Friday, February 6, 2015

Top Ten Brain Posts 2015

Brain Posts on diet and exercise lead the list of topics with the most page views in 2014.

Here are the top five most viewed blog posts. Merry Christmas to all and best wishes for a productive and peaceful 2015.

Clicking on the title will link you to the full Brain Post blog on the topic.

5. Aging, Exercise and Brain Plasticity

This post examined a review of the effects of aging and exercise on the brain. Exercise appears to reduce the rate of atrophy of the brain hippocampus with age. Enhanced brain blood flow with exercise may provide a boost in brain plasticity needed to deal with vascular degeneration.

4. Lo Carb-Mediterranean Diet Combo Sheds Fat in Trial

A research team from Greece published results of a trial of a very low carbohydrate diet alternating with low carbohydrate Mediterranean style diet. Over one year subjects in this study lost an average of 35 pounds. Metabolic changes including lower cholesterol levels were favorable in the study subjects.

3. Alternate Day Fasting for Weight Loss and Cardioprotection

A small study compared a 12 week program of alternate day fasting with control who continued their typical diet. The alternate day fasting group was allowed to eat an evening meal of about 500 calories. The alternate day fasting group lost an average of a pound per week and showed evidence of reduced inflammation including lower CRP levels.

2. Varenicline for Smoking Cessation

In this post, I reviewed four manuscripts relevant to varenicline (Chantix in U.S.) treatment in smoking cessation. Varenicline appears an effective options for treatment of smoking cessation and may be combined with other drug agents such as bupropion. It also appears promising for smokers suffering from a psychiatric disorder when used under the supervision of a physician.

1. How the Body Blocks Effect of Exercise After Weight Loss

The number one post for 2014 examined a study of how the body compensate to weight loss. Weight loss results in a dialing back of resting energy expenditure promoting weight regain. This effect contributes to poor long-term maintenance of weight loss and underscores the needed for continued exercise following weight loss.

Follow the author on Twitter WRY999

Photo of Christmas Lights at Rhema Church in Tulsa from the author's files. 


Exercise in the Elderly: BDNF and Executive Function



Exercise promotes cognitive function in children, adults and elderly individuals.

The mechanism for this effect is unclear. Some of the effect may be due to a general improvement in vascular function and health.

Another potential mechanism is via increased neuroplasticity mediated by neurotrophic factors.

Brain-derived neurotrophic factor (BNDF) is a known contributor to brain neuroplasticity. Levels of BNDF can be determined with serum assays.

RL Leckie and colleagues recently found support for BNDF mediation in an exercise in an interventional study with an elderly population.

The key elements of the design for their study included the following elements.

  • Participants: Adults between the ages of 55 and 80
  • Exercise intervention: Daily supervised walking sessions beginning with 10 minutes increasing to 40 minutes. Control intervention included stretching and toning sessions lead by an exercise professional
  • Cognitive assessment: Task-switching paradigm commonly used to assess executive function
  • Blood assay: Serum brain-derived neurotropic factor (BNDF) levels and BDNF genotype
  • Statistical analysis: Multivariate linear regression analysis with key dependent variable being cognitive performance after one year of intervention

The main findings from the study included:

  • Serum BDNF increased in the exercise group
  • This effect was limited to primarily the participants over 70 years of age
  • Enhanced executive function following exercise was demonstrated in those over 70
  • BDNF level increases in the over 70 age group correlated with cognitive performance

The authors note their does not mean exercise is not important for cognitive function in the younger age group (55-70 years of age). Their study only highlights the age interaction with BDNF in moderating a single executive function task.

BDNF levels decrease with age and the level of decrease in BDNF correlates with reduction in volume of the brain hippocampus. The hippocampus plays a key role in memory function and in decline in memory associated with aging.

It is quite possible that regular exercise after age 70 reduces the age related effect on cognition moderated by BDNF.

Readers with more interest in this study can access the free full text manuscript by clicking on the PMID link in the citation below.

Photo of ring kingfisher is from the author's files.

Follow the author on Twitter WRY999

Leckie RL, Oberlin LE, Voss MW, Prakash RS, Szabo-Reed A, Chaddock-Heyman L, Phillips SM, Gothe NP, Mailey E, Vieira-Potter VJ, Martin SA, Pence BD, Lin M, Parasuraman R, Greenwood PM, Fryxell KJ, Woods JA, McAuley E, Kramer AF, & Erickson KI (2014). BDNF mediates improvements in executive function following a 1-year exercise intervention. Frontiers in human neuroscience, 8 PMID: 25566019

Monday, February 2, 2015

Exercise in the Prevention of Alzheimer's Disease

Growing evidence links physical activity to improved cognitive outcome in elderly individuals.

Few studies have examined effects of exercise on those at highest risk for Alzheimer's disease.

