this is the first post that I’ve written based on a source viewed on my Kindle.

fMRI is the basis for most of the brain images we see. It stands for Functional Magnetic Magnetic Resonance Imaging. Here is a brief description of how it works. Functional MRI reveals oxygen consumption and regional blood flow in the brain. Blood that is carrying more oxygen has different magnetic properties than blood that has already given up its oxygen to supply neurons. The brain will first be scanned which the participant is resting in the device to establish a baseline level. Then the participant is asked to perform a particular task of interest. The difference between this baseline and the activity when this specific task is being performed is measured and called the BOLD (blood-oxygen level response). The higher the level of oxygenated to deoxygenated blood in a particular area of the brain, the higher the energy consumption in that region. The basic unit of analysis in fMRI is called the voxel, which is a combination of volume and pixel. It is a three dimensional unit.

Subtraction is performed on a voxel by voxel level. Each voxel is then assigned a color depending on the strength of the difference in activation of that individual voxel between the control and experimental conditions. The computer then generates an image highlighting the regions that become more active in one condition relative to the other. By convention, researchers use color gradations to reflect the likelihood that the subtraction was not due to chance. A bright color like yellow might mean that the there is only one chance in a thousand that the differences are due to chance, whereas a darker color like purple might mean that the chances are higher, and that the brain differences were more likely to be attributable to random fluctuations in the data. Finally, the computer filters out background noise and prepares the data to be mapped onto a three-dimensional template of the human brain.

The final brain scan that we see rarely portrays the brain activity of a single person. Instead it almost always represents the averaged results of all participants in the study. Any resemblance between brain scans and photographs is illusory. Photos capture images in real time and space. Functional imaging scans are constructed from information derived from the magnetic properties of blood flowing in the brain. Scans are simply a representation of local activation based on statistical differences in BOLD signals.

The Persistence of False Beliefs

January 8, 2014

While perusing my copy of the May/June 2013 of the Ohio State Alumni Magazine, I found an interesting article on page 24, “False beliefs persist despite facts.” It reported some interesting research by R. Kelly Garrett and Brian Weeks of the Communications Department. They conducted a study with a diverse group of participants from across the country. The experiment was designed to study reactions to inaccurate statements made in a political blog about electronic health records. The political blog was written by the experimenters. All experimental participants read the same blog, but they were divided into three groups. One group received a statement saying that a fact checking organization, Factcheck.org (a genuine website) had found errors and posted a correction at the bottom of the page. A second group performed an unrelated three-minute task after reading the blog post and then saw the same correction as the first group. The third group did not receive a correction. After the experiment all the participants were asked how difficult it would be for several groups to access electronic health records. Those who received the immediate correction were slightly more likely to answer accurately than those who received the delayed correction. Those who received no correction were the least accurate.

The more interesting results came when the researchers analyzed who was influenced by each type of presentation. For those who at the beginning of the experiment indicated that they supported electronic health care records it is not surprising that the real-time correction worked well. However, for those who opposed the records to begin with, the correction had virtually no effect. Unfortunately, it is difficult to disabuse people of their incorrect beliefs. Moreover, there are organizations who produce false information. This has become an activity with its own name, agnogenesis.

For earlier healthymemory blog posts on this important, but difficult topic, “Misinformation,” “The Origins of Misinformation,” “Cognitive Processing of Misinformation,” and “Solutions and Good Practices for Misinformation.”

I also urge readers to make active use of FactCheck.org.

© Douglas Griffith and healthymemory.wordpress.com, 2013. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

The Problem with Scientific Journals, Especially Elite Ones

January 3, 2014

Examples of elite scientific journals are Science,Nature, and Cell. But this problem generalizes to practically all refereed journals. Unfortunately, a criterion many refereed journals regard as one of success is a high rejection rate for submitted papers. This problem was recently articulated by Randy Schekman, the 2013 Nobel Prize winner in Physiology or Medicine.1 One of his criticisms was the artificial restriction of papers they publish that result in a high rejection rate. The second criticism has to do with published “impact factor” that purports to measure how important a journal is. The result of these pernicious factors is the conclusion John Ioannidis made in 2005 in Plos: Medicine, that most published research findings are false.

The sine qua non of science is replication. But journals do not like to publish replications of research. Much worse, is that failures to replicate are also likely not published. Simply put, that is how the majority of published research findings are false. This problem is so severe that the cover of the October 19th to 25thEconomist read, HOW SCIENCE GOES WRONG. The feature article elaborated on the very brief synopsis that I have provided.

At one time, in the era of paper publishing, there was a serious cost that limited how much research could be published. However, that is no longer the case. There is no limit to how much research can be put online. There is still a cry for research to be refereed. I have participated in the review process both as a reviewer and as a receiver of reviews. I have not been impressed by the process. There is a large factor of arbitrariness, and often form is weighted more strongly than substance. Frankly, I do not need what I read to be refereed. I can quickly ascertain whether a particular paper is worthy of further attention.

I think the major force behind refereeing are the academics. When making tenure decisions, the number of refereed publications is a factor that is heavily weighted. Absent this metric, academics might actually need to read the papers of those they are considering for tenure.

Randy Sheckman has started his own on-line journal. Expect many more in the future. Indeed, expect being able to download more research papers from authors’ websites.

This is certainly a welcome development for poor bloggers such as myself trying to access relevant research. There is also a push to make more data available to researchers. As most of this research is funded with taxpayers’ money, this is certainly appropriate, but I shall stop here before proceeding on another rant.

1What’s wrong with Science, The Economist December 14th 2013, p. 86.

© Douglas Griffith and healthymemory.wordpress.com, 2013. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.