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.

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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

Scientific and philosophical fashion these days is to claim that humans have no free will. That is, we are basically biological robots, driven to our thoughts, beliefs, and actions by unconscious forces in our brain. Our genes and our experiential programming control everything we do. Free will is an illusion.

So goes the assertions of a clutch of activist scientists, such as Richard, Dawkins, Sam Harris, and Daniel Wegner, who have probably gotten rich off their best-seller books arguing the case against free will.

Religion is also nailed to the cross, so to speak. Ideas of moral responsibility originate in views of right and wrong, and every religion expects that followers have the capacity to make the correct choices. Their free-will capacity makes them morally responsible. I think it is no accident that most of the illusory free-will activists I have read are also activists for atheism. Otherwise, their position would be cognitively dissonant.

Legal issues arise, as stated by the legal analyst Jeffrey Rosen, who wrote in The New York Times Magazine, “Since all behavior is caused by our brains, wouldn’t this mean all behavior could potentially be excused? … The death of free will, or its exposure as a convenient illusion, some worry, could wreak havoc on our sense of moral and legal responsibility.”

There are serious social consequences attached to accepting the premise of illusory free will. One is the obvious conclusion one should draw that consciously willed effort to improve oneself or lot in life is futile.

Another consequence of such thinking is the need to proclaim, as many scientists now do, that consciousness cannot do anything. Freely chosen actions would have to come from a conscious brain. Therefore, the conscious brain must not be the source of actions that occur during consciousness. Consciousness is thus seen as audience watching a movie of what is happening.

Of course, the futility argument is not evidence for free will. It is however, a practical reason to believe in it, for otherwise people would not make much effort to change and improve themselves. They would otherwise become intellectually and emotionally paralyzed by such nihilism.

This is not the place to elaborate the research that neuroscientists claim provides the basis for asserting illusory free will. I do that in my just-released book, Mental Biology: The New Science of How Brain and Mind Relate. I point out the uncontrolled variables in the experiments conducted in the 1980s that purported to show there is no free will. Subsequent reports that confirmed those findings had the same poorly controlled variables. Moreover, there are some new studies using better designs that show that the original findings do not withstand scrutiny.

So, is there a reasoned counter-argument? Eddy Nahmias points out that "the sciences of the mind do give us good reasons to think that our minds are made of matter. But to conclude that consciousness or free will is thereby an illusion is too quick. It is like inferring from discoveries in organic chemistry that life is an illusion just because living organisms are made up of non-living stuff."

In my new book, I have a large section defending the position that consciousness IS able to do things, among them exerting at least a significant modicum of freely chosen thoughts and actions. One line of argument, which is in line with the learning and memory theme of this blog site, is memorization. It is true that the brain is forming memories of a day's events while you sleep and obviously unconscious. But the initial encoding and working memory are performed while you are conscious. Moreover, conscious use of mnemonic devices profoundly enhances the formation of memory, as I will demonstrate in future posts about how "memory athletes" do such astonishing working-memory feats as learning the sequence of a shuffled deck of cards in a minute and a half or memorizing 80-digit number strings. Conscious use of mnemonics is required. Using these mnemonics is challenging, requiring intense selective attention and strongly will executive functions. You obviously cannot do such things when you are unconscious.

Skeptics will say that such feats are all driven and performed by the unconscious mind and that consciousness is just around to realize it has happened. But consciousness is also around to recite what was memorized. Try that in your sleep.

Sources:

Klemm, W. R. (2014). Mental Biology. The New Science of How Brain and Mind Relate. New York: Prometheus.

Nahmias, Eddy (2011). Is neuroscience the death of free will? New York Times. http://opinionator.blogs.nytimes.com/2011/11/13/is-neuroscience-the-death-of-free-will/?_php=true&_type=blogs&_r=0