J Carson Smith and colleagues recently published a prospective study of a cohort of older adults using structural magnetic resonance imaging.

The key elements of the design of their study included the following elements:
Participants: 97 adults between the ages of 65 and 89
Physical activity level: Frequency and intensity of leisure activity was assessed using the Stanford Brief Activity Survey
Alzheimer's risk status: Assessed using APOE genotype
Brain scanning protocol: Magnetic resonance imaging of brain using a 3T scanner at baseline and 18 months later. The brain hippocampal volume was identified as a key structure involved in APOE-related atrophy and memory decline
Statistical analysis: Participants were grouped in low and high physical activity groups and those with and without high-risk APOE Alzheimer's risk

The research team identified a statistically significant interaction between high-risk Alzheimer's participant and physical activity:
"Hippocampal volume decreased 3% in the High Risk/Low PA (physical activity) group whereas the volumetric changes in the remaining three groups were negligible."
The high-risk Alzheimer's group that participated in higher levels of physical activity appeared to have significant protection against hippocampal atrophy. To reach the higher levels of physical activity in the study they had to endorse one of the following levels:
  • Brisk walking 15 minutes daily three or more days per week
  • Jogging 15 minutes daily three or more days per week
  • Swimming 15 minutes daily three or more days per week
  • Moderately difficult chores 45 minutes daily three or more days per week
  • Regular jogging, running, bicycling or swimming 30 minutes or more
  • Playing sports such as handball or tennis an hour or more 

The authors examine the potential mechanisms for physical activity to reduce hippocampal atrophy in those with the high risk APOE genotype.

They note the beneficial effect of exercise may be through effects on cholinergic function, brain lipid metabolism or reduced neuroinflammation.

If this study is replicated it is an important finding with several implications.

One implication is that it may be one of the first research findings to support routine genetic testing for APOE and Alzheimer's risk. Those identified as high risk by APOE status could be targeted for aggressive behavioral interventions to increase physical activity along with increased surveillance of cognitive function.

Readers with more interest in this research can access the free full-text manuscript by clicking on the PMID link in the citation below.

Follow the author on Twitter WRY999

Photo of roseate spoonbill at sunset is from the author's files.

Smith JC, Nielson KA, Woodard JL, Seidenberg M, Durgerian S, Hazlett KE, Figueroa CM, Kandah CC, Kay CD, Matthews MA, & Rao SM (2014). Physical activity reduces hippocampal atrophy in elders at genetic risk for Alzheimer's disease. Frontiers in aging neuroscience, 6 PMID: 24795624

How Schools Make Learning Harder Than Necessary

Keep your "nose to the grindstone" is the advice we often give as an essential ingredient of learning difficult tasks. An old joke captures the problem with the old bromide for success, "Keep your eye on the ball, your ear to the ground, your nose to the grindstone, your shoulder to the wheel: Now try to work in that position."

Over the years of teaching, I have seen many highly conscientious students work like demons in their study yet don't seem to learn as much as they should for all the effort they put in. Typically, it is because they don't study smart. And sometimes the problem is created by the teachers' method of instruction.

In an earlier post, I described a learning strategy wherein a student should spend repeated short (say 10-15 minutes) of intense study followed immediately by a comparable rest period of "brain-dead" activity where they don't engage with a new learning task. The idea is that memory of the just-learned material is more likely to be consolidated into long-term memory because there are no mental distractions to erase the temporary working memory while it is in the process of consolidation.

Now, new research now suggests that too much nose-to-the-grindstone can impair learning.
Margaret Schlichting, a graduate student researcher, and Alison Preston, an associate professor of psychology and neuroscience at the University of Texas tested the effect of mental rest with a learning task of remembering two sets of a series of associated photo pairs.  Between the two task sets, the participants rested and were allowed to think about whatever they wanted. Not surprisingly, those who used the rest time to reflect on what they had learned earlier were able to remember more upon re-test. Obviously, in this case, the brain is not really resting, as it is processing (that is, rehearsing) the new learning. But the brain is resting in the sense that no new mental challenges are encountered.

The university press release quotes the authors as saying, "We've shown for the first time that how the brain processes information during rest can improve future learning. We think replaying memories during rest makes those earlier memories stronger, not just impacting the original content, but impacting the memories to come." Despite the fact that this concept has been anointed as a new discovery in a prestigious science journal, the principle has been well-known for decades. I have explained this phenomenon in my memory books as the well-established term of "interference theory of memory,"

What has not been well understood among teachers is the need to alter teaching practices to accommodate this principle. A typical class period involves teachers presenting a back-to-back succession of highly diverse learning objects and concepts. Each new topic interferes with memory formation of the prior topics. An additional interference occurs when a class period is disrupted by blaring announcements from the principal's office, designed to be loud to command attention (which has the effect of diverting attention away from the learning material). The typical classroom has a plethora of other distractions, such as windows for looking outside and multiple objects like animals, pictures, posters, banners, and ceiling mobiles designed to decorate and enliven the room. The room itself is a major distraction.

