Posts Tagged ‘dendritic reorganization’

A Neurocognitive Framework for Ameliorating Cognitive Aging

May 31, 2014

This post is taken from a chapter with the same name, “Ameliorating Cognitive Aging:  A Neurocognitive Framework”  in the book Nurturing the Older Brain and Mind  by Greenwood and Parasuraman.  Brain aging needs to be dealt with.  There is cortical shrinkage and there are white matter changes.  The shrinkage and white matter changes have a small effect on cognitive performance.  Neurotransmitter  dysfunction is a matter of more concern.  Then there are genetic factors.  First of all there is the genotype, then the gene expression from this genotype.  Although some individuals suffer from a genetic predisposition to dementia, these are not deterministic, but rather predispositions.  That is, given such and such experiences or external factors, the likelihood of dementia increases.  Then there are epigenetics, which determine how the genes are actuated.  Epigenetics are affected  by lifestyle and experiential factors such that favorable factors can enhance the probability of favorable genetic readouts.

Turning to the lifestyle and experiential factors, education, exercise, diet, learning and training, and combinations of these factors enhance the likelihood of good cognitive performance throughout one’s lifespan.   More details on these individual factors will be provided in subsequent healthymemory blog posts.

Then there is the matter of neuronal plasticity that includes neurogenesis, synaptogenesis, dendritic arborization, and network reorganization.   An example of network reorganization is the greater use of both hemispheres as we age.  When I was a graduate student I was taught that our nervous system was fixed and could not be modified when damaged or was damaged to aging.  Fortunately, what I was taught as a graduate student has been found to be woefully in error.  These processes can occur well into old age.  But they need to be activated by new learning and experiences for them to occur.

Next there is cognitive plasticity.  Top-down processing strategies can be used to make better use of our accumulated knowledge.  Then there are our well-developed prefrontal lobes for effective executive functioning.

I have often written of the importance of building a cognitive reserve.  Although advice was provided as to how to build one’s cognitive reserve, Greenwood and Parasuraman have provided the first neurocognitive framework to explain how this occurs.

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