Then, to compound the problem, the class bell rings, and students rush out into the hall for their next class, socializing furiously in the limited time they have to get to the next class (on a different subject, by a different teacher, in a differently decorated classroom). You can be sure, little reflection occurs on the academic material they had just encountered.

The format of a typical school day is so well-entrenched that I doubt it can be changed. But there is no excuse for blaring loudspeaker announcements during the middle of a class period. Classrooms do not have to be decorated. A given class period does not have to be an information dump on overwhelmed students. Short periods of instruction need to be followed by short, low-key, periods of questioning, discussion, reflection, and application of what has just been taught. Content that doesn't get "covered" in class can be assigned as homework—or even exempted from being a learning requirement. It is better to learn a few things well than many things poorly. Indeed, this is the refreshing philosophy behind the new national science standards known as "Next Generation Science Standards."

Give our kids a rest: the right kind of mental rest.

Sources:


Schlichting, M. L., and Preston, A. R. (2014). Memory reactivation during rest supports upcoming learning of related content Proc. Nat. Acad. Science. Published ahead of print October 20, 2014.

http://scicasts.com/neuroscience/2065-cognitive-science/8539-study-suggests-mental-rest-and-reflection-boost-learning/

http://www.nextgenscience.org/


Dr. Klemm's latest book, available at most retail outlets, is "Mental Biology. The New Science of How the Brain and Mind Relate" (Prometheus). 

Sunday, February 1, 2015

Analytical Thinking — Logic Errors 101

Improving learning and memory entails developing learning and thinking competencies. Chief among these competencies are logical analysis, insightfulness, and the ability to remember what has been learned. Most of my posts have dealt with improving memory. Here, I start a two-series posting on the other two basic learning competencies: critical thinking and creativity. In this post, I will summarize the more common thinking errors that corrupt analysis. Most of the thinking errors below can be described as "specious," which means superficially plausible but actually wrong.

AD HOMINEN ARGUMENT: discounting a position or conclusion on the basis of the credentials of the person who makes it, rather than the merits of the argument itself. Example: Your professor has no credibility to teach on cognitive neuroscience, because he is a veterinarian. Such statements not only fail to acknowledge whatever truth is in the teaching, but also fail to consider that the person has more experience and knowledge than his or her label would imply. See "all-or-none thinking" below.
Two related argumentation tactics for discounting one's credibility are politicization and ridicule. In politicization, the tactic is to align one's position with the majority, as if that conferred more logical validity. With ridicule, the tactic aims to prevent serious consideration of the ridiculed position and create a default endorsement of the protagonist's position.

ALL-OR-NOTHING THINKING: thinking of things in absolute terms, like “always”, “every” or “never”. Nuance is absent.

ANTHROPOMORPHISM:to attribute qualities and properties to non-people that only people can have. Example: “the purpose of evolution is to ….” Evolution happens, but not because it has a purpose.

APPEAL TO AUTHORITY: attempts to justify the conclusion by quoting an authority in its support. This also includes greater readiness to accept ideas if they come from someone with the appropriate credentials rather than the intrinsic merit of the ideas.

APPEAL TO CONSENSUS: positions defended on the basis that many people hold the same view. This is sometimes called the “Bandwagon Fallacy.” Correctness of a position does not depend on who or how many hold it. See also the comments above about politicization

APPEAL TO IGNORANCE: using an opponent’s inability to disprove a conclusion as proof of the conclusion’s errors. Absence of evidence is not evidence of absence.

APPEAL TO FINAL CONSEQUENCES: claiming validity for one’s position on the basis of the expected outcome or consequence (also known as a "teleological" argument or sometimes as a "circular argument"). Example: people have free will because otherwise they can’t be held responsible for bad behavior. This is not evidence for the assertion, but merely a statement of a supposed consequence.

ARGUMENT SELECTIVITY: using arguments supporting your position while glossing over the weaknesses and leaving out important alternative arguments. This is often called “cherry picking.” A related argumentation error is to ignore the valid ideas of another while focusing on their ideas that are easier to attack. A related inappropriate selectivity is rejecting an idea altogether just because some part of it is wrong.
A variation of this error is “false dichotomy,” where a set of valid possibilities is reduced to only two.

BEGGING THE QUESTION: an argument that simply reasserts the conclusion in another form. This is a common fallacy where one tries to explain an idea or position by restating a description in a different way. The restatement is still a description, giving the illusion that this new way of stating something explains it.

BIASED LABELING: how one labels a position can prejudice objective consideration of the position. For example, calling a position “Science-based” does not necessarily make it true. Or, conversely, calling a position “colloquial” does not necessary invalidate it.

CIRCULAR REASONING: reasoning where a belief in a central claim is both the starting point and the goal of the argument.

CLOUDING THE ISSUE (OBFUSCATION): using multiple complex ideas and data of unclear relevance to overwhelm the capacity for reason, yet giving the impression of authority and reason— in other words, "baffling them with B. S." Simple language in the service of lucid thought is the sign of superior intelligence.

COGNITIVE SHORTCUT BIAS (Einstellung). This is the dogged tendency to stick with a favored view or argument for a position, and ignoring, in the process, other more fruitful possibilities. Even chess masters, for example, may use an established gambit when a better tactic is available.

CONFIRMATION BIAS. People have a natural tendency to notice only the facts that support their position while discounting those that do not — in other words, believing what you want to believe.

CONFUSING CORRELATION WITH CAUSATION. When two things happen together, and especially when one occurs just before the other, people commonly think that one thing causes the other. Without other more direct evidence of causation, this assumption is invalid. Both events could be caused by something else. In case people need convincing, just remind them of this example: rain and lightning go together, but neither causes the other.

CONFUSING FORCE OF ARGUMENT WITH ITS VALIDITY: repeating erroneous argument does not validate it. Saying it louder doesn’t help either.

DEDUCTION FALLACIES: a valid deductive argument must have consistent premises and conclusions (both must be either true or both false). Failure to be consistent produces “non sequiturs,” that is, conclusions that are not logical extensions of the premise.

EMOTIONAL REASONING: Making decisions and arguments based on how you feel rather than objective reality. This is an emotional "knee jerk" kind of thinking, often the first thing that comes to mind, which often precludes or overwhelms rational analysis. This error is common in political discourse. People who allow themselves to get caught up in emotional reasoning can become completely blinded to the difference between feelings and facts. For example, scientists sometimes unduly value a position because it is “parsimonious,” or elegant, or easily understood (or even complex and sophisticated).

EXLUSIVITY CONFUSION. When several apparent ideas or facts are examined, it is important to know whether they are independent, compatible, or mutually exclusive. Example: concepts of evolution and creationism, as they are typically used, are mutually exclusive. However, stated in other ways, they might be more compatible.

FALSE ANALOGY: explaining an idea with an analogy that is not parallel, as in comparing apples and oranges.

HALO EFFECT: Generalizing merit to an idea or thought on the basis of irrelevant merit of something else. For example, if you like someone, you are more likely to be accepting of their thinking and minimize the defects. Similarly, favorable first impressions are more likely to yield positive impressions later.

INTUITIVE THINKING: relying on a "gut feeling" without fact checking. Example:
            A bat and ball costs $1.10.
            The bat costs $1.00 more than the ball.
            How much does the ball cost?

Most people, even students at the most selective universities, give the wrong intuitive answer of 10 cents. The right answer is 5 cents. Do the math.

JUMPING TO CONCLUSIONS. This error occurs under a variety of situations. The most common cause is failure to consider alternatives. An associated cause is failure to question and test assumptions used to arrive at a conclusion.

MAGNIFICATION & MINIMIZATION. Exaggerating negatives and understating positives. Be aware of how easy it is for you and others to exaggerate the positives of a position and understate the negatives.

MISSING THE POINT. Sometimes this happens unintentionally. But frequently recognition that one’s argument is weak creates the temptation to shift focus away from the central issue to related areas where one can make a stronger argument.

NOT LISTENING. Have a clear notion of the issue and the stance that others are taking. If you have to read another’s mind or “read between the lines,” seek clarification lest you end up putting your words in somebody else’s mouth.

OVER-GENERALIZATION. It is illogical to assume that what is true for one thing is true for something else. Example: some scientists studying free will claim that the decision-making process for making a button press is the same for more complex decisions.

UNSUPPORTED ASSERTION. Recognize when a claim is made without supporting evidence. This also occurs when one confuses a judgment or opinion for a fact.


Further Reading

Clayton, C. W., (2007). The Re-Discovery of Common Sense: a Guide to: The Lost art of Critical Thinking. iUniverse. Lincoln, Nebraska.

Gilovich, T. (1993) How We Know What Isn't So: The Fallibility of Human Reason in Everyday Life. The Free Press, New York.

Hughes, W. et al. (2010) Critical Thinking, Sixth Edition: An Introduction to the Basic Skills. The Broadview Press. Peterborough, Ontario, Canada.

Kahnemann, Daniel (2011). Thinking Fast and Slow. Farrar, Straus, and Girous. New York.


Read reviews of my books at http://WRKlemm.com. Follow me on Twitter @wrklemm.